Patent Application
20240307727
The present application claims priority to European Application No. 23162487.5 which was filed on Mar. 16, 2023, and the contents of which are hereby incorporated by reference in their entirety.
The present disclosure relates to the processing of biohazardous waste. In particular, the disclosure relates to the treatment of waste to prepare it to enter a recycling process. More particularly, the disclosure relates to the handling of by-products from the shredding and disinfection of biohazardous waste prior to recycling.
Currently, biohazardous waste generated from various different sources is typically autoclaved, incinerated and ultimately sent to landfill. As a result, there is currently little to no known recycling of biohazardous waste globally, due to a lack of availability of suitable treatment processes.
Further, recycling processes are sensitive to contaminants and some degree of cleaning of waste materials may be necessary prior to entering a recycling process. Recycling processes may require relatively small particles of waste materials in order to process them effectively.
Cleaning or disinfection and shredding processes can create by-products, such as effluent which may not be suitable for direct disposal to public waste systems.
There exists a need for improved handling of by-products from waste treatment and shredding processes.
According to an aspect, there is provided a waste processing apparatus, comprising one or more of the following: a waste processing vessel for holding waste and treatment fluid during processing; a blade arrangement provided in the waste processing vessel, for shredding the waste. The apparatus may comprise treatment fluid delivery means configured to deliver a treatment fluid to the waste processing vessel. The apparatus may comprise neutralisation agent delivery means configured to deliver a neutralisation agent to the treatment fluid. The neutralisation agent delivery means may comprise a liquid delivery system. The neutralisation agent delivery means may comprise liquid pumping means and/or flow control means, which may be configured to provide a controlled amount of liquid neutralisation agent to the treatment fluid. The neutralisation agent delivery means may be configured to deliver a neutralisation agent to the waste processing vessel.
The waste processing apparatus may further comprise a waste receiving opening, and a closure arrangement for closing the waste receiving opening, to retain treatment fluid and waste in the waste processing vessel during the simultaneous shredding and fluid treatment of the waste in the vessel. The neutralising agent delivery means may be comprised in the closure arrangement. The waste processing apparatus may comprise a controller. The controller may be configured to initiate a neutralisation process. The neutralisation process may include activating the waste processing apparatus to deliver a neutralisation agent to the treatment fluid. The neutralisation process may include opening the vessel to allow a neutralisation agent to be added into the vessel. The neutralisation process may include controlling a fluid delivery device so as to deliver a neutralising agent into the vessel. The controller may be configured to control the fluid delivery device to deliver the neutralising agent into the vessel after terminating the shredding function of the shredding device. The neutralisation process may include delivering a neutralising agent to the treatment fluid outside of the vessel.
According to another aspect, there is provided a method of treating waste, the method comprising one or more of the following steps:
After completion of a waste processing operation, the treatment fluid may not always be suitable for direct discharge into a municipal sewer. For instance, where the treatment fluid comprises a solution comprising a disinfectant and a diluent as described herein (also referred to herein as a disinfectant solution), it may be too acidic for direct discharge into a municipal sewer, risking corrosion of the sewer walls, and the production of unwanted gaseous by-products within the sewer. Therefore, the addition of a neutralising agent to the treatment fluid allows for the treatment fluid to be directly discharged into a municipal sewer, minimising the risk of corrosion of the sewer walls, and the production of unwanted gaseous by-products within the sewer.
The pH of the treatment fluid, before addition of the neutralising agent, may be in the range of from about 2 to about 5. The pH of the treatment fluid, following addition of the neutralising agent, may be in the range of from about 4 to about 10. It may be the case that the pH of the treatment fluid, following addition of the neutralising agent, is in the range of from about 6 to about 10. It may be the case that the pH of the treatment fluid, following addition of the neutralising agent, is in the range of from about 6 to about 9.5. It may be the case that the pH of the treatment fluid, following addition of the neutralising agent, is in the range of from about 6 to about 8. It may be the case that the pH of the treatment fluid, following addition of the neutralising agent, is in the range of from about 6.5 to about 7.5. It may be the case that the pH of the treatment fluid following addition of the neutralising agent is proximate to 7. Such pH values allow for the treatment fluid to be directly discharged into a municipal sewer, minimising the risk of corrosion of the sewer walls, and the production of unwanted gaseous by-products within the sewer.
The pH of the neutralising agent may be in the range of from about 9 to about 14. The neutralising agent may comprise a strong base, a weak base, or a combination thereof. The neutralising agent may comprise a strong base. As used herein, the term “strong base” takes its usual meaning in the art and relates to a base that is completely dissociated in an aqueous solution. The strong base may comprise a group I metal hydroxide, a group II metal hydroxide, or a combination thereof. The strong base may comprise lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, rubidium hydroxide, strontium hydroxide, cesium hydroxide, barium hydroxide, or combinations thereof. The strong base may comprise sodium hydroxide, potassium hydroxide, calcium hydroxide, or a combination thereof. The strong base may comprise sodium hydroxide. The neutralising agent may comprise a weak base. As used herein, the term “weak base” takes its usual meaning in the art, and relates to a base which, upon dissolution in water, does not fully dissociate. The weak base may comprise any weak base wherein the solubility of said weak base is not impacted by temperature. Weak bases of this nature are advantageous as the neutralising agent will not easily fall out of solution if stored for long periods of time in cool storage conditions prior to use in methods as described herein. The weak base may comprise a metal carbonate, a metal hydroxide, or a combination thereof. Examples of weak base include, but are not limited to, sodium carbonate, potassium carbonate, calcium carbonate, magnesium hydroxide, ferric hydroxide, or a combination thereof. The weak base may comprise sodium carbonate, potassium carbonate, calcium carbonate, or a combination thereof.
When the neutralising agent comprises a strong base, the pH range of the neutralising agent may often be in the range of from about 12 to about 14. When the neutralising agent comprises a weak base, the pH range of the neutralising agent may often be in the range of from 9 to about 12.
The neutralising agent may be added in the form of a tablet. As used herein, the term “tablet” relates to a solid substance, which is often initially formed from a powder, that has been pressed or compacted into a solid dosage form. Additionally, or alternatively, the neutralising agent may be in the form of a powder. As used herein, the term “powder” relates to a solid substance of fine, loose particles.
Additionally, or alternatively, the neutralising agent may be added in the form of a solution or a suspension, wherein the solution or suspension comprise the neutralising agent and a diluent. As used herein, the term “diluent” takes its usual meaning in the art and relates to a substance that is added to dilute a solution or a mixture. It may be the case that the neutralising agent is added in the form of a solution. As used herein, the term “solution” relates to liquid mixture in which the minor component(s) (I.e., the neutralising agent) is uniformly distributed throughout the major component (I.e., the diluent). The neutralising agent in the form of a solution may also be referred to as the neutralising solution. As used herein, the term “suspension” relates to a heterogeneous mixture of a liquid (i.e., the diluent) that contains solid particles (i.e., the neutralising agent) sufficiently large for sedimentation. The neutralising agent in the form of a suspension may also be referred to as a neutralising suspension. The diluent of the solution or suspension may comprise, consist essentially of or preferably consist of water. The concentration of the neutralising solution or neutralising suspension may be in the range of from about 15% to about 30% by weight of the neutralising agent.
The treatment fluid may comprise a disinfectant and a diluent. The treatment fluid may comprise a solution comprising a disinfectant and a diluent. As used herein, the term “diluent” takes its usual meaning in the art and relates to a substance that is added to dilute a solution or a mixture. As used herein, the term “solution” relates to liquid mixtures in which the minor component(s) (i.e., the disinfectant) is uniformly distributed throughout the major component (i.e., a diluent as described herein with respect to the waste processing apparatus). The diluent may comprise, consist essentially of or preferably consist of water. The solution as described herein may also be referred to as the “disinfectant solution”. The disinfectant solution may be acidic. The pH of the disinfectant solution may be in the range of from about 2 to about 6.
The disinfectant may comprise peracetic acid and hydrogen peroxide. As used herein, peracetic acid may also be referred to as peroxyacetic acid. Peracetic acid may be present in the range of from about 10% to about 20% based on the total weight of the disinfectant. Hydrogen peroxide may be present in the range of from about 15% to about 30% based on the total weight of the disinfectant. It may be the case that the disinfectant solution comprising a diluent and a disinfectant comprising peracetic acid and hydrogen peroxide is of a concentration in the range of from about 0.5% (v/v) to about 5% (v/v). It may be the case that the disinfectant solution comprises a diluent and a disinfectant comprising peracetic acid in the range of from about 10% to about 20% based on the total weight of the disinfectant and hydrogen peroxide in the range of from about 15% to about 30% based on the total weight of the disinfectant; and wherein the solution is of a concentration in the range of from about 0.5% (v/v) to about 5% (v/v). The diluent may comprise, consist essentially of or preferably consist of water.
According to another aspect, there is provided a use of a neutralising agent in a process for combined shredding and treatment of waste. The waste may be biohazardous waste.
Further features and advantages of the present disclosure will become apparent from the following description of aspects thereof, presented by way of example only, and by reference to the drawings, in which:
A large amount of biologically hazardous waste is generated from different sources, including but not limited to clinical facilities, diagnostic laboratories, and research institutes. This waste requires specialised treatment. Such treatment typically occurs off-site and therefore also requires specialised transportation and handling ahead of treatment, which can increase costs, poses a contamination or public health risk and increases the carbon footprint. Treatment of hazardous waste, biohazardous medical, or other regulated waste in particular, often requires energy intensive processes, such as transport for off-site processing, along with autoclaving and/or incineration, whose emissions, water and energy usage, and environmental impact can be improved upon.
A particular aspect of biologically hazardous (biohazardous) waste is that the risks relating to contaminants present in or on the waste need to be handled throughout its processing, until such time as it is considered safe for contact with humans or the environment.
The inventors have identified particular areas for improvement in the processing of contaminated, hazardous or biohazardous waste. More particularly, the inventors have developed a technology that shreds and disinfects biohazardous waste at source and hence facilitates the recycling of these waste streams. In doing so, the apparatus and methods described herein combine several of the processes that take place separately in a recycling work-flow, hence increasing the downstream usability of the treated end product produced.
The disclosed systems and its various aspects are particularly suited to use with the vast array of different biohazardous waste products that are produced in laboratories. Such waste streams may contain glass, paper, polymers, blood, urine, sharps, PPE, etc. and hence the blade arrangement needs to cope with a range of hard and soft materials, some being pliable and malleable others being hard and brittle. None of these materials can be recycled while they are considered to be of a biohazardous nature. To reliably disinfect biohazardous waste, the waste needs to be shredded sufficiently to ensure that a treatment chemical comes into contact with the biohazardous materials. Once the initially biohazardous waste is sufficiently treated to be considered non-hazardous and safe for handling and transportation, it can be sent to recycling facilities for separation and pelletisation. The disclosed system facilitates recycling, as the waste processed in the system can be made safe. Combined disinfection or decontamination and shredding is an advantage to downstream recyclers as they can skip several steps in the usual known processes at recycling plants, with the output from blade arrangements and systems as disclosed herein.
As used herein, the term “biohazardous waste” (also commonly referred to as “infectious waste”) takes its usual meaning in the art and relates to waste that has been contaminated with potentially infectious agents, or other materials that are deemed to be a threat to either public health or to the environment. For example, biohazardous waste includes medical waste generated in laboratory or clinical settings (such as hospitals), which has been contaminated with blood, body fluids, and/or cell lines from humans or animals. Such waste can also sometimes fall within the terms medical waste or regulated waste, depending on the different national regulatory definitions.
The waste processing apparatus described herein provides a number of advantageous features and aspects. One advantageous feature is the system being able to perform shredding of waste while the waste is submersed or immersed in a reservoir of the treatment fluid, which provides simultaneous treatment, such as sterilisation or disinfection, simultaneously with the shredding of the waste. This can reduce overall processing times and improve the reliability of the shredding and disinfection or sterilisation, or other cleansing process. The treatment fluid may comprise liquid, such as water, and may comprise a treatment agent. The treatment fluid may be in the form of a homogenous liquid mixture or a solution. The treatment agent may be provided in solid, liquid or gel form and may be combined with a diluent, which may be a liquid diluent such as water. As described herein, the term “diluent” takes its usual meaning in the art and relates to a substance that is added to dilute a solution or a mixture. The treatment fluid may comprise a gaseous component in some arrangements. The treatment fluid may comprise liquid and gaseous components, e.g. the treatment fluid may include liquid particles suspended in a gas (e.g. an aerosol) or gas particles suspended in a liquid, or a mixture of liquid and gas components. In one arrangement, the treatment fluid may include gaseous chlorine dioxide. The treatment fluid may include aqueous chlorine dioxide. The treatment fluid may include chlorine dioxide gas dissolved in a liquid, e.g. water.
As used herein, the term “solution” relates to liquid mixture in which the minor component(s) (i.e., the treatment agent) is uniformly distributed throughout the major component (i.e., the diluent). The treatment agent in the form of a solution may also be referred to as the treatment solution. The diluent may comprise, consist essentially of or preferably consist of, water. The treatment solution may be acidic. The pH of the treatment solution may be in the range of from about 2 to about 6.
Advantageously, the process may use peracetic acid (CH3CO3H) and hydrogen peroxide in the waste shredding and disinfecting process. This and other such fluids as described herein can improve the efficiency and efficacy of the treatment of the waste simultaneously with the shredding process. The design of the waste processing apparatus is particularly suited to the treatment of hazardous waste, such as biohazardous waste or other waste containing harmful or toxic substances or infectious agents, from which a user must be protected before during and after processing of the waste. Advantageous aspects of the design of the blade arrangement used in the process for improved shredding efficiency and flexibility are also described. Advantageous control schemes and methods of operation of the process are also described, which improve the efficacy, user experience and user safety and overall process efficiency of the device.
One aspect of improvement identified is the combined shredding and treatment of waste in a closed-bottomed receiver, in which a treatment fluid such as a liquid treatment of the types described herein is present, over an extended period, such that shredding and cleaning and/or disinfection of the waste takes place simultaneously. In one aspect, a waste processing apparatus is provided, comprising one or more of the following features: a waste processing vessel for holding waste and treatment fluid during processing; and a blade arrangement provided in the waste processing vessel, for shredding the waste; the waste processing vessel comprising a waste processing zone, in which fluid can be retained, such that waste provided to the waste processing vessel can be shredded by the blade arrangement while immersed in treatment fluid in the waste processing zone.
The waste processing apparatus described herein provides an advantageous arrangement in which during the shredding operation, the waste being shredded is immersed in treatment fluid. This is an improvement compared to prior art systems in which, in order for repeated passes through a standard vertical shredding device to take place, waste has to be drawn out of treatment fluids and re-passed through a vertical shredder such that treatment fluid generally runs off the waste being shredded and treated while it passes once more through the shredding arrangement.
The blade arrangement may comprise a fixed blade array and a rotatable blade array, at least a portion of the fixed blade array preferably being disposed in the waste processing zone, such that waste material can be shredded against the fixed blade array, by the rotatable blade array, under the surface of treatment fluid retained in the waste processing zone. The waste processing vessel may comprise a substantially fluid-tight closed-bottomed container, configured such that a treatment fluid can be retained in the waste processing zone during waste processing, optionally at a substantially constant volume. The waste processing apparatus may further comprise a waste receiving opening, and a closure arrangement for closing the waste receiving opening. The closure may be arranged to retain treatment fluid and waste in the waste processing vessel during the simultaneous shredding and fluid treatment of the waste in the vessel.
