CN107840535A - A kind of laundrywastes filtration process device and method - Google Patents

Abstract

The invention discloses a laundry wastewater percolation treatment device, which comprises a water inlet tank, a water inlet pipe and a percolation device connected in sequence, wherein, the percolation device is provided with an active soil layer, a quartz sand filter, Material bed and zeolite layer, active soil layer: quartz sand filter material layer: the volume ratio of zeolite layer is 1: (6-9): 2; The outside of described quartz sand filter material layer is provided with ventilation pipe, the bottom of zeolite layer The side is connected to the return pump, the return pipe and the return valve in sequence and leads to the active soil layer. The present invention further proposes a method for treating laundry wastewater using the above-mentioned device. The removal rate of surfactant can reach more than 95%, and the removal rate of COD, NH ₃ ‑N and TP can reach more than 80%, 90% and 60% respectively. The invention has high pollutant removal efficiency, stable operation, no clogging, no secondary pollution, low operation cost and convenient operation and management. The invention has the advantages of high treatment effect, no clogging, no secondary pollution, low operating cost and convenient operation and management.

Description

Apparatus and method for percolation treatment of laundry wastewater

technical field

The invention belongs to the field of sewage treatment, and more specifically relates to a treatment device and method for laundry wastewater.

technical background

With the continuous development of the synthetic industry and the continuous improvement of people's living standards, synthetic detergents are used more and more in daily life. Washing supplies have become the necessities of life for every household, and people's demands for washing supplies are increasingly diversified with the improvement of living standards. Today's global detergent market is full of strife and unprecedented competition. Detergent advertisements are overwhelming in various media. Major detergent manufacturers are competing to launch multi-functional washing products to meet the diverse needs of consumers everywhere. my country's detergent industry has developed rapidly in recent years, and its output has increased year by year. Survey data show that: in 1985, my country's synthetic detergent production was 1.004 million tons, increased to 1.514 million tons in 1990, 2.218 million tons in 1995; 3.828 million tons in 2000, and 4.6 million tons in 2005.

The main components of washing powder generally include: surfactants, builders, stabilizers, dispersants, brighteners, essences and enzymes, among which the most important components are surfactants and builders. Since the emergence and application of washing powder products, it has been found that the use of sodium tripolyphosphate additives used to improve washing performance in traditional washing powder formulations has caused the problem of eutrophication of water bodies. After switching to phosphorus-free detergents, people gradually discovered that the pollution sources of water quality deterioration include not only phosphorus, but also surfactants, various organic substances, and suspended solids.

Surfactants in washing powder are difficult to degrade and are discarded into the water environment system, which seriously affects the balanced development of the surrounding ecosystem. At the same time, domestic sewage containing a large amount of household detergent will not only inhibit and kill Microorganisms in water, but also inhibit the degradation of other toxic substances. In addition, surfactants can change soil physical, chemical and biological properties to a certain extent after entering the soil.

Laundry wastewater mainly includes cleaning wastewater, washing wastewater and drying wastewater. The volume of washing wastewater: the volume of washing wastewater: the volume of drying wastewater is about 3:6:1. Sorting of wastewater concentration: washing wastewater > washing wastewater > drying wastewater. Among them, the washing wastewater contains surfactants, sodium tripolyphosphate, etc., the pH is 6.5-7.5, the COD is 300-800mg/L, and the content of suspended solids is relatively high, generally 500-1200mg/L. Phosphate entering the water will cause water pollution. The eutrophication of the surfactant, after the surfactant enters the water body, it will poison the aquatic animals and plants to death, solubilize some micro-pollutants in the water; the cleaning wastewater has a large amount, a small amount of foam, less suspended solids, and a smaller COD .

Patent application number 01115050.5, kneading and pressing multi-channel drainage drum washing machine. Kneading and pressing type multi-way drainage drum washing machine: it mainly improves and solves two problems. The first one: mainly improve the unsatisfactory cleanliness of the drum washing machine. Its main features are: there is a cylindrical drum with many permeable holes on the wall of the drum, a window for picking and placing clothes is opened on the peripheral surface of the drum, and a kneading pressure plate is installed in the drum, and the kneading pressure plate passes through the threaded shaft and the pulley. , connected with the motor, and can reciprocate in the drum under the drive of the motor, so as to achieve the purpose of repeatedly squeezing the clothes and washing them. The second one: it mainly solves the problem that the washing machine in the past had only one drain for drainage. It is inconvenient for people to separate and collect the water with lighter stains for several times during the rinsing process of the washing machine for reuse. Its main features are: using multiple electric valves or multiple drainage pumps to send the washing machine sewage to different drainage pipes according to the drainage program designed by people, which is convenient for people to collect and reuse laundry sewage. This invention does not relate to the problem of laundry wastewater treatment.

