Method for wastewater treatment by urine separation, seawater addition, and nitrification and in-sewer denitrification

Patent metadata

Field	Value
Publication number	US-10093568-B2
Application number	US-201214123151-A
Country	US
Kind code	B2
Filing date	May 28, 2012
Priority date	Jun 1, 2011
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

A method for wastewater treatment which comprises (a) separating and/or collecting urine from the wastewater for pretreatment, (b) removing phosphorus from urine using seawater, (c) optionally oxidizing nitrogen from urine, and (d) discharging the phosphorus-removed and/or nitrogen-oxidized urine to a sewer.

First claim

We claim:

1. A method for wastewater treatment providing phosphorus recovery from urine, comprising:
(a) collecting urine or urine mixed with flushwater, separate from wastewater not used for said collecting said urine or urine mixed with flushwater, for pretreatment,
(b) introducing seawater to the collected urine or urine mixed with flushwater;
(c) at least after introducing the seawater, using a biological hydrolysis reactor to biologically hydrolyze urea in the urine to release ammonia from the urine and increase pH, causing precipitation of phosphorus;
(d) obtaining a low-phosphate ammonia-rich supernatant as an effluent from the biological hydrolysis reactor;
(e) nitrifying the urine by nitrifying the ammonia hydrolyzed from the urine to nitrate and/or nitrite using a biological nitrification reactor;
(f) removing nitrogen from the nitrified urine comprising discharging nitrified urine to a foul sewer to mix with the other wastewater for in-sewer denitrification and organic carbon removal; and
(g) discharging the low-phosphate ammonia-rich supernatant to a foul sewer for further wastewater treatment and, after discharging to the foul sewer, applying wastewater treatment to the phosphorus-removed urine to mix with other wastewater, thereby reducing phosphorus loading of domestic sewage in the further wastewater treatment.

2. The method of claim 1 , wherein the biological reactor comprises a biofilm reactor.

3. The method of claim 2 , wherein the biofilm reactor comprises a fixed biomass producing urease.

4. The method of claim 1 wherein the hydrolysis comprises allowing rapid hydrolysis of urine to a degree corresponding to a pH of about 8.9 or above.

5. The method of claim 1 , wherein the removal of phosphorus comprises recovery of phosphorus in the form of magnesium ammonium phosphate (MAP) or struvite.

6. A method for wastewater treatment providing phosphorus recovery from urine, comprising:
(a) collecting urine or urine mixed with flushwater, separate from wastewater not used for said collecting said urine or urine mixed with flushwater, for pretreatment,
(b) introducing seawater to the collected urine or urine mixed with flushwater;
(c) at least after introducing the seawater, using a biological hydrolysis reactor to biologically hydrolyze urea in the urine to release ammonia from the urine and increase pH, causing precipitation of phosphorus;
(d) obtaining a low-phosphate ammonia-rich supernatant as an effluent from the biological hydrolysis reactor;
(e) oxidizing nitrogen from the urine;
(f) nitrifying the urine by nitrifying the ammonia hydrolyzed from the urine to nitrate and/or nitrite using a biological nitrification reactor;
(g) removing nitrogen from the nitrified urine comprising discharging nitrified urine to a foul sewer to mix with the other wastewater for in-sewer denitrification and organic carbon removal; and
(h) discharging the phosphorus-removed and the nitrogen-oxidized urine to a foul sewer, enabling further wastewater treatment and, after discharging to the foul sewer, applying wastewater treatment to the phosphorus-removed urine to mix with other wastewater to achieve organic carbon removal, thereby reducing phosphorus loading of domestic sewage in the further wastewater treatment.

7. The method of claim 6 , wherein the biological reactor comprises a biofilm reactor.

8. The method of claim 7 , wherein the biofilm reactor comprises a fixed biomass producing urease.

9. The method of claim 6 wherein the hydrolysis comprises allowing rapid hydrolysis of urine to a degree corresponding to a pH of about 8.9 or above.

10. The method of claim 6 , wherein the removal of phosphorus comprises recovery of phosphorus in the form of magnesium ammonium phosphate (MAP) or struvite.

11. A method for wastewater treatment providing phosphorus recovery from urine, comprising:
(a) collecting urine or urine mixed with flushwater, separate from wastewater not used for said collecting said urine or urine mixed with flushwater, for pretreatment,
(b) introducing seawater to the collected urine or urine mixed with flushwater;
(c) at least after introducing the seawater, using a biological hydrolysis reactor to biologically hydrolyze urea in the urine to release ammonia from the urine and increasing pH, causing precipitation of phosphorus;
(d) obtaining a low-phosphate ammonia-rich supernatant as an effluent from the biological hydrolysis reactor; and
(e) discharging the phosphorus-removed urine to a foul sewer for further wastewater treatment and, after discharging to the foul sewer, applying wastewater treatment to the phosphorus-removed urine to mix with other wastewater to achieve in-sewer denitrification and organic carbon removal while reducing phosphorus loading of domestic sewage in the further wastewater treatment.

12. The method of claim 11 , wherein the removal of phosphorus comprises recovery of phosphorus in the form of magnesium ammonium phosphate (MAP) or struvite.

Assignees

• Chen Guanghao
• Mackey Hamish Robert
• Jiang Feng
• Chui Ho Kwong
• Univ Hong Kong Sci & Tech

Inventors

• Chen Guanghao
• Mackey Hamish Robert
• Jiang Feng
• Chui Ho Kwong

Classifications

• C02F2307/08

  Treatment of wastewater in the sewer, e.g. to reduce grease, odour · CPC title

• C02F2103/08

  Seawater, e.g. for desalination · CPC title

• C02F2103/005

  Black water originating from toilets · CPC title

• C02F3/02 Primary

  Aerobic processes · CPC title

• C02F2209/06

  pH · CPC title