CN103641272B - High concentrated organic wastewater and percolate zero-discharge treatment system - Google Patents

Abstract

The invention discloses a zero-discharge treatment system for high-concentration organic wastewater and landfill leachate, which belongs to the field of sewage treatment. Its main structure consists of: a pretreatment system, an anaerobic system, a nitrification and denitrification system, a tubular ultrafiltration MBR system, and a nanofiltration system. , gas-liquid contact evaporation system, etc., in which the pretreatment system and the anaerobic system are connected by pipelines, the anaerobic circulation tank in the anaerobic system and the denitrification tank in the nitrification and denitrification system are fixed and connected side by side, and the nitrification and denitrification system It is connected to the tubular ultrafiltration MBR system through pipelines, the tubular ultrafiltration MBR system is connected to the nanofiltration system through pipelines, the nanofiltration system is connected to the gas-liquid contact evaporation system through pipelines, and the tubular ultrafiltration MBR system is connected to the excess sludge treatment The system is connected by pipelines; the invention has simple processing technology, greatly enhanced volume load, simple installation and debugging, shortened processing time, low energy consumption, and the treated second-class pollutants reach the third-class standard, realizing zero discharge of pollutants.

Description

High-concentration organic wastewater and landfill leachate zero-discharge treatment system

technical field

The invention relates to a treatment system for waste water and garbage, belonging to the field of sewage treatment in the environmental protection industry, and in particular to a zero-discharge treatment system for high-concentration organic waste water and landfill leachate.

technical background

In the past 10 years, my country's industrialization and urbanization process has accelerated. The total amount of urban waste is increasing at a rate of more than 10% per year. In 2010, my country's urban domestic waste reached more than 200 million tons. Landfill leachate is a kind of high-concentration, multi-component, and variable sewage produced in the process of waste treatment. One ton of leachate is equivalent to the concentration of pollutants contained in 300 tons of urban sewage.

The leachate of urban waste landfill has complex components and is recognized as one of the most difficult to treat high-concentration organic wastewater in the world. It is mainly manifested in high concentrations of BOD5 and CODcr, high ammonia nitrogen content, a considerable range of water quality and quantity fluctuations, and microbial nutrient elements. Disproportion, etc. Leachate is a secondary pollution source in the landfill process. If it is directly discharged into the environment without treatment, it will cause serious environmental pollution. In recent years, landfill leachate has caused serious pollution to groundwater, soil and surface water in waste sites. The control and treatment of landfill leachate is a key factor in ensuring the long-term and safe disposal of solid waste.

At present, the treatment of landfill leachate is one of the weak links in the construction and management of landfill sites in my country. The country has formulated a new standard for landfill leachate GB16889-2008. The on-site treatment and discharge of landfill leachate require more complicated requirements. Processing technology, higher management level and higher cost. But so far, the leachate treatment process that is suitable for my country's national conditions and meets the "high efficiency and low consumption" treatment standard is still in the research and development stage. Therefore, exploring the rationality of landfill leachate treatment process is of great significance to the construction and implementation of modernized and standardized garbage sanitary landfills and economical and efficient landfill leachate treatment projects.

In recent years, with the development of new separation technology, membrane separation technology has been initially applied in landfill leachate treatment. It is easy to operate and manage, without setting up a secondary settling tank, and the effluent can meet the reuse standard, realizing the gas-liquid contact evaporation of pollution. The system or process deserves to be vigorously promoted. However, although the existing organic membranes used are low in cost and high in filling area, they are prone to pressure resistance and poor oxidation resistance during use, and are easily polluted, and regeneration is difficult. The life of the membrane is generally short, and the water discharge Unstable water quality, etc.

Contents of the invention

In order to solve the deficiencies in the prior art, the present invention provides a zero-discharge treatment system for high-concentration organic wastewater and landfill leachate. The treatment process is simple, the volume load is greatly enhanced, the installation and debugging are simple, the treatment time is shortened, and the energy consumption is reduced. The land occupation is reduced, and the treated second-class pollutants reach the third-class standard, realizing zero discharge of pollutants, and will not cause secondary pollution to the environment.

