CN114772859A

CN114772859A - Low-carbon biological treatment system for pig farm excrement and method for treating excrement

Info

Publication number: CN114772859A
Application number: CN202210474232.5A
Authority: CN
Inventors: 王红艳; 徐胜台; 宫明; 魏源送
Original assignee: Beijing Zhinonggu Technology Co ltd; Beijing Dabeinong Technology Group Co Ltd
Current assignee: Beijing Zhinonggu Technology Co ltd; Beijing Dabeinong Biotechnology Co Ltd
Priority date: 2022-04-29
Filing date: 2022-04-29
Publication date: 2022-07-22

Abstract

The utility model provides a dirty low carbon biological treatment system of pig farm excrement, includes tank, grid pond, sand setting catch basin, equalizing basin, anaerobic jar, natural pond liquid collecting tank, solid-liquid separation pond, one-level A pond, one-level O pond, second grade A pond, second grade O pond, sedimentation tank, thoughtlessly congeal/flocculation basin, final sedimentation tank, disinfection pond and oxidation pond to connect gradually through the pipeline. After pretreatment (a grating tank and a grit collecting tank) is carried out on raw water in a water storage tank, most of the raw water enters an anaerobic tank to generate methane, meanwhile, a small amount of sewage enters a first-stage A tank and a second-stage A tank respectively, the collected anaerobic methane liquid enters the first-stage A tank after solid-liquid separation, and the subsequent tank bodies are connected in sequence. And the supernatant obtained by mud-water separation in the sedimentation tank enters an oxidation pond for storage after being treated in a coagulation/flocculation tank, a final sedimentation tank and a disinfection tank. The system realizes biological carbon and nitrogen removal with low energy consumption and low medicine consumption in a multi-point water inlet and multi-point backflow mode. The method can greatly reduce the standard discharge treatment cost of the livestock and poultry manure, is low-carbon and simple and convenient to operate, and is easy to popularize.

Description

Low-carbon biological treatment system for pig farm excrement and method for treating excrement

Technical Field

The invention belongs to the field of livestock and poultry breeding environment protection, and particularly relates to a low-carbon biological treatment system for feces in a pig farm and a method for treating the feces by using the same.

Background

CODcr of the livestock and poultry breeding wastewater is as high as 3,000-12,000 mg/L, ammonia nitrogen is as high as 800-2,200 mg/L, and SS exceeds standard by tens of times. With the gradual importance of China on the resource utilization of livestock and poultry breeding manure, anaerobic fermentation and biogas engineering become the most important manure resource utilization modes. The biogas slurry produced by anaerobic fermentation has the characteristics of low C/N, proper temperature (about 35 ℃) and high ammonia nitrogen concentration, and is suitable for being treated by adopting a novel biological denitrification technology.

Although the two-stage AO process is preferred in biogas slurry treatment of most pig farms which are discharged up to the standard, an external carbon source is required for denitrification and denitrification due to the failure of full utilization of the carbon source in the original sewage and the biological denitrification principle, and a large amount of aeration wastes electric energy in the nitrification process, so that the two-stage AO process is uneconomical, low-carbon and environmentally-friendly.

Disclosure of Invention

In order to solve the technical problems, the invention mainly aims to provide a low-carbon biological treatment system for the excrement in the pig farm. The specific scheme is as follows:

a pig farm feces low-carbon biological treatment system is characterized by comprising a storage tank, a grid tank, a grit water collecting tank, an adjusting tank, an anaerobic tank, a biogas slurry collecting tank, a solid-liquid separation tank, a first-stage A tank, a first-stage O tank, a second-stage A tank, a second-stage O tank, a sedimentation tank, a coagulation/flocculation tank, a final sedimentation tank, a disinfection tank and an oxidation pond which are sequentially connected through pipelines;

after raw water in a storage pool is pretreated by a grating pool and a grit collecting pool, about 96-99% of sewage (the actual proportion is determined according to the field situation) enters an anaerobic tank to generate biogas, and the rest small amount of sewage respectively enters a first-stage A pool and a second-stage A pool, so that multi-point water inlet is realized, and the existing carbon source in the raw sewage is fully utilized;

the second-stage O tank is respectively connected with the first-stage A tank and the second-stage A tank through reflux pumps, and biological nitrogen removal and carbon removal with low energy consumption and low medicine consumption are realized through multi-point reflux.

