CN115818845A

CN115818845A - Garbage transfer station sewage treatment system and process

Info

Publication number: CN115818845A
Application number: CN202310159693.8A
Authority: CN
Inventors: 刘苏; 宋灿辉; 杜昱; 汤波
Original assignee: Suzhou Suke Environmental Protection Science & Technology Co ltd
Current assignee: Suzhou Suke Environmental Protection Science & Technology Co ltd
Priority date: 2023-02-24
Filing date: 2023-02-24
Publication date: 2023-03-21

Abstract

The invention discloses a sewage treatment system of a garbage transfer station, which comprises a microbial pretreatment reactor, an anoxic tank, an aerobic tank and a built-in membrane tank which are sequentially communicated and treated, wherein a built-in membrane tank is arranged in the built-in membrane tank and is connected with a self-priming pump to realize negative pressure suction and filtration of outlet water, the microbial pretreatment reactor, the aerobic tank and the built-in membrane tank are connected with an air blower to realize aeration, the built-in membrane tank is connected with the anoxic tank and a sludge pipeline through a reflux pump, on one hand, nitrification liquid is refluxed to the anoxic tank, on the other hand, sludge is discharged through the sludge pipeline, and the microbial pretreatment reactor directly discharges sludge through the sludge pipeline. A treatment process utilizing the system is also disclosed. The invention can improve the removal efficiency of the pretreated pollutants, reduce the potential safety hazard, reduce the occupied area, reduce the operation energy consumption, simplify the process flow, reduce the carbon emission and realize the COD capture.

Description

Garbage transfer station sewage treatment system and process

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a sewage treatment system and a sewage treatment process for a garbage transfer station.

Background

Waste transfer station sewage is comparatively common sewage kind among the daily life, mainly produces in two links, firstly presses the filtrating that extrudes through rubbish compression system compression rubbish in-process, including the moisture that rubbish itself contains and the moisture that precipitation brought into, and the moisture that rubbish itself contains accounts for 5~ 15% of rubbish weight usually, secondly washes the sewage that rubbish holds the container and produce.

The types and the concentrations of pollutants in the garbage sewage are changed due to factors such as regions, seasons and the like, and the garbage sewage has the advantages of wide pollution source, complex and changeable water quality, high pollutant concentration, high-concentration COD (chemical oxygen demand) and BOD (biochemical oxygen demand) ₅ And ammonia nitrogen and total nitrogen are important characteristic contaminants. Typical waste transfer station wastewater quality is generally COD:5000 to 50000mg/L, BOD ₅ :3000 to 30000mg/L, ammonia nitrogen: 200 to 800mg/L, total nitrogen: about 200 to 800mg/L, high concentration of suspended matters, high salinity, certain heavy metals, oil substances and the like. It can be seen that the waste transfer station sewage has the characteristics of high COD, high SS, low ammonia nitrogen, heavy metal and oil-containing substances, good biodegradability, sufficient carbon source and the like.

In the prior art, a great deal of research and engineering examples exist for the treatment of domestic waste sewage, and almost all sewage treatment technologies and combinations thereof are used up. And the number of research and engineering examples for sewage treatment of a transfer station is small.

The current commonly used processes are as follows:

1. dosing pretreatment, anaerobic fermentation, aerobic fermentation and coagulation sedimentation, application number: 201010584824.X;

2. air flotation + pH adjustment + adsorption, application number: 201410103203.3;

3. flocculation + ozone oxidation + aerobic biological treatment, application No.: 201410721418.1;

4. DTRO + electrolytic oxidation + evaporation, application No.: 202011558089.5;

5. preliminary sedimentation tank + MBR + Fenton oxidation + high-density sedimentation tank + ozone oxidation, application number: 202011597749.0.

the treatment performance has the following problems:

1. pollutants such as pretreatment COD are removed efficiently, and the potential safety hazard exists in the anaerobism: sewage from refuse transfer stationWater quality is complex, pollutant concentration is high, COD:5000 to 50000mg/L, BOD ₅ :3000 to 30000mg/L, ammonia nitrogen: 200 to 800mg/L, total nitrogen: about 200 to 800mg/L, high suspended matter concentration, high salinity, certain heavy metals, oil substances and the like. Efficient preprocessing techniques are generally required for this situation. The conventional pretreatment techniques are mainly classified into the following types.

Hydrolysis acidification is used as a pretreatment process: belongs to the anaerobic hydrolysis acidification stage, controls the anaerobic biological treatment in the hydrolysis acidification stage, has low removal efficiency on COD, ammonia nitrogen, total nitrogen, heavy metal and grease, can only remove a small amount of suspended solid SS, is mainly used for improving the biodegradability of garbage sewage, and has limited effect.

