CN100415662C - Device and method for sewage treatment system of baffled wetland filter + lateral subsurface flow wetland bed - Google Patents

Abstract

The invention relates to a baffling wetland filter tank and lateral undercurrent wetland bed sewage treatment system and a method, wherein the system is formed by connecting a pretreatment structure, a baffling wetland filter tank group and a lateral undercurrent wetland bed group in a gradient downward mode in sequence by water channels; each filter chamber of the baffling wetland filter tank group is internally provided with at least one vertical flow baffle wall, water flows pass through the filter chambers in a vertically baffling flow state, ceramsite or zeolite filler is placed in the filter chambers, and aquatic plants are planted at the top of the filter chambers; the lateral subsurface flow wetland bed group consists of a multi-stage lateral subsurface flow wetland bed, a natural reoxygenation area and a facultative pond; the water in each lateral undercurrent wetland bed is S-shaped and horizontally submerged, and the upper stage wetland bed is connected with the lower stage wetland bed by a natural reoxygenation area, so that the sewage is subjected to multi-stage aerobic → anoxic → aerobic circular biological reaction. The system has the advantages of high utilization rate of the tank volume, small occupied area, good treatment effect of the method, long-term maintenance and particular suitability for treating high-concentration urban sewage.

Description

Device and method for sewage treatment system of baffled wetland filter + lateral subsurface flow wetland bed

technical field

The invention belongs to the technical fields of sewage treatment and environmental protection, and in particular relates to a sewage treatment system device and treatment method of a baffle wetland filter + lateral subsurface flow wetland bed.

Background technique

Through scientific and technological novelty search, there is no research literature report on the use of baffled wetland filter and lateral subsurface flow wetland bed technology to treat urban sewage at home and abroad, and there is no combination of baffled wetland filter + lateral subsurface flow wetland bed Related reports on technology treatment of sewage.

The ecological treatment process using the "natural purification system" plays a role by recycling and utilizing the resources in the biological system. It is a low-cost, low-energy, simple and effective treatment technology combined with ecological landscape in sewage treatment. It is a desirable water pollution prevention and control technology in areas where the technology is lacking.

The existing sewage treatment methods in constructed wetlands mainly include: free surface (open flow, surface flow) type, subsurface flow type, subsurface flow infiltration type, step type, etc. The treatment principle of the free surface constructed wetland is similar to that of the biological pond, but its treatment efficiency is low, the land occupation and pool capacity are large, and the investment is high. Subsurface flow wetlands mainly use the interception and partial biological absorption of fillers to remove pollutants. The main problem is that the sewage is mainly under anaerobic or anoxic conditions, and the effluent quality is poor, and dead water areas and blockages are prone to occur. The subsurface infiltration constructed wetland is actually a kind of infiltration land treatment system. The sewage is distributed by the water distribution system, passes through the filler layer and the soil layer downwards, and is finally collected by the water collection pipe buried in the soil. It mainly uses the filler and Soil filtration and adsorption to remove pollutants. The main problems of these artificial wetland treatment methods are: more complicated water distribution system is required, short flow is easy, the treatment effect is difficult to maintain for a long time, clogging is easy to occur, and the area is large, mainly suitable for low-concentration raw sewage or slightly polluted water, etc. , the effect on urban sewage is generally not good, and there is no good example of success.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention provides a device and method for a baffle wetland filter + lateral subsurface flow wetland bed sewage treatment system, which solves the problem of low utilization rate of pool capacity in the prior art, large floor area, easy short flow, The treatment effect is difficult to maintain for a long time, and it is not suitable for the treatment of high-concentration urban sewage.

Technical scheme of the present invention is as follows:

A baffle wetland filter + lateral subsurface flow wetland bed sewage treatment system device, which is composed of a pretreatment structure, a baffle type wetland filter group, and a lateral subsurface flow wetland bed group in the form of gradient downwards, which are sequentially connected by waterways .

The baffle type wetland filter group is composed of multi-stage filter tanks forming a downward gradient. Each filter tank is provided with a vertical retaining wall, leaving a water flow channel at the top or bottom of the filter tank, and the water flow is folded upwards and downwards. The flow state of the flow passes through the filter tank, and ceramsite or zeolite filler is placed in the filter tank and aquatic plants are planted.

The lateral subsurface flow wetland bed group is composed of a multi-level gradient downward lateral subsurface flow wetland bed, a natural reoxygenation area and a facultative oxygen stabilization pond; each side subsurface flow wetland bed is provided with parallel staggered diversion walls, The space in the bed is divided into S-shaped water flow channels, and ceramsite fillers are placed in the channels, and aquatic plants are planted; the upper wetland bed and the lower wetland bed are connected by a natural reoxygenation zone, and the last wetland The bed is connected to the stabilization pond, which is a water-holding structure with a drainage pipe at the bottom of the end.

