CN108275782B - Integrated three-dimensional wetland sewage treatment effluent TN control device and method - Google Patents

Abstract

The invention provides an integrated three-dimensional wetland sewage treatment effluent TN control device and method, wherein the treatment device comprises a sewage pretreatment area, a horizontal flow wetland sewage purification area, a vertical flow wetland sludge purification area and a vertical flow sewage purification area, wherein the horizontal flow wetland sewage purification area and the vertical flow wetland sludge purification area are arranged above the sewage pretreatment area in parallel; the vertical flow sewage purification area is arranged on the side edge and is separated by a concrete structure, the vertical flow sewage purification area is sequentially provided with a rubble layer, a natural vermiculite layer, a river sand layer and a biological filler ball layer from top to bottom, each layer is assembled in a modular manner, and the filling ratio of the biological filler balls in the biological filler ball layer is 20% -65%. The device can reduce the nitrogen content in the sewage and reduce the harm of harmful substances in rural domestic drainage to the surrounding water environment. The method has the advantages of small occupied area, stable treatment effect, convenient operation and management and no secondary pollution, and is suitable for various sewage treatments.

Description

Integrated three-dimensional wetland sewage treatment effluent TN control device and method

Technical field

The invention belongs to the technical field of sewage treatment, and specifically relates to an integrated three-dimensional wetland sewage treatment effluent TN control device and method, which can reduce the content of nitrogen, phosphorus and organic matter in domestic sewage, thereby protecting the water environment, and is especially suitable for rural areas in my country.

Background technique

China is a large agricultural country with a large population. The per capita water resources are about 2200m ³ , which is less than 1/4 of the world average. There is a serious shortage of water resources. With the continuous improvement of my country's economic level and the improvement of people's living standards, the resulting deterioration of the water environment has also attracted people's attention. However, people only focus on the water environment problems in cities, thus ignoring the water pollution conditions in rural areas, especially the domestic sewage problems in rural areas.

Kitchen sewage, cleaning sewage, toilet bathing sewage, etc. discharged by residents in rural areas in their daily lives are collectively referred to as rural domestic sewage. Compared with the domestic sewage of urban residents, due to the simple lifestyle of rural residents and low per capita water consumption, the overall sewage discharge in rural areas is much lower than that in urban areas. This makes the problem of domestic sewage treatment in rural areas of my country not addressed. The local government pays enough attention. Moreover, the water supply facilities in rural areas of our country are too crude, and tap water is not fully popularized, resulting in rural domestic sewage causing serious pollution to the surrounding environment. At the same time, the distribution of residential areas in rural areas of our country is irregular, which makes domestic sewage in rural areas highly dispersed and random, making it difficult to use centralized sewage treatment methods like urban areas. Moreover, the quality of sewage in rural areas fluctuates greatly. It generally does not contain heavy metals and toxic and harmful pollutants, and only contains a certain amount of nitrogen and phosphorus. At the same time, domestic sewage in rural areas in my country has strong biochemical properties, and the pollution concentration of sewage is relatively high. Low.

The area of rural areas in my country accounts for about 90% of the country's total area, and the total discharge of domestic sewage in rural areas accounts for more than 20% of the total discharge of domestic sewage in the country. In our country, rural residents have no awareness of environmental protection, and daily sewage is usually discharged directly into surrounding rivers or lakes without treatment. This not only causes serious eutrophication of rivers, lakes and other water bodies in rural areas, but also affects the living environment of rural residents. It has been seriously polluted, which is very detrimental to the healthy life of residents in rural areas.

At present, constructed wetlands have been widely used in water treatment. A composite constructed wetland treatment system was disclosed in 201410150093.6. Its characteristic is that the vertical flow constructed wetland treatment tank is set at the water inlet end of the system, and the subsurface flow constructed wetland treatment tank is set at the system. At the water outlet end, the system also includes a water distribution tank with a diversion wall set up inside the water distribution tank. The water distribution tank is located at the water inlet end of the system, and its water outlet is connected to the water inlet pipe of the vertical flow constructed wetland treatment pool in the vertical flow constructed wetland treatment pool. The fillers are coarse-grained filler layer, medium-grained filler layer and fine-grained filler layer from bottom to top. This treatment system does not consider the problem of filler clogging. When replacing the filler, the amount of infrastructure work is large and the construction is complicated. 201610873243.5 discloses a high-efficiency purification system for artificial wetlands, which is characterized by being composed of 3 to 5 processing units. Each processing unit consists of a filter body, plants, organic layer, first filtration layer, second filtration layer, biological layer, and three filtration layers. It is composed of an anti-seepage plate and the filter body is located on the side of the water inlet of the treatment unit. An anti-seepage layer is installed at the bottom of each treatment unit. Anti-seepage walls are installed at both ends. The sewage or low-pollution water that needs to be purified enters the constructed wetland through the water inlet pipe and undergoes various treatments in turn. The unit is then purified and finally discharged into the collection tank through the outlet pipe. This method has a single treatment method. When the temperature is low in winter, the artificial wetland operation efficiency is low and the treatment effect is not stable enough.