The present invention is achieved through the following technical solutions:

High-concentration organic wastewater and landfill leachate zero-discharge treatment system, its main structure consists of: pre-treatment system, anaerobic system, nitrification and denitrification system, tubular ultrafiltration MBR system, nanofiltration system, gas-liquid contact evaporation system, residual The sludge treatment system and the accident pool are composed of the pretreatment system and the anaerobic system connected by pipelines, the anaerobic circulation pool in the anaerobic system and the denitrification pool in the nitrification and denitrification system are fixed and connected side by side, and the nitrification and denitrification system is connected with the The tubular ultrafiltration MBR system is connected through pipelines, the tubular ultrafiltration MBR system is connected to the nanofiltration system through pipelines, the nanofiltration system is connected to the gas-liquid contact evaporation system through pipelines, and the tubular ultrafiltration MBR system is connected to the excess sludge treatment system Connected by pipeline, the accident pool is connected by the sewage pipe and the basket filter in the pre-treatment system.

The structure of the pre-treatment system includes: a basket filter, a grit chamber, and a regulating tank, wherein the basket filter and the grit chamber are connected through pipelines, the grit chamber and the regulating pond are fixed and connected side by side, and the basket filter The device can filter out large particles of impurities, the grit chamber can further precipitate impurities, and the regulating tank can adjust the water quality and quantity and hydrolyze with acidification.

Described anaerobic treatment system, its structure is made of: anaerobic water inlet pump, EUASB anaerobic reactor, anaerobic circulation tank, anaerobic circulation pump, wherein anaerobic water inlet pump and EUASB anaerobic reactor are connected by pipeline, EUASB The anaerobic reactor and the anaerobic circulation tank are fixed and connected side by side. The anaerobic circulation tank and the anaerobic circulation pump are connected through pipelines. The EUASB anaerobic reactor removes most of the organic matter in the leachate, and the anaerobic circulation tank can be mixed with the anaerobic tank. Clear liquid and adjust subsequent water intake.

Said nitrification and denitrification system, its structure is composed of: denitrification tank, nitrification tank, mixer, aeration circulation pump, Roots fan, jet aerator, wherein the mixer is fixedly installed in the denitrification tank, denitrification tank and nitrification The tanks are fixed and connected side by side, the nitrification tank and the aeration circulation pump are connected through pipelines, the aeration circulation pump and the jet aerator are connected through pipelines, the jet aerator is fixedly installed in the nitrification tank, and the Roots blower and the jet aerator are connected through pipelines connection, use the denitrification of the denitrification tank to remove nitrate nitrogen, and then use the nitrification of the nitrification tank to convert ammonia nitrogen into nitrate nitrogen and greatly remove organic matter; the ultrafiltration MBR system, on the one hand, plays the role of separating water and sludge Function, on the other hand, functions to preserve and strengthen the microbial system.

The tubular ultrafiltration MBR system is structured by: an ultrafiltration water inlet pump, an ultrafiltration MBR membrane group, an ultrafiltration circulation pump, an ultrafiltration cleaning pump, and a cleaning bucket, wherein the ultrafiltration water inlet pump and the ultrafiltration circulation pump pass through Pipeline connection, ultrafiltration circulation pump and ultrafiltration MBR membrane group are connected through pipelines, ultrafiltration cleaning pump and ultrafiltration circulation pump are connected through pipelines, cleaning bucket and ultrafiltration cleaning pump are connected through pipelines, ultrafiltration membrane system adopts 8 inch 3m outside Install PVDF ultrafiltration MBR membrane group.

The structure of the nanofiltration system is composed of: nanofiltration raw water bucket, nanofiltration water inlet pump, nanofiltration high-pressure pump, nanofiltration membrane group, cleaning bucket, nanofiltration cleaning pump, nanofiltration concentrated liquid storage tank, wherein the nanofiltration The raw water tank is connected to the nanofiltration inlet pump through pipelines, the nanofiltration inlet pump is connected to the nanofiltration high-pressure pump through pipelines, the cleaning bucket is connected to the nanofiltration cleaning pump through pipelines, the nanofiltration cleaning pump is connected to the nanofiltration high-pressure pump through pipelines, and the nanofiltration The high-pressure pump is connected to the nanofiltration membrane group through pipelines, and the nanofiltration membrane group is connected to the nanofiltration concentrated liquid storage tank through pipelines. The nanofiltration membrane treatment system plays the role of intercepting impurities through the nanofiltration membrane module.

The gas-liquid contact evaporation system is structured as follows: an evaporation system inlet pump and a gas-liquid contact evaporation device, wherein the nanofiltration concentrated liquid storage tank is connected to the evaporation system inlet pump through a pipeline, and the evaporation system inlet pump is connected to the gas-liquid contact evaporation system. The contact evaporation device is connected through pipelines, and the gas-liquid contact evaporation system realizes solid-liquid separation through low-temperature evaporation to achieve zero discharge of pollutants.

