CN110820913A

CN110820913A - Rainwater comprehensive treatment system

Info

Publication number: CN110820913A
Application number: CN201911228653.4A
Authority: CN
Inventors: 孙昕; 杨晴; 解岳; 许振威; 詹紫薇
Original assignee: Xian University of Architecture and Technology
Current assignee: Xian University of Architecture and Technology
Priority date: 2019-12-04
Filing date: 2019-12-04
Publication date: 2020-02-21

Abstract

The invention discloses a rainwater comprehensive treatment system which comprises a desanding device, a rainwater garden, a sand filter and a water storage tank. Rainwater firstly enters the desanding device through a pipeline. By utilizing the unique structural design of the desanding device, rainwater entering the desanding device generates a hydraulic cyclone effect, so that the separation of silt and water in the rainwater is realized, and the silt is precipitated at the bottom of the desanding device. A suspended matter (SS) probe is arranged in the sand removing device and used for detecting the SS content in water, and if the SS content exceeds a set value, the controller can start an electric butterfly valve to discharge rainwater into a municipal sewage pipe network. The outlet water of the sand removing device enters the rainwater garden again, and when the rainwater amount is small, the rainwater permeates and is purified through the transverse hierarchical structure on the left side; when the rainwater volume is big, the rainwater flows through the top of left side hierarchy structure, and then permeates and purifies through the vertical hierarchy structure on right side simultaneously. The effluent of the rainwater garden is further purified by a sand filter. The comprehensive treatment and reutilization of rainwater are realized through the synergistic effect of the sand removing device, the rainwater garden and the sand filter.

Description

Rainwater comprehensive treatment system

Technical Field

The invention belongs to the field of water resource utilization and protection, and particularly relates to a comprehensive rainwater treatment system which is suitable for treating slightly polluted rainwater.

Background

Due to the increase of the proportion of the impervious pavement, the rainwater is easy to carry suspended matters (SS), nitrogen, phosphorus and other pollutants in the atmosphere and on the ground to enter a receiving water body or a drainage pipe network in the process of descending and washing the pavement.

The rainwater collection and purification is a new way for the comprehensive utilization of water resources. At present, the manual treatment of rainwater generally adopts the traditional treatment process, and the main process units comprise a screen and a grid, and the coagulation, the precipitation and the filtration are carried out; wherein the devices such as coagulation, sedimentation, filtration and the like have larger occupied area and higher operation cost.

The natural treatment of rainwater is mainly to adopt the rainwater garden, and the current rainwater garden is basically a downward hierarchical structure from top to bottom, and comprises vegetation, a water storage layer, a covering layer, a planting soil layer, a packing layer and a gravel layer in sequence. Through the effects of soil infiltration, ecological detention and the like, the rainfall flood flow can be effectively reduced by the rainwater garden, and the ground rainwater runoff can be reduced by 75-80% on average as shown by multiple rainfall flood monitoring results.

The rainwater garden can effectively perform rainwater infiltration and also has multiple functions; harmful substances such as suspended matters, organic pollutants, heavy metal ions, pathogens and the like in the runoff can be effectively removed; through reasonable plant configuration, the transpiration of the plants can be utilized to adjust the humidity and the temperature of the air in the environment and improve the microclimate environment. In addition, compared with the traditional lawn landscape, the rainwater garden has lower construction cost and simpler maintenance and management, and can give new landscape perception and visual perception to people. However, if the content of suspended matters such as silt in the ground rainwater runoff is too large or the rainwater flows through the rainwater garden for a long time, the suspended matters are continuously deposited on the surface layer of the rainwater garden and are difficult to clean, and the function of reducing the rainwater flood and the pollution load of the rainwater garden is seriously influenced.

Disclosure of Invention

The invention aims to provide a system for better comprehensively treating lightly polluted rainwater. The treatment process flow of the system comprises a sand removing device, a rainwater garden, a filter and a water storage tank, and the pollution removing device sequentially performs the synergistic pollution removing effect of the structural units to treat pollutants in rainwater and purify the rainwater. Thereby improving the living environment of people.

