Patent Application
20100243575
The present invention relates, generally, to apparatuses, methods, and systems for separating liquids from solids, usable for filtration and treatment of sludge and other solid-liquid mixtures.
The term “sludge” is usable to refer to a variety of solid-liquid mixtures, including slurries, emulsions, or any similar mixture, such as sewage, industrial waste, or contaminated mud. A sludge can contain any number of liquid or solid components, and can have any ratio of liquid to solid, though typically, a sludge has somewhat more liquid than solid material contained therein. Due to the inherent properties of solid-liquid mixtures, many difficulties exist relating to their handling, treatment disposal, and analysis.
Environmental regulations require that prior to disposal of a sludge in a landfill, the water content of the sludge be reduced to an acceptable level. Additionally, a solid-liquid mixture containing a significant quantity of liquid is considerably heavier than a mixture from which some or all of the liquid has been removed, causing transport of the mixture to be difficult and cumbersome. Often, freight carriers and other transporters of a sludge, or similar solid-liquid mixture, assess costs based on the weight of the material transported.
To facilitate efficient and less expensive transport and disposal of solid-liquid mixtures, while complying with environmental regulations, various types of liquid-solid separators have been used to remove the liquid components of the mixture from the solid media. Additionally, the separation of solid-liquid mixtures has many noteworthy industrial applications where it is desirable to retain one or more solid or liquid components for treatment, analysis, processing, or use.
Generally, separation of a solid-liquid mixture is accomplished through filtration, using either vacuum drainage or gravitational drainage. Vacuum drainage requires use of an on-site pump to draw liquid through a filter, and typically necessitates use of a filtrate cavity that remains beneath the surface of the liquid throughout the filtering process. The force of the pump draws solid particles, as well as the liquid portion of the mixture, toward the filter, which can cause blockage of the filter, reducing the speed and efficacy of the separation process.
Gravitational drainage involves simply placing a solid-liquid mixture into a container having one or more filters therein and allowing gravity to pull the liquid through the filters while the solid media is retained. The solid-liquid mixture is normally flocculated using one or more suitable polymers prior to filtration, which facilitates the separation of the mixture. Often, a number of polymers are tested against a waste source or other source of the solid-liquid mixture to determine which polymer will be the most effective for flocculating the mixture. Since no vacuum pumping is required for gravitational drainage, it is not necessary to retain the filtrate cavity beneath the liquid level of the sludge. Filters extending throughout the entire height of the container can be used to maximize surface area for the separation process and minimize the potential for blockage of filters.
However, gravitational drainage is an extremely slow process, often requiring multiple days, or weeks, to separate a significant quantity of sludge. Additionally, due to uneven distribution of the sludge within a container, and uneven rates of drainage for differing portions of the sludge, it is common for large quantities of liquid to be retained in certain portions of the container for a significant length of time while other portions of the liquid are separated more rapidly.
A need exists for a system for separating a solid-liquid mixture having a controllable distribution system, oriented and configured to selectively provide the solid-liquid mixture to multiple discrete areas of a filtering vessel to promote uniform distribution and efficient filtration of the mixture.
A further need exists for a system for separating a solid-liquid mixture that enables observation of the separation process, as well as the condition and flow rate of water, polymer, and/or solid-liquid, so that the flow rate and distribution of the solid-liquid mixture within the container can be selectively modified based on the observation of the process.
A need also exists for a system for separating a solid-liquid mixture having one or more portholes, transparent mixers and tubes, or similar transparent and/or openable portions to enable monitoring of the mixtures and separation process and responsive control of the flow and distribution of the materials responsive to the monitoring.
Additionally, a need exists for an apparatus and system for separating a solid-liquid mixture that is portable, able to be transported to a variety of locations to receive and separate solid-liquid mixtures, and able to transport the separated components to a variety of disposal and/or treatment sites.
The present invention meets these needs.
An embodiment of the present invention relates to a system for separating liquids from solids. One or more tanks, or other sources containing a polymer solution are used to provide a mixture of one or more polymers and water, for flocculating a solid-liquid mixture. A number of polymers, known in the art, typically negatively charged polymers, are usable to flocculate a sludge or other solid-liquid mixture. Implementation of the present system can include testing a plurality of polymers against the solid-liquid mixture to be separated to determine which polymer or combination of polymers will provide the maximum effectiveness.
