CN105461075A - Urban runoff non-point source pollution advanced treatment and reuse technology - Google Patents

Abstract

The invention relates to a process for advanced treatment and reuse of urban runoff non-point source pollution. The process includes three parts: an urban runoff collection system, a processing system and a storage and recovery system; the urban runoff collection system includes a system for collecting and initially purifying urban non-point sources. Roadside permeable plant belts and permeable urban green spaces; the treatment system includes ecological gravel beds and wetlands that further remove pollutants such as heavy metals, nitrogen and phosphorus in urban non-point sources; the storage system includes high-quality water self-purification landscape ponds, which can realize the depth of urban runoff It is purified and has a landscape effect, and provides high-quality recycled water for urban greening, watering, and groundwater replenishment. Aiming at urban runoff non-point source pollution, the invention provides a process for efficiently removing various pollutants in urban non-point source runoff and producing recycled high-quality reclaimed water by optimizing and improving each unit.

Description

A process for advanced treatment and reuse of urban runoff non-point source pollution

technical field

The invention belongs to the technical field of sewage treatment, and in particular relates to an advanced treatment and recycling process of urban runoff non-point source pollution.

Background technique

Non-point source pollution has become one of the important sources of water environment pollution at home and abroad. With the effective control of urban industrial wastewater and domestic sewage discharge in my country, non-point source pollution with urban road runoff, livestock and poultry breeding manure and rural domestic garbage as the main source of pollution has gradually been paid attention to. Due to the scattered source of non-point source pollution, difficult identification of generation location, strong accidental and large impact load, traditional centralized sewage treatment technology is difficult to be used for non-point source pollution prevention and control. The existing non-point source pollution treatment processes mainly focus on using pollution barrier belts to reduce pollutants carried in runoff, such as using green space buffer belts to filter sediment sediment, and using plants to absorb nutrients such as nitrogen and phosphorus and various pollutants. Atmospheric particulate matter, etc. This type of technology has a single treatment method and low treatment efficiency, so the effect on the treatment of various pollutants is limited. Chinese patent 201210210495.1 discloses "point-line-surface three-dimensional configuration based on non-point source pollution control technology", the dyeing treatment process can adapt to the instability of rural non-point source pollution, and can adapt to local conditions, but it occupies a large area and the system is complicated. Not suitable for dealing with urban non-point source pollution. Chinese patent 201410743613.4 discloses "a system and method for purifying water area non-point source pollution". Although this process optimizes and improves each unit process of non-point source pollution control, the primary and advanced treatment only rely on physical purification, the method is single, and is limited by the amount of water inflow. The impact is difficult to ensure sufficient hydraulic retention time, and it is impossible to realize all-round water environment governance.

In this technology, an urban runoff non-point source pollution control system with simple technology, wide application range, easy urban construction, and suitable integration with surrounding landscapes is constructed. The system can not only deal with urban non-point source pollution, but also build an integrated urban landscape belt; while buffering the impact load of non-point source and effectively intercepting pollution, it can also carry out in-situ treatment and deep purification of non-point source sewage, providing Water cycle and saving fresh water resources provide a reliable way out.

Contents of the invention

The invention provides a low-investment, easy-to-manage, easy-to-operate and widely applicable, which can not only carry out decentralized treatment of urban non-point source pollution, but also carry out centralized advanced treatment of non-point source sewage in a certain area, and perform secondary recovery of treated sewage Utilize crafting and combination systems.

To achieve the above object, the technical scheme adopted in the present invention is as follows:

The present invention is an advanced treatment and recycling process of urban runoff non-point source pollution. The process includes three parts: an urban runoff collection system, a processing system, and a storage and recovery system; the urban runoff collection system includes a roadside seepage plant belt and a permeable urban green space ;The treatment system includes ecological gravel beds and wetlands; the storage and recovery system includes high-quality water self-purification landscape ponds; when the system is running, the sewage passes through the roadside permeable plant belts and permeable urban green spaces to collect and initially purify urban non-point sources; ecological Gravel beds and wetlands further remove pollutants such as heavy metals, nitrogen, and phosphorus in urban non-point sources; high-quality water self-purification landscape ponds can achieve deep purification of urban runoff and have landscape effects, which can provide high-quality water for urban greening, watering, and groundwater supplementation. Quality recycled water.