Further, the sum of the water inlet of the first-stage A pool and the second-stage A pool from the grit water collecting pool is about 1% -4% of the total water amount.

Further, the reflux ratio of the second-level O pool to the first-level A pool and the second-level A pool is respectively 200% and 100%.

Further, the first-stage O tank and the second-stage O tank are respectively provided with an aeration system for regulating and controlling aeration quantity.

Further, the sedimentation tank sets up mud backwash pump and supernatant delivery pipe, the sedimentation tank pass through the mud backwash pump with one-level A pond is connected, the sedimentation tank pass through the supernatant delivery pipe with it connects to congeal/flocculation basin.

Furthermore, the biological treatment system also comprises a sludge tank, a mud pressing system and a composting system, wherein the sedimentation tank, the anaerobic tank and the final sedimentation tank are all connected with the sludge tank and enter the composting system after passing through the mud pressing system, the grid slag of the grid tank is transported outwards, and the sludge in the solid-liquid separation tank also enters the sludge tank and enters the composting system after passing through the mud pressing system.

Further, the biological treatment system also comprises a gas storage membrane, a methane purification system and a boiler system, wherein the anaerobic tank is connected with the gas storage membrane, the gas storage membrane is connected with the methane purification system, the methane purification system is connected with the boiler system, and the boiler system can heat the anaerobic tank and can also heat shower water of staff.

The invention also provides a method for treating livestock and poultry excrement by using the biological treatment system, which comprises the following steps:

(1) after raw water in the storage pool is pretreated by a grid pool and a grit collecting pool, 96-99% of sewage enters an anaerobic tank to generate methane, and the rest sewage respectively enters a first-stage A pool and a second-stage A pool;

(2) treating digestive juice of the anaerobic tank by sequentially passing through a primary A pool, a primary O pool, a secondary A pool, a secondary O pool, a sedimentation pool, a coagulating sedimentation pool, a disinfection pool and an oxidation pond;

(3) in the treatment process, the nitrifying liquid in the second-stage O tank respectively flows back to the first-stage A tank and the second-stage A tank;

(4) in the treatment process, the mixed liquid in the second-stage O pool is subjected to mud-water separation treatment in a sedimentation pool, and the supernatant is treated in a coagulation/flocculation pool, a final sedimentation pool and a disinfection pool and then enters an oxidation pond for storage; and the sludge in the sedimentation tank flows back to the first-stage A tank.

Further, in the step (1), the sum of the water inlet of the first-level A pool and the water inlet of the second-level A pool is about 1-4% of the total water amount.

Further, in the step (3), the reflux ratio of the second-level O pool to the first-level A pool and the reflux ratio of the second-level A pool to the second-level A pool are respectively 200% and 100%.

Compared with the prior art, the invention has the following beneficial effects:

in order to reduce the medicine consumption and the energy consumption in the biological treatment process, the invention reasonably distributes and fully utilizes the carbon source in the raw water by multi-point water inlet; meanwhile, the denitrification process is skillfully preposed by combining multipoint reflux, so that low-carbon and high-efficiency biological carbon and nitrogen removal is realized, and the high-efficiency, low-consumption and standard-reaching discharge of the livestock and poultry breeding sewage is promoted.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

Example 1

A pig farm feces low-carbon biological treatment system comprises a storage tank, a grid tank, a grit collecting tank, an adjusting tank, an anaerobic tank, a biogas slurry collecting tank, a solid-liquid separation tank, a first-level A tank, a first-level O tank, a second-level A tank, a second-level O tank, a sedimentation tank, a coagulation/flocculation tank, a final sedimentation tank, a disinfection tank and an oxidation pond, which are sequentially connected through pipelines;

after raw water in the storage pool is pretreated by the grid pool and the grit water collecting pool, 98 percent of sewage enters the anaerobic tank to produce methane, 1.5 percent of sewage enters the first-stage A pool, and 0.5 percent of sewage enters the second-stage A pool, so that multi-point water inlet is realized, and the existing carbon source is fully utilized;

the second-stage O tank is respectively connected with the first-stage A tank and the second-stage A tank through reflux pumps, the reflux proportion is respectively 200% and 100%, and biological denitrification and carbon removal are adjusted through multi-point reflux.

