CN103880257A - Ecological combined treatment method and device for rural distributed sewage - Google Patents

Abstract

The invention discloses an ecological combined treatment method and device for rural decentralized sewage, the steps are: A, rural sewage collection and pretreatment; B, biological filter treatment; C, artificial wetland and stable pond treatment; D, ecological landscape configuration. The main water inlet pipe is connected to the grid tank and the adjustment tank respectively, the adjustment tank is connected to the horizontal flow biological filter through the water distribution pipe, the horizontal flow biological filter is connected to the vertical flow biological filter through the filter screen-water distribution pipe, and the vertical flow biological filter The filter tank is connected to the first-level artificial wetland through the perforated water collection pipe placed horizontally, the first-level artificial wetland is connected to the second-level artificial wetland through the overflow weir, and the second-level artificial wetland is connected to the stabilization pond through the straight-line drainage pipe. Main drain. This method does not require energy consumption, is easy to operate and maintain, has landscape effects and economic benefits, and has a simple structure and low investment. It realizes efficient purification of rural decentralized living and aquaculture sewage, and the removal rates of nitrogen, phosphorus and COD in the treated sewage are all 80% %above.

Description

An ecological combination treatment method and device for rural decentralized sewage

technical field

The invention belongs to the technical field of sewage ecological treatment. More specifically, it relates to an ecological combination treatment method of rural decentralized sewage, and also relates to a device for ecological combination treatment of rural decentralized sewage, which is suitable for rural decentralized living and breeding sewage treatment, and can improve the rural ecological environment. Especially in the southern hilly area, the natural elevation difference of the terrain can be used, and the whole sewage treatment device can realize zero-power operation, which is convenient for rural popularization and application.

Background technique

In recent years, with the rapid development of my country's rural economy and the continuous advancement of urbanization, the discharge of rural decentralized living and aquaculture sewage has continued to increase, which has caused serious pollution to surrounding natural water bodies and soil. At the same time, rural decentralized sewage discharge is becoming the main source of pollution in river basins, and it is also increasingly becoming the main source of nitrogen and phosphorus in downstream estuaries and lakes, causing eutrophication of water bodies. Therefore, effective treatment of rural sewage is becoming an urgent problem to be solved. However, urban sewage treatment plants have high infrastructure and operating costs and complex management. This high-input sewage treatment method is difficult to promote in the vast rural areas of our country. The ecological treatment mode includes various technologies such as artificial wetland, land seepage treatment process, oxidation pond, and biological filter. It has the advantages of low construction cost, easy management, and good sewage treatment effect, providing a new way for rural sewage treatment. However, a single ecological treatment technology may have disadvantages such as unstable treatment effect and large footprint. Therefore, based on the rural economic conditions and the local natural environment, it is an important guarantee for the effective control of rural sewage to develop a stable and efficient ecological combined treatment process with low investment, low energy consumption, convenient operation and management, and low operating costs.

Contents of the invention

The purpose of the present invention is to provide an ecological combined treatment method for rural decentralized sewage. The method aims at environmental problems such as the current low level of rural decentralized sewage treatment and increasingly serious agricultural non-point source pollution. pond, regulating pond, horizontal flow biofilter, vertical flow biofilter, two-stage surface flow artificial wetland, and stabilization pond to build an ecological combined treatment system for rural decentralized sewage, to realize effective treatment of rural decentralized domestic and aquaculture sewage, and to realize Sewage purification and safe discharge. This method does not require power consumption, is easy to operate and maintain, and also has certain landscape effects and economic benefits.

Another object of the present invention is to provide a device for ecological combined treatment of rural decentralized sewage. The device has a simple structure, low investment, zero power operation, and convenient management, and can realize efficient treatment of rural decentralized living and aquaculture sewage. Purification, the removal rate of nitrogen, phosphorus and COD in the treated sewage is above 80%. At the same time, aquatic economic vegetables are planted in the second-level artificial wetland to realize the reuse and resource utilization of nitrogen and phosphorus nutrients in sewage, and produce aquatic economic vegetables. Fish farming in stable ponds can obtain economic benefits, thereby increasing farmers' enthusiasm for adopting this technology.

In order to achieve the above object, the present invention adopts the following technical measures:

The invention utilizes the natural elevation difference of the terrain in the southern hilly area, concentrates the rural distributed domestic and pig-raising sewage through the pipe network system, and constructs a sewage ecological combination treatment device at a low-lying place, including a grid pool, a regulating pool, and a horizontal flow biological filter , vertical flow biofilter, first-level surface-flow constructed wetland and second-level surface-flow constructed wetland, stabilization pond, the above treatment units are organically combined to form a complete set of rural sewage treatment process.

An ecological combined treatment method for rural decentralized sewage, the steps of which are:

1. Rural sewage collection and pre-treatment: Use PVC pipes to collect rural distributed domestic and aquaculture sewage, establish a rural sewage collection pipe network, and then introduce the sewage into the grid pool through the general water pipeline. The grid pool is used for filtering, intercepting suspended solids or floating solids larger than 2 cm, and for primary sedimentation of sewage. In the southern hilly area, domestic or aquaculture sewage from farmer settlements distributed at the foot of the mountain or on the side of the mountain can flow into the low-lying, grid pool by gravity flow through pipelines at all levels. The effluent of the grid pool enters the regulating pool, and the regulating pool further settles the solid particles in the sewage, and microorganisms anaerobically degrade some organic matter in the sewage. Then overflow through the parallel multi-pipeline (more than 3) water distribution system and enter the horizontal flow biofilter.