The structure of the excess sludge treatment system is composed of: a sludge thickening tank, a dewatering centrifuge, a dosing barrel, a dosing pump, and a sludge pump, wherein the sludge thickening tank and the sludge pump are connected through pipelines, and the sludge The pump is connected to the dehydration centrifuge through pipelines, the dosing barrel is connected to the dosing pump through pipelines, and the dosing pump is connected to the dehydration centrifuge through pipelines.

The working process of the high-concentration organic wastewater and landfill leachate zero-discharge treatment system of the present invention is as follows:

The leachate passes through the basket filter to filter out large particles and impurities, then enters the grit chamber for further precipitation, and then enters the regulating tank to adjust the water quality and quantity, and pre-acidify and hydrolyze to reduce the pollutant load for the subsequent treatment process;

The sewage in the regulating tank is lifted into the EUASB anaerobic reactor through the anaerobic inlet pump, and the organic matter in the wastewater is decomposed by the metabolism of anaerobic microorganisms in the EUASB anaerobic reactor, so that the dissolved organic matter passes through a series of Biochemical process, remove most of the organic matter in the leachate, reduce COD, remove most of the organic pollutants in the leachate, at this stage COD is reduced to a certain extent, the anaerobic cycle adopts the combination of reaction zone circulation and effluent backflow , in order to avoid secondary pollution, the generated biogas is collected and sent to the waste storage of the power plant;

The effluent from the anaerobic circulation pool flows into the anoxic/aerobic membrane bioreactor by itself. The reactor adopts the form of pre-denitrification. The reflux liquid in the nitrification section is fully mixed, and in the state of low dissolved oxygen, the nitrate nitrogen is removed through denitrification, and then enters the nitrification tank; in the nitrification tank, the jet aeration of the jet aerator makes the mixed liquid in the tank in a state of high dissolved oxygen, After a sufficient nitrification reaction, the ammonia nitrogen in the water is transformed into nitrate nitrogen, and the concentration of organic pollutants is greatly reduced; Circulation forms a high-speed turbulent flow on the membrane surface, making it difficult for pollutants to adhere to the membrane surface. At the same time, the circulation pump forms a transmembrane pressure, and the water component in the mud-water mixture passes through the membrane to form a permeate to be discharged. The permeate can be discharged up to the standard or Enter the next processing unit to continue processing, the concentrated mixed solution is still returned to the denitrification tank and digestion tank to increase the sludge concentration, and the remaining sludge is discharged to the sludge concentration tank;

The ultrafiltration product water is pressurized into the nanofiltration membrane system through the nanofiltration inlet pump and the nanofiltration high-pressure pump, and the interception effect of the nanofiltration membrane module on the solute is used to reduce various pollution indicators. Evaporation system treatment realizes zero discharge of pollutants;

The remaining sludge generated by the biochemical system enters the sludge concentration tank for concentration treatment. The concentrated sludge and the residue generated by the gas-liquid contact evaporation system are lifted by the sludge pump to the dewatering centrifuge for centrifugal dehydration, and the desludged clear liquid returns to the biochemical system. The system continues to process; because the organic matter contained in the sludge is an effective bio-energy source, the dried sludge can generate 16.65-20.93MJ/t of heat, which is a low calorific value fuel, and the moisture content of the sludge after concentration treatment is 80%. Left and right, it is in the shape of a mud cake, about 0.6t per day. The dehydrated sludge will not cause secondary pollution to the environment during the transportation process, and it can be transported to the incinerator and mixed with domestic waste for incineration.

Due to the adoption of the above technical solutions, the present invention has the following advantages and advantages compared with traditional products:

1) Realize the separation of HRT and SRT: anaerobic and aerobic follow-up set up tubular MBR membrane biochemical reactor, this process adopts the combination of biochemical and ultrafiltration membrane, ultrafiltration membrane replaces the traditional secondary sedimentation tank The complete separation of water and microbial cells in activated sludge not only realizes the complete separation of hydraulic retention time (HRT) and sludge retention time (SRT), the resulting highly active aerobic microorganisms have a strong effect on leachate The high-load organic pollutants in the medium have extremely high degradation efficiency.

2) It is easy to retain and domesticate the biological flora: the microbial flora is completely trapped in the membrane bioreactor, which is conducive to the retention of microorganisms with a long generation cycle, and domestication produces microbial flora with strong degradation ability for refractory organic matter. Organic matter that is difficult to biodegrade in the leachate can also be effectively degraded, ensuring better effluent quality and stable water quality.

