Integrated deammonification process for wastewater reclamation

Patent metadata

Field	Value
Publication number	US-11220449-B2
Application number	US-202016862481-A
Country	US
Kind code	B2
Filing date	Apr 29, 2020
Priority date	Apr 29, 2019
Publication date	Jan 11, 2022
Grant date	Jan 11, 2022

Abstract

A deammonification system 100 and process for treating wastewater are disclosed herein. The system and process may involve an anaerobic reactor 204 operable to produce biogas 2 from organic carbon in the wastewater 1, and a deammonification unit including (i) one or more anoxic chambers 302 in fluid communication with the anaerobic reactor 204, wherein each of the one or more anoxic chambers 302 houses a plurality of biocarriers 306, wherein each of the plurality of biocarriers 306 includes a biofilm of anaerobic ammonium oxidation bacteria, and (ii) one or more oxic chambers 304 operable to produce nitrite from ammonia and/or ammonium, wherein the wastewater processed in an anoxic chamber 302 of the one or more anoxic chambers 302 is channeled to an oxic chamber 304 of the one or more oxic chambers 304 which is adjacent to and downstream of the anoxic chamber 302.

First claim

The invention claimed is:

1. A deammonification system for treating wastewater comprising:
an anaerobic reactor operable to produce biogas from organic carbon in the wastewater;
a degasser configured to receive wastewater from the anaerobic reactor, wherein the wastewater from the anaerobic reactor comprises the biogas dissolved therein, wherein the degasser is operable to recover the biogas dissolved in the wastewater from the anaerobic reactor; and
a deammonification unit comprising (i) one or more anoxic chambers in fluid communication with the anaerobic reactor, wherein each of the one or more anoxic chambers houses a plurality of biocarriers, wherein each of the plurality of biocarriers comprises a biofilm of anaerobic ammonium oxidation bacteria, and (ii) one or more oxic chambers operable to produce nitrite from ammonia and/or ammonium, wherein the wastewater processed in an anoxic chamber of the one or more anoxic chambers is channeled to an oxic chamber of the one or more oxic chambers which is adjacent to and downstream of the anoxic chamber.

2. The deammonification system of claim 1 , wherein the plurality of biocarriers housed in the one or more anoxic chambers occupy a volume of 30% to 50% thereof.

3. The deammonification system of claim 1 , wherein the wastewater fed to the one or more anoxic chambers has a COD/N ratio of 1 or less.

4. The deammonification system of claim 1 , wherein each of the one or more anoxic chambers and each of the one or more oxic chambers are configured to have a volume ratio ranging from 1:1 to 4:1.

5. The deammonification system of claim 1 , wherein oxygen is supplied to all of the one or more oxic chambers for producing the nitrite from the ammonia and/or ammonium.

6. The deammonification system of claim 1 , wherein the anaerobic reactor comprises an outlet to discharge the biogas produced in the anaerobic reactor.

7. The deammonification system of claim 1 ,
wherein the degasser comprises a flash chamber, wherein the flash chamber is configurable to be in fluid communication with a buffer tank arranged downstream of the flash chamber but upstream of the one or more anoxic chambers; or
wherein the degasser comprises a mixing chamber in fluid communication with one or more overflow weirs arranged in a cascading manner, wherein the wastewater is channeled from the mixing chamber to a cascade chamber of the degasser, wherein the cascade chamber is operable to strip the biogas dissolved in the wastewater from the anaerobic reactor, and wherein the wastewater from the cascade chamber is to be channeled to the one or more anoxic chambers.

8. The deammonification system of claim 1 , wherein the biogas comprises methane.

9. The deammonification system of claim 1 , further comprising a clarifier or a membrane filtration unit operable to separate sludge from the wastewater processed in the deammonification unit and to recycle the sludge to a most upstream anoxic chamber.

10. The deammonification system of claim 9 , further comprising
a reverse osmosis unit arranged in fluid communication and downstream of the membrane filtration unit, wherein (i) the membrane filtration unit and (ii) the reverse osmosis unit are operable to produce water; and/or
an anaerobic digestion unit operable to:
(a) receive sludge from:
(i) the anaerobic reactor; and/or
(ii) the clarifier or the membrane filtration unit;

and
(b) to produce biogas from the sludge.