The waste processing vessel may be movable to and from, and retainable in, at least one of: a first position in which the waste processing vessel is oriented towards a waste filling position to facilitate loading of waste into the waste processing vessel; a second position, in which waste treatment fluid can be provided to, and remains in, the waste processing vessel; a third position, in which waste and/or treatment fluid can be tipped out of the waste processing vessel. The waste processing apparatus may further comprise positional locking means configured to lock the waste processing vessel in at least one of the first, second or third positions. The positional locking means may comprise one or more locking mechanisms comprising an actuator and a pin. The actuator may be configured to move the pin to engage with the waste processing vessel so that the waste processing vessel is locked or lockable in one or more of the first, second and third positions. The waste processing vessel may comprise a vessel rotation axis about which the vessel may be rotated to occupy one or more of the first, second or third positions. The waste processing apparatus may further comprise a conveying means to which treated and shredded waste may be tipped from the waste processing vessel. The conveying means may be configured to perform conveying of the waste away from the waste processing vessel. The blade arrangement may comprise a rotatable blade array rotatable about a first axis. The apparatus may comprise one or more of: first drive means for driving the rotatable blade array about the first axis; and second drive means configured to drive the waste processing vessel about the vessel rotation axis. The first axis may be parallel to the vessel rotation axis. The apparatus may comprise treatment agent delivery means configured to deliver a treatment agent to the waste processing vessel. The treatment agent delivery means may be comprised in the closure arrangement.
The treatment agent delivery means may comprise first delivery means configured to deliver a treatment agent to the waste processing vessel. The treatment agent delivery means may comprise second delivery means configured to deliver a diluent to the processing vessel. The first delivery means may comprise a liquid delivery system, comprising pumping means and flow control means configured to deliver treatment liquid from a treatment liquid container to the waste processing vessel. The second delivery means may comprise a liquid delivery system comprising flow control means, and may be arranged to be connected to an external fluid supply, such as a mains water supply.
The waste processing apparatus may further comprise a chassis comprising outer walls which define an outer enclosure. The waste processing vessel, the waste receiving opening and the closure arrangement may be enclosed within the outer walls. The outer walls may comprise a loading hatch, which may be arranged to be allowed to be opened to load the waste processing vessel and which may be arranged to be kept closed during waste processing in the waste processing vessel.
A further aspect provides a method of treating waste, the method comprising one or more of the following steps: addition of waste and a treatment fluid to a waste processing vessel of a waste processing apparatus, wherein the waste processing vessel comprises a waste processing zone, and wherein the treatment fluid is retained in the waste processing zone; activation of a blade arrangement, such that the waste in the waste processing vessel can be shredded by the blade arrangement while in contact with or while immersed in the treatment fluid retained in the waste processing zone of the waste processing vessel; deactivation of the blade arrangement after a pre-determined cycle time. After shredding by the blade arrangement, the method may further comprise addition of a neutralising agent after shredding by the blade arrangement. Addition of a neutralising agent may be carried out after a predefined period of shredding.
With reference to
Whether rotationally mounted and rotationally displaceable or not, it can be advantageous to lock the waste processing vessel 120 in position during the waste processing cycle. This inhibits vibration of the waste processing vessel 120 which may be caused by rotation of the blades. To this end, positional locking means may be provided to the vessel to retain the vessel in place within the chassis 1001 and prevented generally from rotational and/or translational movement during the processing cycle. Examples of positional locking means may include friction brakes, bolts clamps or other means for retaining the vessel in place. In the present example, positional locking means are provided by locking mechanisms 180. Each locking mechanism 180 includes a linear actuator 181 and a pin 182, as illustrated in
Turning to
The waste processing vessel 120 may be provided with one or more ports 1261, 1262, 1263 for receiving process validation samples. The one or more ports 1261, 1262 may be arranged to be externally accessible with respect to the waste processing vessel, so that the user can access the ports to install and/or remove process validation samples from the waste processing vessel. It can be advantageous to have the one or more ports 1261, 1262, 1263 located in a waste processing zone of the waste processing vessel 120. The one or more validation ports 1261, 1262, 1263 may be arranged to provide an opening through one or more walls of the waste processing vessel, such as wall 1220. The one or more validation ports 1261, 1262, 1263 provide exposure of process validation samples to the interior of the vessel 120.
In the figures, a plurality of validation ports 1261, 1262, 1263 are provided. The plurality of validation ports 1261, 1262, 1263 are spaced apart from one another so as to provide an opening into different locations of the vessel 120 interior, and to different regions of the waste processing zone Z. As can be seen in
The one or more ports may include one or more lower ports 1261, 1262. The one or more lower ports 1261, 1262 may be provided in a lower region of such wall so as to be located in a region of the waste processing vessel in the waste processing zone Z (
As shown in
In
It will be appreciated that the treatment fluid may include components in the vapour or gaseous phase, e.g. the treatment fluid may include a mixture of gaseous and liquid substances and/or some of the treatment liquid may evaporate and be present in at least the upper region of the vessel 120 and/or the treatment fluid may include liquid particles suspended in a gas, e.g. an aerosol. In such an arrangement, the upper region of the vessel 120 may contain a portion of the treatment fluid in liquid or gas form. The one or more upper ports may be arranged to expose process validation samples to the treatment fluid in the upper region of the vessel 120.
While several of the processes described herein relate to use of fluids, which may be fluids comprising chemical treatment agents as described herein, for disinfection or sterilisation of the waste, other means for treating waste to achieve a desired level of sterilisation or disinfection are known and can be validated by the process validation methods described herein. These other means, processes or methods for disinfection or sterilisation include autoclave processes, in which heat and/or pressure may be applied to disinfect or sterilise waste material. Other disinfection or sterilisation means, methods or processes may be applied and validated using the methods described herein. These can include electromagnetic radiation, microwave radiation, light radiation, such as Ultra-Violet radiation, for example. In some examples, ozone may be utilised to sterilise and/or disinfect waste material in the vessel 120. Any combination of processes for disinfection or sterilisation of waste may be implemented. Any such means, method or process can be applied to the waste in the waste processing vessel described herein, and the efficacy of such a disinfection or sterilisation means, method or process can be validated using the methods described herein. Any aspect or component of the validation process, method or apparatus may be applied to a known waste processing method or apparatus, using the validation methods described to validate treatment processes such as those using the application of heat, and/or pressure, electromagnetic radiation, microwave radiation, or light radiation, such as UV radiation, to treat waste.
As will be discussed in more detail in the “Validation Process” section below, the arrangement of the validation ports shown in the figures provides a means for testing the efficacy of the fluid treatment process of the waste, whilst also providing a means for testing the quality of the atmosphere including any infectious aerosol contaminants (e.g. aerosolised particles from the waste material) in the vessel 120 prior to opening the vessel 120 and releasing any gases or airborne material therein to the atmosphere. In this way, including the upper ports 1263 can provide an indication of the efficacy of the treatment process as regards the atmosphere in the full volume of the waste processing vessel, including in the upper region of the vessel 120 (e.g. above the upper level S of liquid in the waste processing zone Z). The arrangement can therefore help to ensure that any waste that may have become airborne has been sufficiently disinfected. The presence of upper and lower validation ports 1261, 1262, 1263 provides increased awareness as to the effectiveness of disinfection achieved to waste by the waste treatment process across the entire vessel 120 (e.g. including any airborne waste).
The one or more validation ports 1261, 1262, 1263 may be provided with blanking plates when the validation process is not being carried out and the vessel 120 is being used for waste processing. Such blanking plates may be replaced with validation sample holders when a validation cycle is to be carried out. A validation cycle is a process in which a normal shredding and treatment cycle is run in the machine, and validation samples are held in the waste processing zone of the waste processing vessel, such that the validation sample contained in a validation sample holder is exposed to the same degree of treatment fluid as the waste in the waste processing zone. This can provide a reliable validation of the waste processing cycle, as will be described in more detail in later sections.
The blade arrangement 300 may be driven in rotation about a blade rotation axis 311, optionally via a gear arrangement 152. Gear arrangement 152 may comprise first 153 and second 154 gears arranged to transfer a drive from the drive source such as the drive source 152 the blade arrangement 300. In one arrangement as shown, the vessel rotation axis V may be substantially parallel to the blade rotation axis 311. The gear arrangement 154 may be arranged to transfer a drive between the vessel rotation axis V and the blade rotation axis B. As can be seen, drive for both the blade arrangement 300 and rotation of the waste processing vessel 120 may be provided on the same axis, such that the waste processing vessel is arranged to rotate around a same axis V along which the drive provided for driving the blade arrangement 300.
An exploded view of the waste processing vessel 120 can be seen in
The waste processing vessel 120 comprises a waste processing zone Z. The waste processing zone Z may be an area in the waste processing vessel 120 in which waste is shredded and exposed to a treatment fluid and/or to the treatment process. In the figures, the waste processing zone Z is defined by the interior of the waste processing vessel 120. The waste processing zone Z may be configured to retain the treatment fluid. It will be appreciated that in alternative arrangements, the waste processing vessel 120 may include separate chambers. In this case, the waste processing zone Z is defined as the chamber in which the waste is shredded and exposed to the treatment fluid.
When the vessel is in its operating state, the rotational axis 311 may be at the lower 311 position as shown in
It may be the case that the temperature of the diluent is in the range of from about 1° C. to about 40° C. It may be the case that the temperature of the diluent is in the range of from about 10° C. to about 30° C.
Operation of the waste processing apparatus will now be described with reference to
An operating sequence may start by orienting the waste processing vessel 120 in the first position, in which waste may be loaded into the waste processing vessel 120. This may include orienting the waste receiving opening 1270 of the waste processing vessel 120 towards a loading position, and may include arranging the waste receiving opening 1270 towards the loading hatch 160 to enable waste to be loaded through the loading hatch 160 into the waste processing vessel 120 in the direction of arrow 1601 as shown in
The waste processing vessel 120 may be moved to a second position. The second position can involve orienting the waste receiving opening 1270 towards a more upward or more vertical orientation relative to the first position. An example of such a second position is shown in
The apparatus can advantageously shred waste to a sufficiently small size that the waste can be immersed in treatment fluid in the waste processing vessel 120, which may take place in the waste processing zone Z. This can be performed for all waste added to the waste processing vessel. One way of achieving this is for the waste to be shredded to a size smaller than a depth of the treatment fluid retained the waste processing vessel, for example so that it fits below level S. The apparatus can also advantageously mix the waste with treatment fluid during and/or after the shredding of the waste by the blades. This can be achieved by continued operation of the blades for a sustained period. An advantage of methods described herein is that no heat energy need necessarily be applied to the waste for the treatment process. This can provide economies in energy consumption.
The arrangement of the blade arrangement in the waste processing vessel is such that it can shred the waste into smaller particles and provide a number of advantageous functions and advantages. These can include exposing the material to the chemical for disinfection, making the waste unrecognisable, for example so that the form or function of the un-shredded waste is unrecognisable, or such that any branding or personal data applied to the waste is unrecognisable. This can be advantageous when handling medical waste which may have this type of data applied. A further function may be to render the waste un-reusable, so that it can no longer perform the function it was manufactured for, for example such that a syringe or sample tube could not be re-used for the same function. It is also relevant that the entire treatment vessel is disinfecting waste regardless of whether or not it is in the liquid area.
An advantage of the system described herein is that both the functions of shredding and of disinfecting are carried out in the same enclosed area. This can be advantageous as compared to systems which may shred waste in a first area or operation and then treat, sterilise or disinfect the waste in a second area or operation. If the functions are separated, in the intermediate phase between shredding and disinfection, there could be a risk of aerosol infection, in particular if intervention for maintenance, for example, is required when a waste processing cycle is incomplete.
An aspect of the apparatus described is that it can apply the treatment fluid from the top down, which may be carried out via the first 1510 and/or second 1520 fluid delivery means. If performed before the blades are rotated, this can help to provide that the waste is substantially covered in treatment fluid prior to commencing shredding. Subsequently, the shred process may start by rotating the blades at a first speed, which may be a lower speed, while a higher rotation speed may be used later in the cycle. Treatment fluid or diluent may be applied simultaneously with rotation of the blades, at any point during the shredding process, and in particular at the beginning of the shredding process. Applying fluid from the top down during shredding can also help to prevent infectious aerosols propagating from the waste away from the treatment fluid, for example in an upward direction. This risk can be greatest at the beginning of the cycle, when containers are initially broken down and opened, so applying a spray at the early stages can have a particular advantage.
When the waste processing operation is complete, the closure mechanism 130 may be actuated to open the closure arrangement 170 and the waste processing vessel 120 may be moved to a third position, in which the opening 1270 faces at least partially, or fully, downwards. In this orientation, waste and/or treatment fluid may be tipped out of the waste processing vessel 120 through the opening 1270. An example of such a third position is shown in
The treatment fluid may comprise liquid, such as water, and may comprise a treatment agent. The treatment fluid may be in the form of a homogenous liquid mixture or a solution. The treatment agent may be provided in solid, liquid or gel form and may be combined with a diluent, which may be a liquid diluent such as water. As described herein, the term “diluent” takes its usual meaning in the art and relates to a substance that is added to dilute a solution or a mixture. The treatment fluid may comprise a disinfectant. The treatment fluid may comprise a disinfectant and a diluent. The treatment fluid may comprise a solution comprising a disinfectant and a diluent. The treatment fluid may be acidic. The pH of the treatment fluid may be in the range of from about 2 to about 6.
As used herein, the term “solution” relates to liquid mixtures in which the minor component(s) (i.e., the disinfectant) is uniformly distributed throughout the major component (i.e., a diluent as described above with respect to the waste processing apparatus). The diluent may comprise, consist essentially of or preferably consist of water. The solution as described herein may also be referred to as the “disinfectant solution”. The disinfectant solution may be acidic. The pH of disinfectant solution may be in the range of from about 2 to about 6.
The disinfectant solution may be provided via the first 1510 and/or second 1520 fluid delivery means. It may be the case that at least some of the total volume of the diluent is provided to the vessel 120 via the second fluid delivery means. The disinfectant solution may therefore be provided in a ‘pre-mixed’ state via only one fluid delivery means into the waste processing vessel 120. Alternatively, different components of the disinfectant solution may be delivered separately into the waste processing vessel via different fluid delivery means. The diluent may comprise, consist essentially of or preferably consist of water.
In one example, in a first step, a first component, such as the disinfectant, is provided to the waste processing vessel 120 via the first fluid delivery means 1510 in a desired amount. A second component such as the diluent may be delivered to the waste processing vessel in a second amount, to achieve a desired mixture, with desired relative concentrations, of the first and second components. In a first example, the diluent and disinfectant or other component(s) are added to the vessel simultaneously. However, it will be appreciated that in other examples, the diluent may be added to the waste processing vessel in a first step and followed by the disinfectant or other component, or vice versa. Adding the diluent first may avoid high concentrations of disinfectant in the vessel 120, for example.
As used herein, the term “disinfectant” relates to a chemical agent, which is able to inactivate viruses, bacteria, and other microorganisms that can cause infection and disease.
