CN100395194C - Bio-ecological filtration system and method for purifying rainwater and sewage - Google Patents

Abstract

The invention belongs to an integrated technology for treating rainwater and sewage by utilizing environmental engineering technology and ecological engineering technology, and particularly relates to a biological-ecological filtering system and method for purifying rainwater and sewage. The system is composed of biofilter of environmental engineering unit and ecological wetland of ecological engineering unit. The biological filter can remove organic pollutants, ammonia nitrogen, total suspended solids, etc. in the sewage, and does not require aeration equipment; the ecological wetland can adopt multi-stage series connection, which improves the treatment effect of the ecological wetland, and the setting of the pre-sedimentation tank can reduce The load of the small ecological wetland can be further purified by the filtration of the ecological wetland and the growth and absorption of plants; the pollutants in the storm runoff can be directly treated by the ecological wetland. The invention has the characteristics of remarkable treatment effect, low operating cost, environmental friendliness, water resource saving and the like, and the treated rainwater and sewage can be reused or irrigated.

Description

Bio-ecological filtration system and method for purifying rainwater and sewage

technical field

The invention belongs to an integrated technology for treating rainwater and sewage by utilizing environmental engineering technology and ecological engineering technology, and particularly relates to a biological-ecological filtering system and method for purifying rainwater and sewage.

Background technique

Urban non-point source pollution is one of the main reasons for the deterioration of water environment quality. From the point of view of time, the emission of non-point source pollution in cities is discontinuous. Pollutants accumulate in sunny days and are discharged in rainy days. From the perspective of pollutant types, urban non-point source pollutants include total suspended solids, total nitrogen, total phosphorus, COD _cr , Escherichia coli, petroleum hydrocarbons, heavy metals, pesticides, etc. The types and emission intensity of pollutants are closely related to factors such as the degree of development of the city, the type of economic activity, and the behavior of residents, and the natural background effect is very low. After point source pollution has been basically controlled, storm runoff from towns or other heavily polluted areas has become the main source of water pollution.

When urban non-point source pollution is discharged, a large amount of suspended matter enters the water body and directly changes the physical habitat of the water body, reduces light transmittance, and silts the water body. Excessive input of nutrients will cause eutrophication of the receiving water body, causing algae or harmful plants such as water hyacinth to grow wildly, leading to deterioration of water quality. Pathogenic bacteria, petroleum hydrocarbons, and heavy metal pollutants will poison aquatic organisms, reduce drinking water quality resources and threaten human health. Urban non-point sources can also cause groundwater pollution, damage urban landscapes, affect the sustainable development of social economy, and endanger human health.

In non-point source pollution, there is a special category of pollution sources with high pollution concentration, small water volume, stable water volume and perennial discharge. This kind of pollution source is some discrete points on a large scale, which has the characteristics of area sources, and shows the characteristics of point sources on a small scale. Due to the distance from the urban pipe network or the lack of funds, such pollution sources are generally discharged nearby, seriously polluting the water body. Such pollution sources are generally reused or discharged after nearby treatment, which can reduce the investment in pipelines; water is used for reuse, which can also save water resources. For small point sources with higher concentrations, environmental engineering facilities can generally be used. However, if the small point sources with low pollutant concentration are treated by sewage treatment process, the concentration will be low and it will be difficult to operate normally, and it will be difficult to remove the dissolved pollution without biochemical treatment. Too high and the effect is not good, shortening the wetland life.

Many engineering and management measures can effectively reduce non-point source pollution. American scholars (Novotny) proposed that all measures to reduce surface runoff and soil erosion can reduce non-point source pollution. German scientists (Bendorf) found that the front reservoir built on the river reservoir can effectively reduce the sediment and nutrients such as phosphorus and nitrogen entering the reservoir. New Zealand scholars have found that the riverside buffer zone technology, which has long been used to stabilize the shore zone, can significantly reduce the non-point source pollutant load entering the water body. American scholars (Mitsch) found that artificial and natural wetland systems around lakes can retain a large number of non-point source pollutants.