The diameters of the fillers placed in the different levels of baffled wetland filters and the lateral subsurface flow wetland beds are successively reduced.

The natural reoxygenation zone adopts the form of a drop water aeration tank in areas with steep terrain, and there is a drop water drop of 1.0 to 1.5 meters between the drop water aeration tank and the upper-level lateral subsurface flow wetland bed.

The natural reoxygenation area adopts the form of a thin water layer reoxygenation ditch in a relatively flat area. The thin water layer reoxygenation ditch is a horizontal channel, and the water flow forms a thin water layer with a thickness of 3 to 10 mm in the ditch. , so that water and air fully contact to achieve the purpose of natural reoxygenation.

Submerged plants or emergent plants are planted in the stable pond.

The pretreatment structure is sequentially composed of a grid and a grit chamber.

The steps of using the above-mentioned system device to treat sewage in a baffled wetland filter + lateral subsurface flow wetland bed are as follows:

1. Pre-treat urban sewage first to remove floating solids, suspended solids and sediment with larger particle sizes;

2. The pretreated sewage enters the baffled wetland filter group, and the sewage pushes through the filter in the way of up and down baffles, forming an anaerobic biofilm on the surface of the filler in the filter. The role of sewage in anaerobic microorganisms Under the environment, anaerobic reaction and hydrolysis reaction occur, and dissolved oxygen is transmitted to the middle of the filter through the leaves, stems and roots of aquatic plants, forming an aerobic microenvironment, and removing organic matter and nutrients nitrogen and phosphorus in sewage;

3. The water treated by the baffle type wetland filter flows downward into the lateral subsurface flow wetland bed, and the sewage is pushed through the subsurface flow in the wetland bed in an S-shape. Under the action of aquatic plants, the wetland bed is basically under facultative oxygen conditions, and the sewage Natural reoxygenation is carried out through the natural reoxygenation zone between the wetland beds to increase the oxygen content in the subsequent wetlands, and repeated multi-level hypoxia → aerobic → anoxic Oxygen → aerobic cycle biological reaction, removal of organic matter and nitrogen;

4. The treated water finally enters the stabilization pond, further evolves in the simulated natural pond ecosystem, and is discharged after testing that the water quality meets the discharge standard.

4. Advantages and positive effects of the invention

Compared with the existing artificial wetland technology, this baffle wetland filter + lateral subsurface flow wetland bed sewage treatment technology has the following advantages.

① Existing constructed wetland treatment technologies are mainly aimed at low-concentration micro-polluted water (such as polluted river water, rainwater), and there are not many successful examples of direct treatment of high-concentration urban sewage. The technology of the present invention is developed for urban sewage with higher concentration.

②The treatment effect is good and can be maintained for a long time. The sewage first undergoes anaerobic biological reaction in the baffled wetland filter to convert the high-molecular organic matter in the raw sewage into low-molecular organic matter, improving the biodegradability of the sewage, and then in the aerobic and facultative lateral subsurface flow wetland bed. Most of the pollutants are removed in the water, and finally enter the stabilization pond to ensure the quality of the effluent. When the hydraulic retention time is within 12 to 24 hours (the hydraulic retention time required by the existing artificial wetland treatment technology generally takes 5-10 days), the effluent water quality can fully meet the national "Urban Sewage Treatment Plant Pollutant Discharge Standard" (GB18918- 2002) Class I B standard. The fillers are arranged in the direction of the entire process, and the particle size ranges from large to small, which can make full use of the interception effect of the fillers, and is not easy to block, and can maintain the treatment effect for a long time.

③The utilization rate of the pool capacity is high, the floor area is small, and no additional power is required. The existing artificial wetland sewage treatment technology often has dead water areas due to uneven water distribution, and the pool capacity utilization rate is not high; at the same time, the treatment efficiency is low and the pool depth is shallow, resulting in a large area. In the technology of the present invention, the sewage travels through the whole system in the form of push flow, passes through the filter in the baffle type wetland filter in an up and down baffle mode, and passes through the filter in an S-shaped flow state in the lateral subsurface flow wetland bed, and the whole system There is no dead water area, and the utilization rate of pool capacity is greatly improved. At the same time, the treatment structure of anaerobic (baffled wetland filter) and then aerobic (lateral subsurface flow wetland bed) is adopted, which greatly improves the treatment efficiency and increases the depth of the pool (mainly in the first stage of the baffled filter). The area occupied is reduced, which is very meaningful for areas with tight land use. The unit area required for the technology of the invention to treat urban sewage is 2-3.5m ² /(m ³ /d), far lower than the 15-50m ² /(m ³ /d) of the existing artificial wetland treatment technology.