2. Biological filter treatment: the effluent from the regulating pool enters the horizontal flow biological filter, and the horizontal flow biological filter is filled with straw and cultivated foxtail algae on the upper layer to form a straw-foxtail algae biofilter system. The horizontal flow biofilter can remove high-load nitrogen, phosphorus, COD and heavy metals can also cover, absorb and remove the odor in sewage.

The effluent from the horizontal flow biofilter enters the surface layer of the vertical flow biofilter through a single-channel distribution pipe. The vertical flow biofilter system is composed of broken wood block layer, rice husk layer, straw layer and dry land red soil layer from bottom to top. At the same time, the soil layer is planted with canna, iris, and water bamboo aquatic plants. Biomass materials (straw, rice husk, wood chips, shavings) in the vertical flow biofilter treatment engineering unit have good porosity and water permeability, while wood chips (0.5-10 cm in size), rice husks, straw, etc. Biomass materials provide a favorable environment for the growth of microorganisms. The abundant microorganisms on the surface of biomass materials can effectively degrade pollutants and purify water quality. The soil layer and canna, iris, and water bamboo plants can absorb and absorb nitrogen, phosphorus, and heavy metals, respectively. Simultaneously setting four layers of different materials in the vertical flow biofilter can greatly reduce the occupied area. At the bottom of the vertical flow biofilter, a horizontal perforated pipe is used to collect water in the wood fragment layer filled with wood fragments (0.5-10 cm in size). The vertical flow biofilter is connected to the upper water diversion pipe, and the vertical flow biofilter discharges the water into the first-level surface flow artificial wetland through the water outlet system.

3. Treatment of artificial wetlands and stabilization ponds: This level of artificial wetlands is surface flow, the wetland substrate is soil, and the wetland plants choose barracuda and pink-green foxtail. The water inlet of the wetland is first planted with the emergent Pikegrass, and behind the Pikegrass is the submerged plant Prunus viridis. Pikegrass and P. viridis have the characteristics of pollution resistance, large biomass, and long growth period. The first-level constructed wetland can withstand ammonia nitrogen pollution of about 400 mg/L, surface flow at a water depth of 5-30 cm, and an aerobic environment formed by rhizosphere oxygen secretion of barracuda and foxtail algae plants, further promoting the decomposition of organic pollutants and During the nitrification and denitrification process, at the same time, the rapid growth of plants can absorb a large amount of nutrients such as nitrogen and phosphorus. The effluent from the first-level constructed wetland enters the second-level surface flow constructed wetland through the overflow weir. The overflow weir can increase the dissolved oxygen content in the water body, and ensure that COD, nitrogen, and phosphorus in the water body are better removed in the second-level constructed wetland. The water discharged from the first-level constructed wetland contains nitrogen and phosphorus nutrients with moderate concentrations (<20 mg/L ammonia nitrogen and <2 mg/L phosphate), providing nutrients for the cultivation of aquatic economic vegetables in the second-level constructed wetland. Aquatic vegetables that are suitable for the local environment, have large biomass, and are easy to manage can be planted in the second-level surface flow constructed wetland. For example, water spinach, cress, wild rice stem, watercress and water chestnut can be planted in southern my country. After further deep purification of nitrogen and phosphorus pollution in the water body by the second-level constructed wetland, it is discharged into the stabilization pond. The water in the first half of the stabilization pond is shallower at about 0.4-0.7 m, and the water in the second half is deeper at about 0.9-1.1 m. Aquatic plants calamus and water lilies are planted at the front and rear ends respectively. After treatment in the stabilization pond, the effluent meets the water quality requirements for safe discharge.

4. Ecological landscaping configuration: In the rural decentralized sewage concentration and treatment method of the present invention, the landscaping design for improving the rural ecological environment is considered, so that no sewage can be seen or smelled on the surface of the treatment area, and rural human settlements can be realized. The effect of landscaping.

First of all, rural sewage is collected with PVC pipe network, and the sewage cannot be seen in the surface environment. Secondly, each treatment unit of the ecological combined treatment engineering system has been treated with corresponding leak prevention, deodorization, landscaping, etc., such as: the grid pool and the regulating pool are sealed around and covered on the surface, so that no sewage can be seen and no odor can be smelled; The third is to plant foxtail algae on the upper layer of the horizontal flow biofilter to cover the sewage and deodorize at the same time; the fourth is to plant cannas with iris and water bamboo on the upper soil layer of the vertical flow biofilter; Constructed wetlands are planted with long-growing and flowering pikegrass and green strips of foxtail algae. Water spinach, watermelon and water chestnuts are planted in spring, summer and autumn in the second-level surface flow constructed wetland, and watercress and watercress are planted in winter. ; The sixth is to plant calamus around the stable pond, and plant water lilies in the pond. The above-mentioned plants are planted together, beautifying the local environment and improving the living environment.

An ecological combination treatment device for rural decentralized sewage, which includes: rural decentralized sewage collection pipe network, grid pool, regulating pool, "three-way" type water distribution and water sampling pipe, horizontal flow biological filter, Filter screens and distribution pipes, vertical flow biofilters, straw, rice husks, wood chips and shavings, horizontal perforated catchment pipes (wrapped in gravel piles) and 45 ^o C sloping upward drains, first stage surface flow constructed wetlands , high-biomass aquatic plants barracuda and chrysanthemum, overflow weir, second-level surface flow artificial wetland, aquatic economic crops (water spinach, water celery, wild rice stem, watercress and water chestnut), "─" Straight-flow drainage pipes, stable ponds, calamus, water lilies, and " ∟ " overflow drainage pipes. It is characterized in that: the distributed villagers' life and breeding sewage are connected to the grid pool and the adjustment pool respectively through the main water inlet pipe through the centralized pipe network, and the adjustment pool is connected to the horizontal flow biological filter through the three-way water distribution and water sampling pipe , the filter tank is filled with straw and foxtail algae are cultivated on the upper layer to form a straw-foxtail algae biological filter system. The horizontal flow biological filter is connected to the vertical flow biological filter through the filter screen-water distribution pipe,