For the small point source in the area source, the environmental engineering research has been very mature. For point sources with higher concentrations, biochemical methods are generally used to deal with them. For point sources with low concentration, physical and chemical methods are generally used for treatment, such as filtration, coagulation, chemical-dosing air flotation, etc., which can be used in conjunction with biofilm biochemical treatment to improve the treatment effect.

Wetlands can retain a large amount of non-point source pollutants, but they occupy a large area and have low treatment capacity per unit area.

Filtration has the characteristics of good removal of suspended solids in water bodies, small equipment size, simple power facilities, convenient operation and management, and little impact on animals and plants in water bodies. It is often used in landscape water body treatment. However, conventional filtration methods have basically no effect on the removal of dissolved pollutants in water bodies, and dissolved pollutants will accumulate in water bodies. The biological aerated filter system uses the biofilm method to treat pollutants in water, and has a good removal effect on both soluble and insoluble pollutants, but requires aeration equipment, high energy consumption, complicated operation management and high noise. However, the concentration of pollutants in the surface water body is very low, and microorganisms are not easy to grow, which makes the operation of the biological aerated filter difficult.

Contents of the invention

One of the objectives of the present invention is to provide a biological-ecological filter system for purifying rainwater and sewage, and to provide a high-efficiency, low-consumption and resourceful approach for rainwater and sewage treatment.

Another object of the present invention is to provide a method for purifying rainwater and sewage in a biological-ecological filter system for purifying rainwater and sewage.

The ecological wetland in the environment-friendly rainwater and sewage purification and reuse technology of the present invention uses the pre-sedimentation tank to collect and store the rainwater near the point source, which reduces the processing capacity of the wetland per unit time, reduces the area of the wetland, and removes large amounts of water in the water. Some pollutants will prolong the service life of wetlands. The use of multi-stage wetlands in series can improve and ensure the removal efficiency of wetlands.

The biofilter in the environment-friendly rainwater and sewage purification and reuse technology of the present invention uses a general filtration system to improve the water inlet mode and filter material, has the characteristics of an aerated biological filter, and can remove the solubility in the water body pollutants.

The biological-ecological filtration system for purifying rainwater and sewage of the present invention is composed of an environmental engineering unit biofilter and an ecological engineering unit ecological wetland, and is characterized in that:

A first sedimentation tank I is connected with the ecological wetland IV through pipelines;

A second sedimentation tank II is connected with the biological filter III through the pipeline, and the biological filter III is connected with the ecological wetland IV through the pipeline;

Ecological wetland IV is connected with clear water pool V through pipelines.

Small point source sewage with low concentration and rainwater near the point source are collected by pre-set sedimentation tanks; biofilter and biofilm formed on the filter material are used to treat low concentration small point source sewage, which can effectively degrade organic pollutants At the same time, ammonia nitrogen and total suspended solids are removed; the effluent of the biofilter is further purified by the filtration of ecological wetlands and the growth and absorption of plants; the pollutants in the storm runoff are directly treated by ecological wetlands; the treated water is reused or used for irrigation. Biological filters and ecological wetlands operate all year round to treat sewage, and excess storm runoff in rainy days is collected and treated step by step.

The technical process of the biological-ecological filtration system for purifying rainwater and sewage of the present invention is: sewage first enters the second sedimentation tank II to precipitate and remove part of the suspended particle pollutants, and then enters the biofilter III, where it is filtered and biologically After being degraded, it enters the ecological wetland IV; further filtered by the ecological wetland and absorbed and degraded by plants; the storm runoff first enters the first sedimentation tank I for collection, and after sedimentation in the sedimentation tank, it is slowly pumped into the ecological wetland IV for treatment; the treated sewage or storm runoff Stored in Clear Water Pool V.

Biofilter III in the bio-ecological filtration system for purifying rainwater and sewage of the present invention is mainly composed of filter material, water distribution area, triangular weir, filter plate, short handle filter head, water inlet pipe, backwash pipe, clear water collection pipe, It consists of top cover, backwash pump, sewage pump and other units.

