Device and method for sulphur cycle-based advanced denitrification of waste water coupling autotrophic denitrification and heterotrophic denitrification

Patent metadata

Field	Value
Publication number	US-11434159-B2
Application number	US-202017081596-A
Country	US
Kind code	B2
Filing date	Oct 27, 2020
Priority date	Apr 10, 2020
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

The present invention provides a device and method for sulphur cycle-based advanced denitrification of wastewater coupling autotrophic denitrification and heterotrophic denitrification, and belongs to the technical field of wastewater treatment. The unit generating hydrogen sulfide during the wastewater treatment process adopts a lye to absorb hydrogen sulfide; the absorbed sulfide is introduced into an anoxic tank that removes nitrate nitrogen through sulfur-based autotrophic denitrification; and the remaining organic matters in the anaerobic methane-producing reaction tank are subjected to heterotrophic denitrification in the anoxic tank, and the anoxic unit combines the sulfur-based autotrophic denitrification with the heterotrophic denitrification of organic matters. The coupling of sulfur-based autotrophic denitrification and heterotrophic denitrification strengthens the removal of nitrate nitrogen. The biogas desulfurization process system only absorbs hydrogen sulfide and uses the absorbed sulfide in an anoxic system to realize the recovery and utilization of sulfur.

First claim

What is claimed is:

1. A device for sulphur cycle-based advanced denitrification of waste water coupling autotrophic denitrification and heterotrophic denitrification, comprising an anaerobic methane-producing reaction tank, a nitrification and denitrification reactor, and a sulfur recovery reaction tank that communicate with each other; wherein,
the bottom of the anaerobic methane-producing reaction tank is provided with a water distribution pipe connected to a duckbill valve, and an inlet pipe of the anaerobic methane-producing reaction tank communicates with the water distribution pipe;
the nitrification and denitrification reactor is sequentially provided with an anoxic denitrification zone, an aerobic nitrification zone and a sedimentation tank; and an outlet pipe of the anaerobic methane-producing reaction tank is connected to the anoxic denitrification zone; and
the top of the sulfur recovery reaction tank is provided with a gas collection pipe, the bottom of the sulfur recovery reaction tank is provided with a gas distribution device, a circulation pipe on the gas collection pipe is connected to the gas distribution device, and a circulation pump is disposed on the circulation pipe.

2. The device for sulphur cycle-based advanced denitrification of waste water coupling autotrophic denitrification and heterotrophic denitrification according to claim 1 , wherein: the top of the anaerobic methane-producing reaction tank is provided with a three-phase separator, a gas chamber and a biogas pipe; the top of the three-phase separator is provided with a first outlet weir connected to the outlet pipe; and a first hydrogen sulfide gas analyzer is installed on the biogas pipe.

3. The device for sulphur cycle-based advanced denitrification of waste water coupling autotrophic denitrification and heterotrophic denitrification according to claim 2 , wherein: the anoxic denitrification zone is equipped with a stirrer; the aerobic nitrification zone is provided with an aerator connected to a blower; the aerobic nitrification zone is connected to the anoxic denitrification zone via a nitrification liquid return pump; the top of the sedimentation tank is provided with a second outlet weir; and the bottom of the sedimentation tank is provided with a sludge return pipe connected to the anoxic denitrification zone via a sludge return pump.

4. The device for sulphur cycle-based advanced denitrification of waste water coupling autotrophic denitrification and heterotrophic denitrification according to claim 3 , wherein: the sulfur recovery reaction tank is provided with a lye feeding pipe connected to a lye feeding pump, and the lye feeding pump is connected to a lye storage tank.

5. The device for sulphur cycle-based advanced denitrification of waste water coupling autotrophic denitrification and heterotrophic denitrification according to claim 4 , wherein: a pH probe is installed in the sulfur recovery reaction tank, and a second hydrogen sulfide gas analyzer is installed on the circulation pipe.

6. The device for sulphur cycle-based advanced denitrification of waste water coupling autotrophic denitrification and heterotrophic denitrification according to claim 5 , wherein: the bottom of the sulfur recovery reaction tank is provided with a lye return pipe connected to the anoxic denitrification zone via a lye return pump.

