# US 2014/0151294 A1 · Method and Apparatus for Residential Water Recycling > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0151294 A1 - Document ID: US20140151294A1 - Status: Published application - Kind: A1 - Application number: 13/690,320 - Filed: 2012-11-30 - Published: 2014-06-05 - Earliest claimed: 2012-11-30 - Assignees: Tangent Company LLC - Applicants: Tangent Company LLC - Inventors: William C. Prior; James E. Bolton; Lyle E. Kirman; David F. Rath; Adam Arnold; Glenn Graff; Kevin J. Elliot - Web page: https://patentgrep.com/patent/US20140151294A1 ## CPC - C02F 9/00: Multistage treatment of water, waste water or sewage - C02F 1/008: {Control or steering systems not provided for elsewhere in subclass C02F} - C02F 1/02: by heating (methods of steam generation F22B; preheating boiler feed-water or accumulating preheated boiler feed-water F22D) - C02F 1/28: by sorption (using ion-exchange C02F1/42; sorbent compositions B01J) - C02F 1/283: {using coal, charred products, or inorganic mixtures containing them} - C02F 1/32: with ultraviolet light - C02F 1/441: {by reverse osmosis} - C02F 1/442: {by nanofiltration} - C02F 1/46: by electrochemical methods - C02F 1/4695: {electrodeionisation} - C02F 1/76: with halogens or compounds of halogens {(C02F1/4674 takes precedence)} - C02F 1/78: with ozone {(C02F1/4672 takes precedence)} - C02F 3/1242: {Small compact installations for use in homes, apartment blocks, hotels or the like} - C02F 3/223: {using "air-lift"} - C02F 3/302: {Nitrification and denitrification treatment (C02F3/308 takes precedence)} - C02F 2103/002: {Grey water, e.g. from clothes washers, showers or dishwashers} - C02F 2103/005: {Black water originating from toilets} - C02F 2209/008: comprising telecommunication features, e.g. modems or antennas - C02F 2209/03: Pressure - C02F 2209/11: Turbidity - C02F 2209/29: Chlorine compounds - C02F 2209/40: Liquid flow rate - C02F 2209/42: Liquid level - C02F 2303/16: Regeneration of sorbents, filters - Y02W 10/10: Biological treatment of water, waste water, or sewage - C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes) - Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT ## Abstract A wastewater recycling system includes a biological reactor having anaerobic, anoxic, and aerobic chambers. A lift station including a pump is operatively connected to the biological reactor. The lift station receives biologically treated liquid from the biological reactor and pumps the liquid from the lift station. A filtration subsystem is operatively connected to the lift station. The filtration subsystem receives and filters the liquid pumped by the lift station. The filtration subsystem includes a salt-rejecting membrane filter comprising a concentrate recirculation conduit operatively connected to recirculate salt-rejecting membrane filter concentrate to a point along the wastewater recycling system upstream of the salt-rejecting membrane filter, thereby forming a salt concentration loop between said point along the wastewater recycling system and the salt-rejecting membrane filter. A post-filtration subsystem is operatively connected to receive salt-rejecting membrane filter permeate, and comprises a water disinfection system that disinfects the permeate thereby generating potable water. ## Claims ### Claim 1 A wastewater recycling system, comprising: a) a biological reactor, the biological reactor comprising an anaerobic chamber, an anoxic chamber, and an aerobic chamber; b) a lift station comprising a pump, wherein the lift station is operatively connected to the biological reactor to receive biologically treated liquid from the biological reactor and pump the biologically treated liquid from the lift station; c) a filtration subsystem, operatively connected to the lift station, that receives and filters the biologically treated liquid pumped by the lift station, the filtration subsystem comprising: i) a salt-rejecting membrane filter comprising a concentrate recirculation conduit operatively connected to recirculate salt-rejecting membrane filter concentrate to a point along the wastewater recycling system upstream of the salt-rejecting membrane filter, thereby forming a salt concentration loop between said point along the wastewater recycling system and the salt-rejecting membrane filter; and d) a post-filtration subsystem operatively connected to receive salt-rejecting membrane filter permeate, wherein the post-filtration subsystem comprises a water disinfection system that disinfects the salt-rejecting membrane filter permeate thereby generating potable water. ### Claim 2 (depends on 