A filter plate divides the biofilter III into two areas: the upper filling area and the lower water distribution area; the filter plate is a perforated plate (with small holes), and a short handle filter head is installed at the small hole of the filter plate; The water distribution area below the plate is equipped with clean water collection pipes and backwash pipes; the packing area above the filter plate is filled with filter material, and a triangular weir is installed on the side wall of the biofilter III above the filter material. The water pipe is installed above the triangular weir.

The top of the biofilter III has a top cover, and the top cover is provided with observation ventilation holes.

The water inlet pipe of the biofilter III is connected to the sewage pump, the sewage pump is installed in the second sedimentation tank II, the backwash pipe is connected to the backwash pump, and the backwash pump is installed in the clean water tank V; the other end of the clean water collection pipe It is connected with the sewage pipe on Ecological Wetland IV.

The internal filter material of the biological filter is ceramsite filter material, and the water outlet of the water inlet pipe falls into the water; the biological filter III can be set as one or more than one parallel connection as required.

The ecological wetland IV in the biological-ecological filtration system for purifying rainwater and sewage of the present invention is mainly composed of sedimentation tanks, wetlands, sewage pipes, rainwater inlet pipes, wetland water inlet and outlet pipes, substrates, aquatic plants, rainwater pumps, cement clapboards And so on.

In the ecological wetland IV, the cement partition divides the ecological wetland IV into wetland 1, wetland 2, wetland 3 and sedimentation tank. The sewage pipe and rainwater inlet pipe are installed on the side wall outside the sedimentation tank. The rainwater inlet pipe and the first The rainwater pump in the sedimentation tank I is connected; on the other side wall of the ecological wetland IV, a pipeline communicating with the clear water tank V is installed.

The wetland 1, wetland 2, and wetland 3 operate in series. The substrate of the wetland is filled from bottom to top by loam, peat, vermiculite, coarse sand, steel slag, pebbles and geotextiles. Aquatic plants are planted, and there is a certain height difference among Wetland 1, Wetland 2, and Wetland 3, which gradually decreases from the wetland adjacent to the sedimentation tank to Wetland 3; The substrate is slightly taller. The water inlet and outlet pipes of the wetland are arranged according to the high and low.

The cement partition is equipped with a water pipeline, the pipeline on the partition of the side wall of the sedimentation tank is at the upper part of the substrate of the wetland, and the pipeline on the partition between wetland 1 and wetland 2 is at the bottom of the substrate of the wetland. The pipes on the partition between wetland 2 and wetland 3 are on the upper part of the wetland matrix, and the pipes on the partition on the side wall of ecological wetland IV are at the bottom of the wetland substrate.

The biological-ecological filtration system of the present invention purifies rainwater and sewage The method for purifying rainwater and sewage is as follows:

Sewage from small point sources and rainwater near point sources are collected by the first sedimentation tank I and second sedimentation tank II respectively; the organic matter in sewage from small point sources with low concentration is treated by the filtration of biofilter III and the biofilm formed on the filter material. Pollutants, ammonia nitrogen and total suspended solids are removed at the same time; the effluent of the biofilter is further purified and treated by the filtration of the ecological wetland IV and the growth and absorption of plants; the pollutants in the storm runoff are directly treated by the ecological wetland IV; the treated water is sent to the clear water pool V is collected for reuse or for watering. Biofilter III and Ecological Wetland IV operate all year round to treat sewage, and the excess rainstorm runoff in rainy days is collected by the first sedimentation tank I and then gradually treated.

The specific method of the biological-ecological filtration system for purifying rainwater and sewage of the present invention to purify rainwater and sewage can be referred to Fig. 1～3:

The small point source sewage is collected and settled in the second sedimentation tank II, then lifted by the sewage pump 11, and falls into the biofilter III through the water inlet pipe 6, and enters the water distribution area 2 through the short handle filter head 5 after being treated in the filter material area 1. After being collected by the clean water collection pipe 8, it enters the sedimentation tank 12 of the ecological wetland from the sewage pipe 16 of the ecological wetland, enters the wetland one 13 through the wetland water inlet pipe 18, enters the wetland two 14 through the bottom pipe 19 after filtering and absorbing, and flows from the wetland two 14 After the upper pipe 20 is collected, it enters the wetland 3 15, and after being filtered and absorbed by the wetland 3 15, it is collected and discharged into the clear water pool V for storage through the bottom wetland outlet pipe 21. The biofilter III is backwashed after running for a period of time. When backwashing, first turn off the clean water collection pipe 8 and the sewage pump 11; then turn on the backwash pump 10, and the backwash water enters the water distribution area 2 through the backwash pipe 7, After the rectification of the water area 2, it enters the filter material area through the short handle filter head 5 to wash the filter material; the backwash water is collected by the triangular weir 3 and then discharged into the second sedimentation tank II.

