CN101928096A - Method and system for sewage treatment in ecologically sensitive areas - Google Patents

Abstract

The invention discloses a sewage treatment method and system in an ecologically sensitive area. The method includes: using a collection well with a mechanical coarse grille at the entrance to remove large suspended matter in the sewage, and then entering the pretreatment tank, the coarse grille further removes suspended matter, and then the oil separation tank removes animal and vegetable oil and mineral oil, and finally enters The regulating tank balances the water quantity and quality; the pretreated sewage enters the anaerobic tank and mixes with the reflux mixed solution from the anoxic tank; Oxygen pool; the effluent from the aerobic pool enters the membrane pool, and after biodegradation is completed, the effluent is treated by membrane filtration. The present invention adopts the combination of anaerobic-anoxic-aerobic-MBR, which has high treatment efficiency and stability, meets the efficient removal of COD, BOD, TN, TP and oil in sewage, and the effluent meets the first-level A discharge Requirements, but also as a source of water reuse, environmental protection, water conservation, especially for rural domestic sewage and catering wastewater treatment in ecologically sensitive areas.

Description

Sewage treatment method and system in ecologically sensitive areas

technical field

The invention relates to an integrated MBR (Membrane Bioreactor, membrane bioreactor) treatment method and system for domestic sewage and catering wastewater treatment in ecologically sensitive areas. the

Background technique

Ecologically sensitive areas refer to sandstorm source areas, oases in deserts, areas with severe water shortages, rare animal and plant habitats or special ecosystems, natural forests, tropical rainforests, mangroves, coral reefs, fish and shrimp spawning grounds, important wetlands and natural fishery etc. Ecologically sensitive areas have precious water resources to maintain the survival of special species. In these areas, the water quality requirements for discharged sewage are high or zero discharge is required, and water resources are scarce, so the demand for sewage recycling is obvious. Therefore, it is particularly important to prevent the pollution of sewage to discharge water resources in the protection of ecologically sensitive areas. the

In these areas, except for some areas where people are strictly forbidden to live in, such as national key protected areas, some farmers in my country often live in villages. In addition to sewage treatment equipment, rural areas in most areas do not have effective sewage treatment facilities, but are directly discharged into the surrounding water system. Rural domestic sewage contains a large amount of organic matter and N, P and other elements. Discharging into the water body will cause the content of chlorophyll a in the water body to increase by an order of magnitude, resulting in the proliferation of algae in the water body, causing eutrophication, and causing the receiving water body The deterioration of water quality has seriously affected the ecological environment in ecologically sensitive areas. With the continuous development and deepening of the market economy, many rural areas have developed tourism and developed entertainment facilities in the form of farmhouses and resorts based on the superior geographical and ecological environment characteristics of sensitive ecological areas. While improving the economic development level of the entire countryside, the increase of catering wastewater has accelerated the environmental pollution in ecologically sensitive areas. Therefore, it is urgent to strengthen the treatment of domestic sewage in rural areas around ecologically sensitive areas. the

my country's rural sewage treatment is still in its infancy. Since the traditional large-scale urban sewage collection and centralized treatment mode cannot be generally extended to rural areas, especially for ecologically sensitive rural areas, the requirements for drainage water quality are high, and water resources are scarce, so the demand for sewage regeneration and reuse is obvious. Therefore, collection within a certain area can be adopted, and decentralized sewage treatment stations can be built to achieve standard discharge or reuse of sewage after treatment. the

