CN1263688C - Composite artificial wet land denitrifying and dephosphorizing method for living waste water vertical fluid-horizontal fluid - Google Patents

Abstract

The vertical flow-horizontal flow composite constructed wetland method for nitrogen and phosphorus removal of domestic sewage involves the field of environmental protection management technology. The vertical flow constructed wetland and the horizontal flow constructed wetland are used in series to form a composite system to treat domestic sewage. The vertical flow constructed wetland is operated in an alternating dry and wet manner. The horizontal flow constructed wetland adopts a continuous operation mode, and some untreated sewage directly enters the horizontal flow constructed wetland to replenish carbon sources, improving the nitrogen removal effect of the horizontal flow constructed wetland. The vertical flow constructed wetland is filled with blast furnace slag rich in oxides such as iron, calcium, silicon and aluminum, and the horizontal flow constructed wetland is filled with calcium-rich marble or limestone and cinder. The flowers planted in the vertical flow constructed wetland are terrestrial flowers such as canna, rose and fresh-cut flowers-roses, gerbera, and the vegetables planted in the horizontal flow constructed wetland are watercress, water spinach, leek, lettuce, cucumber, tomato (cherry tomato), arrowroot and wild rice.

Description

Nitrogen and phosphorus removal method for domestic sewage vertical flow-horizontal flow composite constructed wetland

Technical field

The invention patent relates to sewage treatment technology.

technical background

The domestic sewage constructed wetland treatment methods mainly include vertical flow constructed wetland, horizontal flow constructed wetland and horizontal flow and vertical flow composite constructed wetland.

The height of the vertical flow artificial wetland bed is more than 100cm, and finer substrates such as sand are usually used as the infiltration medium. The sewage is treated in the process of vertical infiltration from the surface downward, and most of the plants used are reeds and windmill grasses. , vetiver, regalia, sedge and canna etc.

The height of the horizontal subsurface flow constructed wetland bed is about 60-80cm, and a relatively coarse substrate such as gravel is used as the treatment medium. The sewage flows horizontally under the surface of the constructed wetland, and large emergent plants with the ability to secrete oxygen are planted in the substrate layer, such as reeds, Cattail, water onion, iris and calamus, etc., use the oxygen-secreting ability of aquatic plants to provide oxygen for the biofilm on the substrate of the constructed wetland to decompose the organic matter in the sewage.

The horizontal flow and vertical flow composite constructed wetlands are connected in series in the order that the horizontal flow constructed wetlands come first and the vertical flow constructed wetlands follow. The domestic sewage firstly removes most of SS, COD, BOD ₅ and some ammonia nitrogen through the horizontal flow constructed wetland, and then distributes water to the vertical flow constructed wetland to complete the complete removal of oxygen-consuming organic matter and complete nitrification of the remaining ammonia nitrogen, and the vertical flow The nitrification treatment effluent of the constructed wetland is returned to the head end of the horizontal flow constructed wetland according to the reflux ratio of 50-100% for pre-denitrification and denitrification treatment of the internal carbon source; the horizontal flow constructed wetland and the vertical flow constructed wetland are filled with high phosphorus adsorption substrates, Aquatic plants are planted on the substrate of the horizontal flow artificial wetland, and aquatic plants or terrestrial flowers are planted on the substrate of the vertical flow artificial wetland.