The vertical flow biofilter system is composed of broken wood block layer, rice husk layer, straw layer and dry land red soil layer from bottom to top, wherein the soil layer is planted with canna, iris and water bamboo aquatic plants. The vertical flow biofilter is connected to the first-stage surface flow artificial wetland through the horizontally placed perforated water collection pipe and the 45 ^o C upward water delivery pipe. The water inlet of the wetland is planted with emergent pike grass first, and submerged plant powder is planted behind pike grass Green foxtail. The first-level surface-flow constructed wetland is connected to the second-level surface-flow constructed wetland through the overflow weir. Aquatic vegetables are mainly planted in this level of wetland, such as water spinach, cress, wild rice stem, watercress and water chestnut, which are suitable for planting in southern my country. The second-level surface flow artificial wetland is connected to the stabilization pond through a straight-flow drainage pipe. The stabilization pond is divided into front and rear ends, and different water depths are set according to the difference of aquatic plants such as calamus and water lilies. At the end of the stabilization pond, a ∟- shaped overflow main drainage pipe is installed.

The depths of the grid pool and conditioning pool were 0.5 m and 1.0 m, respectively. The water storage depth of the adjustment tank is 0.4~1.0 m. The "three-way" type water distribution and water sampling pipe is equipped with a switch to control the water depth in the adjustment tank. When the biological filter and the artificial wetland are to be managed in the process, through Turning off the switch allows the sewage to be temporarily stored in the regulating tank and not discharged into the horizontal flow biological filter, and the sewage undergoes preliminary anaerobic degradation in the regulating tank. One outlet of the "three-way" water distribution and water sampling pipe is connected to the horizontal flow biological filter. The horizontal flow biological filter is 0.7 m deep and can control the water depth of 0.6 m. The polluted sewage enters the straw layer (below the soil layer) of the vertical flow biofilter through the filter screen and water distribution pipe. The vertical flow biofilter is 1.5 m deep and filled with 0.3 m red soil, 0.3 m straw layer, and 0.4 m rice husk layer in sequence and a 0.4 m layer of broken wood, the water depth can be controlled to about 1.1 m. Both the layout pipe and the water collection pipe are made of UPVC pipes. The water distribution pipe is directly connected to the straw layer below the soil layer. Gravel piled blockage), placed in the broken wood block layer, connected to the water collection pipe is the water diversion pipe, the water diversion pipe is arranged obliquely upward at 45 ^o C, and the water diversion pipe goes up to the middle of the straw layer and then connected to a straight drain pipe, the drain pipe will be treated Sewage is discharged directly into the constructed wetland. The first-level surface flow artificial wetland was rebuilt from paddy fields and low-lying land. After preparing the site and digging down about 0.1 m, the soil dug down was piled up around the surrounding area to widen the wetland boundary to prevent leakage. Pikegrass was planted in the front and back sections respectively. and Foxtail algae, the planting area ratio of the two plants is about 1:3, and the water depth of the front and rear plant sections can be controlled to about 0.3 m. The first-level artificial wetland is planted with emergent plants Pikegrass in the front part to remove suspended solids and sediment, and in the back part is planted with foxtail algae (absorbing nitrogen and phosphorus pollution, while enriching oxygen for the sewage flowing through), and the wetland treats the effluent along the overflow The weir flows into the second-level horizontal flow artificial wetland for advanced treatment. The second-level surface flow artificial wetland is also rebuilt from rice fields and low-lying lands, and the ground is excavated about 0.1 m (the depth of the excavation of the field is determined by the terrain, that is, the high-level difference between it and the first-level artificial wetland), ensuring that it is consistent with the first-level artificial wetland. The wetland maintains a natural drop of more than 0.1 m, and the water depth can be controlled at about 0.3 m. The specific water depth depends on the aquatic vegetables planted. About 0.3 m. Dig down 0.5 m and 1 m in the front and back sections of the stabilization pond respectively, and the area ratio of the front and back sections is 1:1. The excavated soil is piled up around the perimeter, and the pond foundation is widened to prevent water from leaking out. The emergent water plant calamus is planted, and the submerged water lily is planted in the latter part.

In addition, the length-to-width ratios of grid pools, regulating pools, horizontal flow biofilters and vertical flow biofilters are all about 1.5-2:1, and the area of grid pools and regulating pools is designed at 1:10; The area ratio of the flow biofilter and the vertical flow biofilter is 2.5:2.5:1; the aspect ratio of the first and second surface flow constructed wetlands is about 3:1, and the area ratio is 1:1.5; the aspect ratio of the stabilization pond 3:1, and the area ratio of the second-level surface flow constructed wetland is designed at 1:1. The specific size is slightly adjusted according to the total amount of rural sewage to be treated and the terrain characteristics.

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

The design of the technical process of the method of the present invention refers to the relevant theories and technologies of water conservancy engineering, ecological engineering, and sewage treatment engineering, and combines factors such as the amount of sewage production, distribution, and development planning within the scope of serving rural areas, and can adapt to complex and diverse rural sewage components. The characteristic of changing, to realize the efficient purification of rural decentralized living and breeding sewage.