At present, the decentralized treatment of rural sewage mainly adopts artificial wetland treatment system, contact oxidation process, biological filter, SBR (Sequencing Batch Reactor Activated Sludge, sequencing batch activated sludge method) and other processes. Although the constructed wetland has a good landscape effect, there are also many shortcomings: its construction occupies a large amount of land area, which has a non-negligible impact on my country's lack of land resources; In particular, it has a very significant and long-term impact on the reclamation of the project construction area; the management system of the constructed wetland is not perfect, so that after the construction of the constructed wetland, many of them have become a burden to the local government. The contact oxidation process has a high volume load on water quality, and has a good adaptability to changes in water quality and water volume. At the same time, the amount of sludge produced is small. The disadvantage is that the biofilm between the fillers in the tank may sometimes be blocked, and subsequent management is inconvenient. In rural areas, there are basically no professional management personnel engaged in sewage treatment, so it is impossible to deal with related problems, which eventually leads to the phenomenon that sewage treatment is not up to standard. The biological filter has good treatment effect, stable operation, easy management, and energy saving, but it occupies a large area, the filter material is easy to be blocked, and it is easy to produce odor and filter flies, which deteriorates environmental sanitation. SBR is suitable for decentralized sewage treatment. It has the advantages of simple process flow, stable treatment effect, small footprint, strong impact load resistance, and denitrification and phosphorus removal capabilities. Farmers often don't pay enough attention to the opening and operation of the device, which also affects the final sewage treatment effect. the

The existing MBR treatment system is mainly aimed at the treatment of urban sewage. In view of the obvious differences in the characteristics of urban sewage and rural sewage, it is often unreasonable to use relevant design and operation data to guide the construction of rural sewage treatment systems. It is necessary to investigate and analyze the characteristics of rural drainage. Based on the regional characteristics, collection methods, and changes in the volume and quality of sewage, the basic data combined with rural living habits are obtained, and the parameter design of the treatment system is finally determined. At present, there are no design parameters and operating parameters of an integrated MBR treatment system that combines the treatment characteristics of rural sewage in ecologically sensitive areas in my country. In these areas, the discharge standards after rural sewage treatment are strict, or sewage discharge is not allowed, and the sewage treatment system is required to operate stably. Therefore, studying the relevant parameters of MBR single treatment technology for rural sewage treatment can ensure the sewage in these environmentally sensitive areas. processing effect. In addition, in the rural areas of economically developed eastern my country, MBR sewage treatment technology can be promoted for miniaturized, decentralized, and courtyard sewage treatment. the

Contents of the invention

The purpose of the present invention is to provide a system mainly for treating domestic sewage in ecologically sensitive areas in view of the defects and deficiencies in the prior art. the

To achieve the above object, the invention provides a method for treating sewage in ecologically sensitive areas, comprising steps:

S1, pretreatment: use the collection well with mechanical coarse grille at the entrance to remove the larger suspended matter in the sewage, and then the sewage enters the pretreatment tank, and the coarse grille installed at the entrance of the pretreatment tank is used to further remove the suspended matter in the sewage Then use the grease trap to remove floating oil and heavy oil in the sewage, and finally the sewage enters the regulating tank for treatment;

S2, biological treatment and sludge treatment: the pretreated sewage enters the anaerobic tank, where it is mixed with the backflow mixture from the anoxic tank; the effluent from the anaerobic tank is mixed with the backflow mixture from the membrane tank Oxygen tank; the effluent from the anoxic tank enters the aerobic tank to realize the return of the mixed liquor and sludge at the same time; the effluent from the aerobic tank enters the membrane tank, and the filtration treatment is completed under the negative pressure of the membrane tank. the

Wherein, the residence time of the sewage in the water collection well is 1 to 2 hours. the

Wherein, the grid spacing of the mechanical coarse grid is 20mm; the grid spacing of the coarse grid is 5mm; the fine grid is set between the regulating tank and the anaerobic tank, and the grid spacing is 0.5mm. the

Among them, the residence time of sewage in the grease trap is 2 to 4 hours, and a belt type oil skimmer is set in the grease trap. the

Wherein, the residence time of the sewage in the regulating tank is 8 to 16 hours, and a mixer is arranged in the regulating tank or a perforated pipe is arranged at the bottom thereof for aeration. the

Among them, the treatment time of sewage in the anaerobic pool is 2 to 4 hours; the treatment time in the anoxic pool is 2 to 4 hours; the treatment time in the aerobic pool is 3 to 5 hours, and the sludge age is 15- 25d; Install a microporous aerator in the aerobic tank to supply oxygen to the aerobic tank. The aperture of the microporous aerator is ￠215, and the air-water ratio in the aerobic tank is 8:1. the