1) The wastewater recycling system of claim 1, wherein said point along the wastewater recycling system is downstream of the anaerobic chamber, the anoxic chamber, and the aerobic chamber. ### Claim 3 (depends on 1) The wastewater recycling system of claim 1, wherein the salt-rejecting membrane filter concentrate is recirculated to the lift station. ### Claim 4 (depends on 1) The wastewater recycling system of claim 1, wherein: i) the anaerobic chamber is operatively connected to supply liquid to the anoxic chamber, and the anaerobic chamber is adapted for anaerobically treating wastewater within the anaerobic chamber, ii) the anoxic chamber is operatively connected to receive liquid from both of the anaerobic chamber and the aerobic chamber, wherein the anoxic chamber is adapted for anoxically treating the liquid received from both of the anaerobic chamber and the aerobic chamber within the anoxic chamber thereby biologically removing nitrates from the liquid treated within the anoxic chamber, iii) the aerobic chamber is operatively connected to recirculate aerobically treated liquid to the anoxic chamber, and iv) the anoxic chamber and the aerobic chamber include sludge return conduits respectively connected to transport sludge from the anoxic and aerobic chambers to the anaerobic chamber. ### Claim 5 (depends on 1) The wastewater recycling system of claim 1, wherein the water disinfection system comprises an advanced oxidation system operatively connected to receive the salt-rejecting membrane filter permeate, wherein the advanced oxidation system produces hydroxyl radicals within the salt-rejecting membrane filter permeate. ### Claim 6 (depends on 5) The wastewater recycling system of claim 5, wherein the advanced oxidation system is configured to add an oxidizing agent to the salt-rejecting membrane filter permeate, and the advanced oxidation system comprises an ultraviolet light generator that irradiates the oxidizing agent within the salt-rejecting membrane filter permeate. ### Claim 7 (depends on 6) The wastewater recycling system of claim 6, wherein the ultraviolet light generator comprises a 185 nm lamp. ### Claim 8 (depends on 1) The wastewater recycling system of claim 1, wherein the filtration subsystem further comprises: ii) a chemical cleaning system operatively connected to the salt-rejecting membrane filter and configured to expose the salt-rejecting membrane filter to a cleaning solution, thereby producing a cleaning waste liquid, and wherein the filtration subsystem comprises a waste conduit operatively connected to recirculate the cleaning waste liquid to the biological reactor for biological treatment in the biological reactor. ### Claim 9 (depends on 8) The wastewater recycling system of claim 8, wherein the cleaning solution is acidic and comprises citric acid and a biodegradable detergent. ### Claim 10 (depends on 1) The wastewater recycling system of claim 1, wherein the filtration subsystem further comprises: ii) a preliminary membrane filter operatively connected to the salt-rejecting membrane filter so as to supply preliminary membrane filter permeate to the salt-rejecting membrane filter for further filtering by the salt-rejecting membrane filter, wherein the preliminary membrane filter comprises another concentrate recirculation conduit operatively connected to recirculate preliminary membrane filter concentrate to said or another point along the wastewater recycling system. ### Claim 11 (depends on 10) The wastewater recycling system of claim 10, wherein the preliminary membrane filter concentrate is recirculated to the lift station. ### Claim 12 (depends on 10) The wastewater recycling system of claim 10, wherein the filtration subsystem further comprises: iii) an adsorbent, operatively connected between the preliminary membrane filter and the salt-rejecting membrane filter so as to receive the preliminary membrane filter permeate, wherein the adsorbent adapted for removing organic molecules from the preliminary membrane filter permeate prior to filtration of the preliminary membrane filter permeate by the salt-rejecting membrane filter. ### Claim 13 (depends on 10) The wastewater recycling system of claim 10, wherein the salt-rejecting membrane filter comprises a nanofilter. ### Claim 14 (depends on 10) The wastewater recycling system of claim 10, wherein the salt-rejecting membrane filter comprises a reverse osmosis device. ### Claim 15 (depends on 10) The wastewater recycling system of claim 10, wherein the preliminary membrane filter comprises an ultrafilter. ### Claim 16 (depends on 10) The wastewater recycling