The polymer solution can transported and utilized on site, however in an embodiment of the invention, the solution can be formed on site by mixing one or more selected polymers with water from one or more public or private water sources, on site. The system can include one or more mixers, which in a preferred embodiment of the invention can include transparent sections of hose, tubing, and/or piping having one or more flow disruptors within. The disruption of flow causes the water and polymer to mix to form the solution, while the transparency of the mixers enables an operator to readily view the flow rate and/or condition of the polymer solution and directly or remotely adjust the flow of the polymer and/or the water responsive to the visual monitoring of the mixers. Any number of pumps, motors, and/or control valves can be directly or remotely actuated to control the flow of water, polymer, and/or polymer solution. Additionally, any number of inline flowmeters or other flowmeters can be used to monitor the flow rate of the polymer, the water, and/or the polymer solution.
The polymer solution source is placed in communication with one or more sources of sludge or a similar solid-liquid mixture, such that the combination and mixing of the polymer solution and the solid-liquid mixture flocculates the solid-liquid mixture to facilitate separation thereof. One or more mixers, motors, pumps, valves, or similar devices can be used to transport and combine the solid-liquid mixture and the polymer solution to promote flocculation.
The flocculated solid-liquid mixture is then flowed to a separation apparatus used to filter the mixture, separating the liquid and solid components. In an embodiment of the invention, one or more transparent sections of tube, pipe, and/or hose can be disposed between the polymer solution source, the solid-liquid mixture source, and the separation apparatus to enable visualization of the condition and flow rate of the flocculated solid-liquid mixture. Flow rates of the polymer solution and the solid-liquid mixture can be adjusted accordingly, responsive to the visual monitoring. Additionally, the flow rate of the flocculated solid-liquid mixture into the separation apparatus can also be monitored and controlled accordingly. As described previously, any number of pumps, motors, and/or control valves can be directly or remotely actuated to control the flow of the polymer solution, the solid-liquid mixture, and/or the flocculated solid-liquid mixture, and any number of inline flowmeters or other flowmeters can be used to monitor the flow rate of any of the materials.
Embodiments of the present invention also relate to a separation apparatus usable for separating the solid-liquid mixture, removing liquid components from solid components. The apparatus includes a tank having a floor and at least one exterior wall, defining a cavity for receiving the solid-liquid mixture. The tank can have any dimensions and any shape, depending on the quantity of material to be separated, the size and shape of the space available to accommodate the tank or any vehicles available to transport the tank, or other similar factors or considerations. Embodiments of the system can include simultaneous or sequential use of multiple separation apparatuses, when necessary.
In a preferred embodiment of the invention, the tank can have one or more interior walls, which can divide the tank into multiple cavities, providing an increased surface area for separation of a solid-liquid mixture, thereby improving the efficiency of the separation process.
A liquid-permeable filtration member is disposed over the floor, the exterior walls, the interior walls, if present, or combinations thereof, for retaining solid media in the cavity while permitting liquid from the solid-liquid mixture to pass through the filtration member. In an embodiment of the invention, the separated liquid can pass into an interior cavity beneath the filtration member for later collection or disposal. Any liquid-permeable filtration medium can be used, depending on the nature of the solid-liquid mixture to be separated. Usable filtration members can include a monofilament modified satin weave polyester filter material, having a 390 CFM, tensile strength ranging from 500 LB/In to 1820 LB/IN, and a particle retention of 330 microns. An interior space can exist between the filtration member and the exterior walls and/or the floor, usable to retain separated liquid.
The floor, exterior walls, and/or interior walls can include a support structure, which in an embodiment of the invention, can include a structure formed from expanded and/or perforated metal members having a significant amount of pore space to expedite the filtration process. Use of a support structure can enable the filtration member to withstand a greater weight of sludge in the tank and can define the interior space between the support structure and the exterior walls of the tank to collect the separated liquid.
An outlet can be in communication with the interior space for removing the liquid from the tank. The interior space between the filtration member and the exterior walls and/or floor of the tank can further contain one or more pipes, nozzles, or similar devices to spray water, or another liquid, toward the interior of the tank, to facilitate cleaning of the filtration media after use and emptying of the tank by loosening and washing away dried solid material.
The separation apparatus can include a controllable distribution system, having multiple inlets oriented such that each inlet provides the solid-liquid mixture to a differing discrete area of the cavity. Each inlet can be individually actuated, to enable the solid-liquid mixture to be selectively distributed to differing areas of the cavity. Through use of the controllable distribution system, an even, controlled, and efficient separation can be achieved by avoiding an accumulation of excess material in one or more areas of the tank. Conventional filtration vessels often suffer from areas within the vessel, especially proximate to the vessel's center or proximate to the inlet for receiving sludge, that filter more slowly and tend to accumulate excess sludge in absence of a controlled distribution system for evenly administering the solid-liquid mixture.