Wherein, the membrane pool is a membrane bioreactor, and the treatment time of sewage in the membrane bioreactor is 3 to 5 hours, wherein the sludge concentration is 2000 to 5000 mg/L, and the gas-water ratio is 20 to 30: 1. The reflux ratio of the mixed liquid is 500-150%; the self-priming pump of the membrane bioreactor runs for 13 minutes and stops for 2 minutes, the switching time of the blower is 8 hours, and the membrane flux is 10-20L/m2h. the

The present invention also provides a sewage treatment system in an ecologically sensitive area, including: a water collection well, a pretreatment pool, an anaerobic pool, an anoxic pool, an aerobic pool, and a membrane pool connected in sequence, and the sewage from the water collection well is pretreated After the pool treatment, the tank is adjusted, and then enters the anaerobic pool, where the sewage is mixed with the return mixed liquid from the anoxic pool; The effluent of the pool enters the aerobic pool; the effluent of the aerobic pool enters the membrane pool, and the filtration treatment is completed in the membrane pool. the

Among them, it also includes a mechanical coarse grid, which is located at the entrance of the water collection well; it also includes a coarse grid, which is located at the entrance of the pretreatment tank; it also includes a fine grid, which is located at the adjustment tank and the drain between oxygen pools. the

Wherein, the membrane pool is a membrane bioreactor MBR, which includes a membrane module, a perforated aeration pipe, a water outlet system, a backwash system, a cleaning system, a purging system, and a hoisting system. directly above the pipe, and the purging system is arranged below the membrane module. the

Among them, the system also includes a programmable logic controller system, which is used to adjust the residence time of sewage in the adjustment tank, adjust the flow rate of the lift pump installed between the adjustment tank and the anaerobic tank, and adjust the And the running time and air volume of the fan in the membrane tank. the

Wherein, an online liquid level gauge for monitoring the water level is arranged in the regulating pool. the

Features of the system include:

1) The system of the present invention is mainly used for the treatment of rural sewage and catering wastewater, which can meet the efficient removal of COD, BOD, TN, TP and oil in the sewage, and the effluent can also reuse the water source while meeting the first-class A discharge requirements , while achieving the goals of environmental protection and water conservation;

2) The mixed liquid is returned from the membrane tank, and the mixed liquid and sludge are returned at the same time, reducing the sludge return link, making the system easier to operate and control, and reducing the sludge return pump, reducing investment and operating costs;

3) In view of the characteristics of large fluctuations in the amount of rural sewage and catering wastewater, an optimized control system is adopted, and an online liquid level gauge is installed in the regulating pool to monitor the water level of the regulating pool and adjust it through the PLC (Programmable Logic Control, programmable logic controller) system Adjust the time of sewage in the tank and the flow rate of the lifting pump, adjust the running time and air volume of the fans in the aerobic tank and membrane tank, realize the adjustment of system operating parameters and system energy consumption with the daily changes of water volume and the changes of low and high seasons, and ensure the treatment effect Achieve energy saving and consumption reduction on a basic basis;

4) Adopt reasonable pretreatment, such as multi-stage fine grids and fine grids, and optimized operating conditions, such as combined aeration, gas purging and optimized aeration volume, intermittent water discharge, etc. to realize the membrane in the biological reaction tank Through the self-cleaning of aeration and intermittent water discharge, the pollution degree of the membrane during operation is reduced, the frequency of membrane cleaning is reduced, the water flux of the membrane system is guaranteed, the service life of the membrane is extended, and the operating cost is reduced. the

5) The treatment system adopts a reasonable elevation design to make use of gravity flow as much as possible to reduce sewage lifting. Most of the treatment facilities can be placed underground, and greening can be carried out on the ground to meet the landscape requirements. And the system facilities are easy to maintain. the

6) Membrane area is equipped with MBR membrane module system and supporting water discharge, backwash, cleaning, purging, hoisting and other systems. The membrane module is located directly above the perforated aeration pipe. The lower part of the membrane module is equipped with a special purge system to purge and shake the membrane elements to delay the accumulation of sludge concentration around the membrane elements. the