The above-mentioned advanced treatment and reuse process of urban runoff non-point source pollution is characterized in that: the collection system, the treatment system and the storage and recovery system are arranged along the elevation from high to low, and the water flows automatically in the form of horizontal flow and composite flow.

The above-mentioned advanced treatment and reuse process of urban runoff non-point source pollution is characterized in that: the roadside seepage plant belt and the permeable urban green space include upper and lower layers, namely the upper vegetation layer and the lower gravel seepage layer, and the urban runoff flows from top to bottom. Downward infiltration; roadside seepage plant belts and permeable urban green spaces are 2-10cm lower than the road.

The above-mentioned advanced treatment and reuse process of urban runoff non-point source pollution is characterized in that: the bottom of the roadside seepage plant belt and the permeable urban green space is compacted with plain soil to prevent sewage seepage; the lower gravel seepage layer is filled with a thickness of 10 to 30 cm , zeolite, gravel or functional filler with a particle size of Φ4-30mm; the lower gravel seepage layer keeps a slope of 2-5.0‰ along the side of the water distribution channel to the gravel bed, so that urban runoff automatically flows into the ecological gravel bed according to the topography from high to low , reduce the use of pipes, and use it as a substrate for biofilm and plant growth; the upper vegetation layer is covered with 5-20cm thick planting soil, and plant landscape crops with developed root system, good pollution resistance and strong adaptability in the soil layer , plants can remove particulate matter, nitrogen and phosphorus from urban runoff.

The above-mentioned advanced treatment and reuse process of urban runoff non-point source pollution is characterized in that: the ecological gravel bed is connected in series with wetlands and high-quality water self-purification landscape ponds through horizontal flow or composite flow; the ecological gravel bed and wetland hydraulic retention The time ratio is controlled at 1:2~5; the wetland can adopt surface flow or subsurface flow to realize advanced treatment of ammonia nitrogen, total nitrogen, and total phosphorus in sewage.

The above-mentioned advanced treatment and recycling process of urban runoff non-point source pollution is characterized in that: the ecological gravel bed includes two layers, namely an upper layer of sandy filter layer and a lower layer of gravel layer, and the bottom plate is compacted with plain soil; wherein the lower layer of gravel bed is thick 10-30cm, filled with Φ8-25mm functional filler; the upper sandy filter layer is 5-20cm thick, filled with Φ3-15mm functional filler, planted landscape plants, shrubs or emergent plants; the entire gravel bed maintains a slope of 2-5.0‰ , to ensure that the sewage flows into the follow-up treatment unit by itself, reducing the use of pipelines.

The above-mentioned advanced treatment and reuse process of urban runoff non-point source pollution is characterized in that the wetland is an improved surface flow or compound flow wetland. From bottom to top, the composite flow wetlands are ceramsite filter materials of Φ15-25mm and functional fillers of Φ3-5mm respectively, and wetland plants are planted according to a certain density; the runoff is purified through the joint action of plants, substrates and microorganisms.

The above-mentioned advanced treatment and reuse process of urban runoff non-point source pollution is characterized in that: the water depth of the high-quality water self-purification landscape pond is 0.5-4m, the hydraulic retention time is greater than 1.0d, and emergent plants and floating plants are planted in the shallow water area. A sand protection layer and a coarse sand filter layer are laid at the bottom; an automatic drainage device is installed at the outlet of the pond, which can release water to nearby rivers, park green spaces or directly supplement groundwater according to water reuse requirements.

Compared with the prior art, the present invention has the following advantages:

1. The present invention connects roadside permeable plant belts and permeable urban greenbelts, ecological gravel beds and wetlands, and high-quality water self-purification landscape ponds in series, and has the advantages of simple structure, low investment, easy construction, easy operation, and easy maintenance. advantage.

2. The present invention can realize on-site, in-situ purification and advanced treatment of urban non-point source runoff, and realize in-situ treatment and direct recycling of urban non-point source pollution.

3. The technology developed by the present invention is closely integrated with the construction of existing urban green spaces and urban rivers and lakes. The existing urban green spaces, rivers and lakes can be constructed by simply transforming the system.