In an embodiment of the invention, one or more interior walls, if present, and/or one or more exterior walls of the tank can have a support structure mounted thereon, such as a catwalk, platform, or similar structure able to support the weight of an individual, for enabling visual observation of the cavity from above. Control means for the inlets of the controllable distribution system can be accessible from the support structure, enabling one or more individuals to selectively control the provision of the solid-liquid mixture into various discrete areas of the cavity based on observation performed from the support structure. Additionally, transparent mixers and/or tubes, hoses, or pipes, flowmeters, and similar equipment can be visualized from the support structure, and remote modifications to the flow rate of water, polymer, polymer solution, solid-liquid mixture, and/or flocculated solid-liquid mixture can be made responsive to visual observations performed from the support structure.
In a further embodiment of the invention, one or more of the exterior walls of the tank can have one or more exterior openings, such as portholes, having a transparent cover for enabling visual observation of the cavity through the exterior wall. Exterior openings can be used to facilitate an immediate and efficient determination of the level of solid-liquid mixture in the tank by an observer at the side of the tank. Use of openings in the exterior wall can also be useful in instances when the depth of the solid-liquid mixture in the tank is unclear when viewed from above.
The covers of the openings can be openable, for permitting access to the cavity to facilitate the entry and use of various cleaning devices, usable to remove solid media from the tank after the filtration and/or disposal processes are complete.
The tank and associated contents and equipment, as well as hoses, mixers, and/or other system components, can be mounted on or otherwise engaged with a transportable member, such as a trailer or a vehicle, enabling the present system to be transported to a variety of sites for collecting and separating solid-liquid mixtures, and to a variety of disposal sites, as needed. In addition to providing the present system with transportability, use of a transportable member can provide the present system with a desirable amount of elevation, which can facilitate access to outlets for recovering liquid removed from the solid-liquid mixture or for cleaning the tank, and can facilitate attachments between the tank and various treatment and/or mixing tanks, sludge sources, or other similar equipment.
Embodiments of the present invention also relate to a method for separating liquids from solids that includes providing a filtration vessel having multiple discrete areas, providing a solid-liquid mixture to at least one of the discrete areas while visually observing the filtration vessel, then selectively providing the solid-liquid mixture to at least one other discrete area based on the observation. Filtration of the solid-liquid mixture is thereby performed with improved efficiency when compared to conventional separation methods by ensuring optimal distribution of the solid-liquid mixture within the filtration vessel throughout the filtration process.
The solid-liquid mixture can be treated prior to introduction to the filtration vessel, such as by mixing with one or more polymers to promote flocculation, for improving the efficacy of the filtration process. The method can further include testing a plurality of polymers on the solid-liquid mixture to determine an optimal polymer or combination of polymers, which can be used to form the polymer solution.
The separated liquid can be discarded, or collected for treatment, use, analysis, or combinations thereof. The method can then include cleaning the filtration vessel and/or disposing of the remaining solid component. In an embodiment of the invention, cleaning of the remaining solid component can include providing water or another liquid to an interior space between a filtration member and the exterior walls of the filtration vessel.
In the detailed description of the embodiments of the invention presented below, reference is made to the accompanying drawings, in which:
Embodiments of the present invention are detailed below with reference to the listed Figures.
Before explaining the described and depicted embodiments of the invention in detail, it is to be understood that the present invention is not limited to the particular embodiments described and depicted and that the present invention can be practiced or carried out in various ways.
Referring now to
The separation apparatus includes a tank (10), which is defined by a floor (14), a first exterior wall (16), a second exterior wall (18) parallel to the first exterior wall (16), a third exterior wall (20), and a fourth exterior wall (21) parallel to the third exterior wall (20). The fourth exterior wall (21) is depicted being openable via one or more hinges, or similar movable connectors, to facilitate disposal of material within the tank (10) and to facilitate access to the tank (10) for cleaning.
In an embodiment of the invention, any individual exterior wall or multiple exterior walls of the tank (10) can be hinged or otherwise movable to enable the one or more walls to be opened, facilitating dumping of the tank (10) for disposal of the separated solid media, and for facilitating access to the tank (10) for cleaning any remaining solid media after the disposal process.
While
The tank (10) is also shown having an interior dividing wall (22) extending across the length of the tank (10), substantially parallel to the first and second exterior walls (16, 18). The interior dividing wall (22) divides the tank (10) to form two cavities: a first cavity (12) between the first exterior wall (16) and the interior dividing wall (22), and a second cavity (13) between the interior dividing wall (22) and the second exterior wall (18).
