CN202099163U - Combined layering biological filter for sewage treatment - Google Patents

Abstract

A combined layered biofilter for sewage treatment in the technical field of sewage treatment, including: a sump, a combined layered biofilter, an intermediate pool and a horizontal subsurface wetland, wherein: the sump, the biofilter, The intermediate pool and the horizontal subsurface wetland are connected in series in sequence. This device uses layered biofilter to pretreat the organic matter, suspended matter and ammonia nitrogen in the sewage, and uses the artificial wetland to further treat the nitrogen, phosphorus and remaining organic matter in the sewage, and achieve purification through comprehensive physical, chemical and biological effects. water quality purposes. When the traditional biological filter process is used alone, the treated effluent can reach the second-class standard. The combined process application example provided by this device has all the indicators of effluent water quality tested. Class I B standard, the area occupied by a ton of water is about 3.5m ² .

Description

Combined layered biological filter for sewage treatment

technical field

The utility model relates to a device in the technical field of sewage treatment, in particular to a combined layered biofilter used for sewage treatment in villages and towns.

Background technique

Domestic sewage in villages and towns is one of the important sources of non-point source pollution in vast rural areas. More than 95% of villages and more than 90% of small market towns in my country do not have perfect sewage collection and treatment facilities. After any treatment, it is directly discharged into water bodies (rivers, ponds, groundwater, etc.), causing serious pollution of water bodies in villages and towns. Black and smelly rivers, ponds and eutrophic lakes have become a common phenomenon.

Domestic sewage treatment in villages and towns has the following characteristics: 1) Wide area, scattered, large fluctuations in water quality and water volume, and unsound drainage network; 2) The economic strength of villages and towns is weak, and sewage treatment technology or process requires low investment and low energy consumption , low operating costs; 3) There is a lack of sewage treatment professionals in villages and towns, and the treatment facilities should be simple to operate and manage, and easy to maintain; 4) There is a lack of targeted advanced and applicable sewage treatment technologies, and it is not appropriate to adopt more mature urban sewage processes in villages and towns sewage treatment , and some so-called ecological processes often cannot meet the treatment requirements, or lack the conditions for implementation (such as land resources). Therefore, it is necessary to adopt some advanced and applicable technologies with simple process, good treatment effect, low land occupation, low energy consumption, simple operation and management, and less secondary pollution, and use a decentralized treatment mode.

At present, for the decentralized treatment of village and town sewage, three major types of technologies and processes are mainly used at home and abroad. One is to learn from the successful experience of secondary biochemical treatment in urban sewage treatment plants, miniaturize some traditional secondary biochemical treatment processes in urban sewage treatment plants, and apply them to decentralized sewage treatment in villages and towns. Such as SBR, oxidation ditch, A/O, even A2/O, MBR and so on. From a technical point of view, these technologies and processes are relatively mature and can meet the requirements of sewage treatment. However, these technologies and processes are usually more complicated and require more equipment. Therefore, the investment is relatively large, the system maintenance and management are more complicated, the energy consumption and operation management costs are high, and some secondary pollution problems may also occur. Such a processing system is very incompatible with the actual social and economic conditions of our country's villages and towns. As a result, a large amount of investment has been spent, and the built sewage treatment plant (station) is in a state of abnormal operation or out of operation due to high operating costs, lack of normal maintenance and management, and other reasons.

The second category is to adopt some relatively simple ecological sewage treatment technologies, including artificial wetlands, oxidation ponds, and land treatment systems. The advantages of this type of technology are simple process, small investment, low energy consumption, easy maintenance, and environmental friendliness, etc. The disadvantage is that the treatment efficiency is low, and it usually takes certain conditions to achieve stable treatment effects and maintain the long-term normal operation of the system. Such as lower hydraulic load and organic load and longer HRT, which requires a larger land area that can be used.