When the low-carbon biological treatment system for the pig farm excrement runs, the pig farm excrement, urine and pig farm flushing water are collected into the storage tank together, are pretreated by the grating tank and the grit collecting tank, then enter the regulating tank, and then enter the anaerobic tank to produce methane, so that energy is recovered. Biogas generated by the anaerobic tank is stored by the gas storage membrane, purified by the biogas purification system and then heated by the boiler system, can be used for heat preservation of the anaerobic tank body in winter, and can be used for hot water shower of staff in summer. Meanwhile, 1.5 percent of the raw sewage enters the first-stage A tank and is subjected to denitrification or partial denitrification with the reflux nitrifying liquid in the second-stage O tank, and the energy consumption for oxidizing organic matters in the first-stage O tank is reduced. Collecting biogas slurry in an anaerobic tank, performing solid-liquid separation, allowing the biogas slurry to enter a first-stage A pool, treating, and allowing the biogas slurry to enter a first-stage O pool for oxidation reaction; then the mixture enters a second-level A pool for reaction, and the pool has low nitrate nitrogen concentration due to low return ratio of the nitrifying liquid and 0.5 percent of raw sewage distribution, and COD/NO of the sewage₃The proportion of-N is easy to control in the range suitable for short-cut denitrification and anaerobic ammonia oxidation, and low-carbon denitrification is realized. The mixed liquid in the second-stage O pool is subjected to mud-water separation treatment in a sedimentation pool, and the supernatant is treated in a coagulation/flocculation pool, a final sedimentation pool and a disinfection pool and then enters an oxidation pond for storage, and finally is discharged after reaching the standard;

the sedimentation tank in the system is provided with a sludge reflux pump and a supernatant discharge pipe; the sedimentation tank is communicated with the first-stage A tank through a sludge reflux pump. And part of sludge enters a first-stage A pool through a reflux pump to adjust biomass. And the excess sludge in the sedimentation tank and the final sedimentation tank, the sludge discharged by the anaerobic tank and the sludge generated by the solid-liquid separation tank all enter a sludge tank, are treated by a sludge pressing system and finally enter an aerobic composting system for composting. And (5) carrying out treatment on the grid slag of the grid pool.

The primary O tank and the secondary O tank in the system can independently open and close the aeration system, independently control the aeration quantity, and are realized by additionally arranging a tee joint, an electric valve and a manual valve at the joint of an aeration pipeline and an air supply pipeline of a blower room.

In the system, after the reaction of the second-stage O tank is finished, the wastewater enters a sedimentation tank for sedimentation, is further dephosphorized and disinfected in a disinfection tank through a coagulation/flocculation tank and a final sedimentation tank, and finally treated water enters an oxidation pond for short-term storage and then is discharged after reaching the standard.

And a reflux pump is arranged in the second-stage O tank, and the nitrified liquid is respectively refluxed to the first-stage A tank and the second-stage A tank, wherein the reflux ratio is respectively 200% and 100%.

The nitrifying liquid in the second-stage O tank flows back to the first-stage A tank, the reflux ratio is set to be higher, and the nitrate nitrogen concentration is high; in combination with the COD of the step-by-step influent water, the COD in the first-level A tank is also higher, so most of the COD and nitrate nitrogen are removed through denitrification, namely denitrification mainly occurs here.

The nitrified liquid in the second-level O tank flows back to the second-level A tank, and the aeration energy consumption of the first-level O tank is greatly reduced because most of COD is removed in the first-level A tank. At the moment, the proportion of the nitrifying liquid which flows back from the second-level O pool to the second-level A pool is adjusted to be low, so that the nitrate nitrogen is in a relative excess state when COD/NO is generated₃when-N is lower than 2.8, the system has short-cut denitrification reaction, even anaerobic ammoxidation reaction, and is beneficial to biological denitrification.