The floor (14), the first, second, and third exterior walls (16, 18, 20), and the interior dividing wall (22) are depicted as generally rigid frames of perforated metal having a liquid-permeable filtration media disposed thereon. In an embodiment, the fourth exterior wall (21) can also include a liquid-permeable filtration media. Depending on the requirements and nature of the separation operation, any or none of the exterior walls (16, 18, 20, 21) can have filtration media disposed thereon, or can lack filtration media.
While any liquid-permeable material having sufficient durability to withstand the weight of a solid-liquid mixture within the tank (10) can be used as a filtration member, in an embodiment of the invention, the filtration member can include a monofilament modified satin weave polyester filter material, having a 390 CFM, tensile strength ranging from 500 LB/In to 1820 LB/IN, and a particle retention of 330 microns.
The floor (14), any of the exterior walls (16, 18, 20, 21), and/or the interior dividing wall (22) can be formed from an expanded or perforated metal framework, having a porosity ranging from 50 percent to 86 percent, or more, providing sufficient support to the filtration member while enabling an optimal amount of liquid from a solid-liquid mixture to pass through both the filtration member and the support, facilitating rapid separation.
A fourth nozzle (29), a fifth nozzle (31), and a sixth nozzle (33) are shown similarly oriented over the second cavity (13). The fourth nozzle (29) is oriented to provide solid-liquid mixture to an area of the second cavity (13) proximate to the fourth exterior wall (21), the fifth nozzle (31) is oriented to provide solid-liquid mixture to the center of the second cavity (13), and the sixth nozzle (33) is oriented to provide solid-liquid mixture to the second cavity (13) proximate to the third exterior wall (20).
Each nozzle (28, 30, 32, 29, 31, 33) can individually or simultaneously provide varying quantities of solid-liquid mixture to the tank (10) through use of a manually or remotely actuatable valve disposed thereon. Other control means are also usable, including any type of automatic, manual, and/or remotely operated valves and/or nozzles.
In conventional filtration vessels, it is common for sludge to accumulate in one or more areas due to blockage of filters, the manner in which the sludge is provided into the vessel, the non-uniform dispersion of solid media within the sludge, the differing availability of filtration surfaces at certain locations in the vessel, and other similar factors. The depicted controllable distribution system facilitates a more efficient separation process by enabling compensation for these and similar difficulties.
As a solid-liquid mixture is filtered through the filtration media disposed on the floor (14) and the walls (16, 18, 20, 22), separated liquid passes into an interior space (24) defined by the tank (10) and the floor (14). An outlet (26) in communication with the interior space (24) can be used to remove separated liquid for disposal, collection, analysis, treatment, and/or use. The outlet can include one or more valves or other control members, threads or other members for engaging a hose or similar transport device, or similar features. In an embodiment, the interior space (24) can include one or more pipes, nozzles, or similar devices oriented for providing liquid to the filtration media of the floor (14) and walls (16, 18, 20, 22), for cleaning the filtration media of dried solid matter after separation of a solid-liquid mixture. One or more inlets for receiving water or another liquid can be in communication with the interior space (24) for this purpose, or the outlet (26) could be used as an inlet for providing the liquid.
Referring now to
Each cavity (12, 13) is shown filled with a solid-liquid mixture (36). The first nozzle (28), second nozzle (30), and third nozzle (32) of the controllable distribution system are shown oriented over the first cavity (12), such that the first nozzle (28) can provide the solid-liquid mixture to an area of the first cavity (12) proximate to the fourth exterior wall (21), the second nozzle (30) can provide the solid liquid-mixture to the center of the first cavity (12), and the third nozzle (32) can provide the solid-liquid mixture to the first cavity (12) proximate to the third exterior wall (20).
Each of the nozzles (28, 30, 32, 29, 31, 33) can be in communication with one or more pipes, tubes, hoses, or other similar conduits, in communication with a source containing the solid-liquid mixture, and, in an embodiment, one or more pumps for flowing the solid-liquid mixture. In an embodiment, one or more pipes or other conduits can be contained within the interior dividing wall (22), or one of the other walls (16, 18, 20, 21) for flowing solid-liquid mixture to the nozzles.
