40results about How to "Improve nitrogen and phosphorus removal capacity" patented technology

The invention belongs to the technical field of environmental engineering, and relates to a subsurface flow constructed wetland combination system and the application of the system. The constructed wetland combination system comprises three wetland units (16, 17 and 18), wherein the three wetland units respectively comprise wetland unit frames (13, 14 and 15), water distribution pipes (1, 3 and 5), water collecting pipes (2, 4 and 6), a water inlet pipe (19), connecting pipes (20 and 21), a water outlet valve (7), a vertical water outlet pipe (8) and a siphon (9), wherein the wetland units (16, 17 and 18) are connected with one another by the water collecting pipes (2, 4 and 6) or the water distribution pipes (1, 3 and 5), the wetland units (16, 17 and 18) are internally filled with substrates (10, 11 and 12), and the three wetland units are vertically distributed in a gradually-falling shape. The system and the application of the system provided by the invention have the advantages of being high in the adaptability to terrain, better in nitrogen and phosphorus removal effect for a water body, hard to block, convenient in operation, maintenance and management, low in project capital construction cost and running cost and the like.

The invention provides a wastewater treatment process and system. The process comprises the following steps: a, performing anaerobic and aerobic treatment on wastewater in sequence to obtain first muddy water mixed liquor, wherein sludge age in the anaerobic and aerobic treatment is 0.5 to 5 days, and the waterpower stay duration is 0.5 to 3 h; b, performing sedimentation on the first muddy water mixed liquor to obtain first sludge and supernate; c, performing anaerobic and aerobic treatment on the supernate in sequence to obtain second muddy water mixed liquor; reacting the second muddy water mixed liquor and a coagulant, and performing sedimentation on obtained reaction liquid to obtain second sludge and effluent; enabling part of the first sludge to flow back and take part in anaerobic treatment; performing hydrolytic acidification on the other part of the first sludge to obtain fourth muddy water mixed liquor; conveying part of the fourth muddy water mixed liquor to take part in anaerobic treatment. The process is free of additional carbon sources, and has a higher nitrogen and phosphorus removal capacity; the system is small in occupied area; the energy self-sufficiency rate of a sewage treatment plant is greatly improved; the resource recovery rate is high; residual sludge output is lower.

The invention discloses a method and a device for biological ecological assemblage for sewage purification and recycling. The method comprises the following steps: A. sewage to be treated passes through a grate / regulating reservoir, and large particulate materials are removed; B. the sewage treated in step A is pumped into an integral membrane bioreactor, and permeates a membrane when pumped by a pump; C. the sewage treated in step B flows into an intermediate water reservoir; and D. the sewage flowing out in step C enters into a composite vertical current manual wetland by graded means. The device comprises four units: the grate / regulating reservoir, the integral membrane bioreactor, the water reservoir and the composite vertical current manual wetland, wherein various units are connected through pipes and controlled by valves. Bypass pipes are arranged on outlets of the various units of the grate / regulating reservoir, the integral membrane bioreactor, the water reservoir and the composite vertical current manual wetland, and combined modes of series connection, shunt connection and parallel connection of the integral membrane reactor and the composite vertical current manual wetland are realized by adjusting valves, so that the method is easy, is simple and convenient to operate, has high operation efficiency and low cost, and realizes sewage purification and direct recycling.

The invention discloses a distributed sewage coupling treatment method. In the distributed sewage coupling treatment method, an efficient biological purification tank, an MBR (Membrane Bio-reactor) pool, a carbon source sustained release area, a control room, an artificial wetland system, a disinfection tank and a water outlet area are adopted. The distributed sewage coupling treatment method is characterized in that sewage enters the efficient biological purification tank; the efficient biological purification tank comprises an anoxic zone, an anaerobic zone and an aerobic zone; the sewage issubjected to organic matter degeneration and removal of nitrogen and phosphorus nutrients through the anoxic zone-anaerobic zone-aerobic zone; suspended matters and organic matters in the sewage andthe chromaticity of the sewage are treated by an MBR area; one part of the sewage which is treated by the MBR area and is used as reflux liquid enters the anoxic zone in the efficient biological purification tank, and the other part of the sewage flows into the artificial wetland system with the carbon source sustained release area and performs deep nitrogen and phosphorus removal treatment; the sewage treated by the artificial wetland system flows into the disinfection tank, is subjected to sterilization treatment, then enters the water outlet area and flows out of the water outlet area. Thedistributed sewage coupling treatment method disclosed by the invention has the advantages of compact structure, small occupied area, high treatment efficiency and good effect; energy is saved; the distributed sewage coupling treatment method is suitable for distributed centralized treatment of the sewage.