Patent application number ZL 200510096289.2, unpowered, decentralized water treatment recycling device and method. The invention relates to a non-powered, decentralized water treatment recycling device and method. The device includes interconnected rainwater discharge pipes, collection pipes and overflow pipes, as well as floor drains located on and above the third floor and connected to the floor drains. Drainage pipes, rainwater drainage pipes are connected to the floor drains of the bathrooms on the top floor through connecting pipes. Except for the top floor and the next floor on the top floor of the building, each bathroom on the other floors of the building is equipped with horizontal drain pipes and water processors. and a water storage tank connected to a water outlet of a water processor through a pipeline, and the water outlet at the bottom of the water storage tank is connected to a flush toilet through a pipeline and a valve; The invention does not involve laundry wastewater treatment process, removal effect, surfactant, ammonia nitrogen, phosphorus removal and other issues.

Patent application number 201210297511.5, dual channels of household running water. A basin of dirty water can be exchanged for a basin of clean water, and a ditch of sewage can be exchanged for a clear spring. To discharge the water from the washing machine to the reclaimed water plant for purification, it is necessary to add a new drainage pipe. Purified reclaimed water is returned to the family, requiring a new water supply pipeline. The recycled water can be used to flush the toilet. In this way, the original tap water for flushing the toilet was replaced by the original laundry sewage, and a new channel for household running water appeared. While the original old passage of the family remains unchanged. The old and new two independent channels constitute the dual channel of family water. The tap water used for flushing the toilet every day is about 10 times of drinking water every day, and the tap water used for flushing the toilet in a year can be drunk for 10 years. A large amount of drinking water is ruined by a small amount of excrement. This invention requires the construction of a sewage pipe network, the distance is long and the pipes are long, and measures such as lifting may be required. There are environmental risks in the dual channels. Once the pipelines cross, the consequences will be disastrous. The treatment effect of the reclaimed water treatment process is not involved, and the investment and operation costs are also unknown.

Patent application number 201410221181.0, car washing sewage and laundry sewage recycling treatment device and water treatment method, the invention relates to a car washing sewage and laundry sewage recycling treatment device and water treatment method, mainly including sewage water inlet pipe, aeration pipe, reuse net Water outlet pipe, T-type sewage into the backwash discharge pipe, T-type dirty washing liquid into the backwash discharge pipe, T-type backwash water into the cleaning liquid outlet pipe, sewage reactor, sewage filter, water purification room, Disinfection dosing box, flocculation dosing box, dirty washing liquid collection chamber and dirty washing liquid filter; this invention requires dosing of chemicals and filtration, high operating costs, secondary pollution of sludge, and complicated operation and management.

Patent application number 201010202356.5, Electrocoagulation-Electric Float Purification Bath and Laundry Wastewater Classification Reuse Device, discloses a electrocoagulation-electric floatation purification bath and laundry wastewater classification reuse device, which is characterized in that the effluent of the sump is set to pass through One of the three links is directly output as the front-end water outlet, and the other is connected in series with the Venturi tube. The anodic oxidation unit is composed of Ti/ _SnO2 anode and Fe anode on both sides of the cathode to form a combined anode, and the cathode uses an air diffusion electrode; two-stage filter units are arranged in series at the outlet of the electrolytic cell, and the two-stage filter unit A secondary water outlet valve is arranged on the secondary filter chamber. The invention can effectively reduce or remove the surfactant and other organic pollutants in the bathing/laundry wastewater, so that the bathing/laundry wastewater can be reused in stages. The invention requires the addition of chemicals, high operating costs, secondary pollution of sludge, and complicated operation and management.