The invention occupies a small area, has stable treatment effect, is convenient for operation and management, has no secondary pollution, and is suitable for various types of sewage treatment.

Contents of the invention

The purpose of this invention is to address the problem of rural domestic sewage pollution control and provide an integrated three-dimensional wetland sewage treatment effluent TN control device and method to reduce the content of harmful substances such as nitrogen, phosphorus and organic matter in rural domestic sewage by treating rural household sewage. In order to avoid eutrophication of rivers, lakes and other water bodies, and protect the ecological environment around rural areas.

Technical solution: In order to achieve the above technical objectives, the present invention proposes an integrated three-dimensional wetland sewage treatment effluent TN control device. The treatment device includes a sewage pretreatment area, a horizontal flow wetland sewage purification area, and a vertical flow wetland sludge purification area. and a vertical flow sewage purification area, wherein the horizontal flow wetland sewage purification area and the vertical flow wetland sludge purification area are arranged side by side above the sewage pretreatment area, and the horizontal flow wetland sewage purification area and the vertical flow wetland sewage purification area are arranged side by side above the sewage pretreatment area. There is a matrix layer below the mud purification area. The matrix layer of the horizontal flow wetland sewage purification area and the vertical flow wetland sludge purification area is separated from the sewage pretreatment area by a concrete structure; the horizontal flow wetland sewage purification area is for preliminary purification of sewage. For treatment, the vertical flow wetland sludge purification area is used to dry the suspended solids, sediment and other impurities in the sewage. The vertical flow sewage purification area is arranged on the side of the horizontal flow wetland sewage purification area, the vertical flow wetland sludge purification area and the sewage pretreatment area and is separated by a concrete structure. The vertical flow sewage purification area is arranged from top to bottom. There are gravel layer, natural vermiculite layer, river sand layer and biological filler ball layer in sequence. Each layer is assembled in a modular manner. According to different effluent water quality requirements and different temperature conditions, the biological filler in the biological filler ball layer The filling ratio of the ball can be set from 20% to 65%. Specifically, when the temperature is >12°C, different filling ratios of the biofiller ball area can be selected to achieve different surface water environmental quality standards. At a filling ratio of 45%, TN can reach the surface water environmental quality Class V standard; at a filling ratio of 60%, TN can reach the surface water environmental quality Class IV standard. When the temperature is <12°C, the treatment efficiency of constructed wetlands is low, and the filling ratio needs to be increased to achieve the required water quality standards. When the filling ratio is less than 60%, TN cannot meet the surface water environmental quality Class V standard; at a filling ratio of 60%, TN can meet the surface water environmental quality Class V standard. The maximum filling ratio must not exceed 65%.

Wherein, the sewage pretreatment area is a regulating tank, and a sludge pump, a sewage pump and an air pump are provided in the regulating tank. The impurities deposited at the bottom of the regulating tank are pumped to the upper vertical flow wetland sludge by the sludge pump. The purification area prevents clogging of the vertical flow sewage purification area and can utilize resources at the same time. The sewage in the regulating tank is pumped by the sewage pump to the horizontal flow wetland sewage purification area, and then processed through the vertical flow sewage purification area; the air pump oxygenates the river sand layer and the biological filler ball layer through the pipeline.

Preferably, the volume ratio of the sewage pretreatment area, horizontal flow wetland sewage purification area, vertical flow wetland sludge purification area and vertical flow sewage purification area is (0.9~1.08): (0.48~0.675): (0.06~0.15 ):1.

The size of the integrated three-dimensional wetland sewage treatment device is designed to be any one of 3m×4m×4m, 4m×5m×4m, or 5m×6m×4m.

