Patent Application
20190010066
Wastewater treatment is a process of removing impurities from wastewater. An objective of wastewater treatment is to produce a stream of treated wastewater suitable for discharge back in the environment. Wastewater treatment may comprise primary treatment, secondary treatment, and/or tertiary treatment. Primary treatment can involve use of septic tanks to separate solids, fats, oils, greases and produce a primary treated wastewater. Secondary treatment may be used to substantially degrade the impurities contained in the wastewater after primary treatment and may include the functions of biochemical oxygen demand (“BOD”) and total suspended solids (“TSS”) removal and reduction, among others. Tertiary treatment is often utilized for the removal of phosphorous and nitrogen-containing impurities.
Municipal wastewater treatment systems use numerous types of treatment systems to treat wastewater. It is a requirement of modern municipal wastewater treatment systems to adequately treat wastewater prior to discharging said treated wastewater. Municipal waste treatment systems generally use a centralized collection system along with primary, secondary and tertiary treatment systems which include physical, biological and chemical processing. These multi-million dollar wastewater treatment systems use a number of different types of wastewater treatment prior to discharge of the treated water from the wastewater system. As an example, see “Primer for Municipal Wastewater Treatment Systems” EPA 832-R-04-001 (September 2004).
All households do not have access to such municipal wastewater treatment systems and, therefore, often utilize decentralized, on-site systems for the treatment of wastewater. In the past, many of these systems merely utilized primary treatment systems, such as septic tanks, and then discharged partially treated wastewater into the environment.
Jokaso-type wastewater treatment systems represent a form of wastewater treatment which was introduced during the last thirty (30) years, is designed for use for decentralized wastewater treatment and is a superior wastewater treatment system to the use of septic tanks alone. Typical Jokaso devices include as many as five functional chambers. In one example, a first chamber works as a trash tank under anaerobic conditions, much like a septic tank. A second chamber is typically filled with filter media for anaerobic biofilm filtration process. A third chamber is also filled with filter media but is kept aerobic by introduction of compressed air. A fourth chamber may be utilized as a buffer storage tank for the treated water. A fifth chamber may be used for disinfection purposes, sometimes referred to as a tertiary treatment system.
One specific type of Jokaso wastewater treatment systems for small scale residential and commercial wastewater treatment is the Fusion® Series Treatment Systems by Zoeller Pump Company, LLC. The Fusion® System, as shown in Fusion® Series Treatment Systems Owner's Manual for small commercial models ZFL1120-ZFL2400, is a treatment system utilizing a sedimentation chamber, an anaerobic filtration chamber, an aerobic contact filtration chamber, and a storage container for the storage of treated wastewater, which can either be discharged or recycled for further treatment within the system.
Some wastewater treatment systems also utilize UV treatment devices to reduce production of organic materials formed within the wastewater treatment system. An example of such a device is shown in U.S. Pat. No. 8,795,600.
A common contaminant in wastewater, which is generally treated by municipal centralized treatment systems, is phosphorous compounds. In these municipal wastewater treatment systems, phosphorous compound removal can be accomplished by various techniques including filtration, chemical complexation, adsorption and biological treatment. Large wastewater treatment facilities often treat phosphorous in a tertiary treatment system. In one form of treatment, these systems subject phosphorous compounds to electro-chemical treatment to precipitate complexed phosphorous compounds from the wastewater, often using ferric ions. After such treatment, the treated wastewater can be discharged through an adsorption bed where the complexed phosphorous compounds are trapped.
There have been various additional systems that have been designed for the removal of phosphorous compounds from wastewater that can be utilized in combination with decentralized systems, such as the Jokaso-type systems. For example, in a tertiary treatment stage, phosphorous compounds may be removed via iron electrolysis, as utilized in the Fuji Clean treatment technology that is discussed in Otowa, et al.: PERSPECTIVES OF UPDATED JOKASO (ONSITE WASTEWATER TREATMENT UNIT) SYSTEM IN AUSTRALIA (2014). Other systems have used natural materials, such as zeolites or sand filters, to remove the phosphorous compounds. Also utilized are iron-containing materials, such as furnace slag. Another methodology for the removal of phosphorous is a post-secondary treatment system using precipitation, wherein Zn, Fe and Al compounds are added to the treated wastewater.
One embodiment of the present invention is a decentralized, on-site wastewater treatment system which includes an unique device and method for complexation and removal of phosphorous compounds from wastewater during a recirculation cycle within the wastewater treatment system.
One embodiment of an on-site or decentralized wastewater treatment system (10), which removes phosphorous compounds from wastewater during a recirculation cycle, is disclosed in
In this embodiment wastewater enters the inlet (12) of the system (10) and flows into a sedimentation chamber (20). This sedimentation chamber is designed to physically separate solids (sludge) (22) and floating materials (scum) from the incoming wastewater. The sludge falls to the bottom of the chamber for later removal. The scum remains in the chamber and is either decomposed or removed. Access to the sedimentation chamber is important for removal of this sludge and scum and is accomplished through convention openings in the top of the chamber.
To monitor the level of the sludge that is present in the sedimentation chamber, preferably a sensor (not shown) is installed in the chamber to alert the user thereof that there has been too much build up of sludge within that sedimentation chamber. This sensor reads the level of sludge that is present in the sedimentation chamber using, for example, an ultrasonic transducer using a sonar technique, pressure sensors and/or infrared LEDs. This sensor is placed in the sedimentation chamber (20) so that it is located where the majority of the sludge settles within the system (10). Further, this sensor preferably has an alarm system (not shown) attached thereto which alerts the user when the level of the sludge is excessive.