11. The deammonification system of claim 9 , wherein two or more anoxic chambers are present, and wherein the membrane filtration unit is integrated in a most downstream anoxic chamber.

12. A deammonification process for treating wastewater, comprising:
introducing the wastewater to an anaerobic reactor operable to produce a biogas from organic carbon in the wastewater;
feeding the wastewater from the anaerobic reactor to a degasser, wherein the wastewater from the anaerobic reactor comprises the biogas dissolved therein, wherein the degasser is operable to recover the biogas dissolved in the wastewater from the anaerobic reactor; and
treating the wastewater from the anaerobic reactor in a deammonification unit, wherein the deammonification unit comprises (i) one or more anoxic chambers in fluid communication with the anaerobic reactor, wherein each of the one or more anoxic chambers houses a plurality of biocarriers, wherein each of the plurality of biocarriers comprises a biofilm of anaerobic ammonium oxidation bacteria, and (ii) one or more oxic chambers operable to produce nitrite from ammonia and/or ammonium, wherein the wastewater processed in an anoxic chamber of the one or more anoxic chambers is channeled to an oxic chamber of the one or more oxic chambers which is adjacent to and downstream of the anoxic chamber.

13. The deammonification process of claim 12 , further comprising operating the anaerobic reactor to render the wastewater, which is fed to the one or more anoxic chambers, to have a COD/N ratio of 1 or less.

14. The deammonification process of claim 12 ,
wherein feeding the wastewater from the anaerobic reactor to the degasser comprises agitating the wastewater from the anaerobic reactor in a flash chamber to recover the biogas dissolved in the wastewater from the anaerobic reactor; or
wherein feeding the wastewater from the anaerobic reactor to the degasser comprises channeling the wastewater from the anaerobic reactor to a mixing chamber in fluid communication with one or more overflow weirs arranged in a cascading manner, wherein the wastewater is channeled from the mixing chamber to a cascade chamber of the degasser, wherein the cascade chamber is operable to strip the biogas dissolved in the wastewater from the anaerobic reactor, and wherein the wastewater from the cascade chamber is to be channeled to the one or more anoxic chambers.

15. The deammonification process of claim 12 , wherein the biogas comprises methane.

16. The deammonification process of claim 12 , wherein treating the wastewater in the deammonification unit comprises providing oxygen to all of the one or more oxic chambers to maintain dissolved oxygen therein at a concentration ranging from 0.3 mg O 2 /L to 2 mg O 2 /L.

17. The deammonification process of claim 12 , further comprising:
channeling the wastewater processed in the deammonification unit to a clarifier or a membrane filtration unit; and
operating the clarifier or the membrane filtration unit to separate sludge from the wastewater processed in the deammonification unit and to recycle the sludge to a most upstream anoxic chamber at a rate ranging from 0.5 to 2.5 times of a flowrate of the wastewater introduced to the anaerobic reactor;
and/or
operating an anaerobic digestion unit to:
(a) receive sludge from:
(i) the anaerobic reactor; and/or
(ii) the clarifier or the membrane filtration unit;

and
(b) to produce biogas from the sludge.

18. The deammonification process of claim 17 , comprising
operating (i) the membrane filtration unit to separate sludge from the wastewater processed in the deammonification unit and to recycle the sludge to the most upstream anoxic chamber at a rate ranging from 0.5 to 2.5 times of a flowrate of the wastewater introduced to the anaerobic reactor, and (ii) a reverse osmosis unit arranged in fluid communication and downstream of the membrane filtration unit, to produce water.

Assignees

• Univ Nanyang Tech

Inventors

• Gu Jun
• Liu Yu

Classifications

• Y02E50/30

  Fuel from waste, e.g. synthetic alcohol or diesel · CPC title

• Y02W10/20

  Sludge processing · CPC title

• B01D19/0036

  Flash degasification (the other groups take precedence) · CPC title

• C02F3/28

  Anaerobic digestion processes · CPC title

• C02F1/444

  by ultrafiltration or microfiltration · CPC title