1. High treatment efficiency: the method of the present invention enters the adjustment tank after intercepting large debris in sewage, and uses physical sedimentation, microbial action and other preliminary degradation processes to remove certain suspended solids and COD, etc.; horizontal flow biofilter, vertical flow biofilter The pool and the first-level constructed wetland are used as intensive treatment units to remove most of the COD, nitrogen, and phosphorus pollution; the second-level constructed wetlands and stabilization ponds are used as advanced treatment units to achieve effluent discharge standards. This treatment process avoids the sewage treatment mode in which a single treatment type can only treat certain pollutants or pollutants in a certain concentration range, and the effluent is clean and stable. The treated water is transparent, clear, and odorless, and the overall treatment efficiency of pollutants in the water remains above 80%, that is, the COD, total phosphorus, total nitrogen, and ammonia nitrogen in the wastewater are respectively lower than 60mg/L, 1 mg/L, and 20mg/L And 8mg/L, the effluent water quality index reaches the first-level B standard of the "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB 18918-2002), and achieves the effect of advanced treatment and removal of nitrogen and phosphorus in rural sewage.

2. "Zero power" operation: Combined with the local natural background conditions (land area, topography, meteorology, hydrological factors, etc.), select fields, depressions or ponds with natural elevation differences, and build a treatment process system to achieve "zero power" operation Require.

3. Low construction and operation costs and simple management: According to the characteristics of different processing units in the process, the processing materials used are mostly materials that are easily obtained in rural areas, such as straw, rice husk, wood chips, red soil, etc., and the construction cost is low. The management of the entire technological process is mainly to regulate the regular cleaning of sedimentation tank sedimentation, the regular harvesting of plants in the artificial wetland, and the removal of insects, etc., and the management is simple. For the construction of a processing system of the present invention with a daily processing capacity of 30 t/d, a land area of about 1500 m ² needs to be utilized, and the initial investment cost is about 50,000 yuan. After the start of the project operation, the power cost is 0 yuan/year, labor costs and maintenance and repair costs mainly include daily maintenance personnel responsible for silt removal, plant replanting, harvest management, etc., monthly salary 300 yuan/month), the entire combined process is one year The total running cost is small.

4. Good ecological environment effect and social effect: the rural sewage treatment system of the present invention can make the surface of the rural area see no sewage, and the rural sewage can be discharged into the downstream river after the treatment reaches the standard, which can effectively control the agricultural non-point source pollution; at the same time, the horizontal flow biological Treatment units such as filters, vertical biofilters, constructed wetlands, and stabilizing ponds are all equipped with aquatic plants, which have good ornamental value; in addition, when the aquaculture wastewater treatment reaches the standard, the constructed wetlands and stabilizing ponds can be planted with harmless aquatic plants. vegetables, create economic benefits, and facilitate the popularization and application of the invented technology in rural areas.

Description of drawings

Figure 1 is a schematic diagram of the purification process of a combined ecological treatment method for rural sewage.

Figure 2 is a schematic diagram of an ecological combination treatment device for rural decentralized sewage.

Among them: 1. Main water inlet pipe, 2. Grid pool, 3. Adjusting pool, 4. "Teee" type water distribution and water sampling pipe, 5. Horizontal flow biological filter, 6. Straw, 7. Powder Green foxtail algae, 8. Filtration screen-water distribution pipe (the front part of the water distribution pipe is filtered with a screen to prevent clogging), 9. Vertical flow biofilter, 10. Red soil, 11. Rice husk, 12. Broken wood, 13. Horizontally placed perforated water collection pipe and 45 ^o C upward water delivery pipe, 14. First-level horizontal flow constructed wetland, 15. Pikegrass, 16. Drainage channel, 17. Overflow weir, 18. Second-level horizontal flow constructed wetland , 19. Aquatic economic plants (cress, water spinach, watercress, watermelon, etc.) 20. "─"-shaped direct-flow drainage pipe, 21. Stable pond, 22. Aquatic plants (calamus, water lily, etc.), 23. " ∟ " Shaped overflow general drainage pipe, 24a. first straw layer, 25. red soil layer, 24b. second straw layer, 26. rice husk layer, 27. broken wood block layer, 28a. first farmland soil layer, 28b. second 2. Farmland soil layer, 29. Stabilize pond bottom mud.

Detailed ways

Embodiment 1 (as shown in Figure 1 and Figure 2):

In Gejiashan Village, Kaihui Town, Changsha County, the household and breeding sewage of a villager group in the village was selected as the treatment object. There are 13 households in this area, with a permanent population of 48 people. The maximum number of live pigs is about 1,000. Pig households have biogas digesters that have been in operation for several years, but the operation effect of the biogas digesters is unstable. The breeding sewage is almost directly discharged outside, and the drainage of some ditches is black water all the year round. This area is a typical southern hilly terrain. The land use pattern from high to low is forest land, residential building land, and farmland. Farmers' houses and pig pens are located on the higher hillside - the foot of the mountain. The rural sewage combined treatment project of the present invention is built near the low-lying farmland, so that the pipe network can be concentrated in the rural life and aquaculture sewage biogas tanks to treat the effluent by self-flow (no need to provide power). Establish rural decentralized sewage ecological demonstration project treatment through the present invention: the design project accepts about 8000 g/d of total nitrogen, about 600 g/d of total phosphorus, about 25 m ³ /d of hydraulic total load, and the effluent water quality implements "urban" Pollutant Discharge Standards for Sewage Treatment Plants (GB18918--2002) Level B Standard). An ecological combined treatment method for rural decentralized sewage, the steps of which are:

1. Research on sewage collection and pre-treatment in rural areas:

According to the amount of sewage discharge in the research area, select pipes of appropriate size (Water Supply and Sewerage Design Manual, Volume 5) to connect the sewage outlets of each household. The material selection is implemented in accordance with relevant standards, and the pipe material is PVC pipe (implemented in accordance with GB/T13663 regulations). Sewage in the research area is concentrated into a general water pipe (pipe diameter 250 mm) through the pipe network and sent to the grid pool of the treatment project (length 2 m*width 1 m*depth 0.6 m, area 2 m ² ). The grid pool conducts primary sedimentation to remove large particles of impurities and grid interception to remove large suspended or floating solids for the incoming sewage. The grid tank is connected to the adjustment tank, and the particulate suspended matter and sediment in the overflow water from the grid tank will further undergo physical sedimentation and interception in the adjustment tank (length 6 m*width 4 m*depth 0.8 m, area 24 m ² ). The tank can store water at a depth of 0.7 m. In special cases, if the external water volume is too large and exceeds the water passing capacity of the horizontal flow biofilter and vertical flow biofilter below, the excess water will be discharged into the first stage through the overflow pipe. Surface stream constructed wetlands.

2. Biological filter treatment: adopt 6 "three-way" type water distribution and water sampling pipes arranged side by side (the water delivery pipeline is set as a three-way switch, and one outlet of the three-way switch can directly collect water samples from the regulating pool. ) Distribute the effluent from the regulating tank into the horizontal flow biological filter (length 7 m* width 3.5 m* depth 0.6 m, area 24.5 m ² ). The horizontal flow biological filter has two layers, the lower layer is filled with a 40 cm deep straw layer, and the straw is covered with pink green algae. There are three oxygen-containing characteristic layers in the rice straw-P. viridis system: the bottom layer is the anaerobic layer of the straw, the middle layer is the anoxic layer formed by the growth and metabolism of the rhizosphere, and the upper layer is mainly the foxtail plants. Grows on water surfaces, presenting as an aerobic layer. In the horizontal flow biofilter, the attached large amount of anaerobic-facultative anaerobic microorganisms and aerobic microorganisms on the surface of the rhizosphere of Foxtail algae plants can remove high loads of nitrogen and COD, and fix phosphorus and heavy metals through rice straw. At the same time, the growth of foxtail algae can absorb nutrients, and more importantly, it can remove the odor in sewage. Sewage treated from the horizontal flow biofilter enters into three side by side independent vertical flow biofilter systems through three side-by-side filter screens and water distribution pipes. Three side-by-side independent filter tanks are of the same size (length 4 m*width 2.5 m*depth 1.5 m, area 10 m ² ). From bottom to top, they are filled with 0.4 m of broken wood, 0.4 m of rice husk, and 0.3 m of straw layer, 0.3 m red soil layer, and at the same time, the soil layer planted canna. The effluent from the horizontal flow biofilter is directly connected to the straw layer below the soil layer through the perforated horizontal collection pipe (wrapped by gravel pile) and the 45 ^o C inclined upward drainage pipe. The drainage system of the vertical flow biofilter is set as follows: Drill small holes around the layer of broken wood and place a 15 cm diameter water collection pipe, wrap 10-30 mm diameter gravel piles around the open hole straight pipe to prevent clogging, and The water collection pipe is connected to the water diversion pipe, which is arranged at an angle of 45 ^o C above. The water diversion pipe goes up to the middle of the straw layer and then connects to a horizontal and straight drainage pipe. The drainage pipe directly discharges the treated sewage into the first-level surface flow constructed wetland. , the height of the water outlet of the drainage pipe is set to control the water depth of 1.1 m in the vertical bioreactor. The microorganisms attached to the surface of biomass materials in this treatment unit mainly perform biological denitrification and phosphorus fixation, and the soil layer can absorb phosphorus and heavy metals.

3. Treatment of constructed wetlands and stabilization ponds:

The effluent from the vertical flow biological filter enters the first-level surface flow constructed wetland. The constructed wetland is rebuilt from a paddy field. The paddy field has a good plow bottom to prevent vertical leakage of pollutants in the sewage. This level of constructed wetland is divided into two sections. The front section is an area (6 m long x 10 m wide) where the emergent plant barracuda is planted (the height of the formed plant is about 1 m), which can buffer the effluent of the vertical biological reaction tank and remove part of N, P, and COD through plant absorption; the back section In order to plant the green foxtail area (length 20 m * width 10 m), foxtail algae has a large biomass and a long growth cycle, which can effectively absorb and remove higher N, P, and COD in sewage. The water depth of the front and rear sections can be controlled up to 0.3 m according to needs. After the treatment of the first-level surface flow constructed wetland, the effluent flows through the overflow weir to the second-level surface flow constructed wetland.

The second-level surface flow constructed wetland (length 30 m*width 10 m) was also reconstructed from the paddy field and excavated about 0.1 m down (the depth of excavation in the field is determined by the topography, that is, the height difference between it and the first-level constructed wetland). Ensure to maintain a natural drop of more than 0.1 m with the first-level artificial wetland, and the water depth can be controlled at about 0.2-0.3 m. The specific water depth is determined by the aquatic vegetables planted. When planting cress, watercress, and water spinach, the water depth is 0.1-0.2 m , the water depth can reach about 0.3 m when planting zucchini. The effluent from the second-level surface flow wetland enters the stabilization pond through the "─"-shaped straight-line drainage pipe. The length and width of the stabilization pond are about 30 m*10 m. The front and rear sections are dug down 0.5 m and 0.9 m respectively, and the area ratio of the front and back sections is 1:1. For infiltration, emergent water plants calamus are planted around and in the front section of the stabilizing pond, and submerged water lily plants are planted in the back section. The effluent that reaches the discharge standard after treatment in the stabilization pond overflows into the adjacent farmland through the " ∟ " shaped overflow drain.