The invention discloses a method for remediating pond water in situ. The method comprises the following steps: suspending a surface aeration system and a BC biological reaction system in water from top to bottom in sequence, wherein the surface aeration system is used for rising and diffusing water, and the BC biological reaction system is used for immobilizing microorganisms; performing rising movement on the water from the lower part of the water under the action of rising force provided by the surface aeration system; passing the water through the BC biological reaction system, and activating immobilized microorganisms in the BC biological reaction system by nutrient substances in water to breed; pushing out the rising water body by the surface aeration system, and circulating the water to the bottom of the pond under the action of water flow density difference. The method for in-situ remediating pond water disclosed by the invention has the advantages that the starting is quick, the needed remediating time is short, the concentration of the microorganisms is high, the bottom sludge is synchronously degraded, the process operation is simple, the energy consumption is low, the secondary pollution is avoided and the remediating effects are stable.

The invention provides a low energy consumption integrated A2 / O-MBR reactor. The reactor is structurally characterized in that two groups of guide plates are symmetrically arranged at the center of a reaction tank body, a vertical section of a region sandwiched between the guide plates is inverted funnel-shaped, and an aerobic zone (comprising a membrane unit zone and an aeration zone) is formed at the center, and descending zones (namely anaerobic / anoxic zones) are formed at two sides; the aeration energy can be sufficiently utilized, the hydraulic scouring effect on the membrane surface is improved, and the sufficient hydraulic circulation can be obtained by the aerobic zone or between the anaerobic / anoxic zones; the water circulating flow between the aerobic zone and the descending zones can be well adjusted through an exchange flow control valve; the nitrogen and phosphorus removal capacity of the reactor can be greatly improved, the aeration amount can be reduced by 50% or above; and meanwhile, the total aeration amount can be reduced by more than 50% by adopting the simple variable aeration technology of a power-driven three-way valve; through the superposition of the above technologies, the aeration amount can be reduced to 20-30% of the original aeration amount; therefore, the reactor has the characteristics of high efficiency in nitrogen and phosphorus removal, small floor area and low energy consumption.

The invention discloses a microbial electrochemical coupling membrane bioreactor system and a sewage treatment method. The system comprises an airlift circulation type membrane bioreactor, a microbialelectrochemical device and a nitrogen and phosphorus recovery area. The airlift circulation type membrane bioreactor comprises a plurality of airlift circulation type membrane bioreactor units; eachairlift circulation type membrane bioreactor unit comprises an anoxic zone, an anaerobic zone and an aerobic zone; the microbial electrochemical device comprises an anode electrode, a cathode electrode and an external circuit for connecting the cathode and the anode; and the nitrogen and phosphorus recovery area comprises an anion exchange membrane, a cation exchange membrane and an area between the anion exchange membrane and the cation exchange membrane. The system not only has the efficient sewage treatment and solid-liquid separation capabilities of the airlift circulation type membrane bioreactor to reduce the sludge backflow energy consumption, but also combines the characteristics of anaerobic and aerobic region distribution of a circulation system, and the overall nitrogen and phosphorus removal capability is enhanced by coupling a microbial electrochemical system, thereby further improving the effluent quality.

The invention belongs to the field of artificial wetland substrate and relates to a novel artificial wetland substrate added with microbial carrier fillings. The artificial wetland substrate added with microbial carrier fillings comprises polyurethane soft microbial carrier material and inorganic matrix, wherein the polyurethane soft microbial carrier material accounts for 1%-10% the total weight of the artificial wetland substrate; the inorganic matrix comprises two or three of fine gravel, vermiculite and blast furnace slag, and specifically the inorganic matrix comprises the following components in proportion by weight: fine gravel 1-4: vermiculite 1-2: blast furnace slag 1-5; the soft polyurethane microbial carrier material has the advantages of high specific surface area, good hydrophilicity and microbe adherence and high mechanical strength, so that the soft polyurethane microbial carrier materials can provide abundant attachment sites to sewage-treating microbes to accelerate biological membrane generation, increase aeration and improve nitrogen and phosphorus removal capacities of the microbes; the biological membrane content in the substrate is increased, absorption, precipitation and removal abilities of the whole wetland system to soluble solids and insoluble organics are increased and blockage of the artificial wetland substrate is reduced.