The invention is realized by adopting the following technical scheme:

a rainwater comprehensive treatment system comprises a desanding device, a rainwater garden, a sand filter and a reservoir; wherein the content of the first and second substances,

the sand removing device comprises a sand removing device, an SS probe arranged in the sand removing device, an electric valve arranged at a water outlet at the bottom of the sand removing device and a controller connected with the output end of the SS probe, wherein the output end of the controller is connected with the control end of the electric valve and used for controlling the electric valve to be started and closed, and the water outlet of the electric valve is communicated to a municipal sewage pipe network; a first covering layer, a first packing layer, a first gravel layer and a water collecting channel are sequentially arranged at the water outlet at the upper part of the sand removing device from inside to outside;

the rainwater garden comprises a water storage layer, a second covering layer, a planting soil layer, a second packing layer and a second gravel layer which are sequentially arranged from top to bottom, wherein a water collecting channel is communicated with the water storage layer, and a water outlet at the upper part of the water storage layer is communicated to a municipal sewage pipe network through an overflow pipe;

the water outlet of the second gravel layer is communicated to a sand filter, a filter layer is arranged in the sand filter, a water circulation loop is formed between the sand filter and the reservoir, and the water outlet at the upper part of the sand filter is communicated to a municipal sewage pipe network.

The invention is further improved in that the electric valve adopts an electric butterfly valve.

The sand filter is further improved in that a bearing layer is arranged in the sand filter, and the filter layer is arranged on the bearing layer.

The invention is further improved in that a water pump is arranged on a pipeline which communicates the sand filter with the reservoir.

The invention is further improved in that the ratio of the bottom width of the desanding device to the width of the upper part is 1:2, and the ratio of the distance from the upper part of the right side of the desanding device to the bottom width is 4.8: 1.

The invention is further improved in that the bottom of the sand removing device is a conical section with an inclination angle of 80 degrees.

The invention is further improved in that the second gravel layer is composed of gravels with the diameter not more than 50mm and the thickness is 200-300 mm.

The invention has the following beneficial technical effects:

according to the comprehensive rainwater treatment system provided by the invention, rainwater firstly passes through the desilting tank, and a rotational flow is generated by using a unique hydraulic structure of the desilting tank, so that the purpose of separating rainwater from silt is achieved. Determining the structural size of the desilting pool 1; the ratio of the width of the bottom of the sand basin to the width of the upper part is 1:2, the ratio of the distance from the upper part of the right side of the sand basin to the bottom to the width of the bottom is 4.8:1, and the inclination angle of the conical section at the bottom of the sand basin is 80 degrees. The SS control device is arranged in the desilting basin, the SS value of the inflow water can be detected by using the SS probe, and when the SS value exceeds a set value, the control device can control the opening of the valve, so that the rainwater flows into a municipal sewage pipe network through the drainage pipe; when the detected SS value is lower than the set value, the control device controls the valve to be closed, and rainwater is in the desilting basin with the unique structure. The sand removing device is built underground and connected with a rainwater garden.

In the invention, a part of the left side of the rainwater garden is transversely provided with a covering layer, a packing layer, a gravel layer and a water collecting channel from left to right in sequence. A water storage layer, a covering layer, a planting soil layer, a packing layer and a gravel layer are sequentially designed from top to bottom in the hierarchical structure of the right part of the rainwater garden. When the amount of rainwater is small, the rainwater first enters the left lateral hierarchical structure to complete a series of infiltration and purification processes, and then flows into the next unit of the system through the water collecting pipe at the bottom of the rainwater garden. When the rainwater quantity is larger, rainwater deposited through rotational flow enters the rainwater garden from the top of the left-side hierarchical structure in addition to the rainwater garden through the left-side hierarchical structure of the rainwater garden, and a series of infiltration and purification processes are completed. And finally flows to the next device through the collector pipe at the bottom of the rainwater garden. The right side part in the rainwater garden is provided with an overflow device, and when the rainwater amount exceeds the load capacity of the rainwater garden, redundant rainwater can flow into the municipal sewage pipe network through the overflow pipe.