The disinfectant may comprise peracetic acid and hydrogen peroxide. As used herein, peracetic acid may also be referred to as peroxyacetic acid.
Without being bound by theory, peracetic acid and hydrogen peroxide demonstrate a synergistic effect when used in combination against infectious agents (such as microorganisms) present in biohazardous waste. For example, hydrogen peroxide can erode the outer layer of the microorganism, allowing peracetic acid to more efficiently degrade the proteins and nucleic acids contained within.
A combination of peracetic acid and hydrogen peroxide results in an equilibrium reaction as outlined below in Equation (I) below:
The term “equilibrium reaction” takes its usual meaning and relates to a chemical reaction in which two opposing chemical reactions are occurring simultaneously. The equilibrium may be shifted by changing various parameters, such as the reaction temperature, pressure, incorporation of a catalyst, or the composition of the reactants/products.
In Equation (I) Acetic acid and hydrogen peroxide react to generate peracetic acid and water. Peracetic acid in the presence of water will degrade to hydrogen peroxide and acetic acid over time.
Peracetic acid may be present in the range of from about 10% to about 20% based on the total weight of the disinfectant. It may be the case that peracetic acid is present in the range of from about 12% to about 17% based on the total weight of the disinfectant. At least 13% peracetic acid may be present based on the total weight of the disinfectant. At least 14% peracetic acid may be present based on the total weight of the disinfectant. At least 15% peracetic acid may be present based on the total weight of the disinfectant. At least 16% peracetic acid may be present based on the total weight of the disinfectant.
Hydrogen peroxide may be present in the range of from about 15% to about 30% based on the total weight of the disinfectant. It may be the case that hydrogen peroxide is present in the range of from about 18% to about 25% based on the total weight of the disinfectant. At least 20% hydrogen peroxide may be present based on the total weight of the disinfectant. At least 21% hydrogen peroxide may be present based on the total weight of the disinfectant. At least 22% hydrogen peroxide may be present based on the total weight of the disinfectant. At least 23% hydrogen peroxide may be present based on the total weight of the disinfectant.
Peracetic acid and hydrogen peroxide present at the abovementioned weight percentages drives the equilibrium reaction shown in Equation (I) towards the formation of peracetic acid and water, without the need for the addition of a strong acid catalyst, such as sulfuric acid. It is desirable to avoid the need for addition of strong acid catalysts, as they are corrosive and difficult to handle.
Moreover, without being bound by theory, driving the equilibrium reaction towards the formation of peracetic acid provides greater disinfectant efficacy in a shorter space of time compared to known disinfectants. For instance, the disinfectant according to the disclosure gives rise to a log reduction over a short cycle time. As used herein, the term “log reduction” takes its usual meaning in the art and relates to the mathematical term used to express the relative number of microorganisms (such as bacteria and viruses, or bacterial or fungal spores) that are inactivated by a disinfectant. The Log reduction value indicates the percentage kill rate of microorganisms. Log reduction can be measured using any known technique. For instance, a biological indicator as described herein below can be exposed to the treatment fluid from the waste processing zone of the waste processing vessel during a waste processing cycle of the waste processing apparatus. The biological indicator can then be extracted following completion of the processing cycle and placed in a culture medium and incubated for a pre-determined time (depending on the nature of the biological indicator in question and its respective desired culture conditions). Following incubation, absence of growth of microorganisms in the culture medium may indicate an efficient disinfection process. For example, an absence of growth may indicate a 99.9999% reduction in the number of active microorganisms and/or a log reduction in the number of active microorganisms. In instances where the biological indicator comprises about 104 microorganisms prior to the treatment process, a log 4 reduction following treatment would be indicative of an efficient disinfection process. In instances where the biological indicator comprises about 105 microorganisms prior to the treatment process, a log 5 reduction following treatment would be indicative of an efficient disinfection process. In instances where the biological indicator comprises about 106 microorganisms prior to the treatment process, a log 6 reduction following treatment would be indicative of an efficient disinfection process. In instances where the biological indicator comprises about 107 microorganisms prior to the treatment process, a log 7 reduction following treatment would be indicative of an efficient disinfection process. In instances where the biological indicator comprises about 108 microorganisms prior to the treatment process, a log 8 reduction following treatment would be indicative of an efficient disinfection process. In instances where the biological indicator comprises about 109 microorganisms prior to the treatment process, a log 9 reduction following treatment would be indicative of an efficient disinfection process. In instances where the biological indicator comprises about 1010 microorganisms prior to the treatment process, a log 10 reduction following treatment would be indicative of an efficient disinfection process.
The cycle time for achieving a log reduction during the waste treatment process may be 20 minutes or less, 18 minutes or less, 16 minutes or less, 14 minutes or less, 12 minutes or less, 11 minutes or less, 10 minutes or less, 9 minutes or less, 8 minutes or less, 7 minutes or less, 6 minutes or less, 5 minutes or less, 4 minutes or less, or 3 minutes or less. In certain examples, the cycle time may be as little as 2 minutes. Factors influencing the effectiveness of different cycle times include the efficiency of the shredding arrangement in shredding solid materials and/or closed containers, so that contaminated surfaces are exposed to the treatment fluid, combined with the chemical efficacy of the treatment fluid comprising a solution comprising a disinfectant and a diluent (also referred to as the disinfectant solution). Therefore, particularly short cycle times may be effective when using the treatment fluids described herein, or the shredding arrangements described herein, and particularly when using those in combination.
It may be the case that the disinfectant solution comprising a diluent and a disinfectant comprising peracetic acid and hydrogen peroxide is of a concentration in the range of from about 0.5% (v/v) to about 5% (v/v). It may be the case that the disinfectant solution comprising a diluent and a disinfectant comprising peracetic acid and hydrogen peroxide is of a concentration in the range of from about 1% (v/v) to about 3% (v/v). It may be the case that the concentration is at least 1% (v/v). It may be the case that the concentration is at least 2% (v/v). It may be the case that the concentration is at least 3% (v/v). As used herein, the term “v/v” denotes volume per volume for concentration of a solution wherein the components within the solution are liquid. The diluent may comprise, consist essentially of or preferably consist of, water.
It may be the case that the disinfectant comprising peracetic acid and hydrogen peroxide is present in the range of from about 100 millilitres to about 1000 millilitres. It may be the case that the disinfectant comprising peracetic acid and hydrogen peroxide is present in the range of from about 300 millilitres to about 800 millilitres. It may be the case that at least 600 millilitres of disinfectant comprising peracetic acid and hydrogen peroxide is present. It may be the case that at least 700 millilitres of disinfectant comprising peracetic acid and hydrogen peroxide is present.
It may be the case that the diluent is present in the range of from about 10 litres to about 30 litres. At least 15 litres of diluent may be present. At least 20 litres of diluent may be present. At least 25 litres of diluent may be present.
It may be the case that the disinfectant solution comprises a diluent and a disinfectant comprising peracetic acid in the range of from about 10% to about 20% based on the total weight of the disinfectant and hydrogen peroxide in the range of from about 15% to about 30% based on the total weight of the disinfectant; and wherein the solution is of a concentration in the range of from about 0.5% (v/v) to about 5% (v/v). The diluent may comprise, consist essentially of or preferably consist of water.
It may be the case that the solution comprises a disinfectant and a diluent, wherein the disinfectant comprises peracetic acid in the range of from about 12% to about 17% based on the total weight of the disinfectant and hydrogen peroxide in the range of from 18% to 25% based on the total weight of the disinfectant; and wherein the solution is of a concentration in the range of from about 1% (v/v) to about 3% (v/v). The diluent may comprise, consist essentially of or preferably consist of water.
It may be the case that the disinfectant solution further comprises an antifoaming agent. The antifoaming agent may be a silicone-based antifoaming agent, a non-silicone based antifoaming agent, or a combination thereof.
As used herein, the term “antifoaming agent” takes its usual meaning in the art and relates to chemical agents which can control the formation of foam.
A silicone based antifoaming agent relates to antifoaming agents comprising polymers with silicon backbones that are either oil or water based. Non-silicone-based antifoaming agents include mineral and organic based products, such as hydrocarbon based antifoaming agents.
Examples of silicone-based antifoaming agents include, but are not limited to, organopolysiloxane oils, such as poly(dimethylsiloxane), poly(methylphenylsiloxane), poly(methylethylsiloxane), poly(diethylsiloxane), poly (ethylphenylsiloxane), or combinations thereof.
Examples of non-silicone based antifoaming agents include, but are not limited to, hydrocarbon-based antifoaming agents. For example, hydrocarbon based antifoaming agents may comprise an aliphatic hydrocarbon oil, an aromatic hydrocarbon oil, an acyclic hydrocarbon oil, or combinations thereof. Additionally, or alternatively, the antifoaming agent may be selected from the foam control agents in the Foamdoctor range from PennWhite® Global chemical solutions (e.g., FoamDoctor® G2777E, FoamDoctor® G2005, FoamDoctor® G2020, FoamDoctor® G2030, or FoamDoctor® G2898).
The antifoaming agent may be present at a volume in the range of from about 5 millilitres to about 50 millilitres. It may be the case that the antifoaming agent is present at a volume of from about 10 millilitres to about 30 millilitres. It may be the case that at least 50 millilitres of antifoaming agent are present. It may be the case that at least 40 millilitres of antifoaming agent are present. It may be the case that at least 30 millilitres of antifoaming agent is present. It may be the case that at least 20 millilitres of antifoaming agent is present.
The antifoaming agent may be provided together with the disinfectant solution. It may be the case that the antifoaming agent is provided via the first 1510 and/or second 1520 fluid delivery means together with the disinfectant and/or diluent. It may be the case that at least some of the total volume of the antifoaming agent is provided to the vessel 120 via the second fluid delivery means.
The antifoaming agent may be added to the waste processing vessel at the same time as the biohazardous waste to be treated. It may be the case that the antifoaming agent is housed within a container. The container may be flexible or solid. The container may be tubular, conical, cubic, or have a bottle-like shape with a neck. and may be substantially cylindrical or may be a sealed bag. The container may comprise a material which is compatible with and does not influence the liquid treatment process. The container may comprise glass, glass fibers, plastic, ceramics, stainless steel, and metal oxides. It may be the case that the container comprises plastic.
Addition of the antifoaming agent in a container as described herein delays contact of the antifoaming agent contained within the biohazardous waste and treatment fluid, as the antifoaming agent is only released upon shredding of the container. Upon simultaneous shredding and treatment of the biohazardous waste, the level of foaming is often more pronounced. Therefore, addition of an antifoaming agent in a container will allow for optimum defoaming of the waste material and treatment fluid within the waste processing vessel.
The disinfectant solution may further comprise a fragrance additive. As used herein, the term “fragrance additive” takes its usual meaning in the art and relates to fragrance additives that are used to mask any unwanted odours of the treatment fluid. The fragrance additive may comprise an aldehyde (such as an aromatic aldehyde or fatty aldehyde comprising between 8 and 13 carbon atoms), a ketone, an ester (such as an aliphatic ester), an ether, an acetate, a nitrile, a terpene hydrocarbon, or an essential oil (such as natural essential oils or synthetic essential oils). An example of an aromatic aldehyde includes, but is not limited to, cinnamic aldehyde. It may be the case that the fragrance additive is RESAFRESH RIO® by MACNAB SALES.
The fragrance additive may be present at a volume in the range of from about 5 millilitres to about 50 millilitres. It may be the case that the antifoaming agent is present at a volume of from about 10 millilitres to about 30 millilitres.
According to another aspect of the disclosure, there is provided a method of processing waste, the method comprising the following steps:
The waste, treatment fluid, and waste processing apparatus can be provided as described hereinabove.
As used herein, the cycle time relates to the time elapsed between the beginning of the mechanical processing, or shredding, of the waste in the presence of the treatment fluid. It therefore begins when the waste and the treatment fluid are present in the waste processing vessel together, and the blade arrangement begins shredding of the waste. It ends when the shredding and mixing of the waste in the vessel 120 stops. When the treatment fluid comprises a disinfectant solution as described herein, the cycle time may be the time taken, or the time sufficient, to reach a log reduction.
The method for treating waste may take place at a temperature in the range of from about 1° C. to about 40° C., optionally in the range of from about 5° C. to about 30° C., optionally in the range of from about 10° C. to about 26° C.
According to another aspect of the disclosure, there is provided the use of a solution comprising a disinfectant and a diluent (also referred to as a disinfectant solution) in the treatment of biohazardous waste. The disinfectant solution may be acidic. The pH of the disinfectant solution may be in the range of from about 2 to about 6.
The disinfectant may comprise peracetic acid and hydrogen peroxide. The diluent may comprise, consist essentially of or preferably consist of water. The disinfectant may comprise peracetic acid in the range of from about 10% to about 20% based on the total weight of the disinfectant. The disinfectant may comprise peracetic acid in the range of from about 12% to about 17% based on the total weight of the disinfectant.
The disinfectant may comprise hydrogen peroxide in the range of from about 15% to about 30% based on the total weight of the disinfectant. The disinfectant may comprise hydrogen peroxide in the range of from about 18% to about 25% based on the total weight of the disinfectant. The solution may be of a concentration in the range of from about 0.5% (v/v) to about 5% (v/v). The solution may be of a concentration in the range of from about 1% (v/v) to about 3% (v/v).
According to another aspect of the disclosure, there is provided a use of a solution comprising a disinfectant and a diluent comprising water in the treatment of biohazardous waste, wherein the disinfectant comprises peracetic acid in the range of from about 10% to about 20% based on the total weight of the disinfectant and hydrogen peroxide in the range of from about 15% to about 30% based on the total weight of the disinfectant.
According to another aspect of the disclosure, there is provided a use of a solution comprising a disinfectant and a diluent comprising water in the treatment of biohazardous waste, wherein the disinfectant comprises peracetic acid in the range of from about 10% to about 20% based on the total weight of the disinfectant and hydrogen peroxide in the range of from about 15% to about 30% based on the total weight of the disinfectant; and wherein the solution is of a concentration in the range of from about 0.5% (v/v) to about 5% (v/v).
According to another aspect of the disclosure, there is provided a use of a solution comprising a disinfectant and a diluent comprising water in the treatment of biohazardous waste, wherein the disinfectant comprises peracetic acid in the range of from about 12% to about 17% based on the total weight of the disinfectant and hydrogen peroxide in the range of from about 18% to about 25% based on the total weight of the disinfectant, and wherein the solution is of a concentration in the range of from about 1% (v/v) to about 3% (v/v), in the treatment of biohazardous waste.
It is desirable to disinfect biohazardous waste, such that it can be disposed of safely or recycled. Moreover, there is a desire to disinfect biohazardous waste as quickly as possible. Use of a solution comprising a disinfectant comprising peracetic acid and hydrogen peroxide in the treatment of biohazardous waste as described above provides for effective chemical treatment of biohazardous waste, wherein a log reduction is achieved over a short cycle time. Moreover, use of a disinfectant solution described herein in combination with aspects of the waste processing apparatus described herein, whereby waste being shredded is immersed in a disinfectant solution during shredding, not only results in a log reduction over a short cycle time, but overcomes the setbacks associated with prior art systems in which, in order for repeated passes through a standard vertical shredding device to take place, waste must be drawn out of treatment fluids and re-passed vertically through a shredder arrangement, such as a conventional two-shaft shredding arrangement in which waste passes vertically downwards through and between the shafts and their associated shredding blades such that a disinfectant solution would generally run off the waste being shredded and treated while it passes once more through the shredding arrangement.