The invention provides a wastewater treatment process and system. The process comprises the following steps: a, performing anaerobic and aerobic treatment on wastewater in sequence to obtain muddy water mixed liquor, wherein sludge age in the anaerobic and aerobic treatment is 0.5 to 5 days, and the waterpower stay duration is 0.5 to 3 h; b, performing sedimentation on the muddy water mixed liquor obtained in the step a, so as to obtain supernate and sludge; c, performing anaerobic ammonia oxidation on the supernate obtained in the step b, and separating obtained muddy water mixed liquor to obtain supernate and sludge; d, mixing the supernate obtained in the step c and a coagulant, and performing sedimentation on obtained reaction liquid to obtain sludge and effluent. The process is free of additional carbon sources, and has a higher nitrogen and phosphorus removal capacity. Test results show that after wastewater is treated by the process, SS is 5 to 10 mg / L, COD is 30 to 46 mg / L, TN is 9 to 13 mg / L, and TP is 0.3 to 0.5 mg / L.

The invention discloses a three-dimensional biological rotating disc which comprises a box body; a speed reducer and a gear box are arranged outside the box body; the speed reducer and the gear box are connected with each other by a bearing, and are used for adjusting and controlling the rotating speed of rotating disc modules arranged in the box body; a storage clapboard is welded between the rotating disc modules; three-dimensional filler is filled between the outer side of the storage clapboard and the rotating disc modules; and a water inlet and a water outlet are respectively formed in the two sides of the bottom of the box body. According to the three-dimensional biological rotating disc, the thickness and the concentration of a biological film on the biological rotating disc are greatly increased, so that the equipment size and the investment of the biological rotating disc are greatly reduced under the same processing scale; furthermore, after a special packing way is adopted, an anaerobic state and an oxygen deficit state can be easily formed in the biological rotating disc, so that the denitrification processing capacity of a system is improved; and the aged biological film on the surface of the filler can rapidly fall off and is updated, so that the treatment efficiency of the whole system is greatly improved.

The invention discloses a biological denitrifying and dephosphorizing efficiency improving method through ultrasonic wave, which is characterized by the following: the partial condensed mud is disposed by ultrasonic radiation in the second-sedimenting pool or intermittent denitrifying and dephosphorizing reactor, which is constructed for several times everyday for water disposal flow with denitrifying and dephosphorizing function; the activity of microbe with denitrifying and dephosphorizing function is accelerated, which improves denitrifying and dephosphorizing ability through refluxing mud to denitrifying and dephosphorizing reactor or equipment.

The invention discloses assembled sequencing batch fluidized bed sewage treatment equipment. The equipment comprises a shell and is characterized in that the shell is an assembled tank body; an umbrella-shaped inner shell is arranged inside the shell; the interior of the umbrella-shaped inner shell is a reaction zone; a settling zone is arranged between the shell and the umbrella-shaped inner shell; suspended fillers suspend in the reaction zone; an aeration device is arranged at the bottom of the reaction zone; a filler isolating net is arranged between the reaction zone and the settling zone; the reaction zone is connected with a water inlet pipe; a water outlet pipe is arranged at the upper part of the shell; a water decanter is arranged in the settling zone; a water outlet of the water decanter is connected with the water outlet pipe. The invention also comprises a process for treating sewage by adopting the equipment. The sewage treatment equipment and the sewage treatment process have the advantages of short construction cycle, investment saving, low energy consumption, low operating cost, strong impact resistance load capacity, good treatment effect, strong nitrogen and phosphorus removal capacity, convenience in operation management, high degree of automation, no noise, flexible assembly and the like.

The invention discloses a method for purifying wastewater by a constructed wetland comprising a microbial carrier. Multilayer filler of a vertical flow constructed wetland includes: a sandy oil covering layer, an aerated brick powdery particle layer and a gravel layer sequentially from bottom to top; Scirpus validus is planted on the sandy soil covering layer, the sandy soil covering layer comprises the microbial carrier, and earthworms are also put in the sandy soil covering layer; the self-made microbial carrier material added herein has good hydrophilicity and microbial attachment and can be added to constructed wetland base to adsorb mass wastewater treatment microbes, improving aeration and the ability of microbes to remove nitrogen and phosphorus; gravels are widely sourced, low in cost, good in breathability and water adsorption and helpful for aeration and oxygen supply for a constructed wetland base system and for adsorbing pollutants; the earthworms added herein can prevent the constructed wetland from being blocked and increase oxygen supply.