Description of drawings

Fig. 1 is a flow chart of the sewage treatment method of the baffled wetland filter + lateral subsurface flow wetland bed;

Fig. 2 is a schematic plan view of a baffled wetland filter + lateral subsurface flow wetland bed sewage treatment system;

Fig. 3 is a view along the direction A of Fig. 2 .

Detailed ways

The present invention is described in further detail below in conjunction with Fig. 1, Fig. 2 and Fig. 3 from the angle of water treatment process:

The urban sewage is sent to the pretreatment structure 2 through the water inlet pipe 1. Firstly, it can be pretreated through the grille 21 and the grit chamber 22 to remove the floating matter, suspended matter and sediment with large particle size, so as to avoid subsequent deflection The wetland filter is clogged. Then the sewage can adjust the water quantity and water quality through the regulating tank 23, and further remove suspended solids with larger particle diameters at the same time.

The pretreated raw sewage enters the baffled wetland filter group 3 through the pipeline. The baffle type wetland filter group 3 is composed of three filter tanks with a depth of 700-1000 mm arranged in a downward gradient. Each filter is provided with a vertical retaining wall 31, and a water flow channel 32 is left at the bottom of the filter. The water flows through the bottom of the pool in a U shape, and the sewage pushes through the filter group in a way of deflecting up and down. Place ceramsite filler or zeolite filler 33 with a particle size of 12-6mm in the baffled wetland filter tank (fillers with uniform particle size can be placed in the same filter tank, but the particle size of fillers in different filter tanks should be reduced in turn). After the baffle type wetland filter is started normally, anaerobic biofilm will be formed on the surface of the filler, and the sewage will undergo anaerobic reaction and hydrolysis reaction under the action of anaerobic microorganisms. The macromolecular organic matter in the raw water will be degraded into small molecular organic matter and inorganic matter such as CH ₄ , H ₂ S and H ₂ O that are easy to be decomposed by aerobic oxygen. At the same time, the aquatic plants 34 planted in the filter can absorb part of the nutrients for use in It grows by itself, and at the same time transmits dissolved oxygen to the middle of the filter through leaves, stems and roots, and forms an aerobic microenvironment locally around the root zone, which facilitates the removal of organic matter and nutrients nitrogen and phosphorus.

After being treated by the baffle type wetland filter, the sewage enters the lateral subsurface flow wetland bed group 4 through the pipeline for treatment. The lateral subsurface flow wetland bed group consists of a multi-level lateral subsurface flow wetland bed 41 , a natural reoxygenation zone 42 and a facultative oxygen stabilization pond 43 . In order to avoid uneven water distribution and improve the utilization rate of the pool capacity, parallel and staggered diversion walls 411 are arranged in each lateral subsurface flow wetland bed, which divides the space in the bed into S-shaped water flow channels 412, and the sewage flows in the wetland in an S-shape. Undercurrent push in the bed. The channel depth of the wetland bed is set at 200-500 mm, and the channel width is 400-1000 mm (determined according to conditions such as the amount of treated water and land use restrictions). Place ceramsite packing in the channel, and the particle size of the packing in different filter tanks should be reduced in turn. Aquatic plants 413 are planted in the ditch. Since the depth of the whole trench is relatively shallow and within the coverage of plant roots, the wetland bed is basically under facultative oxygen conditions under the premise of relatively dense planting. The upper-level wetland bed is connected with the latter-level wetland bed by a natural reoxygenation zone 42 . When the terrain is steep, in order to increase the amount of reoxygenation and increase the oxygen content in the subsequent wetland, the method of falling water aeration can be used; if the terrain is relatively flat and it is difficult to set up falling water aeration, thin water layer reoxygenation can be used Natural reoxygenation of the ditch (as shown in Figure 2 and 3), the ditch is a horizontal channel, that is, the water flows through a horizontal channel to form a thin water layer with a thickness of 3-10mm, so that the water can be widely contacted with the air , to increase reoxygenation efficiency. In this way, after repeatedly passing through the multi-level subsurface flow wetland bed → natural reoxygenation zone → subsurface flow wetland bed → natural reoxygenation zone..., the sewage is continuously in the multi-level anoxic → aerobic → anoxic → aerobic... cycle biological reaction, sewage The organic matter is well removed, and the nitrogen is also removed through multi-stage aerobic nitrification and anoxic denitrification.