3) High biological denitrification efficiency: the process of converting nitrogen-containing pollutants in sewage into nitrogen gas through the combined action of nitrifying bacteria and denitrifying bacteria. The anaerobic/aerobic-MBR membrane biochemical reactor process adopts the biological denitrification method, namely nitrification and denitrification, to effectively remove and degrade ammonia nitrogen and total nitrogen. The removal effect of ammonia nitrogen can reach 99%, and the total nitrogen can reach 75-90%. ; Compared with the traditional biological denitrification process using nitrification and denitrification, the efficiency is only 80-90%, and the total nitrogen is only 50-60%. A large number of engineering practices have proved its great superiority.

4) Enrichment of microorganisms: targeted enrichment of fast-growing flora - nitrosative bacteria and promotion of their growth and MBR membrane bioreactor is the use of mechanical membrane interception, so that tiny and fast-growing nitrosative bacteria can effectively reservation. It not only increases the concentration of activated sludge on the surface, but more importantly, it enriches the most active and vital microorganisms in the activated sludge; it creates an environment conducive to the growth of slow-growing microorganisms, such as nitrous acid and nitrifying bacteria, which can Improve the nitrification capacity of the system, and at the same time help to improve the treatment efficiency of refractory macromolecular organic matter and promote its thorough decomposition; retain and strengthen microorganisms --- as microbial devices, retain efficient engineering microorganisms, which can greatly reduce the degradation speed of efficient strains .

5) EUASB has high efficiency and can be adjusted: the amount of high-concentration sludge in the reactor can avoid the loss of sludge in the reactor by adopting the large circulation method before the three-phase separator. The circulation operation mode before the three-phase separator is beneficial to the self-seeding ability of the reactor, shortens the start-up time, and is conducive to ensuring the amount and activity of high-concentration sludge in the reactor, and will not be affected by changes in the flow rate in the reactor. The separation function of the three-phase separator. Especially for the treatment of organic wastewater with relatively high concentration, internal circulation should be considered to increase the rising flow rate in the reactor. Water distribution from the top of the pool: After long-term operation, the anaerobic pipeline is easy to scale, so the water distribution pipe adopts the method of distributing water from the top of the pool, and there is a casing outside the water distribution pipe, which is convenient for maintenance and replacement.

6) High efficiency of jet aeration: The mud-water mixture in the aeration tank is sent to the inner nozzle of the jet aerator through the circulating water main pipe by the circulating water pump under relatively low pressure, forming a high-speed liquid flow, and at the same time the air is fed into the outer nozzle. The high-speed liquid flow cuts the air and atomizes it into extremely small diameter bubbles, forming a turbulent, chopped gas-liquid mixed flow. Quickly and effectively transfer to the liquid phase and biological phase to complete the rapid transfer process of oxygen. The dissolved oxygen efficiency can reach 28.0~32.0%.

7) Efficient and low operating cost denitrification pool A: denitrification removes nitrogen oxides and organic carbon. By controlling the COD load of the anaerobic pool, it is ensured that the wastewater entering the anoxic pool contains enough carbon sources for denitrification. No additional carbon source is needed, the alkalinity produced by denitrification is recovered, and the operating cost of the project is reduced. HRT: 43-60h; MLSS: 15~20g/L.

8) High-efficiency denitrification and decarbonization O pool: use low-load decarbonization and nitrification aerobic pools to remove most of the ammonia nitrogen through nitrification, and remove most of the organic pollutants in the water body through aerobic microorganisms. HRT: 170h; MLSS: 15~20g/L.

9) Low-energy ultrafiltration MBR: solid-liquid separation and bacterial flora retention. Nitrifying liquid reflux ratio: 600%~1200%; sludge reflux ratio: 80%~100%; membrane flux: 70-80L/m2·h (flat membrane 20-20L/m2·h).

10) High sludge concentration: High sludge concentration is one of the biggest advantages of MBR, and the traditional method cannot be too high (<5g) due to the influence of settlement. Hollow fiber submersibles should not be too high (<8g) to suffer from broken filaments and fouling. The tubular MBR can be as high as the normal MBR is 15g, it can reach 25g, or even 40g.

11) Solve the problem of sludge settlement and expansion: the most troublesome problem of traditional treatment is the problem of settlement and expansion. The tubular MBR biochemical mud-water mixture directly enters the 8mm membrane tube to separate clean water from sludge without sedimentation.