Air flotation, flocculation and precipitation are used as pretreatment processes: most suspended solids, colloidal pollutants, heavy metals and grease substances can be removed, but COD, ammonia nitrogen and total nitrogen removal rate is not high, the COD removal rate is about 20% -30%, and a large amount of chemical agents are required to be added.

The electrochemical flocculation pretreatment process comprises the following steps: also belongs to flocculation, and has high energy consumption and limited treatment effect.

Ozone oxidation and Fenton oxidation: the method has high COD removal effect, particularly has better removal effect on macromolecular degradation-resistant COD, but cannot remove substances such as total nitrogen, ammonia nitrogen and the like, and can generate chemical sludge by Fenton oxidation if the method is used as a pretreatment process with very high operation cost.

2. Potential safety hazards exist: the general garbage transfer stations are built near urban areas, residential areas and densely populated areas. The safety requirement on the process is higher.

Anaerobic biological treatment is used as a pretreatment process: the generated methane has great potential safety hazard. Where methane and hydrogen are both flammable, explosive gases, and hydrogen sulfide is a malodorous gas.

Air flotation, flocculation, precipitation and Fenton oxidation: the processes need to adopt chemical agents such as coagulant, flocculant, acid, alkali, hydrogen peroxide, iron salt and the like, and the agents have potential safety management hazards in use, transportation and storage.

3. Account forThe land area is large: anaerobic biological treatment is used as a pretreatment method, and in a garbage sewage treatment process, the volume load designed by an anaerobic reactor is 5 to 8kgCOD/m ³ The retention time of the anaerobic reactor is generally too long, and is generally 5 to 8 days. Thus, the design volume of the anaerobic reactor is large, the investment cost is increased, and the occupied area is increased.

And the pollutant removal efficiency of the hydrolysis acidification as a pretreatment method is limited, so that the subsequent MBR load is increased, the design volumes of an anoxic tank and an aerobic tank are large, the investment cost is increased, and the occupied area is increased. The removal rate of COD by using air flotation, flocculation and precipitation as pretreatment methods is only 20-30%, and the same problems as those of a hydrolytic acidification method can be caused. And the general garbage transfer stations are in the urban areas, the land area is limited, and the requirements on the occupied area of the process and the system are high.

4. The operation energy consumption is high: the problem of energy consumption is mainly presented in three aspects,

firstly, pretreatment process treatment effect is limited, has increased follow-up MBR design and operating load, leads to whole system design massing grow, and equipment becomes many, and whole operation energy consumption becomes high.

Secondly, pretreatment can not remove macromolecule COD to high efficiency, and macromolecule COD is got rid of by follow-up MBR system, needs a large amount of energy consumptions.

And thirdly, the membrane used by the MBR in the anaerobic reactor and MBR process is generally an external tubular membrane, and the external tubular membrane filters the sewage by a mechanism that the sewage is pumped into the membrane through a water pump with large flow and high lift to carry out cross flow filtration at high flow rate, so that the sludge and water are separated by pressure to obtain clean produced water. In sewage treatment, the energy consumption of external tubular membrane per ton of water is 7 to 9kw.h/ton for 100 ton/day. The operation energy consumption is very high, and is a great waste for energy. Meanwhile, the method is particularly disadvantageous under the condition that carbon peak reaching and carbon neutralization targets need to be realized in China. The operation energy consumption is higher if ozone oxidation, electrolytic oxidation, DTRO, evaporation and other processes are adopted.

5. The complex operation and maintenance of the process flow is difficult to manage: the operation and maintenance capabilities of transfer station managers and operators are generally weak, and the transfer station has no professional operation capability of garbage and sewage treatment. Aiming at the air flotation, flocculation, sedimentation and Fenton oxidation process which needs to accurately control the dosage and add the dosage, the labor intensity and the operation difficulty of operators are increased, the process is not suitable for being used as a treatment process of the sewage of a garbage transfer station, and aiming at the long and complex process such as a pre-sedimentation tank, MBR, fenton oxidation, a high-density sedimentation tank and ozone oxidation, a plurality of point parameters need to be controlled to achieve the treatment effect, and the treatment difficulty is increased.

6. The carbon emission is large: the biogas is combusted through an emergency torch, more than 90% of the biogas consists of methane and carbon dioxide, a large amount of carbon dioxide gas is also generated after the methane is combusted, and the anaerobic reactor is adopted to treat the garbage sewage, so that a large amount of greenhouse gas is discharged into the atmosphere, carbon emission reduction is not facilitated, and carbon sequestration is realized. Is particularly disadvantageous under the carbon peak reaching and carbon neutralization targets in China.