The treated water finally enters the facultative stabilization pond 43, which is a water-holding structure with a drainage pipe 5 at the bottom of the end. Some submerged plants or emergent plants 431 can be planted in the partaerobic stable pond 43, and fish can be raised at the same time, simulating a natural pond ecosystem. The sewage treated by the wetland bed can be further evolved in the stabilization pond, and the fish and other indicator organisms in the stabilization pond can be used to characterize the quality of the water.

The applicant adopts the system and method of the present invention in the sewage treatment station of Lugu Lake Scenic Area in Liangshan Prefecture, Sichuan Province (2000m ³ /d) and the sewage treatment plant of Xinxin Town, Zhongxian County, Chongqing City (800m ³ /d). The treatment effect is Good, the effluent water quality meets the first-class standard of the national standard "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB18918-2002). In the application of the sewage treatment station in Lugu Lake Scenic Area, Liangshan Prefecture, Sichuan Province, the design influent quality of raw sewage is COD350mg/L, BOD 200mg/L, NH ₃ -N 35mg/L, TP 4.0mg/L, and the hydraulic retention time is In 24 hours, the effluent water quality reaches the first-level A standard of the national standard "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB18918-2002).

Claims (7)

1. rotating wetland filtering pond+lateral subsurface flow wetland bed waste water treatment system device is characterized in that: with the downward form of gradient, the water route links to each other and constitutes successively by pre-treatment structures, deflector type wetland filter tank group, lateral subsurface flow wetland bed group in system;

Described deflector type wetland filter tank group is made up of the multistage filter tank that forms downward gradient, be provided with at least one vertical choking wall in each filter tank, reserve water stream channel on top, filter tank or bottom, current pass the filter tank with the fluidised form of baffling up and down, place haydite or zeolite filler in the filter tank and top plantation waterplant;

Described lateral subsurface flow wetland bed group is made up of the downward lateral subsurface flow wetland bed of multistage gradient, natural reaeration district and concurrently oxygen stabilization pond; Be provided with parallel staggered training wall in each lateral subsurface flow wetland bed, separated by spaces in the bed is become the current raceway groove of S shape, in raceway groove, place ceramics filling, and the plantation waterplant; Upper level wetland bed with link to each other by the natural reaeration district between next stage is wetland bed, the wetland bed connection concurrently oxygen stabilization pond of last step, concurrently oxygen stabilization pond are one to hold the water structures, drainage pipeline is arranged at terminal bottom.

2. Sewage treatment systems device according to claim 1 is characterized in that: the packing material size of placing in described rotating wetland filtering pond not at the same level and the lateral subsurface flow wetland bed dwindles successively.

3. Sewage treatment systems device according to claim 1 and 2 is characterized in that: described natural reaeration district is a drop water aeration pond, has 1.0～1.5 meters drop drop between this drop water aeration pond and the upper level lateral subsurface flow wetland bed.

4. Sewage treatment systems device according to claim 1 and 2 is characterized in that: described natural reaeration district is a thin water layer reoxygenation ditch, and this thin water layer reoxygenation ditch is a horizontal channel, and current form thickness in ditch be 3～10 millimeters thin water layer.

5. Sewage treatment systems device according to claim 1 and 2 is characterized in that: plantation has submerged plant or emergent in the described concurrently oxygen stabilization pond.

6. Sewage treatment systems device according to claim 1 and 2 is characterized in that: described pre-treatment structures are made up of grid and settling pit successively.

7. rotating wetland filtering pond+lateral subsurface flow wetland bed sewage water treatment method, treatment step is as follows:

(1) earlier town sewage is carried out pre-treatment, remove bigger floating matter, suspended substance and the silt of particle diameter;

(2) pretreated sewage enters deflector type wetland filter tank group, sewage is walked with mode plug-flow in the filter tank of baffling up and down, filling surface in the filter tank forms the anaerobe film, sewage is under the effect of anaerobion, anaerobic reaction and hydrolysis reaction take place, and leaf, stem and root by waterplant transmit dissolved oxygen to the middle part, filter tank, forms aerobic microenvironment, removes organism in the sewage and nutritive substance nitrogen, phosphorus:

(3) water of handling through deflector type wetland filter tank flows into the lateral subsurface flow wetland bed downwards, sewage is carried out with S type undercurrent in wetland bed, under the effect of waterplant, substantially be in wetland bed under the oxygen condition of holding concurrently, sewage natural reaeration district between wetland bed carries out natural reaeration, improve oxygen level in the follow-up wetland, through the aerobic circulating biological reaction of multistage current wetland bed → natural reaeration district → current wetland bed circulation carrying out multi-stage anaerobic → aerobic-anoxic, remove organism and nitrogen repeatedly;

(4) water after the processing enters stabilization pond at last, further purifies in the pond ecosystem of simulating nature, detects and discharges after water quality reaches emission standard.

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