The rainstorm runoff collects sediment through the first sedimentation tank I, and is lifted by the rainwater pump 24 through the rainwater inlet pipe 17 into the sedimentation tank 12 of the ecological wetland. After further precipitation, it enters the wetland 13 through the wetland water inlet pipe 18, and is filtered and absorbed. Then enter wetland 2 14 from the bottom pipe 19, collect from the upper pipe 20 of wetland 2 14 and enter wetland 3 15, after being filtered and absorbed by wetland 3 15, it will be collected by the bottom wetland outlet pipe 21 and then discharged into the clear water pool V for storage .

The invention integrates the biological filter and the ecological wetland into rainwater and sewage purification and reuse technology, utilizes the filtration of the biological filter and the biofilm formed on the filter material to treat the organic pollutants in the sewage, and simultaneously removes ammonia nitrogen and total suspended solids; Use the filtration of ecological wetlands and the growth and absorption of plants to further purify the effluent of biofilters; the pollutants in the storm runoff are directly treated with ecological wetlands; the treated rainwater and sewage are used for reuse or irrigation. This can not only reduce non-point source pollution, but also save water resources; at the same time, the urban landscape effect is considered in the design, so that the system can adapt to the surrounding environment, which is a promising technology.

The bio-ecological filtration system for purifying rainwater and sewage of the present invention has the following advantages:

1. Combine environmental engineering and ecological engineering, use biological filter as the main body of discrete small point source sewage treatment, use ecological wetland to treat storm runoff and further treat the effluent of biological filter. The integrated technology has the advantages of good processing effect, low energy consumption and convenient operation.

2. The treated sewage and rainwater can be reused or used for irrigation, saving water resources.

3. The pre-set sedimentation tank is used to collect rainwater and sewage, which reduces the processing pressure of ecological engineering and saves engineering investment.

4. The biofilter adopts measures such as water inflow and ceramsite filter material, so that the biofilter has the function of removing insoluble pollutants and soluble pollutants at the same time. The biofilter does not require an aeration system and has low energy consumption. , low noise and other advantages; when designing, multiple small filters are connected in parallel, which reduces the instantaneous water consumption of the biological filter backwash and reduces the requirements for the supporting facilities of the biological filter.

The bio-ecological filtration system and method for purifying rainwater and sewage according to the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Description of drawings

Figure 1. Schematic diagram of the bio-ecological filtration system for purifying rainwater and sewage according to the present invention.

Fig. 2. The schematic diagram of the biofilter of the bio-ecological filtration system for purifying rainwater and sewage according to the present invention.

Fig. 3. A schematic diagram of an ecological wetland in the biological-ecological filtration system for purifying rainwater and sewage according to the present invention.

reference sign

I. The first sedimentation tank II. The second sedimentation tank III. Biological filter

IV. Ecological Wetland V. Clear Water Pool

1. Filter material 2. Water distribution area 3. Triangular weir

4. Filter plate 5. Short handle filter head 6. Inlet pipe

7. Backwash pipe 8. Clear water collection pipe 9. Top cover

10. Backwash pump 11. Sewage pump 12. Sedimentation tank

13. Wetland 1 14. Wetland 2 15. Wetland 3

16. Sewage pipe 17. Rainwater inlet pipe 18. Wetland water inlet pipe

19. Bottom pipe 20. Upper pipe 21. Wetland outlet pipe

22. Filler 23. Aquatic plants 24. Rainwater pumps

25. Partition

Detailed ways

Example 1:

See Figure 1. The system of the invention is composed of an environmental engineering unit biofilter and an ecological engineering unit ecological wetland.