4. Ecological landscape configuration: In the implementation of the rural decentralized sewage concentration and treatment method of the present invention, the improvement and beautification of the rural ecological environment are considered, and part of the landscape design is added.

First of all, PVC pipes are used to collect the drainage of rural distributed life and farming, that is, to ensure that rural sewage is not discharged through surface ditches, so dirty water cannot be seen on the surface. At the same time, each treatment unit of the ecological combined treatment engineering system has appropriate leak-proof, deodorizing, and landscaping treatments: specifically, it is sealed around and at the bottom of the grid pool and regulating pool, and the top is also sealed except for the sludge discharge port reserved for drainage. The sludge outlet is usually covered with a steel plate to prevent the overflow of odors; the upper layer of the horizontal flow biological filter is planted with foxtail algae, and the grown foxtail algae is dense, like a green carpet; the vertical flow biological filter is planted with tall canna Medium water bamboo and low iris form a three-dimensional landscape of high, medium and low levels; in the first-level surface flow constructed wetland, the long-growing and purple-flowered emergent plants barracuda and green carpet-like foxtail are planted respectively. Caucus; the second-level surface flow artificial wetland is planted with water spinach and watermelon in summer and autumn, and watercress and cress in spring and winter; plant calamus around the stable pond, and water lilies in the pond. The above-mentioned plants are planted together, beautifying the local environment and improving the living environment.

An ecological combined treatment device for realizing a kind of rural decentralized sewage, which includes: a main water inlet pipe 1, a grid pool 2, a regulating pool 3, a three-way water distribution and sampling pipe 4, and a horizontal flow biological Filter tank 5, straw 6, foxtail algae 7, filter screen-water distribution pipe 8, vertical flow biofilter 9, red soil 10, rice husk 11, wood fragments 12, horizontal perforated water collection pipe and 45 ^o C Upstream water pipe 13, constructed wetland 14 pike grass 15, drainage channel 16, overflow weir 17, second-level horizontal flow constructed wetland 18, aquatic economic plants 19 (cress, water spinach, watercress, watermelon, etc.), ─-shaped direct drainage pipe 20, stabilizing pond 21, aquatic plants 22 (calamus, water lily, etc.), ∟- shaped overflow main drainage pipe 23, first straw layer 24A, red soil layer 25, second straw layer 24B, rice husk layer 26 , broken wood block layer 27, first farmland soil layer 28A, second farmland soil layer 28B, stable pond bottom mud 29.

The connection relationship is as follows: the distributed villagers' living and breeding sewage are connected to the grid pool 2 and the regulating pool 3 through the main water inlet pipe 1 through the centralized pipe network, and the regulating pool 3 is connected to the grid pool 2 and the regulating pool 3 through the three-way water distribution and sampling pipe 4. Horizontal flow biofilter 5 is connected, and horizontal flow biofilter 5 is connected to vertical flow biofilter 9 through filter screen-water distribution pipe 8, and vertical flow biofilter 9 is connected to vertical flow biofilter 9 through horizontally placed perforated water collection pipe and 45 ^o C upward conveying The water pipe 13 is connected to the first-level surface flow constructed wetland 14, and the first-level surface flow constructed wetland 14 is connected to the second-level surface flow constructed wetland 18 through the overflow weir 17, and the second-level surface flow constructed wetland 18 is connected in the shape of "─". The direct-current drainage pipe 20 is connected to the stabilizing pond 21, and a “ ∟ ”-shaped overflow main drainage pipe 23 is installed at the end of the stabilizing pond 21, and the sewage from the regulating pond 3 enters through six horizontally arranged three-way water distribution and sampling pipes 4 arranged side by side. The horizontal flow biofilter 5 enters the vertical flow biofilter 9 through the filter screen-water distribution pipe 8, and the water from the vertical flow biofilter enters the first-stage surface through the horizontally placed perforated water collection pipe and the 45 ^o C upward water delivery pipe 13 Constructed wetland 14, the treated sewage enters the second-level surface flow constructed wetland 18 through the overflow weir 17. After the pollution is removed, the effluent enters the stabilization pond 21 through the "─" shaped direct current drainage pipe 20, and finally, the effluent flows through the " ∟ " shaped overflow The flow main drain pipe 23 discharges into the surrounding farmland. The detailed combination of the above-mentioned devices is: the main water inlet pipe 1 is the main pipeline where the rural domestic and aquaculture sewage is concentrated; the grid pool 2 and the regulating pool 3 carry out primary sedimentation and filtration of the collected rural domestic and aquaculture sewage; the horizontal flow biofilter 5 , the vertical flow biofilter 9, the first-level surface flow constructed wetland 14, the second-level surface flow constructed wetland 18, and the stabilization pond 21 are sewage purification functional units; the middle and lower layers of the horizontal flow biofilter 5 are placed with straw, and green plants are planted on the straw Foxtail algae, vertical flow biofilter 9 is filled in sequence from bottom to top with 0.4 m broken wood layer, 0.4 m rice husk layer, 0.3 m straw layer, and 0.3 m red soil layer. At the same time, canna is planted in the soil layer; the first stage In the surface flow constructed wetland 14, barracuda grass is planted in the front section, and green foxtail algae is planted in the back section. In the second surface flow constructed wetland 18, according to seasonal changes, water spinach and watermelon are planted in summer and autumn, and watercress and watercress are planted in spring and winter. ; Plant calamus around the stable pond, and plant water lilies in the pond. Each purification functional unit is connected through different connection methods such as "three-way" water distribution and water sampling pipe 4, filter sieve plate-water delivery pipe 8, horizontal perforated water collection pipe and 45 ^o C upward water delivery pipe 13, overflow weir 17. Connect with "─" shaped direct current drainage pipe. The "three-way" type water distribution and water sampling pipe 4 is set in the "three-way" mode, one channel enters the water in the regulating tank 3 into the horizontal flow biofilter 5, and the other outlet is used to collect water samples in the regulating tank. At the same time, through the setting 6 "three-way" type water distribution and water sampling pipes 4 to connect the water in the adjustment pool to the horizontal flow biofilter 5 evenly; Placed under the red soil layer of the vertical flow biofilter 9, the water is directly input below the soil layer; the horizontally placed perforated water collection pipe and the front end of the 45 ^o C upward water delivery pipe 13 pass through a perforated "horizontal pipe" to collect and filter the denitrification tank The treated sewage is led out into the surface flow constructed wetland 14 through a 45° inclined pipe; the overflow weir 17 with a length of 10 m and a width of 0.4 m is used to evenly input the treated sewage into the surface flow constructed wetland 14 of the first stage The second-level surface flow artificial wetland 18; finally, the effluent of the second-level surface flow artificial wetland 18 is connected to the stabilization pond 21 through a "─"-shaped straight-line drainage pipe 20, and finally through a " ∟ "-shaped overflow general drainage Pipe 23 discharges into the surrounding farmland.