In summary, the above technical scheme has the following advantages: the combination of anaerobic-anoxic-aerobic technology has high treatment efficiency and stable treatment effect, and is especially suitable for the treatment of domestic sewage and catering wastewater in rural areas in ecologically sensitive areas . the

Description of drawings

Fig. 1 is the flowchart of the method for the embodiment of the present invention;

Fig. 2 is a structural schematic diagram of the MBR reactor in the embodiment of the present invention. the

Detailed ways

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. the

Fig. 1 is a flow chart of the method of the embodiment of the present invention. This method mainly treats the mixed water of catering water, black water for toilet flushing and miscellaneous drainage in ecologically sensitive areas. The black water for toilet flushing needs to pass through the three-format septic tank for 24 hours before being piped. Sewage is collected through sewage pipes and flowed to the sewage station, where it undergoes pretreatment, biological treatment and sludge treatment in sequence. the

The method of the treatment embodiment of the present invention includes pretreatment, biological treatment and sludge treatment when treating sewage. The applicable water treatment range is 5-1,000t/d. the

Specifically, the sewage first enters the pretreatment section, and then passes through the collection well 1, the pretreatment pond 2 and the regulating pond 3 in sequence. The function of pretreatment is mainly to intercept most of the suspended matter in the domestic sewage, and to remove the oil in the water, so as to ensure the normal operation of the subsequent biological treatment unit. Among them, the mechanical coarse grid is placed at the entrance of the water collection well to remove large suspended solids in the water, retain large suspended solids such as plastics and branches in domestic sewage, and remove part of the insoluble organic matter. Afterwards, the sewage enters the pretreatment tank, and the coarse grid (the second coarse grid) at the entrance of the pretreatment tank is used to further remove the suspended solids in the water, and then the grease trap with an oil skimmer is used to remove the slick oil in the sewage and heavy oil, and finally the sewage enters the regulating tank. The third fine grid is placed between the regulating tank and the anaerobic tank, mainly to ensure the normal operation of the membrane bioreactor. A lifting pump pool is also set at the water outlet of the regulating pool, and the fine grid is placed in the wall of the anaerobic tank, and a lifting guide rail is set to lift the fine grid to the ground for cleaning regularly. In order to ensure the normal operation of the membrane bioreactor, various fibers, slag, waste paper and other debris must be intercepted outside the system. Therefore, fine grids are used to remove small suspended solids in the wastewater. the

The effluent from the regulating tank enters the AAO-MBR integrated bioreactor (including AAO and integrated MBR reactor). Among them, AAO includes anoxic pool, anaerobic pool and aerobic pool. the

The pretreated sewage enters the anaerobic pool 4, where the sewage is mixed with the reflux mixed liquid from the anoxic pool 5, and the reflux ratio is 50%. Under anaerobic conditions, the ATP in the phosphorus accumulating bacteria in the sewage is hydrolyzed to release H ₃ PO ₄ and energy to form ADP to maintain their own growth. Phosphorus in sludge is effectively released under anaerobic conditions, which prepares for the massive absorption of phosphorus by sludge under aerobic conditions. Since the return sludge from the anoxic tank is mixed with the influent water, the hungry and efficient activated sludge can quickly absorb the dissolved organic matter in the raw water, and have a good hydrolysis effect on the refractory organic matter. At the same time, part of NH ₃ -N is removed due to the synthesis of cells, and the concentration of NH ₃ -N and BOD in sewage decrease.

The effluent from the anaerobic tank 4 is mixed with the reflux mixture from the membrane tank 7 and enters the anoxic tank 5, where the removal of TN is completed and the sludge concentration in the biological tank is ensured. The effluent from the anaerobic tank 4 enters the anoxic tank 5, and the return sludge from the membrane tank 7 enters at the same time, and the reflux ratio of the mixed solution is 50%-150%. The primary function of the anoxic tank 5 is denitrification. In this reactor, under the condition of anoxic, the denitrifying bacteria use the organic matter in the sewage as a carbon source to remove a large amount of nitrate in the return sludge of the membrane tank 7. Nitrogen and nitrite nitrogen were reduced to N ₂ and released into the air, BOD ₅ concentration continued to decrease, and nitrate nitrogen concentration also dropped significantly.