The validation process of the present disclosure provides improved means for testing the efficacy of a waste shredding and liquid treatment process. In particular, improved ways of ensuring a validation test sample is exposed to the treatment fluid used in the process in a way which is more representative of the exposure of the waste being processed to the treatment liquid.
The process validation module can fulfil several functions, including holding and protecting a process validation sample from physical impact from items being shredded in the waste processing zone Z, whilst permitting treatment fluid from the waste processing zone Z to contact the process validation sample to enable the efficacy of the process to be validated. An example of a process validation module 700 is shown in
The fixing portion 730 may be arranged to retain the process validation module to the waste processing vessel 120 to hold the validation sample in a substantially fixed position during waste processing. The sample holding portion 710 may comprise one or more fixing portions 711, 712. These may comprise for example a threaded arrangement. The fixing portion 711 may be arranged such that it can engage a corresponding fixing portion 712 of an adjacent sample holding portion 720 in this way, the sample holding portions may be stacked adjacent to one another to permit multiple validation samples to be mounted to a single sample holding portion 730 of a validation module 700. Module 734 may comprise the handle portion to enable a user to carry the module 700. A shaft portion 735 may extend between the handle portion 734 and the sample holding portion(s). A flange portion 731 may be provided for sealing against or around a port provided on the vessel 120. Channels 732, 733 for o-ring seals may be provided for further sealing against the waste processing vessel 120.
Assembly of the process validation module 700 with the waste processing vessel 120 is illustrated in
The port or ports 1261, 1262, 1263 on the vessel 120 are preferably located such that they may be easily accessed by a user at least in between waste processing cycles. In the illustrated example, placing the vessel 120 in the position illustrated in
Control- and method-related aspects of the validation cycle are described separately in the relevant section of this disclosure. The practical aspects of running a validation cycle in the machine can be readily understood when reading that section in combination with the above disclosure. When inserting the process validation module, the system may place the waste processing vessel 120 in a suitable position such that a user can access the validation port or ports 1261, 1262, 1263. The user may then install one or more process validation samples in fluid communication with the waste processing zone Z by attachment of a process validation module into fluid communication with the waste processing zone Z, e.g. by connection to one or more of the validation ports 1261, 1262. A validation cycle may then be run as described in the relevant control section of this disclosure.
While the validation cycle described is in relation to a system in which a treatment fluid is introduced to the waste processing zone Z of the vessel 120, it will be appreciated that the validation cycle and associated apparatus can function with any disinfection and/or sterilisation processes and/or any combination thereof.
In an example arrangement, heat may be applied to the waste processing zone Z of the vessel 120 (e.g. via a heat exchanger arrangement, steam heating, or any suitable means) to disinfect/sterilise the waste located therein as an alternative or supplement to the treatment fluid. For example, the waste processing zone may be heated to temperatures of at least 60° C., optionally in the range of 60° C. to 80° C., optionally greater than 80° C., optionally greater than 100° C., optionally in the range of 160° C. to 180° C. It will be appreciated that different temperatures may be applied depending on the waste intended for treatment in the vessel 120. In this arrangement, a process validation module as described is exposed to the waste processing zone Z (e.g. to the region of the vessel 120 to which heat is applied). In some arrangements, multiple process validation modules may be exposed to different areas of the waste processing zone Z. The process validation modules can determine the efficacy of the heating on the disinfection and/or sterilisation of waste in the zone Z.
In addition or as an alternative arrangement, pressure may be applied to the waste processing zone Z of the vessel 120. In such an arrangement, the closure arrangement of the vessel 120, such as the lid 170, may be sealed with a pressure-tight sealing mechanism so as to allow the vessel to be pressurised. In some arrangements, heat and pressure are applied to the waste processing zone Z. For example, an autoclaving system may be utilised in which steam is generated in the vessel 120, increasing the temperature and pressure therein so as to disinfect and sterilise the waste.
An alternative or additional treatment process to which the validation method and/or apparatus may be applied includes applying radiation to the waste in the waste processing zone Z. For example, an electromagnetic radiation generator may be located within or coupled to the vessel 120 so as to introduce electromagnetic radiation into the vessel 120. In some arrangements, microwaves are introduced into the waste processing zone Z to disinfect the waste therein. Alternatively or additionally, ultraviolet (UV) radiation may be applied to the waste processing zone, e.g. via UV lights being positioned in the vessel. A radioactive source may be positioned within or in communication with the waste processing zone Z so as to generate gamma radiation to sterilise waste.
In some arrangements, the validation method and/or apparatus may be applied to a treatment process in which ozone is introduced into the waste processing zone Z of the vessel 120. The ozone can act to disinfect the waste within the vessel 120. In such an arrangement, ozone is injected into the waste processing zone Z. The ozone may be gaseous or dissolved in a liquid in some arrangements.
It will be appreciated that the validation method may be applied to any combination of the above treatment processes, including applying a treatment fluid. The validation method and apparatus are suitable for determining the efficacy of any treatment process for disinfecting and/or sterilising waste.
The validation method and/or apparatus may be utilised in a steam-based waste treatment system in some arrangements.
One aspect of improvement identified is a novel blade arrangement which can process a vast array of waste streams that differ in size, composition, malleability, strength and composition more reliably and efficiently. The blade arrangement can be termed a shredding assembly. According to an aspect, there is provided a shredding assembly comprising any or all of the following features: a fixed blade array; a rotatable blade array configured to rotate relative to the fixed blade array about a rotational axis. The rotatable blade array may comprise a plurality of rotatable blades. A rotatable blade of the plurality of rotatable blades may comprise any of: a main body extending in an outwardly radial direction with respect to the rotational axis; a first cutting face configured for cutting in a first rotational direction of the rotatable blade array; and a second cutting face configured for cutting in a second rotational direction of the rotatable blade array. The plurality of rotatable blades may be interspersed with the fixed blade array such that, during rotation of the rotatable blade array, at least a portion of the radial extent of the main body passes through a gap between adjacent fixed blades of the fixed blade array. The shredding assembly of the present disclosure provides a device which can shred waste more flexibly and efficiently. Such a shredding assembly can be incorporated into a waste processing vessel for receiving waste to be shredded and treated. The fixed blade array may be a lower fixed blade array, such that it can be positioned at the bottom of the waste processing vessel where waste is collected in the shredding assembly. This can correspond to a waste processing zone of the waste processing vessel in which waste is continuously shredded for a set period of time. By providing a rotatable blade array configured to rotate relative to the fixed blade array, the advantageous shredding assembly can be provided, for example, by a single rotatable shaft, in contrast to arrangements having a twin shaft of interspersing rotatable blades. An advantageous arrangement may therefore provide a rotatable blade array which has blades arranged to interleave with one or more adjacent fixed blade arrays. By providing a first cutting face and a second cutting face, the shredding assembly can be operated such that the rotatable blade array can rotate in a first direction or a second, opposite direction in order to shred waste between the rotatable blades and the fixed blades when the rotatable blade array rotates in either direction. Such bidirectionality of the rotatable blade array is advantageous because it allows for an improved shredding process in which the direction of rotation can be reversed periodically, and/or in response to reaching a threshold torque of the rotatable blade array. The radial extent of the main body can be defined as the maximum radial distance of a radial extremity of the main body from the rotational axis. A maximum width of the main body between the first and second cutting faces may be less than the radial extent of the main body. A maximum width of the main body between the first and second cutting faces may be less than three quarters, preferably less than seven tenths, preferably less than two thirds of the radial extent of the main body. A minimum width of the main body between the first and second cutting faces may be less than one half of the radial extent of the main body. This provides an advantageously dimensioned blade arrangement that efficiently shreds various types of waste. The shredding assembly may be configured such that at least half, preferably at least three quarters, preferably at least eight tenths of the radial extent of the main body passes through the gap between adjacent fixed blades during rotation of the rotatable blade array. By interspersing the fixed blades with the rotatable blades such that a major portion of the radial extent of the main body passes through a gap between adjacent fixed blades of the fixed blade array, the shredding assembly can be suitable for shredding waste having different dimensions while reducing the chance that the shredding assembly becomes jammed. Two or more rotatable blades may extend from the rotational axis at different angles relative to one another. The plurality of rotatable blades may comprise a first rotatable blade and a second rotatable blade, which may be located at a position adjacent along the rotational axis to the first rotatable blade. An angular offset between the first rotatable blade and the second rotatable blade may be at least 15 degrees, preferably at least 30 degrees. The angular offset may be an integer multiple of an angle between 15 and 45 degrees. The angular offset may be an integer multiple of 30 degrees. The plurality of rotatable blades may comprise a group of up to twelve rotatable blades. The shredding assembly may comprise any number between 5 and 50 rotatable blades in different implementations. One or more, or each, of the plurality of rotatable blades in the group may be angularly offset from the other rotatable blades. The group may comprise two, preferably four, preferably eight, preferably twelve rotatable blades. For different implementations, any integer number between 3 and 50 may be suitable. The angular offset between select pairs of blades in the array, or between each blade in the array may be an integer multiple of an angle between 5 and 45 degrees, or between 15 and 45 degrees, and may be 30 degrees in certain examples. In this way, the rotatable blade array can be configured such that, during rotation thereof, the passage of rotatable blades through the gaps in the fixed blade array can be staggered. This can be advantageous in reducing peaks in the maximum torque of the rotatable blade array and can help in reducing overall levels of vibration. However, different implementations may require certain blades in the array or group to be in rotational alignment, i.e., having no angular offset with respect to one another. In certain implementations, plural arrays may be provided, each array comprising blades which are in rotational alignment with each other with the respective array being offset from other arrays by the offsets described herein.
A or each rotatable blade may comprise a fixing portion configured to engage with a shaft. At least one of the first and second cutting faces may extend linearly in a radial direction from the fixing portion to a tip portion of the blade extending between the first and second cutting faces.
A centreline of the main body may be defined along the radial extent thereof. The first cutting face may extend along the main body at a first angle to the centreline. The second cutting face may extend along the main body at a second angle to the centreline. At least one of the first angle and the second angle may be between 1 and 10 degrees. At least one of the first angle and the second angle may be approximately 5 degrees. A plane defined by the centreline and the rotational axis may be a plane of symmetry between the first and second cutting faces. At least one of the first and second cutting faces may comprise a plurality of serrations. The plurality of serrations may comprise a first set of serrations on a first side of the rotatable blade. The plurality of serrations may further comprise a second set of serrations on a second side of the rotatable blade. The first side and the second side may define opposite sides of the rotatable blade at different positions along the rotational axis. The first side and the second side may comprise planar side faces of the main body. The planar side faces may be normal to a direction parallel to the rotational axis. The serrations of the first and/or second set of serrations may be substantially pyramidal. The serrations may extend along a respective cutting face between a tip portion of the blade and a region of the blade proximal to the rotational axis (e.g. a region substantially aligned with the rotational axis or substantially aligned with a mounting portion of the blade).
The shredding assembly may further comprise a recess extending at least partially along the radial extent of the first and/or second cutting face. The recess may extend at least partially along the radial extent of the first and/or cutting face so as to define a first cutting surface of the or each respective cutting face on a first side of the rotatable blade, and a second cutting surface of the or each respective cutting face on a second side of the rotatable blade. The first and second sides may define opposite sides of the rotatable blade at different positions along the rotational axis.
The rotatable blade may comprise a tip portion extending between the first and second cutting faces. The tip portion may be configured to define a third cutting surface. The rotatable blade may comprise at least four cutting surfaces. The rotatable blade may comprise at least five cutting surfaces.
At least one of the first and second cutting faces may comprise a first set of serrations on the first cutting surface. At least one of the first and second cutting faces may comprise a second set of serrations on the second cutting surface. A third set of serrations may be provided on the third cutting surface.
The recess may be located between the first set and second set of serrations. A blade height may be defined as the difference between the smallest radius of the main body about the rotational axis, which may be where the main body is connected to a shaft and the largest radius of the main body, which may be the maximum radial extent of the main body. The blade height may be larger than the lateral distance between the opposing cutting faces. The blade height may be larger than a maximum lateral distance between the opposing cutting faces by at least a quarter, preferably by at least a third, preferably by at least four tenths. The blade height may be larger than a minimum lateral distance between the opposing cutting faces by at least a third, preferably at least four tenths, preferably by at least a half. The minimum lateral distance may be at least half the maximum lateral distance between the opposing cutting faces, preferably at least six tenths, preferably at least three quarters.
The fixed blade array may be an upper fixed blade array provided above and across the rotational axis. The fixed blade array may be a lower fixed blade array provided below the rotational axis.
A fixed blade of the shredding assembly may comprise first and second end regions. The first end region and second end region may have mounting portions for mounting to a fixed body of the shredding assembly, which may be part of a waste processing vessel. The fixed blade may extend between the mounting portions. The fixed blade may extend across the rotatable blade array. The fixed blade may extend transverse to the rotational axis. The fixed blade array may comprise two, preferably three fixed blades. The fixed blade may further comprise an intermediate portion provided between the first and second end region. The intermediate portion may comprise a cutting face. The cutting face may extend between the first and second end regions. The fixed blade may further comprise end cutting portions. The end cutting portions may be oriented toward a centreline of the intermediate portion. The end cutting portions may be provided on the first and second end regions. The fixed blade may lie in a plane normal to the rotational axis.
The cutting face may be an upper cutting face. The upper cutting face may be oriented away from the rotational axis. The fixed blade may further comprise a lower cutting face. The lower cutting face may extend between the first and second end regions. The lower cutting face may be oriented toward the rotational axis. The lower cutting face may have end cutting portions oriented toward a centreline of the intermediate portion. In this way, the fixed blade can have cutting means on opposite sides thereof such that, when a rotatable blade rotates relative to the fixed blade, waste can be shredded against the upper cutting face on a downward swing of the rotatable blade, and can be shredded against the lower cutting face on an upward swing of the rotatable blade.
The fixed blade may comprise a further face. The further face may be oriented toward the intermediate portion. The further face may be provided between an end region and the upper cutting face. The further face may face toward the upper cutting face. The further face may form a wall of a cut-out portion provided between an end region and the upper cutting face. The cut-out portion may be configured to align with an outer radial edge of the rotatable blade when the rotatable blade rotates relative to the fixed blade.
The cutting face may comprise at least a first spike and a second spike adjacent the first spike. The fixed blade may comprise a first side face and a second side face on the opposite side of the fixed blade to the first side face. The first spike may have a surface that is coplanar with the first side face. The second spike may have a surface that is coplanar with the second side face. The first and/or second spike may be substantially pyramidal. An apex of the first spike may be in the plane of the first side face. An apex of the second spike may be in the plane of the second side face.
The fixed blade array may be a first fixed blade array of the shredding assembly, which may be an upper fixed blade array. The first fixed blade array may be provided above and across the rotational axis. The shredding assembly may further comprise a second fixed blade array. The second fixed blade array may extend from the fixed body of the shredding assembly radially toward the rotational axis. The second fixed blade array may be a lower fixed blade array. The second fixed blade array may be provided below the rotational axis.