5. Running effect:

Designed by the Institute of Subtropical Agroecology of the Chinese Academy of Sciences according to the method of the present invention, and supported by the "13th Five-Year" National Science and Technology Support Project, the "Rural Living and Breeding Sewage Ecological Treatment Experimental Demonstration Project" was built at the end of 2012. It is located in Gejiashan Village, Kaihui Town , put into use normally in March 2013. This demonstration project treats the domestic sewage and decentralized aquaculture sewage of farmers in a rural area of Gejiashan. During the one-year operation period, the monthly average concentrations of COD, total nitrogen, ammonia nitrogen and total phosphorus in the influent water were 362 mg/L, 197 mg/L, 133 mg/L and 20.15 mg/L respectively. The removal rate of COD, total phosphorus, total nitrogen and ammonia nitrogen is 50%~60%. After further advanced treatment in vertical flow biofilter and surface flow artificial wetland, the average concentration of COD, total nitrogen, ammonia nitrogen and total phosphorus in the pond effluent will be stabilized. They were 43 mg/L, 5.58 mg/L, 1.37 mg/L and 0.59 mg/L respectively. The average removal rate of each index reached 88%, 97%, 98% and 97%, and the sewage treatment effect was stable and up to standard. The whole project has the characteristics of "zero power" and "clean and safe", and the operation and management are simple and convenient. The invention has the advantages of strong purification ability for rural sewage, stability, low investment, and convenient management. It is suitable for the characteristics of rural decentralized life and aquaculture sewage discharge, and can be popularized and applied as an environmentally friendly mode of harmless and resourceful rural pollution. Improve the rural ecological environment.

6. Operating costs

(1) Power costs are 0 yuan/year; (2) Labor costs and maintenance and repair costs: labor costs are about 3,600 yuan/year (one daily maintenance person is required, responsible for silt removal, plant replanting, harvesting management, etc., monthly The salary is 300 yuan/month), and the total operating cost of the whole combination process is about 5,000 yuan a year.

Claims (7)