The effluent from the anoxic tank 5 enters the aerobic (aeration) tank 6, where the removal of BOD ₅ and the nitrification of ammonia nitrogen are completed. In the aeration stage, the microorganisms, nitrifying bacteria, and phosphorus accumulating bacteria in the activated sludge proliferated in the biological pool are used to degrade or adsorb organic pollutants containing carbon, ammonia nitrogen, and phosphorus in the water, so as to achieve the purpose of purifying water quality.

The effluent from the aerobic pool 6 enters the membrane pool 7, and the membrane block is immersed in the mixed solution. Under the negative pressure condition generated by the osmosis (water outlet) pump, the water passes through the membrane to complete the filtration process. Membrane tank 7 replaces the functions of the secondary settling tank for the separation of suspended matter and liquid and the function of particle filter material filter tank. Among them, Membrane Bioreactor (MBR) is a new technology that combines membrane technology with biochemical reactions in sewage treatment, and is currently being more and more widely used in the world. The membrane pool 7 uses membranes to filter the muddy sewage in the biochemical reaction pool to separate mud and water, and the water from the membrane pool 7 enters the clear water pool 8 . On the one hand, the membrane retains the microorganisms in the reaction tank, greatly increasing the concentration of activated sludge in the tank to a high level, so that the biochemical reaction of degrading sewage can be carried out more quickly and thoroughly. On the other hand, due to the high membrane Filtration accuracy ensures clear and transparent effluent and high-quality water. the

The design flow rate of the membrane module is 10-20L/m ² ·h, the blower is switched every 8 hours, and the self-priming pump works for 13 minutes and stops for 2 minutes. The purging (aeration) in the MBR membrane area has two purposes, one is to oscillate air and water around the membrane module to keep the membrane surface clean, and the other is to provide the oxygen needed for further degradation of organic matter. The biodegraded water passes through the MBR membrane module under the extraction action of the filtrate self-priming pump, and the filtrate is collected and sent to the ozone buffer contact tank through the MBR water collection pipe. Through the high-efficiency interception effect of the membrane, all bacteria and suspended matter are intercepted in the aeration tank, which can effectively intercept nitrifying bacteria, make the nitrification reaction go smoothly, and effectively remove ammonia nitrogen; at the same time, it can intercept macromolecular organic matter that is difficult to degrade and prolong its life. residence time in the reactor to maximize degradation.

It should be noted that no primary sedimentation tank is installed in the system used in this method, because although the primary sedimentation tank can effectively remove SS and BOD ₅ and reduce the engineering cost and operation cost of secondary biological treatment, due to the processing of rural sewage The water concentration is low, and the final treatment level is to achieve phosphorus and nitrogen removal. In order to ensure the basic ratio of biological phosphorus and nitrogen removal C:N and C:P, no primary sedimentation tank is set in this system.

This method prevents the process design of alleviating membrane fouling as follows:

1) Membrane tank is equipped with MBR membrane module system and supporting water outlet, backwash, cleaning, purging, hoisting and other systems. The membrane module is located directly above the perforated aeration tube. The lower part of the membrane module is equipped with a special purge system to purge and shake the membrane elements to delay the accumulation of sludge concentration around the membrane elements. The excess sludge is regularly discharged through the excess sludge pump, which can control the concentration and age of activated sludge in the system. the

2) Multi-level thick and thin grids are used to ensure the pretreatment effect. the

3) Based on the above design, through combined aeration, control of aeration time and intermittent time, self-priming pump operation and intermittent time control, the degree of pollution of the membrane during operation can be reduced, the frequency of membrane cleaning can be reduced, and the water quality of the membrane system can be guaranteed. Flux, prolong membrane life, reduce operating costs. the

It can be seen from the above examples that the method of the embodiment of the present invention mainly uses MBR technology to treat domestic sewage in ecologically sensitive areas, and adopts anaerobic-anoxic-aerobic-MBR combined technology, which has higher treatment efficiency and stable treatment Effect. Experiments show that under the conditions of influent COD of 400mg/L, NH ₄ ⁺ -N of 40mg/L, SS of 200mg/L, total phosphorus of 6mg/L, and total nitrogen of 55mg/L, the MBR reactor effluent COD The ammonia nitrogen is 14mg/L, the ammonia nitrogen is 0.38mg/L, the suspended matter is 10mg/L, the total nitrogen is 5.34mg/L, and the total phosphorus is 0.484mg/L. GB18918-2002) Class A standard.