The third category is anaerobic treatment technology. The anaerobic treatment system based on anaerobic reactor is a low-cost wastewater treatment technology that can recycle energy at the same time. For rural domestic sewage treatment, human and animal manure, crop stalks, weeds, leaves and organic wastewater from agricultural product processing enterprises can be added to the anaerobic digester for anaerobic treatment at the same time as domestic sewage, and the generated biogas can be used For bathroom and home energy. Sewage anaerobic biogas production technology has been effectively promoted and used in some places in my country. However, the anaerobic sewage treatment technology alone cannot make the treated effluent meet the discharge requirements, and subsequent treatment must be carried out.

In addition, the development of small and medium-sized sewage treatment integrated devices integrating pretreatment, secondary treatment and advanced treatment is a trend in the development of sewage decentralized treatment at home and abroad, and has broad application prospects in rural domestic sewage treatment. The integrated device studied in Japan mainly adopts the combined process of anaerobic-aerobic-secondary sedimentation tank, which has the functions of degrading organic matter and denitrification, and its effluent BOD5<20mg/L, TN<20mg/L. The membrane treatment technology developed in recent years can carry out advanced treatment of BOD5 and TN. Many countries in Europe have developed small sewage treatment integrated devices based on SBR, moving bed biofilm reactor, biological turntable and trickling filter technology combined with chemical phosphorus removal. However, this type of integrated device also has problems such as high energy consumption and complicated operation and management, and its scope of application needs to be further expanded.

In the prior art, the decentralized sewage treatment process can meet the pollutant discharge standard of urban sewage treatment plants (GB18918-2002) or the national farmland irrigation water quality standard (GB5084-2005). However, these technologies or processes have the following limitations and deficiencies:

1. The process is complicated and there are too many treatment units, which increases the difficulty of construction, construction and management. The multiple backflows between the filter tank and the anaerobic tank increase the cost of capital construction and operation management.

2. Most of the wetlands are surface flow wetlands. Although they are easy to construct, they have poor sanitary conditions and too long hydraulic retention time, resulting in a large project area, which is easily restricted in use and promotion.

3. A large number of earthworms are added to the earthworm biofilter. Since earthworms are easily affected by environmental factors and sewage water quality, they need to be added regularly, which is difficult to maintain.

Utility model content

Aiming at the above-mentioned deficiencies in the prior art, the utility model provides a combined layered biological filter for sewage treatment. The layered biological filter is used to pretreat the organic matter, suspended matter and ammonia nitrogen in the sewage. Constructed wetlands further process nitrogen, phosphorus and remaining organic matter in sewage, and achieve the purpose of purifying water quality through comprehensive physical, chemical and biological effects. When the traditional biofilter process is used alone, the effluent can reach the secondary standard. If the traditional artificial wetland is used to treat domestic sewage alone, more than 10m ² of land is required for processing 1m ³ of sewage. In the combined process application example provided by this device, all indicators of effluent water quality have been tested to be superior to the first-level B standard of "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB 18918-2002), and the area per ton of water is about 3.5m ² .

The utility model is realized through the following technical solutions, and the utility model comprises: a sump pond, a biological filter pond, an intermediate pond and a horizontal submerged wetland which are sequentially connected in series.

The lower end of the intermediate pool is provided with a return port and is connected with the sump.

The sump is a two-form reinforced concrete structure, and the volume distribution ratio along the direction of water flow is 2:1.

The sump is equipped with a grille, an automatic liquid level controller and a submersible sewage pump, wherein: the grille is located on the retaining wall between the two grids of the sump, and the automatic liquid level controller and the submersible sewage pump are placed on the grille In the water grid behind.

The mesh of the grid is less than 10mm, and the area is greater than or equal to 1.0m ² .

The biological filter comprises from top to bottom: a water distribution device, a filter bed composed of a first pool body and a filter material, and a drainage system, wherein: the filter bed is a layered frame structure, and the height of a single layer is 40-50cm. Interlayer spacing is greater than or equal to 50mm.

The filter material is volcanic rock biological filler, ceramsite and phosphorus removal filler.