Utility model patent application No. 01200009.4, automatic conversion of domestic wastewater throttle, relates to a device for conversion and treatment of domestic wastewater, which includes a filter storage tank and an interceptor storage tank, connected by a single-phase micro-lift pump in the middle, and adopts a single-circulation flow The principle is that there are connecting nozzles on both sides of the interception box, which are used to connect the drain pipes of the face wash and the sink. The waste water from the shower and laundry enters from the top of the upper cover of the interception box. There are also automatic drains and seals in the interception box The plastic water polo at the mouth of the sewer prevents odors from entering the home. The lift pump adopts a time-delayed automatic control switch. The filter box is used to flush the toilet or clean other items after the domestic wastewater is filtered. The utility model has the characteristics of automatic interception, storage, filter storage, replenishment, disinfection, simple structure, cheap installation and unique combined functions. This invention is only physical filtration, and cannot remove nutrients such as organic matter, surfactants, nitrogen and phosphorus, and does not fundamentally solve the pollution problem.

Patent application number 201710474112.4, a constructed wetland system for purifying roof rainwater containing laundry wastewater, discloses a constructed wetland system for purifying roof rainwater containing laundry wastewater, including sequentially connected rain and sewage diversion wells, water distribution pipes, and wetland treatment areas , water collection pipe and flood discharge ditch, a diversion valve is set in the rain and sewage diversion well, and the outlet of the rain and sewage diversion well is respectively connected to the flood discharge ditch and the water distribution pipe. The water distribution pipe is set above the wetland treatment area, and the water collection pipe is set at the bottom of the wetland treatment area. filter layer composition. When the rainstorm flows into the rain-sewage diversion well and the water level is high, the diverter valve opens, and the rainwater is discharged into the flood discharge ditch; when the laundry wastewater flows into the rain-sewage diversion well, the water level is low, the diverter valve is closed, and the laundry wastewater enters the water distribution pipe through the rain-sewage diversion well; It flows into the wetland treatment area vertically through the water distribution pipe, and after being separated and purified by the vertical filter layer in the wetland treatment area, it is collected by the water collection pipe and discharged into the flood discharge ditch. The laundry wastewater is properly treated before it enters the rainwater pipe network system or is discharged into the river, avoiding pollution to the river. This invention is only for treating laundry wastewater when the water level in the rain-sewage diversion well is low. There are few descriptions on nutrients such as organic matter, surfactants, nitrogen and phosphorus, and nothing about how to improve microbial activity and treatment efficiency in wetlands.

Contents of the invention

Purpose of the invention: Aiming at laundry wastewater with high surfactant, high suspended solids, and high phosphate, to solve the problems of low treatment efficiency, high operating cost, difficult operation and management, and secondary pollution of traditional laundry wastewater, the present invention provides a The laundry wastewater percolation treatment device and method realize efficient wastewater treatment, no secondary pollution and sustainable development.

Technical solution: In order to achieve the above technical purpose, the present invention proposes a laundry wastewater percolation treatment device, which includes a water inlet tank, a water inlet pipe and a percolation device connected in sequence, wherein the percolation device is sequentially arranged from top to bottom An active soil layer, a quartz sand filter layer and a zeolite layer are provided, and the volume ratio of the active soil layer: the quartz sand filter layer: the zeolite layer is 1: (6-9): 2; the outer side of the quartz sand filter layer A ventilation pipe is provided, and the bottom side of the zeolite layer is sequentially connected with a return pump, a return pipe and a return valve, and leads to the active soil layer.

Specifically, the active soil layer is plant wood fiber, compost organic matter and soil hydrolytic enzyme with a mass ratio of 40-50:40-50:10-20, and the average particle size of the active soil layer is 0.5-1.0 mm. Through the slowest infiltration of the active soil layer, a large amount of refractory organic matter can be intercepted, and the macromolecular refractory organic matter can be converted into small molecular organic matter. Under aerobic conditions, organic nitrogen can be converted into ammonia nitrogen, and ammonia nitrogen can be converted into nitrate nitrogen for subsequent treatment. Provide the basis.

Preferably, the quartz sand in the quartz sand filter material layer is obtained by the following method: the quartz sand is first crushed, washed with water, and then soaked with 6mol/L hydrochloric acid for 2 hours to remove iron, aluminum, etc. on the surface of the quartz sand, Boil, wash with water until neutral, and dry; the average particle size of the quartz sand is 1.0-1.3 mm. Through the slow penetration of the quartz sand filter layer, under anoxic conditions, the nitrate nitrogen is converted into nitrogen gas, denitrification is completed, and total phosphorus is further removed.

The average particle size of the zeolite filled in the zeolite layer is 4-6mm. The zeolite layer plays a role of stability and support.

Preferably, the permeability coefficients of the active soil layer, quartz sand filter material layer and zeolite layer are 0.003-0.04cm/s, 0.06-0.08cm/s, 15-18cm/s respectively, and the filtration rate ratio is 1:2: (375-600).