7. A denitrification method for waste water using the device for sulphur cycle-based advanced denitrification of waste water coupling autotrophic denitrification and heterotrophic denitrification according to claim 1 , comprising the following steps:
step S 110 : adding anaerobic granular sludge to the anaerobic methane-producing reaction tank, and controlling the water intake (Q) or hydraulic retention time (HRT) of the anaerobic methane-producing reaction tank according to the COD removal rate (R COD ) to control the R COD in the anaerobic methane-producing reaction tank at 80% to 85%;
step S 120 : after the gas produced in the anaerobic methane-producing reaction tank enters the sulfur recovery reaction tank, adding a lye to control the pH at 7.5 to 8.5, and controlling the gas flow via the circulation pump to adjust the hydrogen sulfide removal rate in the sulfur recovery reaction tank to greater than 85%;
step S 130 : inoculating a traditional activated sludge to the nitrification and denitrification reactor, and controlling the sludge concentration at 3,000 mg/L to 5,000 mg/L, the operating pH at 7.0 to 8.5, and the sludge return ratio at 50% to 100%;
step S 140 : controlling the dissolved oxygen (DO) in the anoxic denitrification zone to less than 0.5 mg/L, returning the mixed solution in the aerobic nitrification zone to the anoxic denitrification zone via the nitrification liquid return pump, and controlling the nitrification liquid return ratio at 100% to 300%;
step S 150 : introducing the effluent from the anaerobic methane-producing reaction tank to the anoxic denitrification zone at a position of a front end of the anoxic denitrification zone, and introducing the lye in the sulfur recovery reaction tank to the anoxic denitrification zone at a position of ¼ to ½ of the total length of the anoxic denitration zone away from the front end via a lye return pump;
step S 160 : adjusting the aeration volume of the nitrification and denitrification reactor via the aerator to control the DO in the aerobic nitrification zone at 0.5 mg/L to 3 mg/L and to control the NH 4 + —N to less than 5 mg/L or the a NH 4 + —N removal rate to greater than 95%, wherein, if the indicators do not meet the requirements, the aeration volume is increased by 5% to 10%, and 2 HRTs are set; and
step S 170 : subjecting the mixed solution in the nitrification and denitrification reaction tank to mud-water separation in the sedimentation tank, and discharging the effluent from the mud-water separation.

8. The method according to claim 7 , wherein: in step S 110 , the sludge feeding concentration (MLSS) is 10 g/L to 20 g/L, the temperature in the anaerobic methane-producing reaction tank is adjusted to 30° C. to 35° C., and the pH is adjusted to 6.5 to 8.3.

9. The method according to claim 8 , wherein: in step S 110 , when R COD <80%, the water intake (Q) is reduced by 5% to 10%, and 2 HRTs are set; If R COD increases, the current water intake is maintained, and if R COD does not increase, the water intake is further reduced by 5% to 10%, and 2 HRTs are set;
and the process is repeated until R COD >80%; when R COD >85%, the water intake (Q) is increased by 5% to 10%, and 2 HRTs are set; if R COD continuously decreases, the current water intake is maintained, and if R COD does not decrease, the water intake is further increased by 5% to 10%, and 2 HRTs are set; and the process is repeated until R COD <85%.

10. A denitrification method for waste water using the device for sulphur cycle-based advanced denitrification of waste water coupling autotrophic denitrification and heterotrophic denitrification according to claim 2 , comprising the following steps:
step S 110 : adding anaerobic granular sludge to the anaerobic methane-producing reaction tank ( 1 ), and controlling the water intake (Q) or hydraulic retention time (HRT) of the anaerobic methane-producing reaction tank according to the COD removal rate (R COD ) to control the R COD in the anaerobic methane-producing reaction tank at 80% to 85%;
step S 120 : after the gas produced in the anaerobic methane-producing reaction tank ( 1 ) enters the sulfur recovery reaction tank ( 3 ), adding a lye to control the pH at 7.5 to 8.5, and controlling the gas flow via the circulation pump to adjust the hydrogen sulfide removal rate in the sulfur recovery reaction tank to greater than 85%;
st

Assignees

• Univ Beijing Jiaotong

Inventors

• Yao Hong
• Yang Anming
• Tian Sheng

Classifications

• B01D53/52 Primary

  Hydrogen sulfide · CPC title

• B01D53/18

  Absorbing units; Liquid distributors therefor (B01D3/16, B01D3/26, B01D3/30 take precedence; packing elements B01J19/30, B01J19/32) · CPC title

• C02F2209/08

  Chemical Oxygen Demand [COD]; Biological Oxygen Demand [BOD] · CPC title

• C02F2201/005

  Valves · CPC title

• C02F3/006

  Regulation methods for biological treatment · CPC title