The intermediate pool includes: a second pool body, a water distribution system and a return pipe, wherein: the effective water depth of the second pool body is greater than or equal to 2.0m, and the water distribution system with a triangular weir is located at the water outlet end of the second pool body and distributes the water evenly It is divided into several parts and flows into the wetland respectively and returns to the sump through the return pipe.

The horizontal subsurface wetland comprises, from bottom to top, an anti-seepage layer, a filling layer, a soil layer, a water-resistant plant layer, and a water distribution channel.

Under human control, the comprehensive action of physics, chemistry and biology in the ecosystem composed of substrate-microbe-plant completes the denitrification of sewage nitrogen, adsorption of phosphorus and removal of remaining organic matter, etc., and the effluent of the constructed wetland is discharged from the system through the outlet pipe . In order to improve the treatment effect of the system, part of the effluent from the middle pool can be returned to the sump.

The device works in the following way: the domestic sewage enters the sump after passing through the grille, and is automatically lifted by the pump to the combined layered biological filter, where it fully contacts with the biofilm, and the pollutants are absorbed and degraded by microorganisms; the filter Part of the effluent flows back to the sump after sedimentation, and the rest enters the constructed wetland system, where organic matter, nitrogen and phosphorus are further removed under the joint action of filler-soil-plants, and the effluent is discharged into nearby water bodies after reaching the standard.

Compared with the prior art, this device has the following advantages and beneficial effects:

(1) The layered biofilter and artificial wetland are used for process combination. After the combination, each unit can complement each other while playing its own role, thereby improving the overall effect.

(2) The layered biological filter has good ventilation conditions and strong oxygenation capacity. As a pre-treatment of artificial wet, it improves the impact resistance of the whole process to domestic sewage, and can effectively reduce organic matter and suspended matter in sewage, and generate ammonia nitrogen. The nitrification provides convenience, and greatly reduces the pollution load and floor area of the subsequent constructed wetland (1/3 to 1/2 of the traditional constructed wetland).

(3) Subsurface flow wetlands use aerated concrete with a particle size of 30-50mm as the filler. The filler is made of 70% fly ash, 15% quicklime, 10% cement, 3% phosphogypsum and 2% others. Inflated and compressed, on the one hand, it has strong adsorption performance on phosphorus, which can effectively reduce the total phosphorus content in sewage; on the other hand, the large specific surface area of the filler is easy for microbial film growth, and can effectively remove organic matter and nitrogen in sewage at the same time Phosphorus; third, the use of large particle size fillers is beneficial to improve the water passing capacity of the system, overcomes the shortcomings of traditional wetlands that are easy to block, and can run stably for a long time. Compared with the existing technology, the removal rate of nitrogen and phosphorus of the system has been significantly improved, the removal rate of total nitrogen is 50-60%, the removal rate of total phosphorus is 70-80%, and it has less land occupation and infrastructure investment , easy to manage.

Description of drawings

Figure 1 is a top view of the device;

Fig. 2 is the schematic diagram of embodiment application;

Figure 3 is a cross-sectional view of the filter.

Detailed ways

The embodiment of the device is described in detail below. This embodiment is implemented on the premise of the technical solution of the device, and the detailed implementation and specific operation process are provided, but the protection scope of the device is not limited to the following implementation example.

Example 1. Sewage treatment project in Caojiabang Village, Maogang Town, Songjiang District, Shanghai

The designed treatment scale of the project is 60m ³ /d, covers an area of 250m ² , serves a population of about 900, and collects and treats domestic sewage from about 235 villagers.

This embodiment includes: a sump 1 , a biofilter 2 , an intermediate pool 3 and a horizontal subsurface wetland 4 connected in series in sequence, and no backflow is provided in this example.

The lower end of the intermediate pool 3 is provided with a return port 5 and is connected with the sump 1 .

The sump 1 is a reinforced concrete structure with two formats, and the volume distribution ratio along the direction of water flow is 2:1.

