Waste treatment system

Abstract

A waste treatment system may include a liquid separator for removing water from solid waste, a mixing tank connected to the liquid separator for mixing the solid waste with an oxidizing agent, a heat exchanger connected to the mixing tank for collecting heat generated by an exothermic reaction caused by mixing the oxidizing agent with the solid waste, and a sanitizer connected to the liquid separator to sanitize the water removed from the solid waste. A waste treatment method may involve separating water from solid waste in a liquid separator, mixing the solid waste from the liquid separator with an oxidizing agent in a mixing tank connected to the liquid separator to cause an exothermic reaction, collecting heat from the exothermic reaction in a heat exchanger coupled with the mixing tank, and sanitizing the water from the liquid separator in a sanitizer.

Claims

1. A waste treatment method using a waste treatment system located in or near a commercial or multiple-unit residential building, comprising: removing water from solid waste in a liquid separator, thereby reducing water content of the solid waste to 30% or less; transferring the solid waste from the liquid separator to a mixing tank connected to the liquid separator; transferring the water from the liquid separator to a sanitization tank; mixing the solid waste having a water content of 30% or less with an oxidizing agent in the mixing tank to cause an exothermic reaction and convert the solid waste to processed solid waste; collecting heat from the exothermic reaction in a heat exchanger coupled with the mixing tank; sanitizing the water from the liquid separator in the sanitizing tank; and intermittently diverting the waste from a building sewer system away from the waste treatment system into a public sewer system.

2. The method of claim 1, further comprising, before separating the water from the solid waste: receiving waste from a building sewer system in at least one holding tank; and channeling the waste from the at least one holding tank to the liquid separator.

3. The method of claim 1, further comprising applying the heat from the heat exchanger to a source of domestic hot water connected to the heat exchanger.

4. The method of claim 1, further comprising channeling the sanitized water into a water system for use as toilet water.

5. The method of claim 1, further comprising collecting processed solid waste from the mixing tank in a collection tank.

6. The method of claim 1, further comprising providing processed solid waste from the mixing tank for use as fertilizer.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a system/flow diagram, illustrating an on-site waste treatment system and flow of sewage through the system, according to one embodiment; and

(2) FIG. 2 is a side view diagram, illustrating a portable waste treatment system for installation and use on a truck, according to another embodiment.

DETAILED DESCRIPTION

(3) The various embodiments of a waste treatment system and method described herein provide for waste treatment with improved efficiency and use of water and energy. Some embodiments of the system may be located on-site at a commercial or residential building, while others may be small enough to fit on the back of a flatbed truck or other motorized vehicle. The various embodiments involve mixing solid waste with an oxidizing agent to generate heat from an exothermic reaction. In some embodiments, the system collects the generated heat and provides it as usable energy, such as for heating domestic hot water. In some embodiments, the treated solid waste may be used as fertilizer. Greywater that is separated from the solid waste during the treatment process may be sanitized and used for toilets, watering landscaping or other environmentally safe uses. The various embodiments may be used in any of a large number of settings and locations to provide efficient and effective waste treatment.

(4) The terms waste, wastewater and sewage are sometimes used interchangeably in this application. Unless these terms are specifically described as having a particular meaning, they should be interpreted as being interchangeable.

(5) Referring to FIG. 1, in one embodiment, a waste treatment system 20 may include one or more holding tanks 3, a liquid separator 4, a mixing tank 5, an oxidizing agent 6, a heat exchanger 7, a heated water outflow channel 8, and a sanitizing tank 10. Holding tank 3 may be connected with a building sewer system 1 via one or more connecting pipes 13 and with liquid separator 4 via one or more other connecting pipes 12. Liquid separator 4 may be coupled with mixing tank 5 via one or more connecting pipes 14 and with sanitizer 10 via one or more other connecting pipes 16. Heated water outflow channel 8 may be one or more pipes that feed into a domestic hot water storage tank or other form of domestic hot water supply. System 20 may also optionally include a liquid outflow channel from sanitizer 10 that is one or more additional pipes 18. According to various embodiments, multiples of any of the components of system 20 may be provided.

(6) Waste flows into system 20 through the building's sewage system 1. Water emptying into sewer system 1 from the building comes from sources such as water closets (WC, or toilets), bathtubs (BT, and/or showers), and sinks SK. Other sources may include dishwashers and washing machines, for example. In some embodiments, an emergency bypass 2 may connect with the building sewer system 1 to allow waste to bypass system 20 if there is a problem. Typically, this bypass 2 is not part of waste treatment system 20, although in some embodiments, system 20 may include bypass 2 or communicate with building sewer system 1 to provide an alert when there is a problem, so that waste may be diverted into bypass 2. After waste is processed in mixing tank 5, solid, processed waste 9 may be provided for use, for example as a fertilizer, or may alternatively be disposed of as residual waste. Greywater 11 may be pumped out of sanitizer 10 via a pump 22, which may be part of system 20 or separate from system 20. Greywater 11 may then be diverted back to the building or elsewhere for use, such as in toilets (WC).