The horizontal flow wetland sewage purification area and the vertical flow wetland sludge purification area are separated by plastic partitions, and aquatic plants are planted in both the horizontal flow wetland sewage purification area and the vertical flow wetland sludge purification area.

The gravel layer, natural vermiculite layer, river sand layer and biological filler ball layer are separated by steel wire mesh respectively. The volume ratio of the gravel layer, natural vermiculite layer, river sand layer and biological filler ball layer is ( 0.4～1): (0.6～1): (0.8～1): (1.2～2).

The river sand layer and biological filler ball layer are aerated and oxygenated through an air pump, with an aeration intensity of 1.5 to 2.0 m ³ /m ² ·h.

The substrate layer of the horizontal flow wetland sewage purification area and the vertical flow wetland sludge purification area is cinder, the depth of the substrate is designed to be 10-30 cm, and the aquatic plants are wild rice or cress. Preferably, the planting density of aquatic plants is more than 16 plants per square meter. Preferably, the coal slag has a particle size of 4 to 6 mm and a specific surface area of 0.25 to 0.35 m ² /g.

The particle size of the gravel layer is 5-10mm; the particle size of the natural vermiculite layer is 2-5mm, the specific surface area is ^400-600m2 /g, and the pore volume is ^0.2-0.4cm2 /g; The particle size of the river sand layer is 2 to 4 mm; the biological filler ball layer is a spherical filler ball with a raised surface made of polyethylene or polypropylene plastic, with a surface area of 800 to 2500 m ² /m ³ and a density of 2 to 4 kg /m ³ , diameter is 0.04~0.06m. The present invention further proposes the above-mentioned integrated three-dimensional wetland sewage treatment device for sewage treatment method, which includes the following steps:

First, all the sewage is discharged into the regulating tank. The sewage is adjusted and initially settled in the regulating tank. The impurities settle at the bottom and are pumped to the upper vertical flow wetland sludge purification area by the sludge pump. The sewage in the regulating tank is pumped to the horizontal by the sewage pump. The wetland sewage purification area is purified through the gravel layer, natural vermiculite layer, river sand layer and biological filler layer in the vertical segmented purification area in sequence; when the temperature is <12°C, most plants die and microbial activity Reduced, the treatment efficiency of constructed wetlands is low, and the filling ratio of the biological filler ball layer can be increased to improve its purification effect.

The integrated wetland sewage treatment device of the present invention is installed in a rural family courtyard. Domestic sewage is first discharged into the regulating tank, and then pumped to the two subdivisions of the micro-constructed wetland by pumps. The sewage passes through the horizontal flow wetland sewage purification area, and then passes through the vertical flow in turn. The gravel, natural vermiculite, river sand and biological purification balls in the sewage purification area are purified. When the temperature is low in winter, the treatment efficiency of constructed wetlands is low, and sewage can be pumped directly to the vertical flow sewage purification area for purification treatment. After the purification device has been running for a period of time, the filler in the vertical flow sewage purification area can be easily replaced and processed through the openable door on one side. In this way, the device can effectively treat sewage for a long time.

Advantages of the invention:

(1) This invention adopts a compact integrated three-dimensional structure, which reduces the floor area by more than 40% and the investment cost by more than 20% compared with traditional artificial wetlands. It has the advantages of small floor space, low investment, convenient operation management and maintenance. advantage;

(2) The filter material in the vertical flow sewage purification area of the integrated three-dimensional artificial wetland device of the present invention is replaceable and uses cinder. Compared with traditional artificial wetlands, the operating cost is reduced by more than 30%, and it is more suitable for various kinds of sewage;

(3) The integrated three-dimensional artificial wetland device of the present invention adopts step-by-step treatment in different zones. The SS removal rate is more than 90%, the nitrogen and phosphorus removal rate is more than 80%, and the sludge is also reduced by 100%, without causing secondary pollution. Reasonable spatial layout delays wetland clogging and improves the film-hanging effect and microbial degradation of filter materials. When the temperature is <12°C, the filling ratio can be adjusted to enhance the treatment effect and improve the stability of effluent TN.

Description of drawings

Figure 1 is a cross-sectional view of the frame of the integrated three-dimensional wetland sewage treatment device.

Figure 2 Top view of the integrated three-dimensional wetland sewage treatment device.