7. COD capture: COD is removed by air floatation, flocculation, sedimentation, fenton oxidation and other processes through adding medicines, and finally the COD is discharged in the form of chemical sludge. Anaerobic biological treatment and MBR decompose COD into carbon dioxide and water through microbial degradation, and the processes are not beneficial to COD capture and resource recycling.

Aiming at the sewage treatment of a refuse transfer station, the anaerobic biological treatment has good effect as a pretreatment process on the whole, but has the problems of methane safety, limited application in the transfer station, low general efficiency of other treatment processes, increased investment cost, increased occupied area, increased operation energy consumption and the like. At present, no process and technology which have the advantages of simple process flow, high efficiency, safety, stability, land occupation saving, low consumption, low carbon and obvious treatment effect and are suitable for the sewage treatment of the refuse transfer station exist.

Disclosure of Invention

The purpose of the invention is as follows: in order to overcome the defects of the background art, the invention discloses a sewage treatment system of a refuse transfer station; the second purpose is to disclose a sewage treatment process of a refuse transfer station.

The technical scheme is as follows: the invention discloses a sewage treatment system of a garbage transfer station, which comprises a microbial pretreatment reactor, an anoxic tank, an aerobic tank and a built-in membrane tank which are sequentially communicated and treated, wherein a built-in membrane tank is arranged in the built-in membrane tank and is connected with a self-priming pump to realize negative pressure suction and filtration of outlet water, the microbial pretreatment reactor, the aerobic tank and the built-in membrane tank are connected with an air blower to realize aeration, the built-in membrane tank is connected with the anoxic tank and a sludge pipeline through a reflux pump, on one hand, nitrification liquid is refluxed to the anoxic tank, on the other hand, sludge is discharged through the sludge pipeline, and the microbial pretreatment reactor directly discharges sludge through the sludge pipeline.

Further, the microorganism pretreatment reactor comprises a reaction chamber, a separation chamber is arranged in the reaction chamber, a water inlet is formed in the reaction chamber, an overflow port is formed in the upper portion of the inner side of the reaction chamber, a guide cylinder is arranged on the upper portion of the separation chamber and communicated with the overflow port, a mud bucket is arranged at the bottom of the separation chamber and connected with a mud pipe, the mud pipe extends out of the microorganism pretreatment reactor, an overflow groove is formed in the upper portion of the separation chamber and connected with a water outlet pipe, the overflow groove extends to an anoxic pond, and an aerator and an evacuation port are arranged at the bottom of the reaction chamber.

Further, the process control conditions of the microorganism pretreatment reactor are as follows: the net growth coefficient of the sludge is 0.25 to 0.45kg/kgCOD, and the unit oxygen demand for removing COD is 0.3 to 0.6kgO ₂ The sludge load is 2.0-3.0 kgCOD/(kgMLSS. D), and the sludge concentration is 8-15g/L.

A sewage treatment process for a refuse transfer station comprises the following steps:

s1, carrying out microbial pretreatment on sewage;

and S2, after pretreatment, discharging the sewage to a built-in MBR for treatment and then discharging, wherein the built-in MBR consists of an anoxic tank, an aerobic tank and a built-in membrane tank.

Wherein S1 adopts the microbial pretreatment reactor to carry out microbial pretreatment, and the process control conditions are as follows: the net growth coefficient of the sludge is 0.25 to 0.45kg/kgCOD, and the unit oxygen demand for removing COD is 0.3 to 0.6kgO ₂ The sludge load is 2.0-3.0 kgCOD/(kgMLSS. D), and the sludge concentration is 8-15g/L.

Further, the process control conditions of the microbial pretreatment reactor are as follows: 99-98% of sludge water content and 20 ℃ of water temperature.

Further, the built-in MBR process control conditions are as follows: the sludge concentration is 12 to 15g/L, the sludge load is 0.1 to 0.3kgCOD/(kgMLSS.d), the denitrification rate is 0.04 to 0.13kgNO ₃ N/(kgMLSS. D), nitration rate of 0.02 to 0.08kgNH4 ⁺ N/(kgMLSS. D), the sludge yield coefficient is 0.15 to 0.30kgMLSS/kgCOD, the sludge age in an aerobic area is 25d, the reflux ratio of the mixed liquid is 20 to 40 times, and the built-in membrane operating flux is 8 to 12L/m ² h。