In one embodiment, the uneven coefficients of the active soil layer are 7.1, and the uneven coefficients of the quartz sand filter layer are 4.0.

The present invention further proposes a method for performing laundry wastewater diafiltration treatment by the above-mentioned laundry wastewater diafiltration treatment device, comprising the following steps:

(1) Collect laundry waste water in the water inlet tank;

(2) The laundry waste water obtained in step (1) is introduced into the percolation device (3) through the water inlet pipe, and the laundry waste water passes through the active soil layer, the quartz sand filter material layer and the zeolite layer successively from top to bottom, and is set in the inlet by control. The water inlet valve on the water pipe controls the water inlet cycle and the drying cycle. At the same time, the efficiency of the drying cycle is improved by opening or closing the ventilation pipe. The treated laundry wastewater is introduced into the return pipe through the return flow pump and enters the active soil layer through the control return flow valve, reducing The concentration of surfactant in the influent water makes the concentration of surfactant in the effluent water less than 0.5mg/L, the removal rate of surfactant can reach more than 95%, and the removal rate of COD, NH ₃ -N and TP can reach 80% respectively %, 90% and more than 60%, so as to meet the emission standards.

Ventilation pipes are provided with ventilation valves, and in spring and autumn, when water enters the condition, the ventilation valves are opened to increase the microbial activity on the filter material in the quartz sand filter material layer. Under the condition of water inflow in summer and winter, the ventilation valve is not opened to ensure that the quartz sand filter layer should not be overheated or overcooled. When the concentration of ammonia nitrogen in the influent water is greater than 25mg/L, open the ventilation pipe.

Preferably, the volume ratio of the active soil layer, the quartz sand filter layer, and the zeolite layer is 1:(6-9):2, and the particle sizes are 0.5-1.0mm, 1.0-1.3mm, and 4-6mm respectively; the permeability coefficients are respectively 0.003～0.04cm/s, 0.06～0.08cm/s, 15～18cm/s, the filtration rate ratio is 1:2:(375-600); the unevenness coefficient of the active soil layer is 7.1, and the quartz sand filter material layer The nonuniformity coefficients were 4.0, respectively.

Preferably, in step (1), the collected laundry wastewater is pre-sedimented in the water inlet tank for more than 18 hours. Precipitate SS and homogeneous water quality, laying the foundation for subsequent treatment.

Preferably, in step (2), the ratio of the water inlet cycle to the drying cycle is 1/3 to 1/10, and each operation cycle is 24 hours; when the total phosphorus effluent concentration> 0.2mg/L, the return pipe is opened, and the return ratio is 10-50% of the influent flow rate, the higher the effluent total phosphorus concentration, the higher the reflux ratio. Water inlet/dry operation mode optimizes the performance of microorganisms in the diafiltration device and improves the removal of pollutants in the system.

Beneficial effect: Compared with the prior art, the present invention has the advantages of:

(1) The present invention uses active soil layer, quartz sand filter material layer and zeolite layer as filter material, which provides good carrier and environmental conditions for microorganisms, and is assisted by ventilation system and reflux system to ensure treatment effect, not easy to block, not to produce Secondary pollution, low operating cost, convenient operation and management;

(2) The present invention has a good removal effect on multiple pollutants in the laundry wastewater, and can be kept at a stable level, possesses certain ability to resist the impact of pollution load, and the surfactant concentration is less than 0.5mg/L, The removal rate of surfactant can reach more than 95%, and the removal rate of COD, NH ₃ -N and TP can reach more than 80%, 90% and 60% respectively.

Description of drawings

Fig. 1 is the overall structural representation of the present invention, wherein, 1, water inlet tank; 2, water inlet pipe; 3, infiltration device; 4, active soil layer; 5, quartz sand filter material layer; 6, zeolite layer; 7, Backflow pump; 8. Drain pipe; 9. Backflow pipe; 10. Backflow valve; 11. Ventilation valve; 12. Water inlet valve; 13. Ventilation pipe.