The first sedimentation tank I is connected with the ecological wetland IV through the pipeline; the second sedimentation tank II is connected with the biological filter III through the pipeline, and the biological filter III is connected with the ecological wetland IV through the pipeline; the ecological wetland IV It communicates with the clear water pool V through the pipeline.

Biofilter III is shown in Figure 2, and the filter material in the biological filter is ceramsite filter material; ecological wetland IV is shown in Figure 3, and the partition is cement partition.

The system of the present invention is used to treat the sewage in the elephant house of Wuhan Zoo.

The Elephant House of Wuhan Zoo is one of the important landscapes of the zoo. There are 2 elephants raised in the museum, and the feed is grass. The elephant house cleans the feeding room every morning from 8 to 9 am. When cleaning, first clean up the feces, transfer them to the transfer station, and take them away by garbage trucks, then wash the ground with tap water, and the flushing water is directly discharged into Macang Lake; the drinking water tank for animals is replenished all day long, and the excess water overflows and is used with flushing water One pipeline discharges, and the flushing water and overflow water of animal drinking water have a total volume of about 5 tons/day.

Next to the Elephant House is a sloping land, and the rainstorm runoff from the sloping land and the roof is collected and discharged into Macang Lake.

The sewage is mainly the washing water of the Elephant Pavilion. The pollution concentration in the early stage of washing is high, TSS: 1000~1367mg/L, CODcr: 728~100mg/L, TN: 42.1~60mg/L, TP: 8~13mg/L. After the sedimentation tank is mixed and diluted with tap water, the concentration of pollutants is reduced, and the water quality entering the biofilter is as follows: TSS: 60~100mg/L, CODcr: 40~70mg/L, TN: 8~12mg/L, TP: 0.5~ 1.0mg/L

The main pollutants of storm runoff are suspended particles, and the water quality entering the ecological wetland after sedimentation in the sedimentation tank is as follows: TSS: 50-90mg/L, CODcr: 120-200mg/L, TN: 10-18mg/L, TP: 0.2- 0.8mg/L

Aiming at the water quality of the elephant house, the environment-friendly rainwater and sewage purification and reuse technology of the present invention is adopted to treat the rainwater and sewage of the elephant house. Biofilters and ecological wetlands operate all year round, and the ecological wetlands also handle storm runoff.

Considering the landscape of the zoo, the ecological wetland is designed in a semi-garden shape, and bamboo forests are planted around the biofilter. At the same time, the slopes are sorted out and shade-loving plants are planted. Treated rainwater and sewage are used for irrigation or discharged into nearby dry ponds.

The results show that the pre-sedimentation tank can not only collect rainwater and sewage, but also have the functions of pretreatment and uniform water quality.

Comparing the influent and effluent water of the biological filter: after the system runs stably, the total nitrogen removal rate after treatment is 50-60%, the total phosphorus removal rate is 16-25%, and the COD _Cr removal rate is 60-70%. TSS removal rate is 80-95%. The effluent of the biological filter is further treated by the ecological wetland. Compared with the influent and effluent of the ecological wetland, the removal rate of total nitrogen is 50-60%, and the removal rate of total phosphorus is 50-60%. Due to the low concentration of COD _Cr and TSS, The removal rate is not high, around 20%.

Comparing the inflow and outflow of ecological wetland rainwater: the removal rate of total nitrogen is 50-60%, the removal rate of total phosphorus is 25-40%, the removal rate of COD _Cr is 60-70%, and the removal rate of TSS is 80-90%.

After the treatment of ecological wetlands and ecological wetlands, the effluent quality of rainwater is as follows: COD _Cr is maintained below 20mg/L, TN is maintained below 5mg/L, TP is maintained below 0.2mg/L, and TSS is maintained below 10mg/L.

The research on the engineering application of the environmentally friendly rainwater and sewage purification and reuse technology in this study shows that the system has the characteristics of remarkable treatment effect, low energy consumption, and environmental friendliness.