The fixed blade array (e.g. the second fixed blade array) may be arranged in a linear array. At least one of the plurality of fixed blades may comprise a substantially triangular portion, which may be truncated in proximity to the rotatable blade array. A fixed blade of the second fixed blade array may comprise a first cutting face and a second cutting face arranged in a similar manner to the first and second cutting faces on the rotatable blade. A first cutting face of the fixed blade may be configured for cutting when the rotatable blade array rotates in its first rotational direction. A second cutting face of the fixed blade may be configured for cutting when the rotatable blade array rotates in its second rotational direction. A main body of the fixed blade may extend from a fixed body of the shredding assembly toward the rotational axis.
At least one of the first and second cutting faces of the fixed blade may comprise a plurality of serrations. The plurality of serrations may comprise a first set of serrations on a first side of the fixed blade. The plurality of serrations may further comprise a second set of serrations on a second side of the fixed blade. The first side and the second side may define opposite sides of the fixed blade at different positions along the rotational axis. The first side and the second side may comprise planar side faces of the main body. The planar side faces may be normal to a direction parallel to the rotational axis. A recess may extend at least partially along the radial extent of the first and/or cutting face of the fixed blade so as to define a first cutting surface of the or each respective cutting face on a first side of the rotatable blade, and a second cutting surface of the or each respective cutting face on a second side of the rotatable blade. The first and second sides may define opposite sides of the fixed blade. At least one of the first and second cutting faces may comprise a first set of serrations on the first cutting surface, and a second set of serrations on the second cutting surface. The recess may be located between the first and second sets of serrations. The rotatable blade array may be configured to only have a single blade in a given plane perpendicular to the rotational axis. In other words, the rotatable blade array may be arranged to consist of one rotatable blade at a given position along the rotational axis. This is in contrast to arrangements having multiple blades extending in different directions from a single position along the rotational axis. This arrangement provides more efficient shredding which can be less likely to jam and may reduce vibrations.
The shredding assembly may comprise a shaft. The shredding assembly may comprise a single shaft. The rotatable blade array may be rotatably mounted on the single shaft. Put another way, the shredding assembly may comprise only one shaft upon which the rotatable blade array is mounted (e.g. the rotatable blade array may not be mounted over multiple shafts, or there may not be multiple rotatable blade arrays each mounted to different shafts).
The rotatable blade array may be provided on a shaft. The rotatable blade may comprise a fixing portion configured to engage with, or surround a major portion or the entirety of the angular extent of, the shaft. The fixing portion may comprise an aperture configured to receive a shaft. The aperture may be configured to engage a shaft and prevent rotation between rotatable blade and a shaft to which the rotatable blade is mounted. The fixing portion may comprise a non-circular aperture. The non-circular aperture may define a spline, or may be polygonal in form. The aperture may comprise a plurality of corners, curves and/or flat faces, configured to engage corresponding faces on a shaft to prevent relative rotation therebetween. The aperture may be any polygon, for engaging any corresponding polygonal shaft and in one example, may be a hexagonal aperture, which may be configured to receive a hexagonal shaft. This provides the advantage of increasing the manufacturability of the shredding assembly. The first cutting face may extend at a first tangent from the fixing portion. The second cutting face may extend at a second tangent from the fixing portion.
The width of the main body may taper away from the rotational axis of the rotatable blade. The width of the main body may decrease linearly with increased radial distance from the rotational axis. The angle between the first tangent and the second tangent may be approximately ten degrees. The angle between the centreline and at least one of the first and second tangents may be between four and six degrees; preferably, this angle is approximately five degrees. A first width (perpendicular to the centreline) of the main body between the first and second cutting faces may be defined at a first radial position, and a second width may be defined at a second radial position further from the rotational axis than the first radial position, and the first width may be greater than the second width. The first width may be measured at a base of the main body, that is, proximate to the rotational axis, and the second width may be measured at an end of the main body, that is, distal from the rotational axis. The rotatable blade may be configured such that its centre of mass is offset from the rotational axis. Alternatively or additionally, a maximum order of rotational symmetry of the rotatable blade with respect to the rotational axis may be one.
The shredding assembly may be configured such that, when a rotatable blade passes through the gap between adjacent fixed blades, the separation between the rotatable blade and a fixed blade is no more than 1 mm with respect to a direction parallel to the rotational axis. The separation may additionally or alternatively be no more than two tenths, preferably no more than one tenth, preferably no more than one twentieth of the thickness of the rotatable blade with respect to a direction parallel to the rotational axis. A non-zero and non-negligible separation is provided, so that materials can pass between the adjacent blades within the gap, to reduce the risk of jamming. The separation may therefore be at least a tenth of a millimetre or at least a multiple of a tenth of a millimetre, including all integer multiples of a tenth of a millimetre up to and including the upper bounds defined above for the separation.
There is also provided a rotatable blade array for the shredding assembly as described hereinabove. In other words, there is provided a rotatable blade array separate from the shredding assembly, i.e. without including any fixed blade array. There is also provided a rotatable blade for the shredding assembly or the rotatable blade array as described hereinabove. In other words, there is provided a single rotatable blade separate from the rotatable blade array. There is also provided is a fixed blade for the shredding assembly as described hereinabove. In other words, there is provided a fixed blade separate from any rotatable blade array. The fixed blade may be a fixed blade of the first fixed blade array or the second fixed blade array, and may have any of the features described hereinabove. Blade arrangements as disclosed can be combined advantageously with any other of the aspects and features disclosed herein.
The inventors have identified particular areas for improvement in the processing of waste, in particular contaminated, hazardous or biohazardous waste. In particular, the inventors have identified improved blade arrangements which can effect both mixing and shredding of waste in a more efficient and effective manner.
The disclosed shredding assembly is particularly suited to use with the vast array of different biohazardous waste products that are produced in laboratories. Such waste streams may contain glass, paper, polymers, blood, urine, sharps, PPE, etc. and hence the blade arrangement needs to cope with a range of hard and soft materials, some being pliable and malleable others being hard and brittle. None of these materials can be recycled while they are considered to be of a biohazardous nature. For a system in which the disclosed blade arrangement is implemented to disinfect biohazardous waste, the waste needs to be shredded sufficiently to ensure that a treatment chemical comes into contact with the biohazardous materials. Once the initially biohazardous waste is sufficiently treated to be considered non-hazardous and safe for handling and transportation, it can be sent to recycling facilities for separation and pelletisation. The disclosed system facilitates recycling, as the waste processed in the system can be made safe. Combined disinfection or decontamination and shredding is an advantage to downstream recyclers as they can skip several steps in the usual known processes at recycling plants, with the output from blade arrangements and systems as disclosed herein.
Disclosed herein is a shredding assembly for the mixing and shredding of waste. The shredding assembly can be incorporated into a device for the treatment of biohazardous waste. In particular, the shredding assembly can be incorporated into a receiver, such as a waste processing vessel for waste to be treated. The shredding assembly can form part of a process for treating waste, which may additionally include treating the waste with a fluid or liquid treatment in order to clean, sterilise or disinfect the waste. Such treatment may occur in the waste processing vessel at the same time as the shredding assembly shreds the waste.
The shredding assembly disclosed herein includes a rotatable shaft having a plurality of blades configured to rotate with the shaft. The blades can be spaced at regular intervals along a rotational axis of the shaft and can extend from the shaft at a variety of different angles. Each rotatable blade on the rotatable shaft has a cutting face on opposite sides of the blade such that the cutting faces are substantially perpendicular to the path of rotation of the rotatable blade. The shredding assembly also includes a lower fixed blade array, which can be fixed relative to the waste processing vessel. The lower fixed blade array has a plurality of lower fixed blades configured to intersperse with the rotatable blades so that the rotatable blades will pass through gaps between the lower fixed blades during rotation of the rotatable blades about the rotational axis. The lower fixed blades can have cutting faces on opposite sides thereof in order to co-operate with the cutting faces of the rotatable blades. The rotatable shaft can be configured to rotate in a clockwise or an anti-clockwise direction. In this way, waste in the bottom of the waste processing vessel can be shredded by the action of the rotatable blades passing through the lower fixed blades in either a clockwise or an anti-clockwise direction.
The shredding assembly can also include one or more upper fixed blades. The upper fixed blades can be provided on a top side of the rotatable shaft, that is, on the opposite side of the rotatable shaft to the lower fixed blade array. The upper fixed blades can be configured to facilitate the breaking down and cutting of larger items of waste before such items are further shredded between the rotatable blades and the lower fixed blade array. Therefore, when a bag of hazardous waste—which may include various items of waste made from different materials, such as glass beakers, plastic tubes, fabric laboratory coats, and so on—is placed into the waste processing vessel, rotation of the rotatable blades can begin to break down the waste by crushing and cutting the waste between the cutting faces of the rotatable blade and the upper fixed blade, until the waste is small enough to fall to the bottom of the waste processing vessel, where the waste can be further shredded between the cutting faces of the rotatable blades and the lower fixed blades.
The plurality of rotatable blades 320 may be interspersed with the lower fixed blade array 360 such that, during rotation of the rotatable blade arrangement 310, at least a portion of the radial extent of a rotatable blade 320 passes through a gap between adjacent lower fixed blades of the lower fixed blade array 360. In
The upper fixed blade array 340 can comprise three upper fixed blades 341 distributed along the rotational axis 311. The upper fixed blade array may be configured such that two, preferably three, more preferably four or more rotatable blades 320 are received in the gap provided between an adjacent pair of upper fixed blades 341. In the arrangement shown, four rotatable blades 320 are positioned along the rotational axis 311 between a first upper fixed blade and a second, adjacent upper fixed blade. The blades can be advantageously arranged to provide a scissor-type action between cutting faces of the rotatable blades and the fixed blades. When one or more of the rotatable blades passes adjacent one or more lower blades, an acute angle (i.e. between 0 and 90 degrees) may be formed between their oppositely oriented cutting faces. Providing such a scissor action using an acute angle between opposing cutting faces can improve the cutting action. Providing such acute angles between cutting faces on both sides of the rotatable blades and preferably on both sides of the lower fixed blades, can help to facilitate effective cutting in both directions of rotation of the rotatable blade array. Multiple cutting and shredding locations can be provided by providing such acute angles between one or two or more faces of at least one rotatable blade and any cutting face of the different fixed blades. This can include cutting faces of the upper fixed blades 340 which either face towards or away from the rotational axis 311, and in particular cutting faces 362 of the lower fixed blades oriented in either direction, or preferably two opposing directions, relative to the direction of rotation of the rotatable blade array. The interfaces can all contribute to more effective and efficient shredding, particularly in combination.
The rotatable blade array 310 may comprise a first rotatable blade 320a and a second rotatable blade 320b adjacent to the first rotatable blade 320a along the rotational axis 311. Each of the first rotatable blade 320a and the second rotatable blade 320b comprises a main body extending from the shaft 312 in a radial direction with respect to the rotational axis 311, and a first and a second cutting face configured to cut waste in a circumferential direction with respect to the rotational axis 311. In this respect, the first and second cutting faces can be substantially perpendicular to a path of rotation of the rotatable blade 320, for example between 80 and 100 degrees to the path of rotation.
At least one adjacent pair of rotatable blades 320 may be separated by a spacer 313 provided around the shaft 312. The main body of each rotatable blade 320 may be connected to a fixing portion which surrounds the rotatable shaft 312 in order to facilitate fixing thereto. The fixing portion may be integrally formed with the main body in some arrangements. As will be described later, the main body of the rotatable blade 320 can be substantially planar such that the main body is normal to a direction parallel to the rotational axis 311. The first and second cutting faces of a rotatable blade 320 can be symmetrical with each other with respect to a centreline of the main body.
An angular offset between the first rotatable blade 320a and the second rotatable blade 320b may be a fraction of a turn wherein the fraction is at least one twenty-fourth, or at least one twelfth, one tenth, one eighth, one sixth, or one quarter. The angular offset may be at least a quarter radian, or a half radian, three quarter radians, one radian, or three half radians. An angle between the centreline of the first rotatable blade 320a and the second rotatable blade 320b may be at least 30 degrees, and may be an integer multiple of 30 degrees.
In the arrangement shown, the rotatable blade array 310 comprises a group of twelve rotatable blades 320, labelled 320a to 320l, wherein each of the group of rotatable blades is orientated at a different angle with respect to the rest of the group. The rotatable blade array 310 includes 17 rotatable blades 320a to 320q. Since there are only twelve distinct orientations of rotatable blades 320 under the constraint that each rotatable blade 320 is offset by an integer multiple of 30 degrees in the circumferential direction, the remaining five rotatable blades 320m to 320q may repeat the angular sequence of the rotatable blades 320a to 320e. The relative angle of each of the rotatable blades 320a to 320q with respect to the rotatable blade 320a is provided in the following sequence: 0, 210, 60, 270, 120, 330, 180, 30, 300, 90, 240, 150, 0, 210, 60, 270, 120. It will be appreciated that each of these corresponds to a clockwise direction, for example ‘0 degrees’ corresponds to 12 o'clock, and 210 degrees Corresponds to 7 o'clock, and so on.
It will be appreciated that the above sequence illustrates just one arrangement for organising the rotatable blades 320a-320q along the shaft 312, but that many other combinations of angles exist. In the arrangement shown, a first rotatable blade 320a is offset from a second rotatable blade 320b by an angle of 150 degrees. The rotatable blade array 310 may comprise a third rotatable blade 320c, arranged such that the second rotatable blade 320b is provided between the first rotatable blade 320a and the third rotatable blade 320c. The third rotatable blade 320c may be offset from the first rotatable blade 320a by 60 degrees. The rotatable blade array 310 can comprise further rotatable blades provided sequentially in order to provide a fourth rotatable blade 320d, a fifth rotatable blade 320e, a sixth rotatable blade 320f and so on.
In the arrangement shown, the fixing portion 327 comprises a hexagonal aperture configured to receive a corresponding hexagonal shaft 312 (not shown). The hexagonal aperture is shaped as a regular hexagon, that is, each internal angle being 120 degrees, and is oriented such that the centreline perpendicularly bisects two opposite edges of the hexagon. It will be appreciated that six different orientations of the rotatable blade can be achieved on a single hexagonal shaft using the rotatable blade 320 of
The rotatable blade 320 may comprise a first side face 321 and a second side face 322. The first and second side faces can define opposite sides of the main body 323, which may be perpendicular to the first and second cutting faces 331, 332. The first and second side faces 321, 322 may be arranged normal to a direction parallel to the rotational axis 311. At least one of the first and second cutting faces 331, 332 may comprise a recess 334 extending at least partially along the radial extent of the cutting face. The recess 334 defines a first cutting surface 333a and a second cutting surface 333b of the or each of the first and second cutting faces 331, 332. The or each first cutting surface 333a is located on the first side face 321 of the blade 320, and the or each second cutting surface 333b is located on the second side face 322 of blade 320. In this way, the recess 334 provides for two cutting surfaces on the or each cutting face 331, 332.
The rotatable blade 320 may further comprise a tip portion 338. The tip portion 338 may be arcuate between the first and second cutting faces 331, 332. The tip portion 338 may provide a substantially triangular portion, which may be truncated, between the first and second side faces 321, 322. The tip portion 338 may define a third cutting surface 333c. In this way, the combination of the tip portion 338 and the recess 334 results in a blade 320 having at least four cutting surfaces, e.g. first and second cutting surfaces 333a, 333b defined by the recess on one of the first and second cutting faces 331, 332, and the third cutting surface 333c at the tip portion 338. In arrangements where the recess 334 is present along both the first and second cutting faces 331, 332, it will be understood that five cutting surfaces may be present, e.g. first and second cutting surfaces 333a, 333b defined by the recess on each of the first and second cutting faces 331, 332, and the third cutting surface 333c at the tip portion 338.
