# US 2014/0197097 A1 · Simultaneous Anoxic Biological Phosphorus and Nitrogen Removal with Energy Recovery > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0197097 A1 - Document ID: US20140197097A1 - Status: Published application - Kind: A1 - Application number: 14/216,052 - Filed: 2014-03-17 - Published: 2014-07-17 - Earliest claimed: 2010-09-20 - Assignees: American Water Works Company, Inc. - Applicants: American Water Works Company, Inc. - Inventors: EUGENIO WILLIAM GIRALDO - Web page: https://patentgrep.com/patent/US20140197097A1 ## CPC - C02F 3/302: {Nitrification and denitrification treatment (C02F3/308 takes precedence)} - C02F 3/1268: {Membrane bioreactor systems} - C02F 3/2846: {using upflow anaerobic sludge blanket [UASB] reactors} - C02F 3/308: {Biological phosphorus removal} - C02F 3/1215: {Combinations of activated sludge treatment with precipitation, flocculation, coagulation and separation of phosphates} - C02F 3/1273: {Submerged membrane bioreactors} - C02F 3/28: Anaerobic digestion processes - C02F 3/307: {characterised by direct conversion of nitrite to molecular nitrogen, e.g. by using the Anammox process} - C02F 2303/10: Energy recovery - C02F 2303/16: Regeneration of sorbents, filters - Y02E 50/30: Fuel from waste, e.g. synthetic alcohol or diesel - Y02W 10/10: Biological treatment of water, waste water, or sewage - Y02W 10/30: Wastewater or sewage treatment systems using renewable energies - 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) - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT ## Abstract Methods and systems are provided for treating wastewater to simultaneously remove nitrogen, carbon, and phosphorus, while recovering energy in the form of methane and carbon dioxide. An ammonia-containing stream is directed to a pretreatment tank that produces excess sludge, biogas, and a pretreated stream. The pretreated stream has at least 45% less carbon than the ammonia-containing stream. The pretreated stream is then directed to an anoxic tank, which promotes phosphorus release and fermentation of particulate and dissolved organic matter. The mixed liquor is transferred to an aerated tank having low dissolved oxygen concentrations to promote development of phosphorus-release bacteria that is eventually recycled to the anoxic tank by way of the return activated sludge. Simultaneous nitrification, denitrification, and phosphorus release occur in the aerated tank. A membrane tank separates treated effluent from activated sludge in a membrane tank. ## Claims ### Claim 1 A process for treating wastewater to simultaneously remove organic matter, nitrogen, and phosphorus with energy recovery, the process comprising: providing a wastewater stream in a pretreatment tank that produces, at least, excess sludge, biogas, and a pretreated stream, wherein the biogas comprises at least methane and carbon dioxide; flowing the pretreated stream and return activated sludge to an anoxic tank operating under anoxic conditions; mixing the pretreated stream and the return activated sludge in the anoxic tank to form a mixed liquor; transferring the mixed liquor to an aerated tank operating under microaerophilic conditions, to simultaneously effectuate nitrification, denitrification, phosphorous release, and phosphorus uptake in the aerated tank; and transferring the mixed liquor to a membrane tank that separates treated effluent from activated sludge containing microorganisms, wherein a first portion of the activated sludge is returned to the anoxic tank as the return activated sludge. ### Claim 2 (depends on 1) The process of claim 1, wherein the wastewater stream is plant influent wastewater that is to be treated by carbon removal. ### Claim 3 (depends on 1) The process of claim 1, wherein the biogas comprises about 60% of the methane. ### Claim 4 (depends on 1) The process of claim 1, wherein the pretreatment tank is an upflow anaerobic sludge blanket (UASB) reactor. ### Claim 5 (depends on 2) The process of claim 2, wherein the biogas is treated such that it can be used to power a wastewater treatment plant that treats the plant influent wastewater by offsetting energy requirements of the wastewater treatment plant. ### Claim 6 (depends on 1) The process of claim 1, wherein the microaerophilic conditions in the aerated tank promote the fermentation of the particulate organic matter in the mixed liquor and allow for development of a microbial population used for phosphorus removal. ### Claim 7 (depends on 1) The process of claim 1, wherein a portion of the wastewater stream bypasses the pretreatment tank and is directed to the anoxic tank. ### Claim 8 (depends on 1) The process of claim 1, wherein the pretreatment tank utilizes chemically enhanced primary treatment (CEPT). ### Claim 9 (depends on 1) The process of claim 1, wherein the pretreatment tank utilizes a one-stage activated sludge system. ### Claim 10 A method for treating a wastewater stream while recovering energy, the method comprising: providing the wastewater stream in a pretreatment tank that comprises anaerobic microorganisms that react with the wastewater stream removing carbon to produce biogas and a pretreated stream, wherein the biogas comprises at least methane and carbon dioxide; upgrading the biogas produced by removing a majority of the carbon dioxide; using the upgraded biogas to generate electric power to offset part or all of electric power used at a water treatment plant that is treating the wastewater stream; and flowing the pretreated stream to an anoxic tank operating under anoxic conditions. ### Claim 11 (depends on 10) The method of claim 10, wherein about 60% of the carbon present in the wastewater stream is removed by a carbon removal pretreatment processes. ### Claim 12 (depends on 10) The method of claim 10, wherein the biogas is comprised of up to 80% methane. ### Claim 13 (depends on 10) The method of claim 10, wherein the biogas comprises at least 45% of the carbon present in the wastewater stream. ### Claim 14 (depends on 10) The method of claim 10, wherein phosphorus release occurs in the anoxic tank. ### Claim 15 (depends on 10) The method of claim 10, further comprising flowing effluent from the anoxic tank to an aerated tank, wherein nitrification, denitrification, phosphorus release, and phosphorus uptake occur simultaneously in the aerated tank. ### Claim 16 (depends on 10) The method of claim 10, wherein a concentration of dissolved oxygen in the aerated tank is less than 1.0 mg/l of fluid. ### Claim 17 A system for treating wastewater to simultaneously remove organic matter, nitrogen, and phosphorus with energy recovery, the system comprising: a pretreatment tank that receives plant influent wastewater and that comprises anaerobic microorganisms that react with the plant influent wastewater to produce, at least, biogas comprising methane, excess sludge, and a pretreated stream; an anoxic tank that receives the pretreated stream and return activated sludge and mix them to form a mixed liquor; an aerated tank that receives the mixed liquor from the anoxic tank, wherein the aerated tank operates under microaerophilic conditions, to simultaneously effectuate nitrification, denitrification, phosphorous release, and phosphorus uptake in the aerated tank; and a membrane tank that separates plant effluent wastewater from activated sludge, a portion of which is recycled to the anoxic tank as the return activated sludge. ### Claim 18 (depends on 17) The system of claim 17, wherein the aerated tank comprises one or more aerated tanks. ### Claim 19 (depends on 17) The system of claim 17, wherein nitrification, denitrification, phosphorus release, and phosphorus uptake occur simultaneously in the aerated tank. ### Claim 20 (depends on 17) The system of claim 17, wherein the concentration of dissolved oxygen in the second tank is less than 0.3 mg/l of the mixed liquor.