Among them, 1 is a concrete frame, 2 is a plastic partition, 3 is a fine-density steel wire filter, 4 is aquatic plants, 5 is a sludge pump, 6 is a clean water pump, 7 is an air pump, and 8 is a micro-constructed wetland matrix.

Detailed ways

Embodiment 1: The present invention will be described in further detail below according to the accompanying drawings:

Referring to Figure 1, an integrated wetland sewage treatment device is constructed using concrete 1, plastic partitions 2, and steel wire filters 3. The device size is 3m×4m×4m. The device is designed into four partitions, one is the sewage pretreatment area, the second is the horizontal flow wetland sewage purification area, the third is the vertical flow wetland sludge purification area, and the fourth is the vertical flow sewage purification area. The volume ratio of the four partitions is set to 1 :0.6:0.15:1. The horizontal flow wetland sewage purification area and the vertical flow wetland sludge purification area are separated by plastic partitions. Both wetlands are planted with aquatic plants 4, and the substrate 8 is designed to be cinder (particle size) with obvious nitrogen and phosphorus adsorption effect. 4 ~ 6mm, specific surface area 0.25 ~ 0.35m ² /g), the substrate depth is designed to be 25cm, aquatic plants 4 choose economic plants such as wild rice and cress, and the planting density is 18 plants per square meter. Use the roots of aquatic plants to absorb nitrogen to achieve the initial removal effect. The vertical flow sewage purification area is divided into 4 layers with a fine-density (pore diameter 0.8±0.02mm) steel wire filter (3). From top to bottom, there are gravel layer, natural vermiculite layer, river sand layer and biological filler balls. The volume ratio of the four packing layers is 0.5:0.7:0.9:1.4. Each layer of packing is modularly assembled to facilitate regular replacement of the packing in the device. Domestic sewage is first discharged into the regulating tank, and then pumped to the two sub-regions of the micro-constructed wetland. The sewage passes through the horizontal flow wetland sewage purification area, and then passes through the gravel, natural vermiculite, river sand and water in the vertical flow sewage purification area. The biological purification ball is purified.

The characteristic values of the inlet water quality of the integrated three-dimensional wetland sewage treatment device are TN: 10～25mg/L, NH ₄ ⁺ -N: 11～20mg/L, NO ₃ ^- -N: 0.5～3mg/L, SS: 100～200mg /L. Through step-by-step treatment in different zones, the final nitrogen removal rate is more than 80%, the sludge is also reduced by 100%, and the SS removal rate is more than 90%. Moreover, the present invention adopts a compact integrated three-dimensional structure, which reduces the floor space by more than 40% and the investment cost by more than 20% compared with traditional artificial wetlands.

The arrow in Figure 1 indicates the direction of water flow. Domestic sewage is first discharged into the regulating tank, and then pumped to the two sub-regions of the micro-constructed wetland by pumps. The sewage flows through the clear water wetland treatment area, and then passes through the gravel layer in the vertical segmented purification area. , natural vermiculite layer, river sand layer and biological filler ball layer are purified. When the temperature is >12°C, choosing different filling ratios in the biofiller ball area can achieve different surface water environmental quality standards. When the effluent quality requirements are high, TN can reach the surface water environmental quality Class V standard at a filling ratio of 45%; TN can reach the surface water environmental quality Class IV standard at a filling ratio of 60%. (Surface water environmental quality standard GB3838-2002, surface water environmental quality Class V standard: TN ≤ 2.0 mg/L; surface water environmental quality Class IV standard: TN ≤ 1.5 mg/L) The specific implementation plan effects are shown in Table 1.

Table 1 The treatment effect of sewage passing through each purification zone under different filling ratios of the biological filler ball layer:

Example 2: The difference between this example and Example 1 is that when the temperature is <12°C, the artificial wetland treatment efficiency is low, and the filling ratio needs to be increased to meet the required water quality standards. When the filling ratio is less than 60%, TN cannot meet the surface water environmental quality Class V standard; at a filling ratio of 60%, TN can meet the surface water environmental quality Class V standard. The specific implementation effects are shown in Table 1.