In the sewage treatment process of the refuse transfer station, a microorganism pretreatment reactor in S1 is used for rapidly adsorbing and degrading COD, ammonia nitrogen, total phosphorus, heavy metal and grease by designing sludge load and controlling aeration quantity and sludge concentration to strengthen the flocculation capacity of microorganisms, wherein one part of the COD, the ammonia nitrogen, the total phosphorus, the heavy metal and the grease are removed by the metabolism of the microorganisms, the other part of the COD, the ammonia nitrogen, the total nitrogen, the heavy metal and the grease are absorbed by the adsorption and flocculation capacity of the microorganisms, and the adsorbed and captured COD, the ammonia nitrogen, the total nitrogen, the heavy metal and the grease are removed in a sludge discharge mode; in S2, in an anoxic tank, part of pollutants are further decomposed and degraded through facultative aerobes, part of COD is removed, denitrification is carried out simultaneously, nitrate and nitrite are converted into nitrogen, so that the function of biological denitrification is achieved, effluent of the anoxic tank automatically flows to an aerobic tank, the pollutants are further decomposed and degraded by the aerobic bacteria, the COD is removed, nitrification is carried out simultaneously, a foundation is laid for denitrification, effluent of the aerobic tank is circulated back to the anoxic tank through a reflux pump, effluent of the aerobic tank flows into a built-in membrane tank, a built-in membrane tank is placed in the built-in membrane tank, the built-in membrane tank can be composed of a PTFE membrane component, negative pressure suction filtration is carried out through a water pump, active sludge is retained outside membrane wires, clean produced water is pressed into the inner sides of the membrane wires, and the clean produced water is collected through a water production pipe to obtain the clean effluent.

Has the advantages that: compared with the prior art, the invention has the advantages that:

1. solves the problem of low efficiency of removing the pre-treated pollutants

The microorganism pretreatment reactor has very high removal efficiency on indexes such as COD, ammonia nitrogen, total phosphorus, heavy metals, grease and the like (the removal efficiency of the COD is 85-95%, the removal efficiency of the ammonia nitrogen and the total nitrogen is 80-90%, and the removal efficiency of the total phosphorus is 85-90%). The method solves the technical difficulties that the removal efficiency of pretreatment processes such as air floatation, flocculation, precipitation, hydrolytic acidification, ozone oxidation, fenton oxidation and the like is low (the removal rate is about 20-30%), ammonia nitrogen and total nitrogen cannot be removed, and the like. And the pretreatment process can not remove the difficultly degraded macromolecular COD, and the difficultly degraded macromolecular COD enters the subsequent MBR, so that the effluent finally does not reach the standard. And the microorganism pretreatment reactor can preferentially adsorb the macromolecular COD difficult to degrade, and then remove through the mode high efficiency of row's mud, ensured that follow-up MBR goes out the stable discharge to reach standard of water.

2. Solve the problem of potential safety hazard

No dangerous and explosive methane or no foul gas such as hydrogen sulfide is generated. Instead, the microbial pretreatment reactor is adopted, which enhances the flocculation capability of microorganisms by controlling aeration quantity and sludge concentration, and quickly adsorbs and degrades COD (macromolecular COD which is difficult to degrade), ammonia nitrogen, total phosphorus, heavy metals and grease.

3. Solves the problem of large occupied area

Firstly, anaerobic biological treatment is taken as a pretreatment method, and the volume load designed by an anaerobic reactor is 5 to 8kgCOD/m in the garbage sewage treatment process ³ The retention time of the anaerobic reactor is generally too long, and is generally 5 to 8 days. The hydrolysis acidification as a pretreatment method has limited pollutant removal efficiency, leads to increased load of the subsequent MBR, further leads to large design volumes of an anoxic tank and an aerobic tank, increases investment cost and increases floor area. The removal rate of COD by using air flotation, flocculation and precipitation as pretreatment methods is only 20-30%, and the same problems as those of a hydrolytic acidification method can be caused. The designed volume load of the microbial pretreatment reactor can be 10 to 20kgCOD/m ³ More than twice of the anaerobic reactor. The volume and the occupied area are only about half of those of the anaerobic reactor. The investment cost and the occupied area are greatly saved.

And secondly, the microorganism pretreatment reactor has very high removal efficiency on key indexes such as COD, ammonia nitrogen, total phosphorus and the like, so that the load of a subsequent MBR process is reduced, the MBR load is greatly reduced, the design volumes of an anoxic tank and an aerobic tank can be greatly reduced, and the investment cost and the occupied area are further saved. For example, the volume of the subsequent MBR process can be reduced by more than 70% by using pretreatment processes such as air flotation, flocculation, precipitation, hydrolytic acidification and the like and using a microbial pretreatment reactor.

4. Solves the problem of high operation energy consumption

Firstly, microorganism pretreatment reactor all has very high efficiency of getting rid of to indexs such as COD, ammonia nitrogen, total phosphorus, heavy metal and grease to having reduced the load of follow-up MBR technology, the MBR load reduces by a wide margin, and whole system design size diminishes, and equipment diminishes, and whole operation energy consumption also can reduce very much.