Claims (9)

1. A biological-ecological filtration system for purifying rainwater and sewage is composed of an environmental engineering unit biofilter and an ecological engineering unit ecological wetland, and is characterized in that: A first sedimentation tank (I) is communicated with the ecological wetland (IV) through pipelines; A second sedimentation tank (II) is communicated with the biofilter (III) through a pipeline, and the biofilter (III) is communicated with the ecological wetland (IV) through a pipeline; The ecological wetland (IV) is connected with the clear water pool (V) through pipelines. 2. The system according to claim 1, characterized in that: said biological filter (III) is one or more than one in parallel. 3. The system according to claim 1 or 2, characterized in that: the biological filter (III) is mainly composed of filter material, water distribution area, triangular weir, filter plate, short handle filter head, water inlet pipe, reverse Flushing pipe, clean water collection pipe unit; A filter plate divides the biological filter (III) into two areas, the upper filling area and the lower water distribution area; the filter plate is a perforated plate, and a short handle filter head is installed at the through hole of the filter plate; the cloth below the filter plate The water area is equipped with clean water collection pipes and backwash pipes; the packing area above the filter plate is filled with filter material, and a triangular weir is installed on the side wall of the biological filter (III) above the filter material, and a water inlet pipe is installed above the triangular weir. 4. The system according to claim 3, characterized in that: the water inlet pipe of the biofilter (III) is connected to the sewage pump, the sewage pump is installed in the second sedimentation tank (II), and the backwash pipe is connected to the backwash pump The backwash pump is installed in the clear water tank (V); the other end of the clear water collection pipe is connected with the sewage pipe on the ecological wetland (IV). 5. The system according to claim 1 or 2, characterized in that: the top of the biological filter (III) has a top cover, and observation ventilation holes are arranged on the top cover. 6. The system according to claim 3, characterized in that: the top of the biological filter (III) has a top cover, and observation ventilation holes are arranged on the top cover. 7. The system according to claim 1, characterized in that: the ecological wetland (IV) is mainly composed of sedimentation tanks, wetlands, sewage pipes, rainwater inlet pipes, wetland water inlet and outlet pipes, substrates, aquatic plants, rainwater Composed of pumps and partitions; In the ecological wetland (IV), the ecological wetland (IV) is divided into wetland 1, wetland 2, wetland 3 and sedimentation tank by partition boards; sewage pipes, rainwater inlet pipes and rainwater inlet pipes are installed on the side walls outside the sedimentation tanks It is connected with the rainwater pump; on the other side wall of the ecological wetland (IV), a pipeline connected with the clear water pool (V) is installed; The wetland 1, wetland 2, and wetland 3 operate in series. The substrate of the wetland is filled in order from bottom to top by loam, peat, vermiculite, coarse sand, steel slag, pebbles and geotextiles, and planted on the substrate There are aquatic plants; from the wetland adjacent to the sedimentation tank to the wetland 3, it gradually decreases; the height of the sewage pipe and the rainwater inlet pipe is higher than the substrate on the top of the wetland; The pipelines for passing water are installed on the clapboard, the pipeline on the clapboard of the side wall of the sedimentation tank is on the upper part of the substrate of the wetland, the pipeline on the clapboard between wetland one and wetland two is at the bottom of the substrate of the wetland, and the wetland 2. The pipes on the partitions between the third wetlands are at the upper part of the substrate of the wetlands, and the pipes on the partitions on the side wall of the ecological wetland (IV) are at the bottom of the substrates of the wetlands. 8. The system according to claim 7, characterized in that: the rainwater inlet pipe is connected with the rainwater pump in the first sedimentation tank (I). 9. A method for system purification rainwater and sewage according to any one of claims 1 to 8, characterized in that: small point source sewage and rainwater near the point source are respectively the first settling tank (1), the second settling tank Pool (II) collection; Utilize the filtration of biofilter (III) and the biofilm formed on the filter material to treat organic pollutants in small point source sewage with low concentration, and remove ammonia nitrogen and total suspended solids at the same time; use ecological wetland (IV ) filtration and plant growth absorption to further remove the effluent from the biofilter; the pollutants in the storm runoff are directly treated by the ecological wetland (IV); the treated water is collected by the clear water pool (V).

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