Following primary treatment for removal of sludge and scum from the wastewater, in one embodiment, the treated wastewater enters an anaerobic treatment chamber (30) which may include filter media, as shown in
Following anaerobic treatment in the anaerobic treatment chamber (30), the treated wastewater flows into an aerobic treatment chamber (40), as shown in
The decentralized wastewater treatment system (10) may contain one or both of an anaerobic treatment chamber and an aerobic treatment chamber. In addition, the order of flow of the wastewater through these respective chambers may be modified at the desire of the user.
In another embodiment, as shown in
In a preferred embodiment, a portion or all of the treated wastewater is recirculated using a recirculation system (50), as shown in
It has been discovered that treatment of wastewater in the recirculation system (50) with chemical agents useful for complexing phosphorous compounds present in the wastewater is surprisingly effective to remove phosphorous compounds from wastewater that enter the wastewater treatment system (10). Examples of such chemical agents include metal salt reagents, such as pre-hydrolyzed metal salt reagents, which may include various metals, metal salts, metal compounds or combinations thereof, with the metals selected from iron, aluminum, manganese, zinc, copper, magnesium and calcium with iron, zinc and aluminum preferred. Although the chemical agents can be introduced in various forms, preferred embodiments utilize introduction in either a solid, tablet form or a dissolved liquid form.
The introduction of these chemical agents into the recirculation system can be by use of various systems, such as a tablet feeder, a solid mass feeder, a liquid chemical feeder, a venturi feeder and other types of introduction devices for introduction of solid or liquid compounds into the recirculating wastewater while present in the recirculation system. Control of the quantity and state of these agents that are introduced into the recirculation system is by use of these systems.
In one embodiment as shown in
In one embodiment, as shown in
To assist in the mixing of the chemical agent throughout the wastewater present in the recirculation system, it has been surprisingly discovered that it is useful to utilize some form of mixing device, such as a static mixer (58) with baffles (59), to create a turbulent flow of the wastewater in the recirculation system, as shown in
It is also preferable that there be a recirculation system phosphorous sensor (56) located in the recirculation system after the static mixer (58) to sense the level of the chemical agent that is present in the recirculation system, as shown in
While, in one embodiment,
In an alternative embodiment as shown in
The particular components of the liquid feeder depend upon the chemical agent being added and the desire of the user of the system. In one embodiment, as shown in
The liquid chemical agent is introduced through the recirculation system liquid feeder opening (54), as shown in
The recirculation piping (52) feeds the treated wastewater back into the sedimentation chamber at which location the complexed phosphorous compounds fall out of the wastewater to be incorporated into the sludge that is present at the bottom of the sedimentation chamber. The sludge, including the complexed phosphorous material, is removed on a regular basis from the sedimentation chamber. By use of this phosphorous complexing chemical agent introduced into the recirculation system, phosphorous materials are removed efficiently from the wastewater without the need for a separate phosphorous removal system.
After the previously treated wastewater has been recirculated into the sedimentation chamber, it mixes with wastewater present in that chamber for further treatment through the sedimentation chamber, anaerobic chamber and the aerobic filter media chamber, as desired. After treatment in the various portions of the treatment system, the treated wastewater can be stored in a treated water storage chamber (60), which is present in the wastewater treatment system, prior to discharge.
Ultimately, treated wastewater is discharged from the system, after there has been sufficient treatment of the wastewater, through the outlet (14) of the system. The ultimate amount of treated wastewater that is discharged during each cycle can be controlled by adjustments to the system, as are known in the industry.
To monitor the level of phosphorous compounds that enter the wastewater treatment system, an inlet phosphorous sensor (16) is preferably present near inlet (12). To determine the overall effectiveness of removal of phosphorous compounds from the system, it is preferable to also utilize an outlet phosphorous sensor (18) near the outlet (14). By comparing the level of phosphorous compounds shown by these sensors, the overall effectiveness of the system to remove phosphorous compounds can be evaluated and adjusted.
In an alternative embodiment, as shown in
In an alternative embodiment as shown in
Alternatively, some systems also include use of a conventional septic tanks prior to the wastewater treatment system.
Further, a secondary wastewater treatment system may be utilized in sequence to further treat the wastewater before final discharge into the environment. Among the secondary wastewater treatment systems that are utilized with the onsite decentralized wastewater treatment system include a packed bed filter, a recirculating sand filter, a gravel filter with a gravel filter preferred, an aerobic treatment system or an anaerobic treatment system.
Other methodologies and other arrangements of sedimentation chambers and secondary and tertiary treatment systems can be utilized for the treatment of wastewater.
It is well recognized by persons skilled in the art that alternative embodiments to those disclosed herein, which are foreseeable alternatives, are also covered by this disclosure. The foregoing disclosure is not intended to be construed to limit the embodiments or otherwise to exclude such other embodiments, adaptations, variations, modifications and equivalent arrangements.
This Application claims priority from provisional application Ser. No. 62/529,159, filed Jul. 6, 2017.
| Number | Date | Country | |
|---|---|---|---|
| 62529159 | Jul 2017 | US |