system of claim 10, wherein the preliminary membrane filter comprises a microfilter. ### Claim 17 (depends on 10) The wastewater recycling system of claim 10, wherein the filtration subsystem further comprises: iii) a salt removal device operatively connected to receive the salt-rejecting membrane filter concentrate, wherein the salt removal device is adapted to remove salts from the salt-rejecting membrane filter concentrate. ### Claim 18 (depends on 10) The wastewater recycling system of claim 10, wherein the filtration subsystem further comprises: iii) an electrochemical device operatively connected along the salt concentration loop, wherein the electrochemical device removes salts from a flow stream through the salt concentration loop. ### Claim 19 (depends on 1) The wastewater recycling system of claim 1, wherein the biological reactor comprises a biologically-active tertiary filter operatively connected to receive aerobically treated liquid from the aerobic chamber, and the tertiary filter filters and biologically treats the aerobically treated liquid from the aerobic chamber, and wherein the biological reactor comprises a tertiary filter backwash conduit operatively connected to recirculate tertiary filter backwash to the anaerobic chamber. ### Claim 20 A method of recycling wastewater through a system comprising a biological reactor, a lift station, and a salt-rejecting membrane filter, wherein the biological reactor comprises an anaerobic chamber, an anoxic chamber, and an aerobic chamber, the method comprising the steps of: biologically treating the wastewater in the biological reactor, thereby generating biologically treated liquid; pumping the biologically treated liquid from the biological reactor by the lift station; filtering the biologically treated liquid through a salt-rejecting membrane filter; recirculating salt-rejecting membrane filter concentrate to a point along the system upstream of the salt-rejecting membrane filter, thereby forming a salt concentration loop between said point along the system and the salt-rejecting membrane filter; and disinfecting salt-rejecting membrane filter permeate thereby generating potable water. ### Claim 21 (depends on 20) The method of claim 20, wherein said point along the system is downstream of the anaerobic chamber, the anoxic chamber, and the aerobic chamber. ### Claim 22 (depends on 20) The method of claim 20, wherein the salt-rejecting membrane filter concentrate is recirculated to the lift station. ### Claim 23 (depends on 20) The method of claim 20, wherein the system further comprises a potable water storage tank, the method further comprising the step of storing the potable water in the potable water storage tank. ### Claim 24 (depends on 20) The method of claim 20, further comprising the steps of: transferring liquid from the anaerobic chamber into the anoxic chamber; recirculating liquid from the aerobic chamber into the anoxic chamber; anoxically treating liquid in the anoxic chamber thereby biologically removing nitrates from the liquid treated within the anoxic chamber; aerobically treating liquid within the aerobic chamber; and transferring sludge from both of the anoxic chamber and the aerobic chamber into the anaerobic chamber. ### Claim 25 (depends on 24) The method of claim 24, wherein the aerobic chamber is a second aerobic chamber, the biological reactor further comprising a first aerobic chamber, the method further comprising the steps of: transferring liquid from the anoxic chamber into the first aerobic chamber; transferring liquid from the first aerobic chamber into the second aerobic chamber; and transferring sludge from the first aerobic chamber to the anaerobic chamber. ### Claim 26 (depends on 20) The method of claim 20, wherein the step of disinfecting the salt-rejecting membrane filter permeate comprises generating hydroxyl radicals within the salt-rejecting membrane filter permeate. ### Claim 27 (depends on 26) The method of claim 26, wherein the step of disinfecting the salt-rejecting membrane filter permeate comprises adding an oxidizing agent to the salt-rejecting membrane filter permeate and irradiating the oxidizing agent in the salt-rejecting membrane filter permeate with ultraviolet light. ### Claim 28 (depends on 27) The method of claim 27, wherein total organic carbon in the potable water is less than 150 μg/L. ### Claim 29 (depends on 27) The method of claim 27, wherein total organic carbon in the potable water is less than 100 μg/L. ### Claim 30 (depends on 20) The method of claim 20, further comprising the steps of: chemically cleaning the