Each index of the sewage water quality that this method is suitable for processing is as shown in Table 1:

Table 1

serial number indicators water quality 1 pH 6～9 2 COD _cr (mg/L)≤ 400 3 5-day biochemical oxygen demand BOD ₅ (mg/L)≤ 250 4 Suspended solids (SS) (mg/L)≤ 200 5 Ammonia nitrogen (mg/L)≤ 40 6 TN(mg/L)≤ 55 7 TP(mg/L)≤ 6 8 Vegetable oil≤ 50 9 Mineral oil≤ 3

After the sewage is treated by this method, the effluent can reach the water quality shown in Table 2, and meet the first-class A discharge standard in the "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB18918-2002). In addition, the effluent of this method can meet the standards in the "Code for Design of Sewage Recycling Engineering" (GB/T 50335-2002) after being disinfected, and can be reused for greening, toilet flushing, car washing and landscape water. the

Table 2

project Class A Standard for Pollutants of Urban Sewage Treatment Plants Water quality standards for reclaimed water reuse in landscape environment pH 6～9 6～9 COD _cr (mg/L) 50 - _BOD5 (mg/L) 10 6 SS(mg/L) 10 10 NH ₄ ⁺ -N (mg/L) 5 5 TN(mg/L) 15 15 TP (mg/L) 0.5 0.5 Total (feces) coliforms (unit/L) 1000 2000

The present invention also provides a sewage treatment system in an ecologically sensitive area, including: a water collection well, a pretreatment pool, an anaerobic pool, an anoxic pool, an aerobic pool, and a membrane pool connected in sequence, and the sewage from the water collection well is pretreated After the pool treatment, the tank is adjusted, and then enters the anaerobic pool, where the sewage is mixed with the return mixed liquid from the anoxic pool; The effluent of the pool enters the aerobic pool; the effluent of the aerobic pool enters the membrane pool, and the filtration treatment is completed in the membrane pool. The connection relationship among the various components of the system and the process parameters used are as mentioned above. In this embodiment, the system is also equipped with a PLC system, which is used to adjust the residence time of sewage in the adjustment tank, adjust the flow rate of the lift pump installed between the adjustment tank and the anaerobic tank, and adjust And the running time and air volume of the fan in the membrane tank. An online liquid level gauge for monitoring the water level is also arranged in the regulating pool.

When carrying out the above experiments, the operating cost of the system is about 1 yuan/ton of water. the

The above are only embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, some improvements and modifications can be made without departing from the technical principles of the present invention. It should be regarded as the protection scope of the present invention. the

Claims (10)

1. an ecological sensitive areas sewage water treatment method is characterized in that, comprises step:

S1, pre-treatment: the pump well (1) that uses inlet to be provided with mechanical coarse rack is removed bigger suspended substance in the sewage, sewage enters pretreatment pool (2) afterwards, the coarse rack that is arranged on pretreatment pool (2) inlet is further removed the suspended substance in the sewage, adopt vegetable and animals oils and mineral oil in the oil trap removal sewage then, last sewage enters equalizing tank (3) and handles;

S2, biological treatment and sludge treatment: pretreated sewage enters anaerobic pond (4), mixes with the backflow mixed liquor from anoxic pond (5) in anaerobic pond (4); Anaerobic pond (4) water outlet be mixed into anoxic pond (5) from the backflow mixed liquor of membrane cisterna (7), realize the backflow of mixed solution and mud simultaneously, anoxic pond (5) water outlet enters Aerobic Pond (6); Aerobic Pond (6) water outlet enters membrane cisterna (7), finishes filtration treatment under biological degradation and the condition of negative pressure at membrane cisterna (7).