The invention relates to a side flow denitrification technique which can be used in combination with an AAO (anaerobic-anoxic-oxic) technique, a CAST (cyclic activated sludge technology) technique, an oxidation ditch technique with a front end anaerobic region and any other activated sludge treatment technique. When the technique is used in combination with the AAO technique, a sludge discharge pipe of a secondary sedimentation tank is connected with a side flow denitrification tank, the upper part of the side flow denitrification tank is connected with a supernate pipe, and the supernate pipe is connected with an anoxic zone and the secondary sedimentation tank. When the technique is used in combination with the oxidation ditch technique with a front end anaerobic region, a sludge discharge pipe of a secondary sedimentation tank is connected with a side flow denitrification tank, and the upper part is connected with a supernate pipe which is connected with an oxidation ditch and the secondary sedimentation tank. When the technique is used in combination with the CAST technique, a sludge discharge pipe of a main reaction region is connected with a side flow denitrification tank, and a supernate pipe is connected with the main reaction region. The side flow denitrification tank provided by the invention enhances the sludge concentration, and the sludge is subjected to endogenous respiration denitrification, thereby greatly lowering the nitrate amount, reducing the influence of the sludge on the anaerobic section of the biochemical reaction tank or the phosphorus release of the biological selection region of the CAST technique, and enhancing the dephosphorization effect of the system.

The invention discloses a combined type multifunctional deep nitrogen and phosphorus removal artificial wetland system for tail water. The system includes a hydrolyzed acidification zone (1), a biomass filling material placement zone (2), a denitrification wetland area (3), a nitrification wetland area (4), a denitrification wetland area (5) and an enhanced phosphorus removal zone (6). Tail waterenters the hydrolyzed acidification zone (1) to be in contact with a biofilm colonization combined filling material, so that the nitrogen and phosphorus elements in the tail water can be effectively utilized; the tail water enters the biomass filling material placement zone (2) through a diversion groove, and the filling material can release organic matters to provide favorable conditions for follow-up denitrification; the denitrification wetland area (3) and (5) adopt enclosed top covers which can provide anoxic environments for microorganisms; and the high calcium fly ash ceramsite and ferro-iron composite filling material in the enhanced phosphorus removal zone (6) can effectively remove phosphorus. The system can effectively solve the contradiction of the demands of the removing of phosphorus and nitrogen in tail water on carbon sources; the system is not easy to block, and is good in effluent water quality and less in investment; and effects of beautifying landscapes can be achieved by cooperatively planting water plants.

The invention provides an adjustable biological membrane-activated sludge sewage treatment method. The sewage treatment method can handle sharp changes of water quality, an external carbon source is not needed, the problem of sludge age contradiction can be solved effectively, higher nitrogen and phosphorus removal capability is realized, pollutant impact load is handled by adjusting the filling ratio of fillers, and the problems of redundancy and deficiency of facilities for sewage treatment plants are solved effectively. Experimental results show that sewage treated by the sewage treatment method can reach the first-class A sewage discharge standard (GB18918-2002). The invention further provides an adjustable biological membrane-activated sludge sewage treatment device. The device can flexibly treat the sewage with a low, medium or high concentration and distribute inlet water; an external carbon source is not needed, and the operation costs of the sewage treatment plants are reduced; the problem of sludge age contradiction can be solved effectively, the higher nitrogen and phosphorus removal capability is realized, and the problems of redundancy and deficiency of the facilitiesfor the sewage treatment plants are solved effectively.

The invention discloses a vertical flow artificial wetland. The vertical flow artificial wetland comprises a first-stage vertical flow artificial wetland pond, a second-stage vertical flow artificial wetland pond and a third-stage vertical flow artificial wetland pond which are sequentially connected in series, wherein aerator pipes are arranged in the first-stage vertical flow artificial wetland pond and the third-stage vertical flow artificial wetland pond, filling layers are arranged above the aerator pipes, soil layers are arranged on the filling layers, and aquatic plants are planted on the soil layers; and the aerator pipe is not arranged in the second-stage vertical flow artificial wetland pond, the other inner structure of the second-stage vertical flow artificial wetland pond is same as that of the first-stage vertical flow artificial wetland pond, and a second water inlet pipe is arranged above the second-stage vertical flow artificial wetland. The invention further provides a method for treating nitrogen, phosphorus and tetracyclines in sewage by virtue of the vertical flow artificial wetland. By virtue of the purification capacity of a middle and rear segment of the vertical flow artificial wetland, the removal load is increased, and the occupied area is reduced; and the effluent index of the vertical flow artificial wetland is increased by virtue of aeration, so that the effluent reaches the standards, and a simple and feasible method for the small-scale sewage treatment is provided.