salt-rejecting membrane filter with an acidic solution, thereby producing a cleaning waste liquid; and recirculating the cleaning waste liquid to the biological reactor for biological treatment in the biological reactor. ### Claim 31 (depends on 20) The method of claim 20, further comprising the steps of: filtering the biologically treated liquid through a preliminary membrane filter prior to filtering the biologically treated liquid through the salt-rejecting membrane filter; and recirculating preliminary membrane filter concentrate to said or another point along the system. ### Claim 32 (depends on 31) The method of claim 31, further comprising the step of removing, by an adsorbent, organic molecules from preliminary membrane filter permeate prior to filtration of the preliminary membrane filter permeate by the salt-rejecting membrane filter. ### Claim 33 (depends on 31) The method of claim 31, further comprising the step of removing, by an electrochemical device, salts from a flow stream through the salt concentration loop. ### Claim 34 (depends on 20) The method of claim 20, wherein at least 80% of the wastewater is recycled into potable water. ### Claim 35 (depends on 34) The method of claim 34, wherein at least 90% of the wastewater is recycled into potable water. ### Claim 36 (depends on 35) The method of claim 35, wherein at least 95% of the wastewater is recycled into potable water. ### Claim 37 A wastewater recycling system, comprising: a) a biological reactor, the biological reactor comprising an anaerobic chamber, an anoxic chamber, and an aerobic chamber; b) a filtration subsystem, operatively connected to the biological reactor, that receives and filters biologically treated liquid from the biological reactor, the filtration subsystem comprising a preliminary membrane filter, a salt-rejecting membrane filter, and a chemical cleaning system, wherein: i) the preliminary membrane filter is operatively connected to the salt-rejecting membrane filter so as to supply preliminary membrane filter permeate to the salt-rejecting membrane filter for further filtering by the salt-rejecting membrane filter, and ii) the chemical cleaning system is operatively connected to at least one of the preliminary membrane filter and the salt-rejecting membrane filter, and configured to expose the at least one of the preliminary membrane filter and the salt-rejecting membrane filter to a cleaning solution, thereby producing a cleaning waste liquid, and wherein the filtration subsystem comprises a waste conduit operatively connected to recirculate the cleaning waste liquid to the biological reactor for biological treatment in the biological reactor; and c) a post-filtration subsystem operatively connected to receive salt-rejecting membrane filter permeate, wherein the post-filtration subsystem comprises a water disinfection system that disinfects the salt-rejecting membrane filter permeate thereby generating potable water. ### Claim 38 (depends on 37) The wastewater recycling system of claim 37, wherein the cleaning solution is acidic. ### Claim 39 (depends on 38) The wastewater recycling system of claim 38, wherein the cleaning solution comprises citric acid and a biodegradable detergent. ### Claim 40 (depends on 37) The wastewater recycling system of claim 37, wherein the cleaning solution is alkaline. ### Claim 41 (depends on 40) The wastewater recycling system of claim 40, wherein the cleaning solution comprises a biodegradable detergent. ### Claim 42 (depends on 37) The wastewater recycling system of claim 37, wherein the post-filtration subsystem comprises a potable water storage tank storing the potable water, wherein the wastewater recycling system is configured to back flush the preliminary membrane filter with the potable water from the potable water storage tank, and recirculate back flush water to the biological reactor through said or another waste conduit. ### Claim 43 (depends on 42) The wastewater recycling system of claim 42, wherein the cleaning waste liquid and the back flush water are recirculated to the anaerobic chamber of the biological reactor. ### Claim 44 (depends on 37) The wastewater recycling system of claim 37, wherein the filtration subsystem further comprises an adsorbent, operatively connected between the preliminary membrane filter and the salt-rejecting membrane filter so as to receive the preliminary membrane filter permeate, wherein the adsorbent removes organic molecules from the preliminary membrane filter permeate prior to filtration of the preliminary membrane filter permeate by the salt-rejecting membrane filter. ### Claim 