(7) Mixing tank 5 may be any suitable, commercial mixer, such as but not limited to high speed mixers, ribbon mixers, plough mixers, conical screw mixers, conical ribbon mixers, double shafts paddle mixers and continuous mixers. In various embodiments, oxidizing agent 6 may be loaded into mixing tank 5 before or after wastewater is passed into mixing tank 5. Heat is generated by mixing the organic waste in mixing tank 5 with a sufficient amount of oxidizing agent 6, which may be potassium permanganate or any other safe oxidizing agent. In one embodiment, oxidizing agent 6 may be stored in a compartment or container (not shown) in or connected to mixing tank 5 and dispensed into mixing tank 5 via one or more valves. Alternatively, oxidizing agent 6 may be manually dispensed into mixing tank 5 from an external source before or after waste is dispensed into tank 5. After processing, processed waste 9 may be removed from mixing tank 5, or alternatively, it may be channeled out of mixing tank 5 through a pipe or other means to a separate solid waste holding tank (not shown).

(8) In addition to providing usable greywater and solid processed waste, system 20 may also provide heat from heat exchanger 7, which may be used as energy. For example, in one embodiment, heat may be applied to water and channeled via heated water channel 8 to a domestic hot water supply.

(9) In one method of processing waste using system 20, a main sewage line 1 discharges into a holding tank 3 (or multiple holding tanks in some embodiments). Holding tank 3 (or tanks) will typically be designed to manage peak flows of the sewer to which it is attached. From holding tank 3, waste is channeled through one or more pipes 12 to liquid separator 4, which separates liquid from solid waste and thus reduces the water content of the solid waste to approximately 30% or less. Liquid waste is diverted through pipe(s) 16 to sanitizing tank 10. Solid matter is transferred through one or more pipes 14 to mixing tank 5. When oxidizing agent (such as potassium permanganate) 6 is mixed with solid waste, it starts an exothermic reaction, resulting in the generation of heat. This reaction may often start quickly, such as in less than one minute or even as quickly as approximately 20 seconds, and may produce large quantities of heat, such as a temperature of about 200 F. The reaction will eventually convert the solid waste material to a dry, odorless, ash-like material. The resulting ash may be used as a fertilizer, for example. Tests of resulting ash material from one embodiment of the method have been conducted, and no phytotoxic signs were observed in a period of 30 days, indicating that the material is environmentally safe.

(10) As previously mentioned, liquid separated from the solids is transferred to sanitizing tank 10. After sanitizing, greywater may be pumped through pipes 18, 11, using pump 22, to supply water closets (WC) with water for flushing and/or to supply greywater for other safe uses.

(11) In one embodiment, system 20 may also include a heat source (not shown). The heat source may be used, for example, to catalyze or facilitate the exothermic reaction, such as by heating the solid waste before and/or during mixing with oxidization agent 6. The heat source may also be capable of incinerating or sterilizing waste, for example if additional incineration or sterilization is desired after the exothermic reaction is complete. The heat source may include, for example, a gas burner, laser heater, microwave heater, radiofrequency heater, electric resistance heater or the like. Heat transfer elements (e.g., metal rods or plates) may be provided to contact or even pierce the waste to accelerate heat transfer and water evaporation. In many embodiments, however, no heat source other than oxidizing agent 6 is needed, since mixing the waste with oxidizing agent 6 is sufficient for waste treatment needs.

(12) In various alternative embodiments, waste treatment system 20 may include fewer or larger numbers of components than described above. For example, any one of the components described above, or any combination of components, may be provided in multiples (e.g., multiple holding tanks 3, multiple liquid separators 4, etc.). In some embodiments, one or more components may be removed from system 20. For example, in one embodiment, holding tank(s) 3 may be eliminated, and liquid separator(s) 4 may serve both as holding tanks and also as separators. In another example, pump 22 may be part of system 20 in some embodiments and not in others.

(13) Referring now to FIG. 2, in another embodiment, a waste treatment system 30 may be portable, for example for implementation and use on the back of a truck 36, such as the flatbed truck 36 pictured in FIG. 2. In this embodiment, waste treatment system 30 includes a sewer collection hose 31, a sewer pump 32, a holding tank 33, a mixing tank 35, and a fertilizer outflow channel 38. Sewer hose 31 and sewer pump 32 may be used to channel sewage directly out of a sewer into holding tank 33. Sewage may then be mixed with an oxidizing agent, such as potassium permanganate, in mixing tank 35, which may be a screw operated mixing tank or any other suitable mixing tank, such as but not limited to the examples listed above. Once waste is treated in mixing tank 35, resulting fertilizer may be diverted out of system 20 through fertilizer outflow channel 38.

(14) In alternative embodiments, waste treatment system 30 may include any of a number of other configurations, combinations of components, sizes, shapes and the like, such as but not limited to one or more of the components or aspects described above in relation to FIG. 1. For example, waste treatment system 30 may include a liquid separator and a water outflow channel for separating water from solid waste and allowing the water to escape system 30. Additionally, system 30 may be sized to fit on any suitable truck or vehicle. Alternatively, waste treatment 30 system may be installed above ground or below ground at a sewer site.

(15) Although this invention has been disclosed in the context of certain embodiments and examples, the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and modifications and equivalents thereof. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above.