And secondly, the microorganism pretreatment reactor can preferentially adsorb macromolecular COD and then efficiently remove the macromolecular COD in a sludge discharge mode. These macromolecular COD are not decomposed, so the energy consumption is low.

5. Solves the problem of difficult operation and maintenance management of complex process flow

The microorganism pretreatment reactor has simple structure, does not need complex control procedures and mainly depends on exerting the strong adsorption and degradation capability of the microorganism.

6. Solves the problem of large carbon emission

Flare combustion is no longer required and further a large amount of carbon dioxide gas is not produced.

7. Realize COD capture

The generated mud cakes with higher heat value are transported to an incineration plant along with a transfer station garbage truck for coordinated incineration treatment, and coordinated energy power generation is performed, so that resource recycling is realized, and the removal mode of pollutants is fundamentally changed.

8. The external tubular membrane filters sewage by a mechanism that sewage is pumped into the membrane through a water pump with large flow and high lift to perform cross flow filtration at high flow rate, so that mud and water are separated by pressure to obtain clean produced water. In sewage treatment, the energy consumption of external tubular membrane per ton of water is 7 to 9kw.h/ton for 100 ton/day. The operation energy consumption is very high, and is a great waste for energy. Meanwhile, the method is particularly disadvantageous under the condition that carbon peak reaching and carbon neutralization targets need to be realized in China. The built-in membrane adopts a negative pressure suction principle, the operation pressure is low, the operation energy consumption is low, and the built-in MBR water energy consumption per ton per day is only 1.2kw.h/ton. The built-in MBR saves energy consumption by more than 85 percent compared with the external MBR process.

Drawings

FIG. 1 is a schematic diagram of a processing system according to the present invention;

FIG. 2 is a schematic view of the structure of a microbial pretreatment reactor according to the present invention.

Detailed Description

The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.

The waste transfer station sewage treatment system shown in fig. 1 comprises a microorganism pretreatment reactor 1, an anoxic tank 2, an aerobic tank 3 and a built-in membrane tank 4 which are sequentially communicated for treatment, wherein the anoxic tank 2, the aerobic tank 3 and the built-in membrane tank 4 form a built-in MBR, a built-in membrane tank 5 is arranged in the built-in membrane tank 4 and is connected with a self-priming pump 6 to realize negative pressure suction filtration of outlet water, the microorganism pretreatment reactor 1, the aerobic tank 3 and the built-in membrane tank 4 are connected with an air blower 7 to realize aeration, the built-in membrane tank 4 is connected with a sludge pipeline through a reflux pump 8, and the sludge pipeline is simultaneously connected with the microorganism pretreatment reactor 1 and the anoxic tank 2 to discharge sludge.

The sewage of the refuse transfer station enters a microbial pretreatment reactor 1, the microbial pretreatment reactor 1 controls aeration through an air blower 7 to strengthen the flocculation capacity and the biological metabolism capacity of microbes, and organic matters, ammonia nitrogen, total nitrogen, heavy metals and grease are quickly adsorbed and degraded. One part of COD, ammonia nitrogen, total phosphorus, heavy metal and grease are removed by the metabolism of the microorganism, the other part of the COD, the ammonia nitrogen, the total nitrogen, the heavy metal and the grease which are adsorbed and captured are absorbed by the strong adsorption flocculation capacity of the microorganism and are removed in the form of sludge discharge. The microorganism pretreatment reactor 1 overflows to an anoxic tank 2, the anoxic tank 2 further decomposes and degrades partial pollutants through facultative bacteria, removes partial COD, simultaneously carries out denitrification, converts nitrate and nitrite into nitrogen, thereby achieving the function of biological denitrification, the effluent of the anoxic tank 2 flows to an aerobic tank 3 automatically, aeration is carried out through an air blower 7, a large amount of aerobic bacteria further decomposes and degrades most of pollutants, most of COD is removed, nitrification is carried out simultaneously, a foundation is laid for better denitrification, mixed liquid in the aerobic tank 3 flows to a built-in membrane tank 4 automatically, a built-in membrane tank 5 is placed in the built-in membrane tank 4, negative pressure suction filtration is carried out through a pump 6, the filtration direction is from outside to inside, active sludge is intercepted outside a membrane wire, clean produced water is pressed into the inner side of the membrane wire, and clean effluent is obtained after collection through a water production pipe and discharged after reaching the standard. The built-in membrane tank 4 is connected with the anoxic tank 2 and a sludge pipeline through a reflux pump 8, on one hand, nitrification liquid is refluxed to the anoxic tank 2, on the other hand, sludge is discharged through the sludge pipeline, and the microbial pretreatment reactor 1 directly discharges sludge through the sludge pipeline.