Detailed ways

Example 1

A laundry wastewater percolation treatment device, comprising a water inlet tank 1, a water inlet pipe 2 and a percolation device 3 connected in sequence, wherein an active soil layer 4 and a quartz sand filter material layer are sequentially arranged inside the percolation device from top to bottom 5 and zeolite layer 6, active soil layer 4: quartz sand filter material layer 5: zeolite layer 6 volume ratio is 1:9:2; particle diameters are 0.5-1.0mm, 1.0-1.3mm, 4-6mm; The coefficients K are 0.003～0.04cm/s, 0.06～0.07cm/s, 15～18cm/s respectively; the uneven coefficients of the active soil layer (4) are 7.1, and the uneven coefficients of the quartz sand filter layer (5) are respectively 4.0. A ventilation pipe is arranged on the outside of the quartz sand filter material layer, and the bottom side of the zeolite layer is connected with a return pump, a return pipe and a return valve in sequence and leads to the active soil layer.

The active soil layer is composed of plant wood fiber, compost organic matter and soil hydrolytic enzymes with a mass ratio of 40:40-50:10-20. Through the slowest infiltration of the active soil layer, it can intercept a large amount of refractory organic matter and degrade macromolecules. Organic matter is converted into small molecular organic matter, organic nitrogen is converted into ammonia nitrogen under aerobic conditions, and ammonia nitrogen is converted into nitrate nitrogen, which provides the basis for subsequent treatment.

The quartz sand filled in the quartz sand filter material layer is obtained by the following method: the quartz sand is first crushed, washed with water, and then soaked with 6mol/L hydrochloric acid for 2 hours to remove iron, aluminum, etc. on the surface of the quartz sand, soaked and washed with water To neutral, obtained by drying. Through the slow penetration of the quartz sand filter layer, under anoxic conditions, the nitrate nitrogen is converted into nitrogen gas, denitrification is completed, and total phosphorus is further removed.

The method for utilizing the above-mentioned device to treat laundry wastewater may further comprise the steps:

(1) Collect laundry wastewater in the water inlet tank, and the collected laundry wastewater is pre-sedimented in the water inlet tank for more than 18 hours. Precipitate SS and homogeneous water quality, laying the foundation for subsequent treatment.

(2) The laundry waste water obtained in step (1) is introduced into the percolation device (3) through the water inlet pipe, and the laundry waste water passes through the active soil layer, the quartz sand filter material layer and the zeolite layer successively from top to bottom, and is set in the inlet by control. The water inlet valve on the water pipe controls the water inlet cycle and the drying cycle, the ratio of the water inlet cycle and the drying cycle is 1/3 to 1/10, and each operation cycle is 24 hours.

At the same time, the efficiency of the drying cycle is improved by opening or closing the ventilation pipe. The ventilation pipe is equipped with a ventilation valve. In spring and autumn, when the water enters the condition, the ventilation valve is opened to increase the efficiency of microorganisms on the filter material in the quartz sand filter layer. active. Under the condition of water inflow in summer and winter, the ventilation valve is not opened to ensure that the quartz sand filter layer should not be overheated or overcooled. When the concentration of ammonia nitrogen in the influent water is greater than 25mg/L, open the ventilation pipe.

In addition, the treated laundry wastewater is introduced into the return pipe through the return pump and enters the active soil layer through the control return valve to reduce the concentration of surfactants in the influent water. The ratio is 10-50% of the influent flow, and the higher the total phosphorus concentration in the effluent, the higher the reflux ratio. The water inlet/dry operation mode can optimize the performance of microorganisms in the diafiltration device and improve the removal effect of pollutants in the system, so that the concentration of surfactant in the effluent water is less than 0.5mg/L, and the removal rate of surfactant can reach more than 95%, COD , NH ₃ -N and TP removal rates can reach 80%, 90% and 60% respectively, so as to meet the emission standards.

According to the above conditions, the removal rate of each pollutant after 45 days of test operation is shown in Table 1.

Table 1 Pollutant removal rate of laundry wastewater

Example 2

The specific operating conditions are roughly the same as in Example 1, except that the volume ratio of active soil layer 4: quartz sand filter material layer 5: zeolite layer 6 is 1:6:2.

According to the above conditions, the removal rate of each pollutant after 60d test operation is shown in Table 2.

Table 2 Pollutant removal rate of laundry wastewater

Example 3

Influent concentration average value 26mg/L, other conditions are the same as example 1, open ventilation pipe, and then improve organic matter degradation and ammonia nitrogen nitrification of quartz sand filter material layer. The effluent concentration of NH3-N is 3.5mg/L.