Claims (5)

1. The integrated three-dimensional wetland sewage treatment effluent TN control device is characterized by comprising a sewage pretreatment area, a horizontal flow wetland sewage purification area, a vertical flow wetland sludge purification area and a vertical flow sewage purification area, wherein the horizontal flow wetland sewage purification area and the vertical flow wetland sludge purification area are arranged above the sewage pretreatment area in parallel, a matrix layer is arranged below the horizontal flow wetland sewage purification area and the vertical flow wetland sludge purification area, and the matrix layer of the horizontal flow wetland sewage purification area and the vertical flow wetland sludge purification area is separated from the sewage pretreatment area by a concrete structure; the vertical flow sewage purification zone is arranged at the side edges of the horizontal flow wetland sewage purification zone, the vertical flow wetland sludge purification zone and the sewage pretreatment zone and is separated by a concrete structure, the vertical flow sewage purification zone is sequentially provided with a rubble layer, a natural vermiculite layer, a river sand layer and a biological filler ball layer from top to bottom, each layer is assembled by adopting a module, the filling ratio of the biological filler balls in the biological filler ball layer is 20% -65%, aquatic plants are planted in the horizontal flow wetland sewage purification zone and the vertical flow wetland sludge purification zone, the substrate layers of the horizontal flow wetland sewage purification zone and the vertical flow wetland sludge purification zone are coal cinder, the substrate depth is designed to be 10-30 cm, the aquatic plant is cane shoots or cress, the sewage pretreatment area is an adjusting tank, a sludge pump, a sewage pump and an air pump are arranged in the adjusting tank, the air pump is used for oxygenating and aerating a river sand layer and a biological filling ball layer through a pipeline, the river sand layer and the biological filling ball layer are aerated and oxygenated through the air pump, the aeration strength is 1.5-2.0 m < 3 >/m < 2 >. H, the size of the integrated three-dimensional wetland sewage treatment effluent TN control device is designed to be any one of 3m < 4 >, 4m < 5 > m < 4 > and 5m < 6 > m < 4 > m, and the volume ratio of the sewage pretreatment area, the horizontal flow wetland sewage purification area, the vertical flow wetland sludge purification area and the vertical flow sewage purification area is 0.9-1.08): (0.48-0.675): (0.06-0.15): 1, the volume ratio of the crushed stone layer, the natural vermiculite layer, the river sand layer and the biological filling ball layer is (0.4-1): (0.6-1): (0.8-1): (1.2-2), wherein the particle size of the crushed stone layer is 5-10 mm; the particle size of the natural vermiculite layer is 2-5 mm, the specific surface area is 400-600 m < 2 >/g, and the pore volume is 0.2-0.4 cm < 2 >/g; the particle size of the river sand layer is 2-4 mm; the bio-filler ball layer is a spherical filler ball with a raised surface, which is made of polyethylene or polypropylene plastic, the surface area of the bio-filler ball layer is 800-2500 m < 2 >/m < 3 >, the density of the bio-filler ball layer is 2-4 kg/m < 3 >, and the diameter of the bio-filler ball layer is 0.04-0.06 m.

2. The integrated stereoscopic wetland sewage treatment effluent TN control device according to claim 1, wherein the impurities are precipitated at the bottom of the regulating tank and pumped by the sludge pump to the upper vertical flow wetland sludge purification zone; sewage in the regulating tank is pumped into a horizontal flow wetland sewage purification area by a sewage pump and then is treated by a vertical flow sewage purification area.

3. The integrated stereoscopic wetland sewage treatment effluent TN control device according to claim 1, wherein the horizontal flow wetland sewage purification zone and the vertical flow wetland sludge purification zone are separated by a plastic partition.

4. The integrated three-dimensional wetland sewage treatment effluent TN control device of claim 1, wherein the crushed stone layer, the natural vermiculite layer, the river sand layer and the biological filler ball layer are separated by a steel wire filter screen, respectively.

5. A method for sewage treatment by using the integrated three-dimensional wetland sewage treatment effluent TN control device as claimed in claim 1, comprising the steps of:

firstly, sewage is completely discharged into an adjusting tank, sewage in the adjusting tank is adjusted and primarily settled, and impurities are settled at the bottom and pumped into a vertical flow wetland sludge purification area at the upper part by a sludge pump; sewage in the regulating tank is pumped into a sewage purification area of the horizontal flow wetland by a sewage pump, and sequentially passes through a crushed stone layer, a natural vermiculite layer, a river sand layer and a biological filler layer in the vertical section purification area to be purified; when the temperature is less than 12 ℃, the filling ratio of the bio-filler ball layer is increased to improve the purifying effect.