The cutting surfaces 333a, 333b, 333c may be defined by any suitable cutting means and any combination thereof, e.g. serrations, a sharp edge, a spiked arrangement or the like.
In the figures, the first cutting surface 333a and the second cutting surface 333b on each cutting face 331, 332 include a plurality of serrations. At least one cutting face 331, 332 may comprise a plurality of serrations comprising a first set of serrations 333a which may define part of the first side face 321 and a second set of serrations 333b which may define part of the second side face 322. The first and second sets of serrations 333a, 333b can be disposed on opposite sides of a cutting face 331, 332. In this way, the sets of serrations 333a, 333b can be provided on the rotatable blade 320 at different positions along the rotational axis.
In the arrangement shown, the recess 334 provides a part-cylindrical surface which extends between the first set of serrations 333a and the second set of serrations 333b. The first and second set of serrations 333a, 333b may be scalloped. At least one serration of the first and/or second set of serrations 333a, 333b may be substantially pyramidal. In this way, at least one serration may have a three-dimensional structure defined by four surfaces converging at a vertex. One surface of the pyramid structure may be coplanar with the first and/or second side face 321, 322.
As shown in
A width of the main body between the first and second cutting faces 331, 332 may taper away from the rotational axis 311. In the illustrated arrangement, the first side face 321 defines a first width W1 perpendicular to the centreline 329 between the first cutting face 331 and the second cutting face 332. The first side face 321 also has a second width W2 perpendicular to the centreline 329 between the first cutting face 331 and the second cutting face 332 at a position further from the rotational axis 311 than the first width W1. The first width W1 may be greater than the second width W2. The width of the main body 323 may decrease linearly with increased radial distance from the rotational axis 311.
The lower fixed blade array 360 may comprise four lower fixed blades 361, preferably at least eight, preferably at least twelve, preferably at least 16 lower fixed blades 361. In the arrangement shown in
The lower fixed blades 361 may comprise a cutting face 362 which may be arranged in a similar manner to the cutting faces 331, 332 of the rotatable blade 320 and may have a similar arrangement of recesses and/or cutting surfaces and/or serrations. In the arrangement shown, the first lower fixed blade 361a defines an end of the lower fixed blade array 360 and its cutting faces may only define a first set of serrations, configured to co-operate with a set of serrations on the first rotatable blade 320a during rotation thereof. However, the other lower fixed blades 361b-361d may comprise two sets of serrations similarly to the rotatable blades 320.
The lower fixed blade array 360 may comprise a support structure at a base thereof configured to be connected to the waste processing vessel 120, and a support structure may include spacers 367 configured to separate adjacent lower fixed blades 361. The lower fixed blades 361 may comprise a substantially triangular portion, which may be truncated by a tip portion 365. The tip portion 365 may be provided on an upper end of a lower fixed blade 361 and may comprise a concave shape corresponding to an outer surface of the shaft 312. Although not shown in
At least one of the first and second end regions 341a, 341b may comprise a cutting face which may have a cutting region such as a knife edge 342. The knife edge 342 can be configured to face in a substantially upward direction with respect to the waste processing vessel 120 and can be configured to co-operate with a rotating blade 320 in order to cut waste. The knife edge 342 labelled in
As shown in
With reference to
By-products of the waste preparation processes may need to be rendered safe before being safely disposed of. The inventors have identified particular areas for improvement in the processing of waste, in particular contaminated, hazardous or biohazardous waste and the handling of by-products such as effluent from such processes.
The methods of treating waste described herein above may further comprise an additional step of adding a neutralising agent (also referred to as neutralisation). As used herein, the term “neutralisation” or “neutralisation process” takes its usual meaning in the art and relates to the chemical reaction involving an acid and a base to form a salt and water and indicates a state of equilibrium between acidity and alkalinity. A neutralisation reaction will typically have a neutral pH (i.e. proximate to a pH of 7). The exact pH value will often be dependent on the temperature of the solution in question.
The additional step of adding a neutralising agent may follow deactivation of the blade arrangement after the pre-determined cycle time. It may be the case that the waste and treatment fluid are neutralised prior to emptying the waste processing vessel. It may be the case that the treatment fluid is neutralised once it has been emptied from the waste processing vessel.
Neutralisation may comprise addition of a neutralising agent. After completion of the waste processing operation, the treatment fluid is not always suitable for direct discharge into a municipal sewer. For instance, where the treatment fluid comprises a solution comprising a disinfectant and a diluent as described herein (also referred to herein as a disinfectant solution), the pH may be in the range of from about 2 to about 6. As such, it may be too acidic for direct discharge into a municipal sewer, risking corrosion of the sewer walls, and the production of unwanted gaseous by-products within the sewer.
As used herein, the term “neutralising agent” relates to a chemical agent that is capable of adjusting the pH of the treatment fluid as described herein towards a neutral pH. It may be the case that the neutralisation agent is capable of adjusting the pH of the treatment fluid to a pH in the range of from about 6 to about 10, often about 6 to about 9.5, often about 6 to about 8, often about 6.5 to about 7.5. The pH of the treatment fluid before neutralisation with the neutralising agent may be in the range of from about 2 to about 6. The pH of the treatment fluid before neutralisation with the neutralising agent may be in the range of from about 2 to about 4. Where the treatment fluid is acidic, for example when peracetic acid is used as part of the liquid treatment process, then the neutralising agent serves to increase the pH of the acidic treatment fluid.
The pH of the treatment fluid following neutralisation with the neutralising agent as defined herein may be in the range of from about 4 to about 10. It may be the case that the pH of the treatment fluid following neutralisation with the neutralising agent is in the range of from about 6 to about 10. It may be the case that the pH of the treatment fluid following neutralisation with the neutralising agent is in the range of from about 6 to about 9.5. It may be the case that the pH of the treatment fluid following neutralisation with the neutralising agent as defined herein is in the range of from about 6 to about 8. It may be the case that the pH of the treatment fluid following neutralisation with the neutralising agent as defined herein is in the range of from about 6.5 to about 7.5. It may be the case that the pH of the treatment fluid following neutralisation with the neutralising agent as defined herein is proximate to 7. Such pH values allow for the treatment fluid to be directly discharged into a municipal sewer, minimising the risk of corrosion of the sewer walls, and the production of unwanted gaseous by-products within the sewer.
The pH of the neutralising agent may be in the range of from about 9 to about 14. The neutralising agent may comprise a strong base, a weak base, or a combination thereof.
The neutralising agent may comprise a strong base. The strong base may comprise a group I metal hydroxide, a group II metal hydroxide, or combinations thereof. The strong base may comprise lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, rubidium hydroxide, strontium hydroxide, cesium hydroxide, barium hydroxide, or a combination thereof. The strong base may comprise sodium hydroxide, potassium hydroxide, calcium hydroxide, or a combination thereof. The strong base may comprise sodium hydroxide. Strong bases as described herein provide for effective and rapid neutralisation of an acidic treatment fluid (as those described herein), resulting in a treatment fluid that is suitable for immediate discharge directly to a municipal sewer. In addition, strong acids will nullify the biocidal effect of the treatment fluid described herein. Eliminating the biocidal effect of the treatment fluid prevents any detrimental impact to the environment, and the production of unwanted gaseous by-products within the sewer.
The neutralising agent may comprise a weak base. The weak base may comprise any weak base wherein the solubility of said weak base is not impacted by temperature. Weak bases of this nature are advantageous as the neutralising agent will not easily fall out of solution if stored for long periods of time in cool storage conditions prior to use in methods as described herein.
The weak base may comprise a metal carbonate, a metal hydroxide, or a combination thereof. Examples of weak base include, but are not limited to, sodium carbonate, potassium carbonate, calcium carbonate, magnesium hydroxide, ferric hydroxide, or a combination thereof.
The neutralising agent may comprise sodium carbonate, potassium carbonate, calcium carbonate, or a combination thereof. The neutralising agent may comprise potassium carbonate. The reaction of an acid with a metal carbonate produces a salt, carbon dioxide, and water, meaning that a neutralising agent comprising a metal carbonate not only raises the pH of the treatment fluid described herein, such that it is suitable for immediate discharge directly to a municipal sewer, but also removes the biocidal effect of the treatment fluid described herein. Reducing the biocidal effect of the treatment fluid minimises the risk of corrosion of the sewer walls, and the production of unwanted gaseous by-products within the sewer.
When the neutralising agent comprises a strong base, the pH range of the neutralising agent may often be in the range of from about 12 to about 14. When the neutralising agent comprises a weak base, the pH range of the neutralising agent may often be in the range of from 9 to about 12.
The neutralising agent may be in the form of a solution or a suspension. As above, the term “solution” relates to liquid mixture in which the minor component(s) (I.e., the neutralising agent) is uniformly distributed throughout the major component (I.e., the diluent). The neutralising agent in the form of a solution may also be referred to as the neutralising solution. As above, the term “suspension” relates to a heterogeneous mixture of a liquid (i.e., the diluent) that contains solid particles (i.e., the neutralising agent) sufficiently large for sedimentation. The neutralising agent in the form of a suspension may also be referred to as a neutralising suspension. The diluent of the solution or suspension may comprise, consist essentially of or preferably consist of water.
The concentration of the neutralising solution or neutralising suspension may be in the range of from about 15% to about 30% by weight of the neutralising agent. The concentration of the neutralising solution or neutralising suspension may be in the range of from about 18% to about 23% by weight of the neutralising agent. It may be the case that the concentration of the neutralising solution or neutralising suspension is at least 20% by weight of the neutralising agent. It may be the case that the concentration of the neutralising solution or neutralising suspension is at least 21% by weight of the neutralising agent. It may be the case that the concentration of the neutralising solution or neutralising suspension is at least 22% by weight of the neutralising agent. It may be the case that the concentration of the neutralising solution or neutralising suspension is at least 23% by weight of the neutralising agent.
It may be the case that the neutralising solution or neutralising suspension is present in the range of from about 100 millilitres to about 600 millilitres. It may be the case that the neutralising solution or neutralising suspension is present in the range of from about 200 millilitres to about 500 millilitres.
The neutralising solution or neutralising suspension may be present in approximately the same volume as the disinfectant agent present in the disinfectant solution. For example, in instances where approximately 600 millilitres of disinfectant comprising peracetic acid and hydrogen peroxide was present in the disinfectant solution, approximately 600 millilitres of neutralising solution or neutralising suspension may be used. As used herein, the term “approximately” includes +/−10% of the volume of disinfectant and/or neutralising solution/neutralising suspension.
The neutralising solution or neutralising suspension may be provided via any of the first 1510 second 1520, and/or third 1530 fluid delivery means, which may form a liquid delivery system. It may be the case that at least some of the total volume of the diluent is provided by the second fluid delivery means. Alternatively, it may be the case that the neutralising solution or neutralising suspension is provided in a ‘pre-mixed’ state via only one fluid delivery means into the waste processing vessel 120 (e.g., either the first fluid delivery means, or the second, or the third, fluid delivery means).
In one example, in a first step, the neutralising agent and a portion of the total volume of diluent may be provided to the waste processing vessel 120 via the first fluid delivery means 1510. A second component, such as the remaining volume of diluent, may be delivered to the waste processing vessel via the second fluid delivery means 1520 to achieve a desired mixture with desired relative concentrations of the neutralising solution or neutralising suspension. Alternatively, the neutralising agent and total volume of diluent may be added to the waste processing vessel in a single step via the first, the second fluid delivery means, or the third fluid delivery means.
In one example, the neutralising solution or neutralising suspension may be provided in a ‘pre-mixed’ state via a fluid delivery means, which may be any one of the first second or third fluid delivery means. Alternatively, in a first step, the neutralising agent and a portion of the total volume of diluent may be provided to the waste processing vessel 120 via the third fluid delivery means. A second component, such as the remaining volume of diluent, may be delivered to the waste processing vessel via the second fluid delivery means 1520 to achieve a desired mixture with desired relative concentrations of the neutralising solution or neutralising suspension.
The neutralising agent may be in the form of a powder. As above, the term “powder” relates to a solid substance of fine, loose particles. The powder may be obtained using any known techniques, such as pulverisation, grinding, crushing, or disintegration. The particles may have a particle size in the range of from about 5 μm to about 500 μm. Particle size analysis of the powder can be determined using any known technique, such as dynamic image analysis (DIA), static laser light scattering, dynamic light scattering (DLS), sieve analysis, or by visual analysis of Transmission Electron Microscopy (TEM) or Scanning Electron Microscopy (SEM) images.
The neutralising agent may be in the form of a tablet. As above, the term “tablet” relates to a solid substance, which is often initially formed from a powder, that has been pressed or compacted into a solid dosage form. The tablet may have a wide range of geometries including, but not limited to, spherical, cubic, prismatic, pentagonal, hexagonal, heptagonal, or octagonal. The geometries will often be mathematically imperfect, such that they may be “substantially” of a given geometry. As used herein, regarding these geometries, the term “substantially” can be taken to mean clearly recognisable as a given geometry (for instance spherical), but not mathematically of that geometry (e.g., not a perfect sphere). This could include elongation along one axis by, perhaps, ±20% or ±10%, maybe in the range 20% or 10% to 1%.
When the neutralising agent is administered as a tablet or as a powder, it may be the case that, following completion of the waste shredding and liquid treatment process, the waste processing vessel 120 is orientated in the first position, in which the neutralising agent may be loaded into the waste processing vessel 120. This may include orienting the waste receiving opening 1270 of the waste processing vessel 120 towards a loading position and may include arranging the waste receiving opening 1270 towards the loading hatch 160 to enable a user to load the neutralising agent in the form of a tablet or a powder through the loading hatch 160 into the waste processing vessel 120 in the direction of arrow 1601. This can be seen in
Once the neutralisation agent has been added (either in the form of a tablet or powder, or in the form of a solution or suspension as described above), the rotatable blade arrangement may be rotated so as to carry out a mixing operation, to mix the shredded waste and the treatment fluid with the neutralising agent, and optional diluent, in the bottom of the waste processing vessel 120. Rotation of the blade arrangement allows for more efficient mixing of the neutralising agent throughout the waste and treatment fluid, resulting in a more efficient neutralisation step.
The blade arrangement may be rotated for a period of time in the range of from about thirty seconds to about 10 minutes. The blade arrangement may be rotated for a period of time in the range of from about 1 minute to about 8 minutes.
It may be the case that the neutralising agent is added to the treatment fluid once it has been emptied from the waste processing vessel.
It may be the case that the treatment fluid is separated from the shredded waste and emptied into a container. The container may be separate from or integral to the apparatus 1000 described herein. Alternatively, the container may be integrated into the apparatus described herein, such that it is fluidly connected to the waste processing vessel. The neutralising agent as described herein may be added to the treatment fluid in the container. In one example, wherein the neutralising agent is in the form of a solution or a suspension, it may be the case that the first, second and/or third fluid delivery means described above are redirected to the container to allow for delivery of the neutralising solution or neutralising suspension. In another example, the neutralising solution or neutralising suspension may be prepared outside the waste processing apparatus described herein and added to the container. Alternatively, the treatment fluid may be emptied from the waste processing vessel directly into an exit conduit for delivery into an external sink, such as an external container, a drain or a municipal sewer. It may be the case that the neutralising agent is added to the exit conduit at the same time as the treatment fluid. Alternatively, the conduit may comprise an inlet for addition of the neutralising agent as described herein.