The sump 1 is provided with a grille 6, an automatic liquid level controller 7 and a submersible sewage pump 8, wherein: the grille 6 is located on the retaining wall between the two grids of the sump 1, and the automatic liquid level controller 7 and The submersible sewage pump 8 is placed in the water grid behind the grid 6 .

The mesh of the grid 6 is less than 10mm, and the area is greater than or equal to 1.0m ² .

The biological filter 2 includes from top to bottom: a water distribution device 9, a filter bed 12 composed of a first pool body 10 and a filter material 11, and a drainage system 13, wherein: the filter bed 12 is a layered frame structure, The height of a single layer is 40-50cm, and the distance between layers is greater than or equal to 50mm.

The filter material 11 is volcanic rock biological filler, ceramsite and phosphorus removal filler.

The intermediate pool 3 includes: a water distribution system 14, a return pipe 15 and a second pool body 16, wherein: the effective water depth of the second pool body 16 is greater than or equal to 2.0m, and the water distribution system 14 with a triangular weir is located in the second pool body 16 the water outlet and divide the water into several parts and flow into the wetland respectively and return to the sump 1 through the return pipe 15 .

The horizontal subsurface flow wetland 4 includes, from bottom to top, an anti-seepage layer 17 , a filler layer 18 , a soil layer 19 , a water-resistant plant layer 20 , an inlet distribution channel 21 and an outlet channel 22 .

The pool 1 has an effective volume of 15m ³ and an effective water depth of 1.0m. The filter tank is divided into 6 layers, and the hydraulic load is 4m ³ /m ³ .d. The filter tank uses volcanic rock, ceramsite and phosphorus removal filter material 11 composite filter material 11. The effective volume of the middle pool 3 is 7.5m ³ , and the hydraulic retention time is 3h. The effective area of the constructed wetland is 180m ² , the hydraulic load is 0.33m ³ /m ² .d, the filler layer 18 is 0.6m thick, aerated concrete is used, the soil layer 19 is 30cm thick, and ryegrass is planted on top. The project was completed and put into operation at the end of October 2007, and has been in stable operation for three and a half years. The project operation is fully automated, the management is simple, no special personnel are required to be on duty, and only regular inspections are required. The operating cost is mainly, and the operating cost per ton of water does not exceed 0.1 yuan.

The average removal rate of ammonia nitrogen, total nitrogen and total phosphorus in Caojiabang domestic sewage treatment project is 75%, 65% and 70%; the effluent concentration is below 60mg/L, 8mg/L and 0.8mg/L respectively, and the effluent has reached the "urban Discharge Standard of Pollutants for Sewage Treatment Plants (GB 18918-2002) Level B Standard.

Example 2: Sewage Treatment Demonstration Project in Pailou Village, Hangtou Town, Pudong New Area, Shanghai

The project design treatment scale is 60m ³ /d, covers an area of 210m ² , and consumes 0.1kWh/m ³ power, serving 350 villagers in Pailou Village and one modern ecological farm.

This embodiment includes: a sump 1, a combined layered biofilter 2, an intermediate pool 3 and a horizontal submerged wetland 4, wherein: the sump 1, the biofilter 2, the intermediate pool 3 and the horizontal submerged wetland 4 are connected in series in sequence The end of the middle pool 3 is provided with a return port and is connected with the sump 1. The effective volume of the sump is 20m ³ , and the effective water depth is 1.0m. The filter tank is divided into 6 layers, the hydraulic load is 4m ³ /m ³ .d, and the composite filter material of volcanic rock, ceramsite and phosphorus removal filter material is used. The effective volume of the middle pool is 7.5m ³ , and the hydraulic retention time is 3h. The effective area of the constructed wetland is 150m ² , the hydraulic load is 0.4m ³ /m ² .d, the thickness of the filler layer is 0.8m, aerated concrete is used, the soil layer is 30cm thick, and turf and shrubs are planted on it. It was officially put into operation at the end of May 2009. After the combined process is put into operation and treated by the system, COD can be reduced by 21.18t, ammonia nitrogen by 1.24t, and total phosphorus by 0.22t every year. The effluent COD, ammonia nitrogen, and total phosphorus can all meet the first-level B standard of the "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB 18918-2002).