12) To overcome the problem that the membrane filaments are easy to be blocked and broken: the most troublesome problem of the submerged MBR is the problem of broken filaments, while the tubular membrane has a very strong support layer, which is basically not broken. Fouling is a common problem in membrane wastewater treatment. The tubular membrane has large channels (8mm or even larger), high surface velocity (4m/s), less pollution, and less chance of fouling. And the special form of PVDF strengthens the substrate membrane and high flow rate, which greatly overcomes the problems of broken wires, fouling and flux drop.

13) Problems of cleaning and flux recovery: Membrane sewage treatment, cleaning is inevitable, but the cleaning is cumbersome and complicated, the cleaning effect is not good, and the flux recovery after cleaning is the most troublesome problem. The tubular MBR membrane only needs to be shut down for flushing with clean water (2-5 minutes), and regular chemical cleaning (once every 1-6 months). The online operation is simple and the cleaning and recovery effect is good. Due to the thin film layer (about 30um) of the tubular membrane, the resistance is small, and the operating flux is 65-140LMH. It is already extremely high flux in sewage treatment, and the flux can be easily restored to 100%.

14) After concentrated treatment, the water content of the sludge is about 80%, and it becomes a mud cake, about 0.6t per day. The dehydrated sludge will not cause secondary pollution to the environment during the transportation process, and can be transported to the incinerator and mixed with domestic waste for incineration.

15) The gas-liquid contact evaporation system achieves zero discharge of pollutants. The liquid flows along the inclined plate. Due to cavitation, a small negative pressure is generated under the plate, and a convex hole appears on the upper surface of the plate; the negative pressure makes the air flow from the bottom of the plate. Entering the flowing liquid, when the long bubbles contact the liquid for a long time, they become saturated water vapor, exchanging solute or heat in other liquids; the low-pressure fan transports air and strengthens the contact of gas and liquid to improve the reaction efficiency. The whole process can use waste flue gas and waste steam as energy to provide energy loss of gas-liquid contact evaporation system.

16) The volumetric load is greatly enhanced, the installation and commissioning are simple, the processing time is shortened, the energy consumption is reduced, and the land occupation is reduced. After the treatment, the second-class pollutants meet the relevant national standards of the first and second grades.

Description of drawings

Fig. 1, is the structural representation of the present invention.

Fig. 2, is the work flowchart of the present invention.

In Figure 1: 1-pretreatment system, 2-anaerobic system, 3-nitrification and denitrification system, 4-tubular ultrafiltration MBR system, 5-nanofiltration system, 6-gas-liquid contact evaporation system, 7-residue Sludge treatment system, 8-accident pool, 11-basket filter, 12-grit chamber, 13-regulation tank, 21-anaerobic inlet pump, 22-EUASB anaerobic reactor, 23-anaerobic circulation tank, 24-anaerobic circulation pump, 31-denitrification tank, 32-nitrification tank, 33-mixer, 34-aeration circulation pump, 35-Roots blower, 36-jet aerator, 41-ultrafiltration inlet pump, 42 -ultrafiltration MBR membrane group, 43-ultrafiltration circulation pump, 44-ultrafiltration cleaning pump, 45-cleaning bucket, 51-nanofiltration raw water bucket, 52-nanofiltration inlet pump, 53-nanofiltration high pressure pump, 54-nanofiltration Membrane group, 55-cleaning barrel, 56-nanofiltration cleaning pump, 57-nanofiltration concentrated liquid storage tank, 61-evaporation system inlet pump, 62-gas-liquid contact evaporation device, 71-sludge concentration tank, 72- Dehydration centrifuge, 73-dosing barrel, 74-dosing pump, 75-sludge pump.

Implementation

As shown in Figure 1, the high-concentration organic wastewater and landfill leachate zero-discharge treatment system, its main structure consists of: pre-treatment system, anaerobic system, nitrification and denitrification system, tubular ultrafiltration MBR system, nanofiltration system, gas-liquid The contact evaporation system, excess sludge treatment system, and accident pool are composed of the pretreatment system and the anaerobic system connected by pipelines, and the anaerobic circulation pool in the anaerobic system and the denitrification pool in the nitrification and denitrification system are fixed and connected side by side , the nitrification and denitrification system is connected to the tubular ultrafiltration MBR system through pipelines, the tubular ultrafiltration MBR system is connected to the nanofiltration system through pipelines, the nanofiltration system is connected to the gas-liquid contact evaporation system through pipelines, and the tubular ultrafiltration MBR system It is connected to the excess sludge treatment system through pipelines, and the accident pool is connected through the sewage pipe and the basket filter in the pre-treatment system.