4. The present invention optimizes and improves urban green spaces, ecological gravel beds, wetlands, and high-quality water self-purification landscape ponds, such as transforming process unit configuration, aeration intensity, water depth, etc., to realize the purification of heavy metals, TN and other substances in urban runoff. , TP, organic matter and other effective removal.

5. The present invention has flexible layout and moderate floor area, which is beneficial to urban construction and can be directly used in the construction of landscape belts.

Description of drawings

Fig. 1 is a structural schematic diagram of an advanced treatment and recycling process of urban runoff non-point source pollution according to the present invention.

The labels in the drawings are explained as follows: 1- roadside permeable plant belt, 2- permeable urban green space, 3- ecological gravel bed, 4- wetland, 5- high-quality water self-purification landscape pond, 7- electric valve, 6- liquid bit controller.

detailed description

The invention is an advanced treatment and recycling process of urban runoff non-point source pollution. The specific implementation method is as follows: the road path flows through the road accumulation canal or directly flows into the roadside permeable plant belt 1 and the permeable urban green space 2 . The road path flows through the upper vegetation layer and enters the lower gravel seepage layer. The large suspended particles in the runoff are intercepted by the plant roots and soil; some TN, TP and heavy metals are absorbed by the plant roots. After being collected by the lower gravel seepage layer, the urban non-point source runoff enters the ecological gravel bed 3. After a certain hydraulic retention time, the upper sandy filter layer and the lower gravel layer of the ecological gravel bed further filter and absorb the urban runoff and desorb it through biological action. After nitrogen and phosphorus removal, the treated water flows into the wetland system 4 by itself. Through plant root absorption, nitrification, denitrification and biological phosphorus removal, as well as the promotion of functional fillers to nitrification and denitrification, the enhanced adsorption of ammonia nitrogen, the promotion of crystallization of phosphate, the acceleration of the degradation of organic matter, and the chemical fixation of heavy metals , disinfection of pathogenic bacteria, and effective control of urban runoff pollution. The outlet water passes through the overflow weir or directly enters the high-quality water self-purification landscape pond 5, and the advanced treatment of sewage is realized through the joint action of bacteria, algae and aquatic plants, and has a good landscape effect. According to the water demand for urban greening, etc., the liquid level controller 7 is controlled by the electric valve 6 to replenish the treated water to urban parks, green belts and other facilities, and finally realize the process of comprehensive treatment and disposal of urban runoff.

Embodiment one:

Utilize above-mentioned method to purify urban runoff sewage. The size of the system is: (1) urban green space: length × width × height = 200m × 40m × 15-30cm, (2) ecological gravel bed: length × width × height = 200m × 50m × 20-30cm (3) wetland: Length × width × height = 200m × 80m × 30-80cm, (4) High-quality water self-purification landscape pond: length × width × height = 200cm × 300cm × 120-300cm.

The influent COD concentration is 20-100mg/L, TP concentration is 0.3-1.2mg/L, TN concentration is 1.9-6.8mg/L, ammonia nitrogen concentration is 1.2-5.8mg/L, temperature is 26.3-28.7℃, hydraulic Under the load of 0.21m ³ /m ² /d, the average removal rates of COD, TP, TN and ammonia nitrogen by the area source system were 65.33%, 54.68%, 43.99%, and 38.05%, respectively.

Embodiment two:

Utilize above-mentioned method to purify urban runoff sewage. The size of the system is: (1) urban green space: length × width × height = 300m × 50m × 25-47cm, (2) ecological gravel bed: length × width × height = 300m × 70m × 30-60cm (3) wetland: Length × width × height = 300m × 90m × 40-90cm, (4) High-quality water self-purification landscape pond: length × width × height = 400cm × 300cm × 150-400cm.

The influent COD concentration is 100-300mg/L, TP concentration is 1.6-3.4mg/L, TN concentration is 3.3-23.2mg/L, ammonia nitrogen concentration is 0.9-22.7mg/L, temperature is 23.5-25.6℃, hydraulic Under the load of 0.12m ³ /m ² /d, the average removal rates of COD, TP, TN and ammonia nitrogen by the area source system were 89.79%, 49.96%, 70.02% and 49.05%, respectively.