Each nozzle (28, 30, 32, 29, 31, 33) is shown having a manually actuatable valve for enabling selected nozzles to be individually or simultaneously actuated, based on observations of the level of the solid-liquid mixture (36) and the separation process. Observations can be performed from the support structure (34) disposed on the top of the interior dividing wall (22). The control members for each of the nozzles (28, 30, 32, 29, 31, 33) is directly or remotely accessible from the support structure (34), enabling a single individual to control the distribution of solid-liquid mixture in the tank (10) and facilitate rapid separation process.
Referring now to
The fourth exterior wall (21) of the tank (10) is shown having a first porthole (44) and a second porthole (46) disposed therethrough, for enabling monitoring of the separation process and the level of the solid-liquid mixture from the side of the tank (10), and for enabling the provision of cleaning materials and/or equipment into the tank (10) after the separation and/or disposal processes are complete.
In an embodiment, the transportable member (38), the tank (10), or combinations thereof, can include one or more mechanical lifting members for enabling an end of the tank (10) to be raised to facilitate dumping and/or disposal of separated solid media, and to facilitate cleaning of the tank (10) after the disposal process.
The height provided to the tank (10) by the transportable member (38) facilitates access to inlets and outlets of the tank (10), streamlining the installation and disassembly of the present system. The truck (42) and transportable member (38) enable the tank (10), the additional tank (40), and other similar equipment to be moved between source sites to obtain one or more solid-liquid mixtures, and between one or more disposal sites, while enabling the separation process to be performed at any location, including while in transit.
Referring now to
A water source (100) is depicted for providing water to the system, to form a usable polymer solution for flocculating the solid-liquid mixture. The water source (100) is depicted as a hose, which can be in communication with one or more public or private water sources, tanks, pools, lakes, reservoirs, or other usable sources of generally clean, fresh water. In areas where a readily accessible public or private water source is not available, the water source (100) can include one or more portable tanks or other vessels containing usable water.
Water is provided from the water source (100) through one or more valves (104), which can include manually actuatable valves, remotely actuatable valves, automatic valves, or combinations thereof. Polymer is provided from the polymer source (102) to a one-way check valve (108), assisted by a polymer pump (106), which can include an electrical, motorized pump having a built-in flow meter. The water and polymer mix in the polymer solution line (110). The resulting polymer solution is passed through a first static mixer (112), which
While
After passing through the mixers (112, 114), the mixed polymer solution is flowed through an inline flowmeter (116), which measures the flow rate of the polymer solution. Other types of flowmeters are also usable. In an embodiment of the invention, the flowmeter (116) can produce a measurement visible from a remote location, such as from the support structure of an adjacent separation apparatus, enabling an operator to adjust the flow of water, polymer, or the combined polymer solution, directly or remotely, responsive to the measurement.
The polymer solution line (110) flows the mixed polymer solution to a sludge pump suction line (118), where the polymer solution is injected for mixing with a solid-liquid mixture. A solid-liquid mixture source (120), such as a waste treatment facility, is shown in fluid communication with the sludge pump suction line (118), for flowing a sludge or another solid-liquid mixture to a sludge pump (122) via the sludge pump suction line (118). As the polymer solution and the solid-liquid mixture are flowed together into the sludge pump suction line (118), the components mix and react, thereby flocculating the solid-liquid mixture. Passage of the mixture through the sludge pump (122) further mixes and flocculates the solid-liquid mixture.
The sludge pump (122) can include a motorized, electrical, variable speed pump, which can be directly controllable, or remotely controllable responsive to the flow rate and the condition of the flocculated solid-liquid mixture, the polymer, the water, the solid-liquid mixture from the source (120), or combinations thereof. The sludge pump (122) draws flocculated solid-liquid mixture from the suction line (118) and flows the flocculated mixture through a sludge line (124), which in an embodiment of the invention can include a line having a diameter of four inches, past a sludge meter (126), which measures the gallons per minute of flocculated solid-liquid mixture flowed to a separation apparatus (128). While
The pumped solid-liquid mixture is flowed through a valve (130), such as a wafer valve, where the mixture passes through a clear section of tube (132). The transparent section of tube (132) enables the condition and flow rate of the flocculated solid-liquid mixture to be remotely visualized, such as when standing on a support structure of the separation apparatus (128), enabling the flow rate of the flocculated-solid liquid mixture and/or other components to be directly or remotely modified responsive to the visual observations of the mixture through the transparent section of tube (132).
The flocculated solid-liquid mixture is then flowed through an inlet (134) into the separation apparatus (128), which
While various specific embodiments of the invention have been described with emphasis, it should be understood that within the scope of the appended claims, the present invention can be practiced other than as specifically described herein.