The structure of the pre-treatment system includes: a basket filter, a grit chamber, and a regulating tank, wherein the basket filter and the grit chamber are connected through pipelines, the grit chamber and the regulating pond are fixed and connected side by side, and the basket filter The device can filter out large particles of impurities, the grit chamber can further precipitate impurities, and the regulating tank can adjust the water quality and quantity and hydrolyze with acidification.

Described anaerobic treatment system, its structure is made of: anaerobic water inlet pump, EUASB anaerobic reactor, anaerobic circulation tank, anaerobic circulation pump, wherein anaerobic water inlet pump and EUASB anaerobic reactor are connected by pipeline, EUASB The anaerobic reactor and the anaerobic circulation tank are fixed and connected side by side. The anaerobic circulation tank and the anaerobic circulation pump are connected through pipelines. The EUASB anaerobic reactor removes most of the organic matter in the leachate, and the anaerobic circulation tank can be mixed with the anaerobic tank. Clear liquid and adjust subsequent water intake.

Said nitrification and denitrification system, its structure is composed of: denitrification tank, nitrification tank, mixer, aeration circulation pump, Roots fan, jet aerator, wherein the mixer is fixedly installed in the denitrification tank, denitrification tank and nitrification The tanks are fixed and connected side by side, the nitrification tank and the aeration circulation pump are connected through pipelines, the aeration circulation pump and the jet aerator are connected through pipelines, the jet aerator is fixedly installed in the nitrification tank, and the Roots blower and the jet aerator are connected through pipelines Connection, use the denitrification of the denitrification tank to remove nitrate nitrogen, and then use the nitrification of the nitrification tank to convert ammonia nitrogen into nitrate nitrogen and greatly remove organic matter; the ultrafiltration MBR system plays the role of separating water and impurities.

The tubular ultrafiltration MBR system is structured by: an ultrafiltration water inlet pump, an ultrafiltration MBR membrane group, an ultrafiltration circulation pump, an ultrafiltration cleaning pump, and a cleaning bucket, wherein the ultrafiltration water inlet pump and the ultrafiltration circulation pump pass through Pipeline connection, ultrafiltration circulation pump and ultrafiltration MBR membrane group are connected through pipelines, ultrafiltration cleaning pump and ultrafiltration circulation pump are connected through pipelines, cleaning bucket and ultrafiltration cleaning pump are connected through pipelines, ultrafiltration membrane system adopts 8 inch 3m outside Install PVDF ultrafiltration MBR membrane group.

The structure of the nanofiltration system is composed of: nanofiltration raw water bucket, nanofiltration water inlet pump, nanofiltration high-pressure pump, nanofiltration membrane group, cleaning bucket, nanofiltration cleaning pump, nanofiltration concentrated liquid storage tank, wherein the nanofiltration The raw water tank is connected to the nanofiltration inlet pump through pipelines, the nanofiltration inlet pump is connected to the nanofiltration high-pressure pump through pipelines, the cleaning bucket is connected to the nanofiltration cleaning pump through pipelines, the nanofiltration cleaning pump is connected to the nanofiltration high-pressure pump through pipelines, and the nanofiltration The high-pressure pump is connected to the nanofiltration membrane group through pipelines, the nanofiltration membrane group is connected to the nanofiltration concentrated liquid storage tank through pipelines, and the nanofiltration membrane treatment system plays the role of intercepting impurities through the nanofiltration membrane module.

The gas-liquid contact evaporation system is structured as follows: an evaporation system inlet pump and a gas-liquid contact evaporation device, wherein the nanofiltration concentrated liquid storage tank is connected to the evaporation system inlet pump through a pipeline, and the evaporation system inlet pump is connected to the gas-liquid contact evaporation system. The contact evaporation device is connected through pipelines, and the gas-liquid contact evaporation system realizes solid-liquid separation through low-temperature evaporation to achieve zero discharge of pollutants.

The structure of the excess sludge treatment system is composed of: a sludge thickening tank, a dewatering centrifuge, a dosing barrel, a dosing pump, and a sludge pump, wherein the sludge thickening tank and the sludge pump are connected through pipelines, and the sludge The pump is connected to the dehydration centrifuge through pipelines, the dosing barrel is connected to the dosing pump through pipelines, and the dosing pump is connected to the dehydration centrifuge through pipelines.