As shown in fig. 2, the microorganism pretreatment reactor 1 includes a reaction chamber 101, a separation chamber 102 is disposed in the reaction chamber 101, the reaction chamber 101 is provided with a water inlet 103 and an overflow opening 104 at an upper portion of an inner side, a draft tube 105 is disposed at an upper portion of the separation chamber 102 and communicated with the overflow opening 104, a sludge hopper 106 is disposed at a bottom of the separation chamber 102 and connected with a sludge discharge pipe 107 to extend out of the microorganism pretreatment reactor 1, an overflow groove 108 is disposed at an upper portion and connected with a water discharge pipe 109 to extend to the anoxic tank 2, and an aerator 110 and an evacuation opening 111 are disposed at a bottom of the reaction chamber 101.

The sewage enters the reaction chamber 101 through the water inlet 103, and the sewage is subjected to high-efficiency reaction in the reaction chamber 101. The air blower conveys air to the aerator 110 through the blast pipe, blast aeration is carried out on the reaction chamber 101 through the aerator 110, the aerator 110 needs to be uniformly arranged in the reaction chamber 101, and then the flocculation capacity and the biological metabolism capacity of microorganisms are enhanced, and organic matters, ammonia nitrogen, total nitrogen, heavy metals and grease are quickly adsorbed and degraded. One part of organic matter, ammonia nitrogen, total nitrogen, heavy metal and grease are got rid of by the metabolism of microorganism oneself, another part is absorbed by the powerful absorption flocculation ability of microorganism, later sewage enters into draft tube 105 through overflow mouth 104, the velocity of flow is reduced, be convenient for separate, later muddy water mixed liquor gets into separator 102 in the draft tube 105, carry out mud-water separation in separator 102, mud gets into in the mud fill 106, mud in the mud fill 106 is discharged through mud pipe 107, water overflow is to in the overflow launder 108, later discharge through outlet pipe 109. During maintenance, the slurry-water mixture in the reaction chamber is discharged through the drain port 111.

The COD of the sewage of the existing refuse transfer station reaches 10000mg/L, the ammonia nitrogen reaches 300mg/L, the total nitrogen reaches 400mg/L, the total phosphorus reaches 40mg/L, and a certain amount of heavy metal and grease substances are contained. Under the condition of high F/M, a large number of microorganisms contained in the garbage sewage are in a logarithmic proliferation stage, and cells are increased in a geometric series.

The waste transfer station sewage treatment system is used for sewage treatment.

Example 1: the sewage firstly enters a microbial pretreatment reactor, and the process control conditions of the microbial pretreatment reactor are as follows: the net growth coefficient of the sludge is 0.35kg/kgCOD, and the unit oxygen demand for removing COD is 0.45kgO ₂ The sludge load is 2.5 kgCOD/(kgMLSS.d), the sludge concentration is 11g/L, the sludge water content is 98.5 percent, and the water temperature is 20 ℃.

After pretreatment: COD is reduced to below 800 from 10000mg/L, the removal rate reaches 92%, ammonia nitrogen is reduced to below 30mg/L from 300mg/L, the removal rate reaches 90%, total nitrogen is reduced to below 30mg/L from 400mg/L, the removal rate reaches 92.5%, total phosphorus is reduced to below 4mg/L from 40mg/L, and the removal rate reaches 90%. The effluent C/N ratio was 26.7.

Sewage enters the built-in MBR, and the process control conditions of the built-in MBR are as follows: the sludge concentration is 13.5g/L, the sludge load is 0.2 kgCOD/(kgMLSS d), and the denitrification rate is 0.09kgNO ₃ N/(kgMLSS d), nitration rate 0.05kgNH4 ⁺ N/(kgMLSS. D), sludge yield coefficient of 0.22kgMLSS/kgCOD, sludge age of aerobic zone of 25d, reflux ratio of mixed liquor of 30 times, and built-in membrane operation flux of 10L/m ² h。

After the waste water is treated by the built-in MBR, COD in the waste water is reduced to below 400 from 800mg/L, the removal rate reaches 50%, and ammonia Nitrogen (NH) is generated ₃ N) is reduced to below 10mg/L from 30mg/L, the removal rate reaches 66.7 percent, the Total Nitrogen (TN) is reduced to 10mg/L from 30mg/L, the removal rate reaches 66.7 percent, the Total Phosphorus (TP) is reduced to below 2mg/L from 4mg/L, and the removal rate reaches 50 percent. Because the built-in membrane is adopted for filtration, the SS is reduced to below 5mg/L, and all indexes completely meet the Integrated wastewater discharge Standard (GB 8978-19)96 And the requirements of the water quality standard of sewage discharge to town sewers (GBT 31962-2016) on COD less than or equal to 500mg/L, ammonia nitrogen less than or equal to 45mg/L, total nitrogen less than or equal to 70mg/L and SS less than or equal to 400 mg/L.