The water storage layer in the rainwater garden provides a temporary storage space for rainstorm, so that partial suspended matters such as silt and the like are precipitated in the water storage layer, organic matters and metal ions attached to the surface of the suspended matters are promoted to be removed, the height of the water storage layer can be 100-250 mm, and the water storage layer is determined according to factors such as peripheral terrain and local rainfall characteristics. The covering layer is generally covered by barks, so that the humidity of soil can be kept, and the permeability reduction caused by hardening of surface soil can be avoided; a microbial environment is created on the interface of the bark and the soil layer, which is beneficial to the growth of microbes and the degradation of organic matters and is also beneficial to reducing the erosion of runoff rainwater. The maximum depth of the covering layer can be 50-80 mm. The vegetation and the planting soil layer provide good places for adsorbing and degrading nitrogen, phosphorus, organic matters, metal ions and other pollutants by the root system of the plant through microorganisms, and have better filtering, adsorbing and biodegradation functions. The sandy soil with a large permeability coefficient is generally selected, the main components of the sandy soil comprise 60-85% of sand, 5-10% of organic components and no more than 5% of clay, the thickness of a planting soil layer is determined according to the type of plants, and when herbaceous plants are adopted, the thickness is generally about 250 mm. Perennial plants are planted in the rainwater garden and can resist waterlogging for a short time. The packing layer is made of natural or artificial materials with high permeability, the thickness of the packing layer is determined according to local rainfall characteristics, the service area of a rainwater garden and the like, and the thickness of the packing layer is 0.5-1.2 m mostly. When sandy soil is selected, the main components of the sandy soil are consistent with those of a planting soil layer. The gravel layer is composed of gravels with the diameter not more than 50mm and the thickness is 200-300 mm. The subsequent system unit of the rainwater garden is a filter tank, and the filter tank can further purify rainwater.

Finally, the rainwater passing through the filter tank flows into a reservoir, so as to achieve the final purpose of rainwater treatment. The filter material can be cleaned by the backwashing device, backwashing water is from the reservoir, and the backwashing water flows into a municipal sewage pipe network.

Therefore, the invention provides a rainwater comprehensive treatment system which combines a rainwater garden with a horizontal and vertical hierarchical structure and a desilting basin with a hydraulic structure. The rainwater comprehensive treatment system can save cost, achieve the effects of preventing rainwater overflow and effectively treating rainwater, and realize the reutilization of rainwater. The system combines the traditional water treatment method with a new rainwater garden, fully exerts the unique rotational flow desanding function of the desanding device, reduces the treatment load of the subsequent rainwater garden and the filter, skillfully utilizes the unique permeability and water purification capacity of the rainwater garden, and effectively reduces the rainfall flood flow and pollution load; and finally purifying the rainwater by the passing filtering action of the subsequent filter tank, and realizing the reutilization of the rainwater by exerting the synergistic pollution removal action of the sand removal device, the rainwater garden and the filter tank. The method has the advantages of reducing rain flood risks, reducing process links, reducing occupied area and the like.

The sand removing device of the invention utilizes a unique hydraulic structure to generate a rotational flow condition, can reduce the use of power equipment and reduce the cost. Compared with the common rainwater garden, the rainwater garden in the rainwater comprehensive treatment system has a unique structure, besides the common vertical hierarchy structure from top to bottom, the left side of the rainwater garden is also provided with the horizontal hierarchy structure from left to right, and when the water quantity is large, water can flow into the right side hierarchical filtering structure of the rainwater garden through the upper drain pipe of the desanding device. The overflow device is arranged in the rainwater garden, when heavy rainfall occurs, redundant rainwater can flow into the municipal sewage pipe network through the overflow device, and therefore good rainwater treatment effect can be achieved. Furthermore, the rainwater treated by the system can be used for greening landscapes and the like. In the invention, the structure of the left part of the rainwater garden combined with the sand settling device is reset, and the layered structure of the rainwater garden, the covering layer, the packing layer and the gravel layer are sequentially and transversely designed from left to right, and the water collecting channel is arranged between the left part and the right part of the rainwater garden to play a role in buffering.