45 (depends on 37) The wastewater recycling system of claim 37, wherein the filtration subsystem further comprises a salt removal device operatively connected to receive salt-rejecting membrane filter concentrate, wherein the salt removal device is adapted to remove salts from the salt-rejecting membrane filter concentrate. ### Claim 46 (depends on 37) The wastewater recycling system of claim 37, further comprising a salt concentration loop, wherein salt-rejecting membrane filter concentrate is recirculated within the wastewater recycling system through the salt concentration loop, the wastewater recycling system further comprising an electrochemical device operatively connected along the salt concentration loop, wherein the electrochemical device removes salts from a flow stream through the salt concentration loop. ### Claim 47 (depends on 37) The wastewater recycling system of claim 37, wherein the preliminary membrane filter comprises one of a microfilter and an ultrafilter. ### Claim 48 A method of recycling wastewater through a system comprising a biological reactor, a preliminary membrane filter, and a salt-rejecting membrane filter, wherein the biological reactor comprises an anaerobic chamber, an anoxic chamber, and an aerobic chamber, the method comprising the steps of: biologically treating the wastewater in the biological reactor, thereby generating biologically treated liquid; filtering the biologically treated liquid through the preliminary membrane filter and then through the salt-rejecting membrane filter; chemically cleaning at least one of the preliminary membrane filter and the salt-rejecting membrane filter with a cleaning solution, thereby producing a cleaning waste liquid; recirculating the cleaning waste liquid to the biological reactor for biological treatment in the biological reactor; and disinfecting salt-rejecting membrane filter permeate thereby generating potable water. ### Claim 49 (depends on 48) The method of claim 48, wherein the cleaning solution comprises citric acid and a biodegradable detergent. ### Claim 50 (depends on 48) The method of claim 48, wherein the system further comprises a potable water storage tank, the method further comprising the step of storing the potable water in the potable water storage tank. ### Claim 51 (depends on 50) The method of claim 50, further comprising the steps of: back flushing the preliminary membrane filter with potable water from the potable water storage tank; and recirculating back flush water to the biological reactor for biological treatment in the biological reactor. ### Claim 52 (depends on 51) The method of claim 51, wherein the cleaning waste liquid and the back flush water are recirculated to the anaerobic chamber of the biological reactor. ### Claim 53 (depends on 48) The method of claim 48, further comprising the step of removing, by an adsorbent, organic molecules from preliminary membrane filter permeate prior to filtration of the preliminary membrane filter permeate by the salt-rejecting membrane filter. ### Claim 54 (depends on 48) The method of claim 48, further comprising the steps of: recirculating salt-rejecting membrane filter concentrate to a point along the system upstream of the salt-rejecting membrane filter, thereby forming a salt concentration loop between said point along the system and the salt-rejecting membrane filter; and removing, by an electrochemical device, salts from a flow stream through the salt concentration loop. ### Claim 55 (depends on 48) The method of claim 48, wherein at least 80% of the wastewater is recycled into potable water. ### Claim 56 (depends on 55) The method of claim 55, wherein at least 90% of the wastewater is recycled into potable water. ### Claim 57 (depends on 56) The method of claim 56, wherein at least 95% of the wastewater is recycled into potable water. ### Claim 58 A multi-chambered biological reactor tank for biologically treating wastewater, comprising: an anaerobic chamber; an anoxic chamber; an aerobic chamber; and a biologically-active tertiary filter; wherein: i) the anaerobic chamber is operatively connected to supply liquid to the anoxic chamber, and the anaerobic chamber is adapted for anaerobically treating wastewater within the anaerobic chamber, ii) the anoxic chamber is operatively connected to receive liquid from both of the anaerobic chamber and the aerobic chamber, wherein the anoxic chamber is adapted for anoxically treating the liquid received from both of the anaerobic chamber and the aerobic chamber within the anoxic chamber thereby biologically removing nitrates from the liquid