As shown in Figures 1 and 2, the working process of the high-concentration organic wastewater and landfill leachate zero-discharge treatment system of the present invention is as follows:

The leachate passes through the basket filter in the pre-treatment system to filter out large particles and impurities, then enters the grit chamber for further precipitation, and then enters the regulating tank to adjust the water quality and quantity, and pre-acidify and hydrolyze to reduce the pollutant load for the subsequent treatment process;

The sewage in the regulating tank is lifted into the EUASB anaerobic reactor through the anaerobic inlet pump, and the organic matter in the wastewater is decomposed by the metabolism of anaerobic microorganisms, so that the dissolved organic matter can go through a series of biochemical processes to remove the leachate Most of the organic matter in the leachate is reduced to reduce COD, and most of the organic pollutants in the leachate are removed. At this stage, the COD is reduced to a certain extent. The anaerobic cycle adopts a combination of reaction zone circulation and effluent return to avoid secondary pollution , the generated biogas is collected and sent to the waste storage of the power plant;

The effluent from the anaerobic circulation pool enters the nitrification and denitrification and tubular ultrafiltration MBR system by itself, and adopts the form of pre-denitrification. In the nitrification and denitrification system, due to the agitation of the agitator in the denitrification tank, the effluent of the anaerobic circulation pool and the nitrification section are refluxed In the state of low dissolved oxygen, the nitrate nitrogen is removed through denitrification, and then enters the nitrification tank; in the nitrification reaction section, under the state of high dissolved oxygen, after sufficient nitrification reaction, the ammonia nitrogen in the water is converted into nitrate At the same time, the concentration of organic pollutants is greatly reduced. The mixed solution in the nitrification section enters the external tubular ultrafiltration MBR system. The tubular ultrafiltration MBR system is equipped with a large-flow ultrafiltration circulating pump, which forms a high-speed turbulent flow on the membrane surface through large-flow circulation. , so that pollutants are not easy to adhere to the surface of the membrane, and at the same time, the transmembrane pressure is formed through the circulating pump, and the water component in the mud-water mixture passes through the membrane to form a permeate to be discharged, and the permeate is discharged up to the standard or enters the next processing unit for further processing , the concentrated mixed solution is still returned to the denitrification and denitrification system to increase the sludge concentration, and the remaining sludge is discharged to the sludge thickening tank.

The ultrafiltration product water is pressurized into the nanofiltration membrane treatment system through the nanofiltration inlet pump and the nanofiltration high-pressure pump. The interception effect of the nanofiltration membrane module on the solute is used to reduce various pollution indicators; the nanofiltration concentrated liquid is contacted by gas and liquid. Evaporation system treatment realizes zero discharge of pollutants.

The remaining sludge generated by the biochemical system enters the sludge concentration tank for concentration treatment. The concentrated sludge and the residue generated by the gas-liquid contact evaporation system are lifted by the sludge pump to the dewatering centrifuge for centrifugal dehydration, and the desludged clear liquid returns to the biochemical system. The system continues processing. Since the organic matter contained in the sludge is an effective bioenergy, the dried sludge can produce 16.65-20.93MJ/t of heat, which is a low calorific value fuel. The moisture content of the sludge after concentration treatment is about 80%, and it becomes a mud cake, about 0.6t per day. The dehydrated sludge will not cause secondary pollution to the environment during the transportation process, and can be transported to the incinerator and domestic garbage mixed incineration.

The second-class pollutants meet the third-class standard of the "Integrated Wastewater Discharge Standard" (GB8978-1996), and the specific indicators are shown in the table below:

Effluent Pollutant Discharge Concentration Limits

In the table: UF is treated by tubular ultrafiltration MBR system, and NF is treated by nanofiltration system.

Claims (4)