The invention utilizes the sand removing device which generates rotational flow and introduces the artificial landscape rainwater garden, thereby not only reducing the scale of the filtering device, but also increasing the filtering speed. And the synergistic effect of the rainwater treatment system can achieve a better rainwater treatment effect.

Drawings

Fig. 1 is a schematic structural diagram of a comprehensive rainwater treatment system according to the present invention.

In the figure: 1-a sand removing device, 2-an SS probe, 3-a controller, 4-a first covering layer, 5-a first packing layer, 6-a first gravel layer, 7-a water collecting channel, 8-a water storage layer, 9-a second covering layer, 10-a planting soil layer, 11-a second packing layer, 12-a second gravel layer, 13-an overflow pipe, 14-a sand filter tank, 15-a filter layer, 16-a supporting layer and 17-a reservoir.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

As shown in fig. 1, the rainwater comprehensive treatment system provided by the invention comprises a desanding device, a rainwater garden, a sand filter 14 and a water reservoir 17; the sand removing device comprises a sand removing device 1, an ss probe 2 arranged in the sand removing device 1, an electric valve arranged at a water outlet at the bottom of the sand removing device 1 and a controller 3 connected with the output end of the ss probe 2, wherein the output end of the controller 3 is connected with the control end of the electric valve and used for controlling the start and the close of the electric valve, and the water outlet of the electric valve is communicated to a municipal sewage pipe network; a first covering layer 4, a first packing layer 5, a first gravel layer 6 and a water collecting channel 7 are sequentially arranged at the water outlet at the upper part of the sand removing device 1 from inside to outside; the rainwater garden comprises a water storage layer 8, a second covering layer 9, a planting soil layer 10, a second packing layer 11 and a second gravel layer 12 which are sequentially arranged from top to bottom, wherein a water collecting channel 7 is communicated with the water storage layer 8, and a water outlet at the upper part of the water storage layer 8 is communicated to a municipal sewage pipe network through an overflow pipe 13; the water outlet of the second gravel layer 12 is communicated to a sand filter 14, a filter layer 15 is arranged in the sand filter 14, a water circulation loop is formed between the sand filter 14 and a reservoir 17, and the water outlet at the upper part of the sand filter 14 is communicated to a municipal sewage pipe network.

Wherein, the electric valve adopts the electric butterfly valve. A bearing layer 16 is arranged in the sand filter 14, and a filter layer 15 is arranged on the bearing layer 16.

During operation, rainwater enters the desanding device 1 through the pipeline. Utilize the structural design of sand removal device 1 for the rainwater that gets into sand removal device 1 produces the whirl effect, makes silt particle can separate, deposits in sand removal device 1 bottom. The sand removing device 1 is provided with an ss probe 2 for detecting the ss content in water, and if the ss content exceeds a set value, the controller 3 starts an electric butterfly valve to discharge rainwater into a municipal sewage pipe network.

Rainwater after sand removal permeates into the rainwater garden from the upper part of the sand removal device 1 through the permeation effect, the left side filtering structure of the rainwater garden adopts the transverse design in consideration of the conditions of small water quantity and large water quantity, so that the filtering is sufficient, and when the water quantity is small, the rainwater flows into the right side structure of the rainwater garden through the upper part drain pipe of the sand removal device 1. The ecological function of the rainwater garden is utilized to further treat the rainwater. Considering that the rainwater garden has limited water storage and treatment capacity, the rainwater garden is provided with the overflow device, and when large rainfall occurs, the treatment load of the rainwater garden is exceeded, and redundant rainwater flows into a municipal sewage pipe network through the overflow device. In the deepest gravel layer 12 of the rainwater garden, a collecting pipe is provided to lead rainwater to the next water treatment device.