The shortcomings are as follows: (1) The horizontal flow constructed wetland has shortcomings such as insufficient aerobic conditions. Although it can remove SS well, it can also remove some BOD. However, it generally does not perform well for ammonia nitrogen removal. Because it cannot complete the nitrification process of most wastewater, even if it has a strong denitrification ability, it cannot independently complete the two treatment processes of wastewater nitrification and denitrification to achieve the purpose of wastewater denitrification treatment. At the same time, the phosphorus removal effect is also poor, generally only 30-40%, and the gravel matrix currently widely used has a short adsorption saturation life for phosphorus, generally 2 to 3 years; The treatment ability and nitrification ability of organic matter are stronger, it has better aerobic conditions than the horizontal flow constructed wetland, and the removal effect of BOD ₅ and COD in the wastewater is better, but the removal effect of SS is lower than that of the horizontal flow constructed wetland Poor; although its ability to treat wastewater with nitrification is very strong, its denitrification ability is also worse than that of horizontal flow artificial wetlands, so it cannot complete the two treatment processes of wastewater nitrification and denitrification alone to achieve the purpose of wastewater denitrification treatment Purpose. At the same time, the phosphorus removal rate is only 40-50%, and the phosphorus removal life of sand and gravel matrix is relatively short, generally 3-4 years. (3) Although the composite constructed wetland of horizontal flow and vertical flow can complete part of nitrification and denitrification of nitrogen, the removal rate of total nitrogen is not high, only 30-45%, and it is necessary to return the effluent of nitrification treatment, which increases power consumption , and with the increase of the reflux ratio, the amount of sewage treatment water is reduced, the floor area is increased, and the phosphorus removal rate is also reduced; secondly, the phosphorus removal effect of the horizontal flow artificial wetland using limestone, marble or dolomite matrix is not high , is only 30-50%, which affects the phosphorus removal life of the composite constructed wetland, and economic crops such as vegetables cannot be grown on the horizontal flow constructed wetland; third, the aerobic treatment capacity and nitrification capacity of the vertical flow constructed wetland cannot be obtained Full play, occupying a larger area.

Contents of the invention

The purpose of the present invention is: ① The vertical flow and horizontal flow artificial wetlands are composed of composite artificial wetlands in the order of vertical flow first and horizontal flow later, and the vertical flow artificial wetlands are fully used to complete most of the oxygen-consuming organic matter and suspended matter. Removal and complete nitrification of domestic sewage, and complete removal of SS, COD and BOD ₅ by using horizontal flow constructed wetlands, and complete removal of most of nitrogen through denitrification; ② A small part of untreated sewage Directly enter the head end of the horizontal flow constructed wetland, under the anoxic condition of the horizontal flow constructed wetland, use the organic matter in domestic sewage as a carbon source to complete the denitrification and denitrification process; ③Fill the blast furnace slag matrix in the vertical flow constructed wetland, Constructed wetlands are filled with slag and blast furnace slag substrates to achieve a higher total phosphorus removal rate and prolong the service life of substrate phosphorus removal; ④ plant terrestrial flowers and fresh-cut flowers in vertical flow constructed wetlands, and plant Vegetables to increase the economic benefits and aesthetic value of the composite constructed wetland.

The nitrogen and phosphorus removal method of domestic sewage vertical flow-horizontal flow composite constructed wetland is: connect the vertical flow constructed wetland and the horizontal flow constructed wetland in series, the vertical flow constructed wetland is in front, and the horizontal flow constructed wetland is behind. The domestic sewage is firstly treated by the bed body of the vertical flow constructed wetland to remove part of SS, COD, BOD ₅ and carry out nitrification. Then, through the hydrostatic pressure of the sump, the water is distributed to the horizontal flow constructed wetland with a slightly lower terrain. In the horizontal flow constructed wetland, the anoxic conditions provided by the poor oxygen supply capacity of vegetable roots and the vertical flow constructed wetland are used to treat the effluent by nitrification. Part of the organic matter is used as the carbon source to complete the denitrification and denitrification process. If the carbon source is insufficient or due to the high DO content in the nitrification treatment water and the anoxic condition cannot be formed, part of the untreated sewage should be directly sent to the front end of the horizontal flow constructed wetland. Supplementary carbon sources to enhance nitrogen removal by horizontal flow. Fill the vertical flow constructed wetland and the horizontal flow constructed wetland with high-efficiency phosphorus removal substrates, plant terrestrial flowers and fresh-cut flowers on the vertical flow constructed wetland, and plant vegetables on the horizontal flow constructed wetland.