The invention discloses a biological stuffing fixed type HMBR process aeration tank. A plurality of guide walls are arranged in an aeration tank; membrane modules are arranged between the guide wallsand tank walls; an external self-priming pump is connected with the membrane modules; an aeration head is arranged under the membrane modules; a sludge discharging pipe is arranged on the bottom of the aeration tank; the fixed biological stuffing is arranged in the aeration tank; raw water is pumped into the aeration tank by a raw water pump through a grating. The invention has the beneficial effects that the aeration tank has high capacity of removing nitrogen and phosphorus and excellent dredging effect.

The invention relates to the technical field of sewage treatment and in particular relates to a household sewage treatment process. The process treats sewage by way of a pre-posed anoxic pond and a post-posed anoxic pond without supplementing a carbon source. The process has a relatively high nitrogen and phosphorus removal ability, and meanwhile, the reflux ratio of a reflux liquid is greatly reduced by the process, so that a lot of cost is lowered. In addition, the process also solves the problem of organic matter degradation and phosphorous removal efficiency caused by sludge age.

The invention particularly relates to a double-filler coupled sewage biological treatment method, belonging to the technical field of sewage treatment in environmental engineering science. According to the method, two biological fillers with different action mechanisms are added into a reactor of an SBR sewage treatment system to generate the double-filler coupled biological treatment effect, thereby increasing and enriching the biomass and the species of various microbial florae, and constituting the relatively stable composite biological treatment system in which attached-growth microbes and suspended-growth activated sludge coexist; and under the biochemical actions of the humic biological filler, the suspended-growth common activated sludge in the SBR system is converted into humic activated sludge with higher nitrogen and phosphorus removal capacity and lower sludge proliferation speed. The method is simple and feasible, has the advantages of lower investment and obvious effects, is capable of improving the properties of the activated sludge in the treatment system, enhancing the sewage treatment effect and lowering the sludge yield, and effectively inhibits the odor of the sludge on the premise of implementing in-situ sludge reduction.

The invention discloses a method and a device for biological ecological assemblage for sewage purification and recycling. The method comprises the following steps: A. sewage to be treated passes through a grate / regulating reservoir, and large particulate materials are removed; B. the sewage treated in step A is pumped into an integral membrane bioreactor, and permeates a membrane when pumped by apump; C. the sewage treated in step B flows into an intermediate water reservoir; and D. the sewage flowing out in step C enters into a composite vertical current manual wetland by graded means. The device comprises four units: the grate / regulating reservoir, the integral membrane bioreactor, the water reservoir and the composite vertical current manual wetland, wherein various units are connected through pipes and controlled by valves. Bypass pipes are arranged on outlets of the various units of the grate / regulating reservoir, the integral membrane bioreactor, the water reservoir and the composite vertical current manual wetland, and combined modes of series connection, shunt connection and parallel connection of the integral membrane reactor and the composite vertical current manual wetland are realized by adjusting valves, so that the method is easy, is simple and convenient to operate, has high operation efficiency and low cost, and realizes sewage purification and direct recycling.

Integrated water treatment equipment comprises a septic tank, a filtration tank and a discharging system, which are all installed below the ground surface with bottoms arranged on a prefabricated concrete slab. One side of the septic tank is provided with a water inlet pipe, and the upper part of the other side is connected to the filtration tank through a connecting pipe. The septic tank and the filtration tank both comprise a tank, a stiffener at the outside of the tank and a ventilating window at the top of the tank. The tank of the septic tank is divided into two septic chambers. A three-way pipe is arranged above a separator plate between the two septic chambers. A flow deflector is vertically arranged above the septic chambers. There is a gap between the flow deflector and the bottom of the tank. A filter, a chlorine dioxide water-purifier and a back-flusher are arranged inside the filtration tank. One side face of the filtration tank is connected to the discharging system. The invention has the following advantages and beneficial effects: the equipment meets special requirements of water treatment systems in remote areas on space and region, and installation trend and standardization of water treatment technology are realized.