Rainwater passing through the rainwater garden needs to be filtered to meet the treatment requirement, the filter layer 15 needs to be backwashed, the backwashed water is filtered, and the backwashed wastewater flows into a municipal sewage pipe network. And a back washing water pump is required to be arranged for back washing.

The treated water may be directed to a reservoir 17 for landscaping and the like.

The water resource and the water environment are the roots of urban development, at present, cities in China are rapidly expanded and continuously developed, the quantity and the water quality requirements are brought to the water resource and the water environment, rainwater, a novel water resource, is required to be developed to form measures for improving the water quality and treating the rainwater, and the water resource developed by the cities is richer.

Due to the acceleration of the urbanization process and the increase of the impervious ground and the roof, the rainwater in rainy season cannot be timely and effectively discharged and treated, and the rainwater can carry various pollutants in the falling process and the road surface flushing process, so that the normal life and the environment of people are seriously threatened. The invention is a novel underground rainwater treatment process which is modified and innovated on the basis of the traditional rainwater treatment in accordance with the modern urban development concept. In which a sand removing device and a rainwater garden having a unique structure are mainly cited.

The invention saves land, has simple structure, and the combination of the process units can fully exert the water treatment capability. The method comprises the following steps: firstly, rainwater passes through the desanding device, and a rotational flow is generated by using a unique hydraulic structure of the desanding device, so that the purpose of separating rainwater from silt can be achieved. The structural size of the desanding device 1 is determined as follows; the ratio of the width of the bottom of the sand removing device to the width of the upper part is 1:2, the ratio of the distance from the upper part of the right side of the sand removing device 1 to the bottom to the width of the bottom is 4.8:1, and the inclination angle of the conical section of the bottom of the sand removing device is 80 degrees. Be equipped with controlling means in the sand removing device, utilize the SS probe can detect the SS value of intaking, when the SS value exceedes the setting value, controlling means can control opening of valve for the rainwater flows into municipal sewer pipe network through the drain pipe, when the SS value that detects is less than the setting value, then controlling means can control valve and close, and the rainwater reaches the purpose of rainwater and silt particle separation through the whirl in the sand removing device that has unique structure. The next system unit is a rainwater garden called as a sponge city mastery force army, and the left side hierarchical structure of the rainwater garden, a covering layer, a packing layer, a gravel layer and a water collecting channel are sequentially and transversely designed. The right part of the rainwater garden has a hierarchical structure, a water storage layer, a covering layer, a planting soil layer, a packing layer and a gravel layer which are sequentially designed from top to bottom. The upper part of the side wall of the sand removing device combined with the rainwater garden has a penetration function, when the rainwater amount is less, the rainwater enters the left side of the rainwater garden through penetration to finish a series of water purification processes, and finally flows into the next device of the system through a water collecting pipe at the bottom of the rainwater garden. When the rainwater quantity is larger, the rainwater passing through the rotational flow desanding device can flow into the right side of the rainwater garden through the top of the left side hierarchical structure, and a series of water purification processes are completed. And finally flows to the next device through the collector pipe at the bottom of the rainwater garden. The right side part in the rainwater garden is provided with an overflow device, and when the rainwater amount exceeds the load capacity of the rainwater garden, redundant rainwater can flow into the municipal sewage pipe network through the overflow pipe. The aquifer in the rainwater garden provides temporary storage space for the rainstorm, so that part of suspended matters such as silt and the like are precipitated in the aquifer, the organic matters and metal ions attached to the suspended matters are promoted to be removed, and the height of the aquifer is determined according to factors such as peripheral terrain, local rainfall characteristics and the like. Generally, the thickness is 100 to 250 mm. The covering layer is generally covered by barks, so that the humidity of soil can be kept, and the permeability reduction caused by hardening of surface soil can be avoided. A microbial environment is created on the interface of the bark and the soil layer, which is beneficial to the growth of microbes and the degradation of pollutants and is also beneficial to reducing the erosion of runoff rainwater. The maximum depth is usually 50-80 mm. The plant cultivation soil layer provides a good place for adsorbing plant roots and degrading nitrogen, phosphorus, organic matters, metal ions and other pollutants by microorganisms, and has good filtering and adsorbing effects. The sandy soil with a large permeability coefficient is generally selected, the main components of the sandy soil comprise 60-85% of sand, 5-10% of organic components and no more than 5% of clay, the thickness of a planting soil layer is determined according to the type of plants, and when herbaceous plants are adopted, the thickness is generally about 250 mm. Perennial plants are planted in the rainwater garden, and the rainwater can be resisted for a short time. The packing layer is made of natural or artificial material with strong permeability, and the thickness of the packing layer is determined according to local rainfall characteristics, the service area of a rainwater garden and the like and is mostly 0.5-1.2 m. When sandy soil is selected, the main components of the sandy soil are consistent with those of a planting soil layer. The gravel layer is composed of gravels with the diameter not more than 50mm and the thickness is 200-300 mm. The subsequent system device of the rainwater garden is a filter tank, the filter tank can further purify rainwater, and finally the rainwater passing through the filter tank flows into a reservoir to achieve the final purpose of rainwater treatment. In consideration of the problem of blocking of the filter material in the filter layer, the filter material is cleaned by using a backwashing device, backwashing water is from a reservoir, and the backwashing water flows into a municipal sewage pipe network. The rainwater treated by the rainwater comprehensive treatment system can be used for landscape greening, road spraying and the like, controlling rainwater runoff pollution, improving urban ecological environment and realizing sustainable development of economy and society.