The water quality parameters of the sewage treated in different stages in the embodiment are shown in the table 1:

table 1: example 1 Water quality parameters of wastewater treated at different stages

Example 2: the sewage firstly enters a microbial pretreatment reactor, and the process control conditions of the microbial pretreatment reactor are as follows: the net growth coefficient of the sludge is 0.25kg/kgCOD, and the unit oxygen demand for removing COD is 0.3kgO ₂ The sludge load is 2.0 kgCOD/(kgMLSS.d), the sludge concentration is 8g/L, the sludge water content is 99 percent, and the water temperature is 20 ℃.

After pretreatment: COD is reduced to below 600 from 10000mg/L, the removal rate reaches 94%, ammonia nitrogen is reduced to below 25mg/L from 300mg/L, the removal rate reaches 91.7%, total nitrogen is reduced to below 25mg/L from 400mg/L, the removal rate reaches 93.8%, total phosphorus is reduced to below 3mg/L from 40mg/L, and the removal rate reaches 92.5%. The effluent C/N ratio was 24.

Sewage enters a built-in MBR, and the built-in MBR has the following process control conditions: the sludge concentration is 12g/L, the sludge load is 0.1 kgCOD/(kgMLSS d), and the denitrification rate is 0.04kgNO ₃ N/(kgMLSS d), nitration rate 0.02kgNH4 ⁺ N/(kgMLSS d), sludge yield coefficient of 0.15kgMLSS/kgCOD, sludge age in aerobic area of 25d, mixed liquid reflux ratio of 20 times, and built-in membrane running flux of 8L/m ² h。

After the built-in MBR, COD in the garbage sewage is reduced to below 300 from 600mg/L, the removal rate reaches 50%, ammonia nitrogen is reduced to below 8mg/L from 25mg/L, the removal rate reaches 68%, total nitrogen is reduced to 8mg/L from 25mg/L, the removal rate reaches 68%, total phosphorus is reduced to below 2mg/L from 3mg/L, and the removal rate reaches 33%. Because the built-in membrane is adopted for filtration, the SS is reduced to be below 5mg/L, and all indexes completely meet the requirements of integrated wastewater discharge standard (GB 8978-1996) and urban wastewater discharge water quality standard (GBT 31962-2016) on COD being less than or equal to 500mg/L, ammonia nitrogen being less than or equal to 45mg/L, total nitrogen being less than or equal to 70mg/L and SS being less than or equal to 400 mg/L.

The water quality parameters of the sewage treated in different stages in the embodiment are shown in the table 2:

table 2: example 2 Water quality parameters of wastewater treated at different stages

Example 3: the sewage firstly enters a microbial pretreatment reactor, and the process control conditions of the microbial pretreatment reactor are as follows: the net growth coefficient of the sludge is 0.45kg/kgCOD, and the unit oxygen demand for removing COD is 0.6kgO ₂ The sludge load is 3.0 kgCOD/(kgMLSS. D), the sludge concentration is 15g/L, the sludge water content is 98 percent, and the water temperature is 20 ℃.

After pretreatment: COD is reduced to below 1200 from 10000mg/L, the removal rate reaches 88 percent, ammonia nitrogen is reduced to below 50mg/L from 300mg/L, the removal rate reaches 83.3 percent, total nitrogen is reduced to below 50mg/L from 400mg/L, the removal rate reaches 87.5 percent, total phosphorus is reduced to below 5mg/L from 40mg/L, and the removal rate reaches 87.5 percent. The effluent C/N ratio was 24.

Sewage enters the built-in MBR, and the process control conditions of the built-in MBR are as follows: the sludge concentration is 15g/L, the sludge load is 0.3 kgCOD/(kgMLSS d), and the denitrification rate is 0.13kgNO ₃ N/(kgMLSS. D), nitration rate 0.08kgNH4 ⁺ N/(kgMLSS. D), sludge yield coefficient of 0.30kgMLSS/kgCOD, sludge age of aerobic zone of 25d, reflux ratio of mixed liquor of 40 times, and built-in membrane operation flux of 12L/m ² h。

After the built-in MBR, COD in the garbage sewage is reduced to below 450 from 1200mg/L, the removal rate reaches 62.5%, ammonia nitrogen is reduced to below 10mg/L from 50mg/L, the removal rate reaches 80%, total nitrogen is reduced to 10mg/L from 50mg/L, the removal rate reaches 80%, total phosphorus is reduced to below 2mg/L from 5mg/L, and the removal rate reaches 60%. Because the built-in membrane is adopted for filtration, the SS is reduced to be below 5mg/L, and all indexes completely meet the requirements of comprehensive wastewater discharge standard (GB 8978-1996) and water quality standard for wastewater discharge to cities and towns (GBT 31962-2016) that COD is less than or equal to 500mg/L, ammonia nitrogen is less than or equal to 45mg/L, total nitrogen is less than or equal to 70mg/L and SS is less than or equal to 400 mg/L.