1. a kind of ecological combination treatment method of rural decentralized sewage, its steps are: A. Rural sewage collection and pre-treatment: Use PVC pipes to collect rural decentralized domestic and aquaculture sewage, establish a rural sewage collection pipe network, and then introduce the sewage into the grid pool through the general water pipeline, and the grid pool is used for filtration, Intercept suspended solids or floating solids larger than 2 cm, and at the same time carry out primary sedimentation of sewage. In the southern hilly area, the domestic or aquaculture sewage of farmers' settlements distributed at the foot of the mountain or on the side of the mountain is poured into the low place by gravity through pipelines at all levels. The grid pool, the grid pool effluent enters the regulating pool, and the regulating pool further settles the solid particles in the sewage, and microorganisms anaerobically degrade some organic matter in the sewage, and enters the horizontal flow biofilter through parallel pipelines; B. Biological filter treatment: the effluent from the regulating tank enters the horizontal flow biological filter, the horizontal flow biological filter is filled with straw, and the upper layer is cultivated with foxtail algae to form a straw-foxtail algae biofilter system, and the horizontal flow biological filter passes through the straw It shows that a large number of attached anaerobic-facultative anaerobic microorganisms and aerobic microorganisms in the rhizosphere of foxtail algae plants degrade, and the growth of foxtail algae itself absorbs nutrients, removes high-load nitrogen, phosphorus, COD and heavy metals in sewage, covers, absorbs and removes foul smell in sewage; The effluent from the horizontal flow biofilter enters the surface layer of the vertical flow biofilter through a single-channel water distribution pipe. The vertical flow biofilter system is composed of broken wood block layer, rice husk layer, straw layer and dry land red soil layer from bottom to top. At the same time, the soil Canna, iris, and water bamboo aquatic plants are planted in layers, and the biomass materials in the vertical flow biofilter treatment engineering unit: straw, rice husk, broken wood, wood shavings, and broken wood: size 0.5-10 cm, rice husk, straw These biomass materials provide a favorable environment for the growth of microorganisms. The abundant microorganisms on the surface of biomass materials can effectively degrade pollutants and purify water quality. The soil layer and canna, iris and water bamboo plants adsorb and absorb nitrogen, phosphorus and heavy metals respectively. Four layers of different materials are set in the flow biofilter at the same time to reduce the floor area. At the bottom of the vertical flow biofilter, wood chips are used: the layer of wood chips filled with a size of 0.5-10 cm is set with a horizontal perforated pipe to collect water. The water pipe is wrapped with gravel piles of 10-30 mm in size to prevent clogging, and at the same time, it is connected to the slanted upward water diversion pipe, and the vertical flow biofilter discharges water into the first-level surface flow artificial wetland through the outlet system; C. Constructed wetland and stabilization pond treatment: Constructed wetlands of this level are surface flow, and the wetland substrate is soil. Wetland plants choose barracuda and pink green foxtail. The water inlet of the wetland is first planted with emergent plants barracuda and barracuda The submerged plant is planted in the rear, and the first-grade artificial wetland can withstand 400 mg/L ammonia nitrogen pollution, the surface flow at a water depth of 5-30 cm, and the aerobic environment formed by the rhizosphere of barracuda and foxtail plants. , to further promote the decomposition of organic pollutants and the process of nitrification and denitrification. At the same time, plants grow and absorb a large amount of nitrogen and phosphorus nutrients. Oxygen content to ensure that COD, nitrogen, and phosphorus in the water body are deeply removed in the second-level constructed wetland, and the water discharged from the first-level constructed wetland contains moderate concentrations: 20 mg/L ammonia nitrogen and 2 mg/L phosphate nitrogen and phosphorus Nutrients, providing nutrients for the cultivation of aquatic economic vegetables in the second-level constructed wetlands, planting aquatic vegetables in the second-level surface flow constructed wetlands, planting water spinach, water celery, wild rice stems, watercress and water chestnuts, passing through the second-level constructed wetlands After further in-depth purification treatment of nitrogen and phosphorus pollution in the water body, it is discharged into the stabilization pond. The water in the first half of the stabilization pond is 0.4-0.7 m, and the water in the second half is 0.9-1.1 m. Aquatic calamus and water lilies are planted at the front and rear ends respectively. After further treatment in the stabilization pond, the effluent meets the requirements for safe discharge water quality; D. Ecological landscape configuration: Improve the landscaping design of the rural ecological environment in the rural decentralized sewage concentration and treatment method, so that no sewage can be seen or smelled on the surface of the treatment area, and the beautification of the rural living environment can be realized: First of all, rural sewage is collected by PVC pipe network, and the sewage cannot be seen in the surface environment; secondly, each treatment unit of the ecological combined treatment engineering system has been treated for leak prevention, deodorization, and landscaping. Covering, no sewage can be seen and no smell; the third is to plant foxtail algae on the upper layer of the horizontal flow biofilter to cover the sewage and deodorize at the same time; the fourth is to plant canna and iris on the upper soil layer of the vertical flow biofilter and water bamboo; fifthly, in the first-level surface-flow artificial wetland, we planted the long-flowering barracuda and green foxtail algae in the growth period, and the second-level surface-flow artificial wetland planted water spinach in spring, summer and autumn. , watermelon, water chestnuts, and watercress and cress in winter; the sixth is to plant calamus around Stable Pond, and water lilies in the pond. The combination of the above plants beautifies the local environment and improves the living environment. 2. The ecological combined treatment device of a kind of rural decentralized sewage according to claim 1, which comprises: the main water inlet pipe (1), the grid pool (2), the regulating pool (3), the horizontal flow biological filter ( 5), filter screen-water distribution pipe (8), vertical flow biofilter (9), horizontal perforated water collection pipe and 45 ^o C upward water delivery pipe (13), first-level horizontal flow constructed wetland (14), The overflow weir (17), the second-level surface flow artificial wetland (18), the stabilization pond (21), and the ∟- shaped overflow main drainage pipe (23), are characterized in that the distributed villagers' living and breeding sewage are concentrated through the pipe network The main water inlet pipe (1) is connected to the grid pool (2) and the adjustment pool (3) respectively, and the adjustment pool (3) is connected to the horizontal flow biological filter ( 5) connected, the horizontal flow biofilter (5) is connected to the vertical flow biofilter (9) through the filter screen-water distribution pipe (8), and the vertical flow biofilter (9) is connected through the horizontally placed perforated water collection pipe and 45 ^o The C upward water pipe (13) is connected to the first-level surface flow constructed wetland (14), and the first-level surface flow constructed wetland (14) is connected to the second-level surface flow constructed wetland (18) through the overflow weir (17) , the second-level surface flow constructed wetland (18) is connected to the stabilization pond (21) through the ─-shaped direct drainage pipe (20), and the ∟ -shaped overflow main drainage pipe (23) is installed at the end of the stabilization pond (21). 3. The ecological combined treatment device for rural decentralized sewage according to claim 2, characterized in that: the middle and lower layers of the horizontal flow biological filter (5) are placed with straw, and green foxtail algae are planted on the straw. 4. The ecological combination treatment device for rural decentralized sewage according to claim 2, characterized in that: the vertical flow biological filter (9) is sequentially filled with 0.4 m wood fragment layer, 0.4 m of rice husk layer, 0.3 m of straw layer, 0.3 m of red soil layer, planting canna in the soil layer. 5. An ecological combination treatment device for rural decentralized sewage according to claim 2, characterized in that: the front section of the first-level surface flow artificial wetland (14) is planted with pike grass and the back section with green foxtail algae. 6. The ecological combined treatment device for rural decentralized sewage according to claim 2, characterized in that: in the second-level surface flow artificial wetland (18), water spinach and watermelon are planted in summer and autumn, and water melons are planted in spring. , Planting watercress and cress in winter. 7. The ecological combination treatment device for rural decentralized sewage according to claim 2, characterized in that: calamus is planted around the stabilization pond (21), and water lilies are planted in the pond.

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