The domestic sewage vertical flow-horizontal flow compound constructed wetland phosphorus removal method uses the process flow of the above-mentioned denitrification method to complete the removal of phosphorus in wastewater while denitrification. The specific method is as follows: firstly, fill the blast furnace slag matrix which has a strong ability to fix phosphorus in the vertical flow artificial wetland, and plant canna, rose and rose, and use the blast furnace slag matrix and flower plants to remove most of the phosphorus in the wastewater; Fill the water distribution area and catchment area of the constructed wetland with substrates with strong phosphorus fixation capacity such as marble or limestone, fill the bed with slag, fill the surface of the bed with blast furnace slag, and plant vegetables such as watercress, water spinach ( Common) vegetables, leeks, lettuce, cucumbers, tomatoes (cherry tomatoes), arrowroot and wild rice, etc., use the substrate and vegetables to remove part of the phosphorus in the sewage.

The present invention is described now in conjunction with accompanying drawing:

Figure 1 is a structural diagram of the vertical flow-horizontal flow composite constructed wetland of domestic sewage.

Fig. 2 is the vertical flow bed structure diagram of domestic sewage vertical flow-horizontal flow compound constructed wetland.

Figure 3 is a structural diagram of the horizontal flow bed in the vertical flow-horizontal flow compound constructed wetland of domestic sewage.

In the figure: 1—Grille, 2—Sedimentation tank, 3—Sewage pipe, 4—Water distribution main pipe, 5—Water distribution branch pipe, 6—Efficient phosphorus removal matrix layer, 7—Gravel cushion layer, 8—Treated water discharge pipe , 9—water collection tank, 10—inlet main pipe, 11—water distribution branch pipe, 12—gravel water distribution area, 13—high-efficiency phosphorus removal matrix layer, 14—overburden layer, 15—gravel catchment area, 16— Drainage pipe, 17—clear water pool, 18—sewage pipe.

Domestic sewage vertical flow-horizontal flow composite constructed wetland is composed of vertical flow constructed wetland, sump, horizontal flow constructed wetland and clear water pool, and is connected in series in the order of vertical flow constructed wetland and horizontal flow constructed wetland to form composite constructed wetland . Place high-efficiency phosphorus removal substrates such as blast furnace slag in the bed of vertical flow constructed wetlands, and plant terrestrial flowers and fresh-cut flowers. Place high-efficiency phosphorus removal substrates such as slag and blast furnace slag in the bed body of the horizontal flow constructed wetland, and plant vegetables on the surface of the covering layer. After the domestic sewage is fixed by the high-efficiency phosphorus removal matrix in the vertical flow constructed wetland, the uptake of the plant root system, and the accompanying physical, chemical, and microbial actions, the partial removal of organic matter and complete nitrification are completed, and the sewage enters the sump for utilization. The hydrostatic pressure and head drop of the sump automatically distribute water to the horizontal flow constructed wetland; the immobilization of the high-efficiency phosphorus removal substrate in the horizontal flow constructed wetland and the uptake of plant roots, as well as the accompanying physical, chemical and microbial effects, remove most of the SS , COD, BOD ₅ , complete the removal of nitrogen through denitrification, and make part of the untreated sewage directly enter the horizontal flow constructed wetland to supplement the carbon source and improve the removal effect of nitrogen.

The vertical flow artificial wetland, sump, horizontal flow artificial wetland and clean water pool in the domestic sewage vertical flow-horizontal flow composite constructed wetland are connected by pipes.

The domestic sewage compound artificial wetland vertical flow bed is composed of a bed body and a water distribution pipe. The bed wall and bottom of the bed body are made of non-seepage materials. If it is built on the ground, the bed wall is a brick structure with cement plaster, and the bottom is a concrete structure. The bed body is distributed from bottom to top as a gravel cushion layer 7 and a high-efficiency phosphorus removal matrix layer 6 . The height of the bed body is above 90cm, the thickness of the gravel cushion layer 7 is 10-15cm, and the limestone with a particle size of about 4cm and the limestone with a particle size of about 1cm are distributed from bottom to top; the thickness of the efficient phosphorus removal matrix layer is 70-80cm, and the efficient phosphorus removal matrix layer Put blast furnace slag, the particle size of blast furnace slag is 0.25mm～5mm. The water distribution pipes are distributed on the surface of the high-efficiency phosphorus removal matrix, and surface water distribution is used to prevent clogging. Plant low dissolved oxygen tolerant flowers such as roses, carnations, gladiolus, gerbera, lilies, pickles, cannas, etc. in the vertical fluid bed.