Example 2

The pig farm manure low-carbon biological treatment system in the embodiment 1 is adopted in a certain pig farm manure cleaning process, COD, SS, ammonia nitrogen and TP of raw manure in a storage pool are 12000-20000, 10000-18000, 800-2000 and 90-180 mg/L respectively in the form of water-soaking manure, and after the raw manure is treated by the low-carbon treatment system, the water quality concentration (same as the above) entering an oxidation pond is about 150, 100, 80 and 8mg/L respectively. Through tests, compared with the traditional two-stage AO process, the process can achieve the same pollutant removal effect by multi-point water inflow and multi-point backflow, can reduce the addition of 20 to 50 percent of external carbon source, reduce the sludge yield by 30 to 70 percent, save the aeration energy consumption by 10 to 30 percent and greatly reduce the operation cost.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A pig farm excrement low-carbon biological treatment system is characterized by comprising a storage tank, a grid tank, a sand setting and water collecting tank, an adjusting tank, an anaerobic tank, a biogas slurry collecting tank, a solid-liquid separation tank, a primary A tank, a primary O tank, a secondary A tank, a secondary O tank, a sedimentation tank, a coagulation/flocculation tank, a final sedimentation tank, a disinfection tank and an oxidation pond which are sequentially connected through pipelines;

the grit water collecting tank is respectively connected with the first-stage A tank and the second-stage A tank through pipelines, so that multi-point water inflow is realized, and the existing carbon source in the original sewage is fully utilized;

the second-level O tank is respectively connected with the first-level A tank and the second-level A tank through a reflux pump, and biological nitrogen removal and carbon removal with low energy consumption and low medicine consumption are realized through multi-point reflux.

2. The biological treatment system of claim 1, wherein the reflux ratio of the secondary O tank to the primary A tank and the secondary A tank is 200% and 100%, respectively.

3. The biological treatment system of claim 1, wherein the sum of the water from the primary and secondary a ponds is about 1% to about 4% of the total water.

4. The biological treatment system as recited in claim 1, wherein the primary O tank and the secondary O tank are respectively provided with an aeration system for regulating and controlling aeration amount.

5. The biological treatment system of claim 1, wherein the sedimentation tank is provided with a sludge reflux pump and a supernatant discharge pipe, the sedimentation tank is connected with the first-stage A tank through the sludge reflux pump, and the sedimentation tank is connected with the coagulation/flocculation tank through the supernatant discharge pipe.

6. The biological treatment system according to claim 1, further comprising a sludge tank, a sludge pressing system and a composting system, wherein the sedimentation tank, the anaerobic tank and the final sedimentation tank are all connected with the sludge tank and enter the composting system after passing through the sludge pressing system, the grid slag in the grid tank is transported outwards for treatment, and the sludge in the solid-liquid separation tank also enters the sludge tank and enters the composting system after passing through the sludge pressing system.

7. The biological treatment system of claim 1, further comprising a gas storage membrane, a biogas purification system and a boiler system, wherein the anaerobic tank is connected with the gas storage membrane, the gas storage membrane is connected with the biogas purification system, the biogas purification system is connected with the boiler system, and the boiler system can heat the anaerobic tank and can also heat shower water of employees.

8. A method for treating livestock and poultry manure by using the biological treatment system of claim 1, which is characterized by comprising the following steps:

(1) after raw water in the storage pool is pretreated by a grating pool and a grit collecting pool, 96-99% of sewage enters an anaerobic tank to generate methane, and the rest sewage respectively enters a first-stage A pool and a second-stage A pool;

(2) anaerobic tank digestive juice is treated by sequentially passing through a primary A tank, a primary O tank, a secondary A tank, a secondary O tank, a sedimentation tank, a coagulation/flocculation tank, a final sedimentation tank, a disinfection tank and an oxidation pond;

(4) in the treatment process, the mixed liquid in the second-stage O tank is subjected to mud-water separation treatment in a sedimentation tank, the supernatant is treated in a disinfection tank, a coagulation/flocculation tank, a final sedimentation tank and a disinfection tank and then enters an oxidation pond for storage, and the sludge in the sedimentation tank flows back to the first-stage A tank.

9. The method of claim 8, wherein in step (1), the sum of the water input from the first-stage A tank and the second-stage A tank from the grit collecting tank is about 1-4% of the total water amount.

10. The method according to claim 8, wherein in the step (3), the reflux ratio of the nitrifying liquid from the secondary O tank to the primary A tank and the reflux ratio of the nitrifying liquid from the secondary O tank to the secondary A tank are respectively 200% and 100%.