Example 4

When the total phosphorus concentration in the effluent is 0.21mg/L, other conditions are the same as in Example 1, the return pipe is opened, and the reflux ratio is 10% of the influent flow rate, so as to improve the removal of total phosphorus and ensure that the total phosphorus concentration in the effluent is lower than 0.10mg/L.

Example 5

When the effluent total phosphorus concentration is 0.5mg/L, other conditions are the same as example 1, open the reflux pipe, the reflux ratio is 50% of the influent flow, improve the removal of total phosphorus, and ensure that the effluent total phosphorus concentration is lower than 0.10mg/L.

Claims (10)

1. a kind of laundrywastes filtration process device, it is characterised in that including the inlet water tank, water inlet pipe and diafiltration dress being sequentially connected Put, wherein, living soil layer, quartz sand filter media layer and zeolite layer are disposed with inside the percolating device from top to bottom, it is living Property soil horizon：Quartz sand filter media layer：The volume ratio of zeolite layer is 1：(6-9)：2；The outside of the quartz sand filter media layer is set There is ventilation duct, the bottom side of zeolite layer is sequentially connected reflux pump, return duct and return valve and passes to living soil layer.

2. laundrywastes filtration process device according to claim 1, it is characterised in that living soil layer is for mass ratio 40~50:40~50:10~20 plant wood fibre, compost organic matter and Soil hydrolase, the living soil layer are put down Equal particle diameter is 0.5-1.0mm.

3. laundrywastes filtration process device according to claim 1, it is characterised in that in the quartz sand filter media layer Quartz sand obtains by the following method：Quartz sand is first passed through into broken, washing, then with 6mol/L hydrochloric acid digestion 2h, removes stone Iron, aluminium on sand surface etc., digestion are washed with water to neutrality, drying；The average grain diameter of the quartz sand is 1.0~1.3mm.

4. laundrywastes filtration process device according to claim 1, it is characterised in that the boiling of filling in the zeolite layer The average grain diameter of stone is 4-6mm.

5. laundrywastes filtration process device according to claim 1, it is characterised in that the living soil layer, quartz The sand filtration bed of material and the infiltration coefficient of zeolite layer are respectively 0.003~0.04cm/s, 0.06~0.08cm/s, 15~18cm/s, are filtered Fast ratio is 1：2：(375-600).

6. laundrywastes filtration process device according to claim 1, it is characterised in that living soil layer nonuniformity coefficient Respectively 7.1, quartz sand filter media layer nonuniformity coefficient is respectively 4.0.

7. a kind of carry out laundrywastes filtration process using any one of the claim 1~6 laundrywastes filtration process device Method, it is characterised in that comprise the following steps：

(1) laundrywastes is collected in inlet water tank；

(2) laundrywastes that step (1) obtains is introduced in percolating device (3) by water inlet pipe, laundrywastes from top to bottom according to Secondary to pass through living soil layer, quartz sand filter media layer and zeolite layer, the water intaking valve being arranged at by control on water inlet pipe controls water inlet Cycle and arid cycle, meanwhile, by be turned on and off ventilation duct improve arid cycle efficiency, by reflux pump will handle after Laundrywastes introduces return duct and by controlling return valve to enter living soil layer, reduces the concentration of surfactant in water inlet, The water outlet surfactant concentration for making to obtain is less than 0.5mg/L, the clearance of surfactant can reach more than 95%, COD, NH₃- N and TP clearance is respectively up to 80%, 90% and more than 60%, so as to qualified discharge.

8. according to the method for claim 7, it is characterised in that living soil layer, quartz sand filter media layer, the volume of zeolite layer Ratio is 1：(6-9)：2, particle diameter is respectively 0.5-1.0mm, 1.0~1.3mm, 4-6mm；Infiltration coefficient is respectively 0.003~ 0.04cm/s, 0.06~0.08cm/s, 15~18cm/s, filtering velocity ratio are 1：2：(375-600)；Living soil layer heterogeneous system Number is respectively 7.1, and quartz sand filter media layer nonuniformity coefficient is respectively 4.0.

9. according to the method for claim 7, it is characterised in that in step (1), it is pre- in inlet water tank to collect laundrywastes Precipitate more than 18h.

10. according to the method for claim 7, it is characterised in that in step (2), water inlet cycle and dry period proportional are 1/3 ~1/10, each cycle of operation 24h；As total phosphorus aqueous concentration ＞ 0.2mg/L, return duct is opened, backflow ratio is feed water flow The 10~50% of amount, water outlet total phosphorus concentration is higher, and reflux ratio is higher.