The water quality parameters of the sewage treated in different stages in the embodiment are shown in the table 3:

table 3: example 3 Water quality parameters of wastewater treated at different stages

To sum up, adopt the technical scheme of this application to carry out sewage treatment and have better removal effect and efficiency.

Claims

1. The sewage treatment system of the garbage transfer station is characterized by comprising a microorganism pretreatment reactor (1), an anoxic tank (2), an aerobic tank (3) and a built-in membrane tank (4) which are sequentially communicated for treatment, wherein the built-in membrane tank (4) is internally provided with a built-in membrane box (5) and is connected with a self-priming pump (6) to realize negative pressure suction filtration of outlet water, the microorganism pretreatment reactor (1), the aerobic tank (3) and the built-in membrane tank (4) are connected with an air blower (7) to realize aeration, the built-in membrane tank (4) is connected with the anoxic tank (2) and a sludge pipeline through a reflux pump (8), on one hand, nitrification liquid flows back to the anoxic tank (2), on the other hand, sludge is discharged through the sludge pipeline, and the microorganism pretreatment reactor (1) directly discharges sludge through the sludge pipeline.

2. The waste transfer station sewage treatment system of claim 1, wherein: the microorganism pretreatment reactor (1) comprises a reaction chamber (101), a separation chamber (102) is arranged in the reaction chamber (101), a water inlet (103) is formed in the reaction chamber (101), an overflow port (104) is formed in the upper portion of the inner side of the reaction chamber, a guide cylinder (105) is arranged on the upper portion of the separation chamber (102) and communicated with the overflow port (104), a mud bucket (106) is arranged at the bottom of the separation chamber (102) and connected with a mud discharge pipe (107) to extend out of the microorganism pretreatment reactor (1), an overflow groove (108) is arranged on the upper portion of the separation chamber and connected with a water outlet pipe (109) to extend to an anoxic pond (2), and an aerator (110) and an evacuation port (111) are arranged at the bottom of the reaction chamber (101).

3. The waste water treatment system of the garbage transfer station according to claim 2, wherein the process control conditions of the microbial pretreatment reactor are as follows: the net growth coefficient of the sludge is 0.25 to 0.45kg/kgCOD, and the unit oxygen demand for removing COD is 0.3 to 0.6kgO ₂ The sludge load is 2.0-3.0 kgCOD/(kgMLSS. D), and the sludge concentration is 8-15g/L.

4. The sewage treatment process of the refuse transfer station is characterized by comprising the following steps:

s1, carrying out microbial pretreatment on sewage;

s2, after pretreatment, discharging the sewage to a built-in MBR for treatment and then discharging, wherein the built-in MBR consists of an anoxic tank, an aerobic tank and a built-in membrane tank;

wherein S1 adopts the microorganism pretreatment reactor of claim 2 to carry out microorganism pretreatment, and the process control conditions are as follows: the net growth coefficient of the sludge is 0.25 to 0.45kg/kgCOD, and the unit oxygen demand for removing COD is 0.3 to 0.6kgO ₂ The sludge load is 2.0-3.0 kgCOD/(kgMLSS. D), and the sludge concentration is 8-15g/L.

5. The waste water treatment process of the refuse transfer station according to claim 4, wherein the process control conditions of the microorganism pretreatment reactor are as follows: 99-98% of sludge water content and 20 ℃ of water temperature.

6. The waste transfer station sewage treatment process of claim 4, wherein the built-in MBR process control conditions are as follows: the sludge concentration is 12 to 15g/L, the sludge load is 0.1 to 0.3kgCOD/(kgMLSS. D), the denitrification rate is 0.04 to 0.13kgNO ₃ N/(kgMLSS. D), nitration rate of 0.02 to 0.08kgNH4 ⁺ N/(kgMLSS. D), the sludge yield coefficient is 0.15 to 0.30kgMLSS/kgCOD, the sludge age in an aerobic area is 25d, the reflux ratio of the mixed liquid is 20 to 40 times, and the built-in membrane operating flux is 8 to 12L/m ² h。