One aspect of improvement identified is controlling a shredding device to move into an operating position (which may be one of several operating positions) in which combined shredding and cleaning and/or disinfection of contaminated or biohazardous waste can take place simultaneously within the shredding device.
In one aspect, there is provided a control system for a waste processing apparatus. The control system comprises a controller configured to perform one or more of the following features: control an actuator of the waste processing apparatus to move a shredding device of the waste processing apparatus into at least a shred position in which a vessel of the shredding device is able to hold liquid; control a fluid delivery device of the waste processing apparatus to deliver a treatment fluid into the vessel of the shredding device; and control the shredding device to perform a shredding function to shred waste within the vessel of the shredding device.
The controller may be configured to receive sensor data from a sensor associated with the vessel, and determine, based on the sensor data, that the vessel is in the shred position.
The controller may be configured to, in response to determining that the vessel is in the shred position, control a closure mechanism of the waste processing apparatus to move a closure arrangement to close the vessel of the shredding device.
The controller may be configured to, in response to determining that the vessel is in the shred position, control one or more locking mechanisms of the waste processing apparatus to lock the shredding device in the shred position.
The controller may be configured to control the actuator to move the shredding device into the shred position in response to receiving an input signal from a user input device of the waste processing apparatus.
The controller may be configured to control the fluid delivery device to deliver a predefined amount of treatment fluid into the vessel of the shredding device.
The waste processing apparatus may comprise a blade arrangement motor configured to drive a blade arrangement of the shredding device to perform the shredding function. The controller may be configured to control the blade arrangement motor to control the rotation speed and/or rotation direction of the blade arrangement.
The controller may be configured to control the blade arrangement motor to alternate between different rotation directions.
The controller may be configured to: control the blade arrangement motor to drive the blade arrangement in a first mode in which the blade arrangement rotates at a first speed, and in response to determining that the torque of the blade arrangement motor has decreased below a first threshold torque value, control the blade arrangement motor to drive the blade arrangement in a second mode in which the blade arrangement motor rotates at a second speed greater than the first speed.
The controller may be configured to control the shredding device to terminate the shredding function after a predefined shredding time has elapsed and/or in response to determining that a torque value of the shredding device is below a second threshold torque value.
The controller may be configured to: control the actuator to move the shredding device into an emptying position in which waste can be emptied out of the vessel of the shredding device, and control a conveying means to move said waste into a waste bin.
The controller may be configured to control a closure mechanism of the waste processing apparatus to move a closure arrangement to close the vessel of the shredding device.
The controller may be configured to control one or more locking mechanisms of the waste processing apparatus to lock the shredding device in the shred position.
The controller may be configured to initiate a neutralisation process. The neutralisation process may include activating the waste processing apparatus to deliver a neutralisation agent to the treatment fluid. The neutralisation process may include opening the vessel to allow a neutralisation agent to be added into the vessel. The neutralisation process may include controlling a fluid delivery device so as to deliver a neutralising agent into the vessel. The controller may be configured to control the fluid delivery device to deliver the neutralising agent into the vessel after terminating the shredding function of the shredding device. The neutralisation process may include delivering a neutralising agent to the treatment fluid outside of the vessel.
The controller may be configured to permit the waste processing apparatus to perform a waste processing operation in response to verifying one or more of the following conditions: a user has entered valid credentials for operating the waste processing apparatus; a water pressure of a water supply for the waste processing apparatus is at least a minimum pressure value; and a level of treatment fluid in a treatment fluid container of the waste processing apparatus is sufficient.
The controller may be configured to control the shredding device to perform the shredding function in response to verifying one or more of the following conditions: a loading hatch of the waste processing apparatus is closed; the shredding device is in the shred position; the vessel of the shredding device is closed by a closure arrangement; the shredding device is locked in the shred position by one or more locking mechanisms; a predefined amount of treatment fluid has been added to the vessel; and a predefined amount of water has been added to the vessel.
The controller may comprise one or more processors.
In another aspect, there is provided a waste processing apparatus comprising one or more of the following features: a shredding device comprising a vessel for holding waste and treatment fluid during processing, wherein the shredding device is configured to perform a shredding function to shred waste within the vessel; an actuator configured to move the shredding device into a shred position in which the vessel is able to hold liquid; a fluid delivery device configured to deliver a treatment fluid into the vessel of the shredding device; and a control system as set out above. The controller of the control system is communicatively coupled to the shredding device, the actuator and the fluid delivery device.
The actuator may comprise a motor configured to rotate the shredding device into at least the shred position.
The fluid delivery device may comprise: a container for holding treatment fluid; and a pump configured to pump treatment fluid from the container into the vessel of the shredding device.
In another aspect, there is provided a method of controlling a waste processing apparatus. The method comprises one or more of the following features: controlling an actuator of the waste processing apparatus to move a shredding device of the waste processing apparatus into a position in which the shredding device is able to hold liquid; controlling a fluid delivery device of the waste processing apparatus to deliver a treatment fluid into the shredding device; and controlling the shredding device to perform a shredding function to shred waste within the shredding device.
In another aspect, there is provided a computer-readable medium comprising instructions which, when executed by a processor, cause the processor to perform one or more of the following features: control an actuator of a waste processing apparatus to move a shredding device of the waste processing apparatus into a position in which the shredding device is able to hold liquid; control a fluid delivery device of the waste processing apparatus to deliver a treatment fluid into the shredding device; and control the shredding device to perform a shredding function to shred waste within the shredding device.
The control system 400 may include a controller 410. The controller 410 may be configured to control the waste processing apparatus 1000 to perform any of the functions or processes described herein. The controller 410 may be configured to control the vessel motor 140 to move the vessel 120 into various positions, such as the positions described above with reference to
In some examples, the controller 410 may include a memory and one or more processors configured to execute instructions stored in the memory to perform control operations, such as moving the vessel 120 into a given position. In other examples, the controller 410 may be implemented using hardware. In some cases, the controller 410 may perform control operations based on a user input. Such a user input may be received from an input device of the waste processing apparatus 1000. Alternatively, or in addition, the controller 410 may perform control operations based on input received from an external system.
In the present example, the controller 410 is a programmable logic controller (PLC). The PLC 410 includes a processor 411 and a memory 412. The processor 411 may be configured to receive signals from input devices (such as sensors) and make decisions based on a program stored in the memory 412 to control devices such as the vessel motor 140. The memory 412 may store instructions that are executable by the processor 411 to perform any of the operations described herein.
The control system 400 may include a communication device 420 which enables communication between the controller 410 and various devices in the waste processing apparatus 1000, such as the vessel motor 140. In the present example, the communication device 420 is an ethernet switch. The communication device 420 may also allow for communication between the controller 410 and one or more external devices or systems. For example, the communication device 420 may be connected to a cloud data storage system via a router (not shown), and the controller 410 can send data to the cloud data storage system via the router. In some cases, the router may buffer the data locally and periodically send the data to the cloud data storage system. If an internet connection is not present, data may be buffered locally in the memory 412 until the communication device 420 can connect to the cloud data storage system again. The data can then uploaded to the cloud data storage system from the memory 412. Data stored in the cloud data storage system may be used for (for example) online dashboards, automatic reporting or automatic service ticketing.
The waste processing apparatus 1000 may include at least one user input device 500 and at least one user output device 600. The input device 500 may allow the user to control various operations of the waste processing apparatus 1000. The input device may be, for example, a button (e.g. an emergency stop button) or a switch. The output device 600 may provide the user with information about the state of the waste processing apparatus, e.g. the current processing cycle that is in progress. The output device 600 may be, for example, a display device. In some examples, the input device 500 and the output device 600 may be implemented together in the same device, such as a touch screen display device.
The waste processing apparatus 1000 may include a power supply 700 which is configured to supply direct current (DC) power to electrical components of the waste processing apparatus 1000, such as the vessel motor 140 and the blade arrangement motor 150.
The controller 410 may be configured to determine the current position of the vessel 120 based on data from a sensor 190 which is associated with the vessel 120. The sensor 190 may be a position sensor, or may be an image sensor such as a camera. In the present example, the sensor 190 is a rotary encoder which outputs a signal indicating the absolute angular position of the shaft of the vessel motor 140. In examples where an image sensor is used, the controller 410 may analyse images received from the image sensor to determine the position of the vessel 120.
The controller 410 can determine that the vessel 120 is in a given position (e.g. the shred position) based on the data from the sensor 190. For example, if the position signal from the rotary encoder indicates that the angular position of the shaft is 5°, then the controller 410 may determine that the vessel 120 is in the shred position. Data specifying the correspondence between different angular positions and different operational positions of the vessel 120 may be stored in the memory 412.
The controller 410 may control the closure mechanism 130 and/or the locking mechanisms 180 based on feedback from the sensor 190. In the present example, the controller 410 is configured to control the closure mechanism 130 to move the closure arrangement 170 into the closed position only when it has determined that the vessel 120 is in the shred position. Similarly, the controller 410 may be configured to control the locking mechanisms 180 to lock the vessel 120 in position only when it has determined that the vessel 120 is in the shred position. This reduces the chance of errors occurring during the engagement of the closure arrangement 170 and/or the locking mechanisms 180. In other examples, the controller 410 may control the closure arrangement 170 and/or the locking mechanisms 180 without relying on feedback from the sensor 190, or the sensor 190 may be omitted altogether.
The controller 410 may be configured to control the fluid delivery apparatus 1500 to deliver one or more fluids into the vessel 120. The controller 410 may be configured to control the fluid delivery apparatus 1500 to deliver predefined amounts of the one or more fluids into the vessel 120 or more generally to the treatment fluid. The amount(s) of fluid(s) delivered into the vessel 120 may be determined by the controller 410 based on feedback from a flowmeter, e.g. flowmeter 1515.
In the present example, controller 410 is configured to control the first fluid delivery means 1510 of the fluid delivery apparatus 1500 to deliver treatment fluid into the chamber 1201 of the vessel 120. In the present example, the controller 410 is configured to control the first fluid delivery means 1510 of the fluid delivery apparatus 1500 to deliver treatment fluid into the chamber 1201 of the vessel 120 only when it has determined that the vessel 120 is locked in position and the closure arrangement 170 is covering the vessel 120. In the present example, the controller 410 is configured to control the treatment fluid pumping means 1513 so as to deliver a predefined amount of the treatment fluid into the chamber 1201, based on feedback from the flowmeter 1515. The predefined amount of treatment fluid may be any of the amounts set out herein.
In the present example, the controller 410 is also configured to control the second fluid delivery means 1520 so as to deliver a predefined amount of diluent (which may be water) into the chamber 1201, based on feedback from the flowmeter 1515. The predefined amount of diluent may be any of the amounts set out herein. This results in the liquid mixture in the chamber 1201 having a particular desired concentration of treatment fluid, which may be any of the concentrations set out herein. Data defining the predefined amounts of treatment fluid and/or diluent may be stored in the memory 412 of the controller 410.
In some examples, the controller 410 may be configured to initiate a neutralisation process. The neutralisation process may include activating the waste processing apparatus 1000 to deliver a neutralisation agent to the treatment fluid. The neutralisation process may include controlling the closure mechanism 130 to open the vessel 120 to allow a neutralisation agent to be added into the chamber 1201, or alternatively may include controlling any one of the first to third fluid delivery means 1510, 1520, 1530 so as to deliver a neutralising agent into the chamber 1201. The controller 410 may be configured to control one of the first to third fluid delivery means 1510, 1520, 1530 to deliver the neutralising agent into the chamber 1201 after terminating the shredding function of the shredding device. Alternatively, or in addition, the neutralisation process may include delivering neutralising agent to the treatment fluid outside of the vessel 120. For example, the treatment fluid may be separated from the shredded waste and collected in a container or conduit. An example of such a conduit may be a pipe, tube or channel for directing fluid away from the waste processing apparatus 1000 towards, for example, a drain or other external sink. The neutralisation process may include adding the neutralisation agent to the treatment fluid in the container or conduit after it has been separated from the shredded waste. A predefined amount of neutralising agent may be used for the neutralisation process. The predefined amount may be measured based on feedback from a flowmeter. The predefined amount of neutralising agent may be any of the amounts set out herein. Data defining the predefined amount of neutralising agent may be stored in the memory 412 of the controller 410.
The controller 410 may be configured to control the blade arrangement motor 150 of the shredding device to rotate the blade arrangement 300 within the vessel 120, in particular when the treatment fluid is present in the chamber 1201. In the present example, the controller 410 is configured to control the blade arrangement motor 150 to rotate the blade arrangement 300 within the vessel 120 only when it has determined that the correct amount of treatment fluid (and in the present case, the correct amount of water) has been added to the chamber 1201.
During operation of the blade arrangement motor 150, the blade arrangement motor 150 may have a given torque, related to the resistance to the blade motion of the waste it is shredding, and the controller 410 may be able to determine a value of the torque by various means. For example, the controller 410 may estimate a torque value of the blade arrangement motor 150 based on the current being used by the blade arrangement motor 150, or may receive a torque value of the blade arrangement motor 150 from a torque sensor (not shown).
The controller 410 can control the blade arrangement motor 150 so as to control, for example, the rotation speed and/or rotation direction of the blade arrangement 300. The controller 410 may select the rotation speed of the blade arrangement 300 based on the torque of the blade arrangement motor 150. For example, the torque of the blade arrangement motor 150 may be relatively high at the beginning of a waste processing cycle due to the high force required to shred the waste. At this stage, the controller 410 may control the blade arrangement motor 150 to rotate the blade arrangement 300 at a low speed, e.g. 10-20 rotations per minute (RPM). As the waste is shredded, the force required to shred the waste decreases, and so the torque of the blade arrangement motor 150 decreases. In response to detecting that the torque of the blade arrangement motor has decreased below a threshold torque value, the controller 410 may increase the rotation speed of the blade arrangement motor 150, e.g. to 30-40 RPM. For example, if the controller 410 estimates the torque of the blade arrangement motor 150 based on the current being used by the blade arrangement motor 150, the controller may increase the rotation speed of the blade arrangement motor 150 in response to the current per phase falling below 10 Amps per phase. At low rotation speeds, smaller pieces of waste may escape the cutting action of the blades, whereas this is less likely at higher speeds. Driving the blade arrangement 300 at an increased speed thus helps to ensure that the waste is shredded to a small particle size. Driving the blade arrangement 300 at an increased speed also helps to effectively mix the waste and the treatment fluid.