treated within the anoxic chamber, iii) the aerobic chamber is operatively connected to recirculate aerobically treated liquid to the anoxic chamber, iv) the anoxic chamber and the aerobic chamber include sludge return conduits respectively connected to transport sludge from the anoxic and aerobic chambers to the anaerobic chamber, and v) the tertiary filter is operatively connected to receive aerobically treated liquid from the aerobic chamber, and the tertiary filter is adapted to filter and biologically treat the aerobically treated liquid from the aerobic chamber. ### Claim 59 (depends on 58) The multi-chambered biological reactor tank of claim 58, wherein the tertiary filter comprises a ceramic filtration media. ### Claim 60 (depends on 58) The multi-chambered biological reactor tank of claim 58, further comprising an air scour subsystem that performs a subsurface air scour of the tertiary filter. ### Claim 61 (depends on 58) The multi-chambered biological reactor tank of claim 58, further comprising an air-lift pump configured to recirculate the aerobically treated liquid from the aerobic chamber to the anoxic chamber. ### Claim 62 (depends on 58) The multi-chambered biological reactor tank of claim 58, further comprising a lift station chamber comprising a pump configured to pump tertiary filter filtrate out of the biological reactor tank. ### Claim 63 (depends on 62) The wastewater recycling system of claim 62, wherein the biological reactor further comprises a tertiary filter backwash conduit operatively connected to recirculate tertiary filter backwash to the anaerobic chamber. ### Claim 64 (depends on 58) The multi-chambered biological reactor tank of claim 58, wherein the anaerobic chamber comprises a submersible pump that transfers liquid from the anaerobic chamber to the anoxic chamber. ### Claim 65 (depends on 58) The multi-chambered biological reactor tank of claim 58, wherein: vi) the aerobic chamber is a second aerobic chamber, vii) the biological reactor tank further comprises a first aerobic chamber, viii) the anoxic chamber is operatively connected to supply liquid to the first aerobic chamber, ix) the first aerobic chamber is operatively connected to supply liquid to the second aerobic chamber, and x) the first aerobic chamber includes a further sludge return conduit connected to transport sludge from the first aerobic chamber to the anaerobic chamber. ### Claim 66 A method of treating wastewater in a multi-chambered biological reactor tank, the multi-chambered biological reactor tank comprising an anaerobic chamber, an anoxic chamber, an aerobic chamber, and a biologically-active tertiary filter, the method comprising the steps of: anaerobically treating the wastewater in the anaerobic chamber; transferring liquid from the anaerobic chamber into the anoxic chamber; recirculating liquid from the aerobic chamber into the anoxic chamber; anoxically treating liquid in the anoxic chamber thereby biologically removing nitrates from the liquid treated within the anoxic chamber; aerobically treating liquid within the aerobic chamber; transferring sludge from both of the anoxic chamber and the aerobic chamber into the anaerobic chamber; transferring aerobically treated liquid from the aerobic chamber to the tertiary filter; and filtering and biologically treating the aerobically treated liquid in the tertiary filter. ### Claim 67 (depends on 66) The method of claim 66, wherein the multi-chambered biological reactor tank further comprises a lift station chamber and a tertiary filter chamber, the method further comprising the steps of: transferring tertiary filter filtrate from the tertiary filter chamber to the lift station chamber; and pumping the tertiary filter filtrate in the lift station chamber out of the biological reactor tank. ### Claim 68 (depends on 67) The method of claim 67, wherein nitrogen concentration in the tertiary filter filtrate is not greater than 10 mg/L. ### Claim 69 (depends on 66) The method of claim 66, further comprising the steps of: backwashing the tertiary filter; and recirculating tertiary filter backwash to the anaerobic chamber. ### Claim 70 (depends on 66) The method of claim 66, wherein the aerobic chamber is a second aerobic chamber, the multi-chambered biological reactor tank further comprising a first aerobic chamber, the method further comprising the steps of: transferring liquid from the anoxic chamber into the first aerobic chamber; transferring liquid from the first aerobic chamber into the second aerobic chamber; and transferring sludge from the first aerobic chamber to the anaerobic chamber.