The invention relates to a sewage treatment method, which comprise the following steps: firstly, the sewage is pre-treated, absorbed and subsided; secondly, the sewage after treated in the first step is mixed with the back-flow substances in the Aerobic pond and sedimentation pond, and enters anoxic pond to finish the denitrifying and degradation of partial organic contaminations; thirdly the water after treated in the anoxic pond flows into the aerobic pond added with biological fillings; fourthly, the sedimentation is treated, the purified water flows out. By the above improved novel sewagetreatment method, the nitrogen-removing and dephosphorization capability of the original AB sewage treatment process is enhanced, under the condition of not adding constructions, the organic substance removal capability of sewage treatment factory can be improved, thereby meeting the requirements of enlarging capacity and enhancing efficiency, and having obvious economic benefit.

The invention relates to the technical field of sewage treatment, in particular to a tail water advanced treatment device and treatment method. The tail water advanced treatment device provided by theinvention comprises a sewage treatment apparatus, an ammonia recovery apparatus, a phosphorus recovery apparatus, a denitration apparatus, a backwash filtering apparatus and a disinfection apparatuswhich are communicated sequentially, and the treatment device further comprises a residual sludge liquefaction apparatus, a sewage outlet of the sewage treatment apparatus is communicated with a feedinlet of the residual sludge liquefaction apparatus, and a liquid outlet of the residual sludge liquefaction apparatus is communicated with a water inlet of the sewage treatment apparatus. Residual sludge discharged by the sewage treatment apparatus is subjected to hydrolytic acidification through the residual sludge liquefaction apparatus so as to be recycled as a carbon source, and the defect ofinsufficient carbon source of village and town sewage is overcome. By adopting the tail water advanced treatment device provided by the invention, efficient denitration, denitrification and phosphorus removal can be carried out on tail water automatically, nitrogen and phosphorus resources are recycled, and to-be-discharged water meeting the standard of surface quasi-class IV water is obtained.

The invention provides a wastewater treatment process and system. The process comprises the following steps: a, performing anaerobic and aerobic treatment on wastewater in sequence to obtain muddy water mixed liquor, wherein sludge age in the anaerobic and aerobic treatment is 0.5 to 5 days, and the waterpower stay duration is 0.5 to 3 h; b, performing sedimentation on the muddy water mixed liquor obtained in the step a, so as to obtain supernate and sludge; c, performing anaerobic ammonia oxidation on the supernate obtained in the step b, and separating obtained muddy water mixed liquor to obtain supernate and sludge; d, mixing the supernate obtained in the step c and a coagulant, and performing sedimentation on obtained reaction liquid to obtain sludge and effluent. The process is free of additional carbon sources, and has a higher nitrogen and phosphorus removal capacity. Test results show that after wastewater is treated by the process, SS is 5 to 10 mg / L, COD is 30 to 46 mg / L, TN is 9 to 13 mg / L, and TP is 0.3 to 0.5 mg / L.

The invention provides a wastewater treatment process and system. The process comprises the following steps: a, performing anaerobic and aerobic treatment on wastewater in sequence to obtain first muddy water mixed liquor, wherein sludge age in the anaerobic and aerobic treatment is 0.5 to 5 days, and the waterpower stay duration is 0.5 to 3 h; b, performing sedimentation on the first muddy water mixed liquor to obtain first sludge and supernate; c, performing anaerobic and aerobic treatment on the supernate in sequence to obtain second muddy water mixed liquor; reacting the second muddy water mixed liquor and a coagulant, and performing sedimentation on obtained reaction liquid to obtain second sludge and effluent; enabling part of the first sludge to flow back and take part in anaerobic treatment; performing hydrolytic acidification on the other part of the first sludge to obtain fourth muddy water mixed liquor; conveying part of the fourth muddy water mixed liquor to take part in anaerobic treatment. The process is free of additional carbon sources, and has a higher nitrogen and phosphorus removal capacity; the system is small in occupied area; the energy self-sufficiency rate of a sewage treatment plant is greatly improved; the resource recovery rate is high; residual sludge output is lower.

The invention relates to the technical field of sewage treatment and in particular relates to a household sewage treatment process. The process treats sewage by way of a pre-posed anoxic pond and a post-posed anoxic pond without supplementing a carbon source. The process has a relatively high nitrogen and phosphorus removal ability, and meanwhile, the reflux ratio of a reflux liquid is greatly reduced by the process, so that a lot of cost is lowered. In addition, the process also solves the problem of organic matter degradation and phosphorous removal efficiency caused by sludge age.