Example 3: Sewage Treatment Demonstration Project in Gangyan Town, Chongming County, Shanghai

The domestic sewage collection and treatment project in Jizhen District, Gangyan Town, Chongming County has a designed sewage collection and treatment scale of 500m ³ /d, serving a population of 4,380 people, a total area of 1,300m ² , a length of 130m from north to south, and a width of 10-11.5m from east to west.

This embodiment includes: a sump 1, a combined layered biofilter 2, an intermediate pool 3 and a horizontal submerged wetland 4, wherein: the sump 1, the biofilter 2, the intermediate pool 3 and the horizontal submerged wetland 4 are connected in series in sequence connection, this example does not set backflow. The effective volume of the sump is 120m ³ , and the effective water depth is 1.0m. The filter covers an area of 100m ² , the filter bed is divided into 7 layers, the hydraulic load is 4m ³ /m ³ .d, and the composite filter material of volcanic rock, ceramsite and phosphorus removal filter material is used. The effective volume of the middle pool is 62.5m ³ , and the hydraulic retention time is 3h. The effective area of the constructed wetland is 1100m ² , the hydraulic load is 0.45m ³ /m ² .d, the filler layer is 0.8m thick, aerated concrete is used, the soil layer is 30cm thick, and ryegrass is planted on top. The project was officially put into operation in October 2009. The operating cost per ton of water is not more than 0.15 yuan.

After combined process treatment, the effluent concentrations of COD, ammonia nitrogen, and total phosphorus are less than 56mg/L, 12mg/L, and 0.9mg/L respectively, all of which have reached the first level of the "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB 18918-2002) B standard.

Claims (9)

1. A combined layered biofilter for sewage treatment, characterized in that it comprises a sump, a biofilter, an intermediate pond and a horizontal underflow wetland connected in series in succession. 2. The combined layered biofilter for sewage treatment according to claim 1, characterized in that, the lower end of the intermediate pool is provided with a return port and is connected to the sump. 3. The combined layered biofilter for sewage treatment according to claim 1, characterized in that the sump is a two-frame reinforced concrete structure, and the volume distribution ratio along the water flow direction is 2:1. 4. The combined layered biofilter for sewage treatment according to claim 1, 2 or 3, characterized in that a grid, an automatic liquid level controller and a submersible sewage pump are arranged in the sump , wherein: the grid is located on the retaining wall between the two grids of the sump, and the automatic liquid level controller and submersible sewage pump are placed in the water grid behind the grid. 5 . The combined layered biofilter for sewage treatment according to claim 4 , wherein the mesh of the grid is less than 10 mm, and the area is greater than or equal to 1.0 m ² . 6. The combined layered biofilter for sewage treatment according to claim 4, wherein the biofilter comprises from top to bottom: a water distribution device, a first pool body and a filter The filter bed and drainage system are composed of materials, wherein: the filter bed is a layered frame structure, the height of a single layer is 40-50cm, and the distance between layers is greater than or equal to 50mm. 7. The combined layered biofilter for sewage treatment according to claim 6, wherein the filter material is volcanic rock biological filler, ceramsite and phosphorus removal filler. 8. The combined layered biofilter for sewage treatment according to claim 1, characterized in that, the intermediate pool comprises: a second pool body, a water distribution system and a return pipe, wherein: the second pool body The effective water depth is greater than or equal to 2.0m. The water distribution system with a triangular weir is located at the water outlet of the second pool and divides the water into several parts, which flow into the wetland and return to the sump through the return pipe. 9. The combined layered biofilter for sewage treatment according to claim 1 or 2, characterized in that the horizontal subsurface wetland sequentially comprises from bottom to top: anti-seepage layer, filler layer, soil layer, water-resistant plant layer and outlet cloth canal.

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