In some examples, the controller 410 may control the blade arrangement motor 150 to alternate between rotation in different directions, so as to rotate the blade arrangement 300 in different rotational directions. This allows the blade arrangement 300 to shred waste in both rotational directions. This reduces the force required to achieve complete shredding of the waste compared to shredding in a single rotational direction only, thereby reducing the power required to drive the blade arrangement 300. The rotation direction of the blade arrangement motor 150 may be adjusted in combination with adjusting the rotation speed. The controller 410 may control the blade arrangement motor 150 to periodically alternate between rotation in different directions. Reversing the direction of the blade arrangement 300 periodically has been found to reduce the incidence of waste collecting in a single area of the vessel 120, and may facilitate more efficient shredding. Alternatively, or in addition, the controller 410 may control the blade arrangement motor 150 to change rotation direction in response to determining that the torque value of the blade arrangement motor 150 has exceeded a maximum value (e.g. the current being used by the blade arrangement motor 150 has exceeded a maximum current value, or the torque measured by a torque sensor has exceeded a maximum value). This may, for instance, indicate that the blade arrangement 300 has encountered a hard object, e.g. a piece of steel, which it cannot immediately shred. Reversing the rotation direction may allow for the object to enter the blade arrangement 300 in a different orientation which allows for easier shredding.
In some examples, the controller 410 is configured to control the blade arrangement motor 150 to rotate the blade arrangement 300 for a predefined shredding time, i.e. the blade arrangement 300 stops rotating after the predefined shredding time has elapsed. Data defining this predefined shredding time may be stored in the memory 412 of the controller 410. Alternatively, or in addition, the controller 410 may be configured to control the blade arrangement motor 150 to rotate the blade arrangement until the controller 410 determines that the torque of the blade arrangement motor 150 has fallen below a minimum torque value (e.g. the current being used by the blade arrangement motor 150 has fallen below a minimum current value, such as 6 Amps per phase, or the torque measured by a torque sensor has fallen below a minimum value). Data defining this minimum torque value may be stored in the memory 412 of the controller 410.
In examples where a neutralising agent is added to the vessel 120, the controller 410 may be configured to control the blade arrangement motor 150 to rotate the blade arrangement 300 for a predefined period of time to mix the shredded waste and the treatment fluid with the neutralising agent, and optional diluent, in the bottom of the waste processing vessel 120. The controller 410 may control the blade arrangement motor 150 to rotate the blade arrangement 300 for a period of time in the range of from about thirty seconds to about 10 minutes, or from about 1 minute to about 8 minutes.
An example of a method of controlling the waste processing apparatus 1000 is shown in
Example operating cycles of the waste processing apparatus 1000 will now be described.
In some circumstances, the controller 410 may verify that certain operating conditions are met before commencing these cycles. If at least one of these operations conditions is not met, the controller 410 may not begin processing. For example, the controller 410 may verify that the water pressure is at least a minimum pressure value (in this case, 1 bar), based on feedback from a water pressure sensor (not shown). Alternatively, or in addition, the controller 410 may verify that the level of treatment fluid in the container of the fluid delivery apparatus is at least a minimum volume (in this case, 0.1 litres), based on feedback from a level sensor (not shown). In some examples, the user may need to present valid security credentials (e.g. via the input device 500) to operate the waste processing apparatus 1000, and the controller 410 will not begin processing until such credentials are received
An example of a waste cycle process is shown in
The controller 410 determines that the loading hatch 160 has been closed, and controls the touch screen display to change the colour of a button “Lock door and run” to grey. In the present example, in response to receiving a selection of the button “Lock door and run” from the touch screen display, the controller 410 locks the loading hatch 160 and controls the vessel motor 140 to rotate the vessel to the shred position (S1002). The rotational position of the vessel in the fill position may be vertical (i.e. 0 degrees), or close to vertical. In the present case, the rotational position of the vessel 120 in the shred position is 5°.
The controller 410 verifies that the vessel 120 is in the shred position based on feedback from the vessel position sensor 190. In response to verifying that the vessel 120 is in the shred position, the controller 410 controls the lid closure mechanism 130 to lower the lid 170 to cover the vessel 120 (S1003). The controller 410 also controls the linear actuators of the locking mechanisms 180 to move the locking pins 182 into their locking positions, so as to lock the vessel 120 to the chassis 1001 (S1004). In the present example, steps S403 and S404 are performed simultaneously. In other examples, these steps may be performed sequentially.
The controller 410 receives position signals from the lid actuator 130 and the locking mechanisms 180, and determines whether the lid 170 and the locking pins 182 are in the correct positions based on these signals. Once the controller 410 has verified that both the lid 170 and the locking pins 182 are in their positions, the controller 410 controls the fluid delivery apparatus 1500 to deliver treatment fluid (and in the present case, water) into the vessel (S1005). The controller 410 may verify that the correct amounts of treatment fluid and water have been delivered into the vessel 120, based on feedback from flow meters.
The controller 410 controls the blade arrangement motor 150 to rotate the blade arrangement 300 to perform the shredding function (S1006). In the present example, the controller 410 controls the blade arrangement motor 150 to rotate the blade arrangement 300 of the shredding device to perform the shredding function for a predefined shredding time (in the present case, 12 minutes). The controller 410 may control the blade arrangement motor 150 to alternately rotate in forward and reverse directions, thereby alternating the rotating direction of the shredding blades.
Once the controller 410 has determined that the shredding time has elapsed, and that the blade arrangement 300 meets little or no resistance (based on the torque of the blade arrangement motor 150), the controller 410 stops the blade arrangement motor 150, thereby terminating the shredding function (S1007). In the present example, the resistance encountered by the blade arrangement 300 is inferred from the current being consumed by the blade arrangement motor 150. As an example, the current of the blade arrangement motor 150 under load conditions may vary between a first current level, such as 6 Amps per phase and a second current level, such as 13 Amps per phase. In this case, if the shredding function has been performed for the shredding time period, such as 12 minutes and the current being consumed by the blade arrangement motor 150 is less than a first current level, such as 6 Amps per phase, then the controller 410 may stop the blade arrangement motor 150.
The controller 410 then controls the linear actuators of the locking pin mechanisms 180 to move to the unlock positions to unlock the vessel (S1008), and controls the lid actuator 130 to raise the vessel lid 170 (S1009).
The controller 410 then controls the vessel motor 140 to rotate the vessel 120 into the emptying position in which waste can be evacuated from the vessel 120 (S1010). In the present case, the rotational position of the vessel 120 in the emptying position is 180° with respect to vertical. The controller 410 can verify that the vessel 120 is in the emptying position based on feedback from the vessel position sensor 190, in the same way as for the fill position and the shred position.
Since the opening 1270 of the vessel 120 is uncovered in the emptying position, the shredded waste falls out of the vessel 120 onto a conveying means (e.g. an auger). The controller 120 may also control the blade arrangement motor 150 to rotate the blade arrangement 300 to help move the shredded waste out of the vessel 120. The controller 410 controls the conveying means to transport the shredded waste to a waste bin (S1011). Once a predefined time has elapsed, the controller 410 controls the vessel motor 140 to rotate the vessel 120 to the shredding position (S1012).
In some examples, a wash cycle is carried out once the vessel 120 has returned to the shredding position. An example of a wash cycle will now be described. With the vessel 120 in the shredding position, the controller 410 controls the locking mechanisms 180 to engage the locking pins 182 and controls the lid closure mechanism 130 to lower the lid 170 to cover the vessel 120. The controller 410 then controls the second fluid delivery means 1520 to deliver water into the vessel 120. The controller 410 also controls the blade arrangement motor 150 to rotate the blade arrangement 300 for a predefined cleaning time (in the present case, 60 seconds). This helps to clean the vessel 120. After the predefined time has elapsed, the controller 410 controls the locking mechanisms 180 to retract the locking pins 182 and controls the lid closure mechanism 130 to raise the lid 170. The controller 410 controls the vessel motor 140 to rotate the vessel 120 to the emptying position, where the water will be drained out of the vessel 120. The controller 410 controls the vessel motor 140 to return the vessel 120 to the shred position, controls the locking pin mechanisms 180 to engage the locking pins 182 and controls the lid 170 to cover the vessel 120. The ends the wash cycle.
An example of a validation cycle process is shown in
The controller 410 can determine that the loading hatch 160 has been closed and controls the touch screen display to change the button “Manifold fitted” to appear grey. In response to receiving a selection of the button “Manifold fitted” from the touch screen display, the controller 410 locks the loading hatch 160. The controller 410 controls the vessel motor 140 to rotate the vessel 120 to the fill position (S1102). The controller 410 can determine that the vessel is in the fill position based on feedback from the vessel position sensor 190. In the present example, the controller 410 controls the touch screen display to make the button “Open door” appear grey, and in response to the receiving a selection of the button “Open door” from the touch screen display, unlocks the loading hatch 160. The operator opens the loading hatch 160 and loads the vessel with the waste to be treated, then closes the loading hatch 160.
The controller 410 determines that the loading hatch 160 has been closed, and controls the touch screen display to change the colour of the button “Lock door and run” to grey. In response to receiving a selection of the button “Lock door and run” from the touch screen display, the controller 410 locks the loading hatch 160. The controller 410 controls the vessel motor 140 to rotate the vessel 120 to the shred position (S1103).
The controller 410 verifies that the vessel 120 is in the shred position based on feedback from the vessel position sensor 190. Once the controller 410 has verified that the vessel 120 is in the shred position, the controller 410 controls the lid closure mechanism 130 to lower the lid 170 to cover the vessel (S1104). The controller 410 also controls the linear actuators of the locking pin mechanisms 180 to move the locking pins 182 to lock the vessel 120 to the chassis 1001 (S1105). In the present example, these steps are performed simultaneously. In other examples, these steps may be performed sequentially.
The controller 410 receives position signals from the lid actuator and the locking pin mechanism 180, and determines whether the lid 170 and the locking pins 182 are in the correct positions based on these signals. Once the controller 410 has verified that both the lid 170 and the locking pins 182 are in their positions, the controller 410 controls the fluid delivery apparatus 1500 to deliver treatment fluid (and in the present case, water) into the vessel (S1106). The controller 410 may verify that the correct amounts of treatment fluid and water have been delivered into the vessel 120, based on feedback from flow meters.
The controller 410 controls the blade arrangement motor 150 to rotate the blade arrangement 300 to perform the shredding function (S1107). In the present example, the controller 410 controls the blade arrangement motor 150 to rotate the blade arrangement 300 to perform the shredding function for a predefined shredding time (in the present case, 12 minutes). As with the waste cycle, the controller 410 may control the blade arrangement motor 150 to alternately rotate in forward and reverse directions, thereby alternating the rotating direction of the shredding blades.
Once the controller 410 has determined that the predefined shredding time has elapsed, and that the blade arrangement 300 meets little or no resistance (based on the torque of the blade arrangement motor 150), the controller 410 stops the blade arrangement motor 150 to terminate the shredding function (S1108). In the present example, the resistance encountered by the blade arrangement 300 is inferred from the current being consumed by the blade arrangement motor 150. As an example, the current of the blade arrangement motor 150 under load conditions may vary between a first current level, such as 6 Amps and a second current level, such as 13 Amps per phase. In this case, if the shredding function has been performed for the shredding time period, such as 12 minutes, and the resistance, which may be indicated by a current being consumed by the blade arrangement motor 150, is less than a first current level, such as 6 Amps per phase, then the controller 410 may stop the blade arrangement motor 150.
The controller 410 then controls the linear actuators of the locking pin devices to move to the unlock positions to unlock the vessel 120 (S1109), and controls the lid closure mechanism 130 to raise the vessel lid 170 (S1110).
The controller 410 then controls the vessel motor 140 to rotate the vessel 120 into the emptying position (S1111). The controller 410 can verify that the vessel 120 is in the emptying position based on feedback from the vessel position sensor 190, in the same way as for the fill position and the shred position. The shredded waste falls from the vessel onto the auger. The controller 410 controls the conveying means to transport the shredded waste to the waste bin (S1112).
With the vessel 120 in the emptying position, the controller 410 controls the touch screen display to change the button “Test strip removed” to grey. The controller 410 then unlocks the loading hatch 160. The operator opens the loading hatch 160 and removes the validation plugs, and replaces the validation plugs with blanking plates. In response to receiving a selection of the “Test strip removed button” from the touch screen display, the controller 410 locks the loading hatch 160. In the present example, the operator presses these buttons on the touch screen display in this sequence: “Manifolds removed”, “Ports blanked”, “Fill door closed” and “Finish cycle”. Upon receiving these inputs from the touch screen display, the controller 410 controls the vessel motor 140 to rotate the vessel 120 to the shredding position (S1113).
In some examples, a wash cycle is carried out once the vessel 120 has returned to the shredding position. The wash cycle may be as described above in relation to the waste cycle.
An example of a reject cycle process is shown in
In the present example, in response to receiving a selection of a “Reject Cycle” button from the touch screen display, the controller 410 will control the display to present a reject cycle screen. The operator puts the reject bin into position, and plugs in a reject bin identifier plug into an identifier socket. The control determines that the reject bin is in place (S1201) once it registers that the reject identifier plug is in position. This verification step ensures that waste will only be emptied from the vessel 120 when the reject bin is in place, reducing the risk of waste being released into the surrounding environment.
The controller 410 controls the touch screen display to turn the button “Reject bin in position” grey. In response to receiving a selection of the “Reject bin in position” button from the touch screen display, the controller 410 controls the touch screen display to turn the button “Reject” grey. In response to receiving a selection of the “Reject” button”, the controller 410 controls the vessel motor 140 to rotate the vessel 120 to the emptying position (S1202). Waste is emptied from the vessel into the reject bin. The controller 410 may control the blade arrangement motor 150 to rotate for a predefined emptying time (e.g. 45 seconds) to help empty the vessel 120. Once the reject cycle has completed, the controller 410 will control the vessel motor 140 to rotate the vessel 120 to the shred position (S1203).
In some examples, a wash cycle is carried out once the vessel 120 has returned to the shredding position. The wash cycle may be as described above in relation to the waste cycle.
In various examples above, operation of the waste processing apparatus 1000 has been described as being controlled by a user. However, in alternative examples, the operation of the waste processing apparatus 1000 may be controlled by an external system (e.g. a testing or processing system which produces contaminated waste or biohazardous waste in use). Such automation further reduces that chances of users coming into contact with biohazardous waste, contaminants, or treatment fluids. In such cases, an automated loading device (e.g. a robotic arm, conveyor or other automated handling system or means) may remove waste from the testing system and load the waste into the waste processing vessel 120 of the waste processing apparatus 1000 without requiring human input. The waste processing apparatus 1000 may then process the waste according to a waste processing cycle and return the waste processing vessel 120 to the loading position so that it can accept another load of waste from the testing system.
Unless otherwise stated, each of the integers described may be used in combination with any other integer as would be understood by the person skilled in the art. Further, although all aspects of the disclosure preferably “comprise” the features described in relation to that aspect, it is specifically envisaged that they may “consist” or “consist essentially” of those features outlined in the claims. In addition, all terms, unless specifically defined herein, are intended to be given their commonly understood meaning in the art.
Further, in the discussion of the various examples, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, is to be construed as an implied statement that each intermediate value of said parameter, lying between the smaller and greater of the alternatives, is itself also disclosed as a possible value for the parameter.
In addition, unless otherwise stated, all numerical values appearing in this application are to be understood as being modified by the term “about”. Any means for providing a function in this disclosure may be provided in the form of an apparatus, device or system for performing that function, or configured to provide that function, including the examples specifically described.
Various modifications, whether by way of addition, deletion and/or substitution, may be made to all of the above-described aspects to provide further aspects, any and/or all of which are intended to be encompassed by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 23162487.5 | Mar 2023 | EP | regional |