Claims

1. A rainwater comprehensive treatment system is characterized by comprising a desanding device, a rainwater garden, a sand filter (14) and a reservoir (17); wherein the content of the first and second substances,

the sand removing device comprises a sand removing device (1), an SS probe (2) arranged in the sand removing device (1), an electric valve arranged at a water outlet at the bottom of the sand removing device (1), and a controller (3) connected with the output end of the SS probe (2), wherein the output end of the controller (3) is connected with the control end of the electric valve and used for controlling the electric valve to be started and closed, and the water outlet of the electric valve is communicated to a municipal sewage pipe network; a first covering layer (4), a first packing layer (5), a first gravel layer (6) and a water collecting channel (7) are sequentially arranged at a water outlet at the upper part of the sand removing device (1) from inside to outside;

the rainwater garden comprises a water storage layer (8), a second covering layer (9), a planting soil layer (10), a second packing layer (11) and a second gravel layer (12) which are sequentially arranged from top to bottom, wherein a water collecting channel (7) is communicated with the water storage layer (8), and a water outlet at the upper part of the water storage layer (8) is communicated to a municipal sewage pipe network through an overflow pipe (13);

the water outlet of the second gravel layer (12) is communicated to a sand filter (14), a filter layer (15) is arranged in the sand filter (14), a water circulation loop is formed between the sand filter (14) and a reservoir (17), and the water outlet at the upper part of the sand filter (14) is communicated to a municipal sewage pipe network.

2. The integrated rainwater treatment system according to claim 1, wherein the electrically operated valve is an electrically operated butterfly valve.

3. A comprehensive rainwater treatment system according to claim 1, characterised in that a supporting layer (16) is provided in the sand filter (14), and the filtering layer (15) is provided on the supporting layer (16).

4. A rainwater comprehensive treatment system according to claim 1, characterized in that a water pump is arranged on the pipeline connecting the sand filter (14) and the reservoir (17).

5. A stormwater integrated treatment system according to claim 1, c h a r a c t e r i z e d in that the sand removing device (1) has a ratio of the width of the bottom to the width of the upper part of the sand removing device (1) of 1:2, and a ratio of the distance from the upper part of the right side of the sand removing device (1) to the bottom to the width of the bottom of 4.8: 1.

6. A rainwater comprehensive treatment system according to claim 5, characterized in that the bottom of the sand removing device (1) is a conical section with an inclination angle of 80 degrees.

7. A stormwater integration treatment system as claimed in claim 1, wherein the second gravel layer (12) is formed of gravel having a diameter of not more than 50mm and a thickness of 200 to 300 mm.