1. High concentration organic wastewater and landfill leachate zero discharge treatment system, its main structure consists of: pretreatment system, anaerobic system, nitrification and denitrification system, tubular ultrafiltration MBR system, nanofiltration system, gas-liquid contact evaporation system , residual sludge treatment system, and accident pool, characterized in that: the pretreatment system and the anaerobic system are connected by pipelines, and the anaerobic circulation pool in the anaerobic system and the denitrification pool in the nitrification and denitrification system are fixed and connected side by side , the nitrification and denitrification system is connected to the tubular ultrafiltration MBR system through pipelines, the tubular ultrafiltration MBR system is connected to the nanofiltration system through pipelines, the nanofiltration system is connected to the gas-liquid contact evaporation system through pipelines, and the tubular ultrafiltration MBR system It is connected with the excess sludge treatment system through pipelines, and the accident pool is connected with the basket filter in the pre-treatment system through sewage pipes; The structure of the pre-treatment system includes: a basket filter, a grit chamber, and a regulating tank, wherein the basket filter and the grit chamber are connected through pipelines, the grit chamber and the regulating pond are fixed and connected side by side, and the basket filter The device can filter out large particles of impurities, the grit chamber can further precipitate impurities, and the regulating tank can adjust the water quality and quantity and hydrolyze with acidification; Described anaerobic treatment system, its structure is made of: anaerobic water inlet pump, EUASB anaerobic reactor, anaerobic circulation tank, anaerobic circulation pump, wherein anaerobic water inlet pump and EUASB anaerobic reactor are connected by pipeline, EUASB The anaerobic reactor and the anaerobic circulation tank are fixed and connected side by side. The anaerobic circulation tank and the anaerobic circulation pump are connected through pipelines. The EUASB anaerobic reactor removes most of the organic matter in the leachate, and the anaerobic circulation tank can be mixed with the anaerobic tank. Clear liquid and adjust subsequent water intake. 2. The zero-discharge treatment system for high-concentration organic wastewater and landfill leachate as claimed in claim 1, characterized in that: said nitrification and denitrification system is composed of: denitrification tank, nitrification tank, mixer, aeration cycle Pump, Roots blower, jet aerator, in which the mixer is fixedly installed in the denitrification tank, the denitrification tank and the nitrification tank are fixed and connected side by side, the nitrification tank and the aeration circulation pump are connected through pipelines, and the aeration circulation pump and the jet aeration The aerator is connected through pipelines, the jet aerator is fixedly installed in the nitrification tank, the Roots blower and the jet aerator are connected through pipelines, the denitrification of the denitrification tank is used to remove nitrate nitrogen, and then the nitrification of the nitrification tank is used to remove nitrate nitrogen. Ammonia nitrogen is converted into nitrate nitrogen and organic matter is greatly removed; the ultrafiltration MBR system, on the one hand, plays the role of separating water and sludge, and on the other hand, plays the function of retaining and strengthening the microbial system. 3. The high-concentration organic wastewater and landfill leachate zero-discharge treatment system as claimed in claim 1, characterized in that: the tubular ultrafiltration MBR system, its structure consists of: ultrafiltration inlet pump, ultrafiltration MBR membrane group , ultrafiltration circulation pump, ultrafiltration cleaning pump, and cleaning bucket, wherein the ultrafiltration water inlet pump and ultrafiltration circulation pump are connected by pipelines, the ultrafiltration circulation pump and ultrafiltration membrane group are connected by pipelines, and the ultrafiltration cleaning pump and ultrafiltration circulation The pump is connected through pipelines, and the cleaning bucket and ultrafiltration cleaning pump are connected through pipelines. The ultrafiltration membrane system adopts an 8-inch 3m external PVDF ultrafiltration MBR membrane group; The structure of the nanofiltration system is composed of: nanofiltration raw water bucket, nanofiltration water inlet pump, nanofiltration high-pressure pump, nanofiltration membrane group, cleaning bucket, nanofiltration cleaning pump, nanofiltration concentrated liquid storage tank, wherein the nanofiltration The raw water tank is connected to the nanofiltration inlet pump through pipelines, the nanofiltration inlet pump is connected to the nanofiltration high-pressure pump through pipelines, the cleaning bucket is connected to the nanofiltration cleaning pump through pipelines, the nanofiltration cleaning pump is connected to the nanofiltration high-pressure pump through pipelines, and the nanofiltration The high-pressure pump is connected to the nanofiltration membrane group through pipelines, and the nanofiltration membrane group is connected to the nanofiltration concentrated liquid storage tank through pipelines; The structure of the excess sludge treatment system is composed of: a sludge thickening tank, a dewatering centrifuge, a dosing barrel, a dosing pump, and a sludge pump, wherein the sludge thickening tank and the sludge pump are connected through pipelines, and the sludge The pump is connected to the dehydration centrifuge through pipelines, the dosing barrel is connected to the dosing pump through pipelines, and the dosing pump is connected to the dehydration centrifuge through pipelines. 4. The high-concentration organic wastewater and landfill leachate zero-discharge treatment system as claimed in claim 1, characterized in that: the gas-liquid contact evaporation system is composed of: an evaporation system inlet pump, a gas-liquid contact evaporation system The structure of the device, in which the nanofiltration concentrated liquid storage tank is connected to the water inlet pump of the evaporation system through pipelines, the water inlet pump of the evaporation system is connected to the gas-liquid contact evaporation device through pipelines, and the gas-liquid contact evaporation system realizes solid-liquid separation through low-temperature evaporation to achieve pollution The purpose of zero discharge of substances.