2. ecological sensitive areas sewage water treatment method as claimed in claim 1 is characterized in that, the residence time of sewage in pump well is 1～2 hour; The residence time of sewage in oil trap is 2～4 hours, and belt skimmer is set in the oil trap; The residence time of sewage in equalizing tank is 8～16 hours, and stirrer is set in equalizing tank or arranges that in its bottom perforated pipe is used for aeration.

3. ecological sensitive areas sewage water treatment method as claimed in claim 1 is characterized in that, the interval of grid strip of described mechanical coarse rack is 20mm; The interval of grid strip of described coarse rack is 5mm; Between equalizing tank (3) and anaerobic pond (4) fine fack is set, its interval of grid strip is 0.5mm.

4. ecological sensitive areas sewage water treatment method as claimed in claim 1 is characterized in that, the treatment time of sewage in anaerobic pond is 2～4 hours; Treatment time in anoxic pond is 2～4 hours; Treatment time in Aerobic Pond is 3～5 hours, and mud age is 15-25d; Micro porous aeration head is set in Aerobic Pond, so that to the Aerobic Pond oxygen supply, the micro porous aeration head aperture is ￠ 215, and the gas-water ratio in the Aerobic Pond is 8: 1.

5. as each described ecological sensitive areas sewage water treatment method of claim 1～4, it is characterized in that, described membrane cisterna is a membrane bioreactor, the treatment time of sewage in described membrane bioreactor is 3～5 hours, and sludge concentration wherein is that 2000～5000mg/L, gas-water ratio are 20～30: 1, return current ratio of the mixed liquid is 500～150%; Stop 2min for operation 13min vacuum primingpump working time of membrane bioreactor, and be that 8 hours, membrane flux are 10～20L/m2h the switching time of its gas blower.

6. ecological sensitive areas Sewage treatment systems, it is characterized in that, comprise: the pump well of Lian Jieing (1), pretreatment pool (2), anaerobic pond (4), anoxic pond (5), Aerobic Pond (6) and membrane cisterna (7) successively, handle equalizing tank afterwards from the sewage that pump well (1) comes through pretreatment pool (2), enter anaerobic pond (4) then, sewage is with mixing mutually from the backflow mixed liquor of anoxic pond (5) in anaerobic pond (4); Anaerobic pond (4) water outlet be mixed into anoxic pond (5) from the backflow mixed liquor of membrane cisterna (7); Anoxic pond (5) water outlet enters Aerobic Pond (6); Aerobic Pond (6) water outlet enters membrane cisterna, finishes filtration treatment in membrane cisterna (7).

7. ecological sensitive areas Sewage treatment systems as claimed in claim 6 is characterized in that, also comprises mechanical coarse rack, and it is positioned at the ingress of described pump well (1); Also comprise coarse rack, it is positioned at the ingress of described pretreatment pool (2); Also comprise fine fack, it is positioned between described equalizing tank (3) and the anaerobic pond (4).

8. ecological sensitive areas Sewage treatment systems as claimed in claim 6, it is characterized in that, described membrane cisterna (7) is membrane bioreactor MBR, it comprises membrane module, boring aeration pipe, outlet system, backwash system, cleaning system, purging system and Lift-on/Lift-off System, described membrane module is positioned at directly over the described boring aeration pipe, and described purging system is arranged on the below of described membrane module.

9. ecological sensitive areas Sewage treatment systems as claimed in claim 6, it is characterized in that, also comprise programmable logic controller system, it is used for regulating sewage at the residence time of equalizing tank (3), the flow that adjusting is arranged at the lift pump between equalizing tank (3) and the anaerobic pond (4), and regulates working time and the air quantity that is arranged at the blower fan in Aerobic Pond (6) and the membrane cisterna (7) respectively.

10. as each described ecological sensitive areas Sewage treatment systems of claim 6～9, it is characterized in that, be provided for monitoring the online liquidometer of water level in the described equalizing tank (3).

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