Claims (8)

1. A process for advanced treatment and reuse of urban runoff non-point source pollution, the process includes three parts: a collection system for urban runoff, a treatment system, and a storage and recovery system; the urban runoff collection system includes roadside seepage plant belts and permeable urban green spaces; The treatment system includes ecological gravel beds and wetlands; the storage and recovery system includes high-quality water self-purification landscape ponds; when the system is running, the sewage passes through the roadside permeable plant belts and permeable urban green spaces to collect and initially purify urban non-point sources; ecological gravel Beds and wetlands further remove pollutants such as heavy metals, nitrogen and phosphorus in urban non-point sources; high-quality water self-purification landscape ponds can achieve deep purification of urban runoff and have a landscape effect, which can provide high-quality water for urban greening, watering, and groundwater supplementation. Recycled water. 2. The advanced treatment and recycling process of urban runoff non-point source pollution according to claim 1, characterized in that: the three systems of collection system, processing system and storage and recovery are arranged from high to low along the elevation, and the water flow is horizontal and composite flow patterns flow automatically. 3. A kind of advanced treatment and recycling process of urban runoff non-point source pollution according to claims 1 and 2, characterized in that: the ecological gravel bed is connected with wetlands and high-quality water self-purification landscape ponds through horizontal flow or composite flow In series; the hydraulic retention time ratio between the ecological gravel bed and the wetland is controlled at 1: (2-5); the wetland can adopt surface flow or subsurface flow to achieve advanced treatment of ammonia nitrogen, total nitrogen, and total phosphorus in sewage. 4. A kind of advanced treatment and recycling process of urban runoff non-point source pollution according to claim 1, characterized in that: the roadside seepage plant belt and the permeable urban green space comprise upper and lower layers, namely the upper vegetation layer and the lower gravel seepage The urban runoff infiltrates from top to bottom; the roadside permeable plant belt and permeable urban green space are 2-10cm lower than the road. 5. A kind of advanced treatment and recycling process of urban runoff non-point source pollution according to claims 1 and 4, characterized in that: the bottom of the roadside seepage plant belt and the permeable urban green space is compacted with plain soil to prevent sewage leakage; The lower gravel seepage layer is filled with 10-30cm thick zeolite or gravel with a particle size of Φ4-30mm, and the lower gravel seepage layer maintains a slope of 2-5.0‰ along the side of the water distribution channel to the gravel bed, so that the urban runoff follows the terrain from high to low Automatically flow into the ecological gravel bed, reducing the use of pipes, and use it as a substrate for biofilm and plant growth; the upper vegetation layer is covered with 5-20cm thick planting soil, and the planting root system in the soil layer is well developed, with good pollution resistance and adaptability Resilient landscape crops, plants remove particulate matter, nitrogen and phosphorus from urban runoff. 6. A kind of advanced treatment and recycling process of urban runoff non-point source pollution according to claim 1, characterized in that: the ecological gravel bed comprises upper and lower layers, i.e. an upper layer of sandy filter layer, a lower layer of gravel layer, and plain soil for the bottom plate Compaction; the lower gravel bed is 10-30cm thick, filled with Φ8-12mm functional filler; the upper sandy filter layer is 5-20cm thick, filled with Φ3-15mm functional filler, and planted with landscape plants, shrubs or emergent plants; the entire gravel bed is maintained The slope of 2-5.0‰ ensures that the sewage flows into the follow-up treatment unit and reduces the use of pipelines. 7. A process for advanced treatment and reuse of urban runoff non-point source pollution according to claim 1, characterized in that: the wetland is an improved surface flow or compound flow wetland; the bottom of the wetland is compacted with plain soil to prevent leakage; the compound flow From the bottom to the top of the wetland, the ceramsite filter material of Φ15-25mm and the functional filler of Φ3-5mm are respectively planted with wetland plants according to a certain density; the runoff is purified through the joint action of plants, substrates and microorganisms. 8. The advanced treatment and reuse process of urban runoff non-point source pollution according to claim 1, characterized in that: the water depth of the high-quality water self-purification landscape pond is 0.5-4m, the hydraulic retention time is greater than 1.0d, and the planting in the shallow water area is For water plants and floating plants, a protective layer of sand and a coarse sand filter layer are laid at the bottom of the pond; a liquid level controller is installed at the outlet of the pond, and water can be regularly released to nearby rivers, park green spaces or directly replenish groundwater according to water reuse needs.