The water distribution pipes are distributed on the surface of the high-efficiency phosphorus removal matrix layer. The water distribution pipes are composed of a water distribution main pipe 4 and a plurality of water distribution branch pipes 5. The water distribution main pipe 4 is distributed in the middle of the bed body, and its length is equivalent to that of the bed body. One end is sealed. The other end is connected with the sewage inlet pipe 3, and the water distribution branch pipe 5 is fixedly connected to both sides of the water distribution main pipe, and the other end is sealed, and its length is half of the width of the bed body, and the water distribution branch pipe has a small hole in the lower part.

The bed bottom of the vertical flow artificial wetland has a certain drainage slope to facilitate drainage. A drainpipe 8 is installed on the drain outlet, and a valve is arranged on the drainpipe 8 to control the drainage speed of the treated water. A sump 9 integrated with the bed is built at the water outlet end of the vertical flow artificial wetland bed. The treated sewage of the bed is discharged to the sump 9 through the drain pipe 8. The outlet of the drain pipe 8 is connected to the water inlet pipe 11. The water inlet should have a drop. The bottom of the sump 9 is provided with a drainpipe 10, and the drainpipe 8 and the drainpipe 10 are provided with valves to control the drainage speed. In addition, a pipe 18 is connected from the sewage inlet pipe 3 to the sump 9, so that a part of the sewage directly enters the horizontal flow artificial wetland to supplement the carbon source.

The bed wall and bottom of the horizontal flow artificial wetland bed in the domestic sewage vertical flow-horizontal flow composite constructed wetland are made of non-seepage materials. If it is built on the ground, the bed wall is a brick structure with cement plaster, and the bottom is a concrete structure. .

字形排水管16上设有阀门，以控制排水速度。The horizontal flow artificial wetland bed is provided with a gravel water distribution area 12, a high-efficiency phosphorus removal matrix layer 13, and a gravel water collection area 15 in sequence from the water inlet to the water outlet. Font drainpipe 16. The gravel water distribution area 12 and the gravel water collection area 15 each account for less than 20% of the total bed length, and the high-efficiency phosphorus removal matrix layer 13 accounts for more than 60% of the total bed length. The gravel water distribution area 12 and the gravel water collection area 15 are filled with crushed marble or limestone with a particle size of 3-5 cm. The efficient phosphorus removal matrix layer 13 is filled with slag. The filling thickness of the blast furnace slag gravel water distribution area 12, the gravel water collection area 15 and the high-efficiency dephosphorization matrix layer 13 is 70 to 80 cm, and the blast furnace slag is filled on the filler as the covering layer 14, and the thickness of the blast furnace slag covering layer is 10 to 15 cm. The height of the horizontal flow artificial wetland bed is above 90cm. Vegetables such as watercress, water spinach, leek, lettuce, cucumber, tomato (cherry tomato), arrowroot, and wild rice stem are planted on the covering layer. Below the blast furnace slag covering layer, a water inlet pipe 11 is arranged, and the water inlet pipe 11 is connected with the drain pipe 8 of the vertical fluidized bed. A clean water pool 17 is built at one end of the water outlet of the horizontal flow artificial wetland bed, and the treated sewage of the bed passes through Zigzag drainpipe 16 discharges to clear water pool 17,

Zigzag drainpipe 16 is provided with valve, to control drainage speed.

The clear water pool 17 is a sand well that collects horizontal flow artificial wetland to process water. Its wall and bottom are made of non-seepage material. If it is built on the ground, its wall is a brick structure with cement plaster, and the bottom is a concrete structure. In order to reduce the construction cost of the treatment pond, three vertical flow constructed wetlands are connected in parallel with a sump in series, and three horizontal flow constructed wetlands are connected in parallel. Each vertical flow constructed wetland is connected to the sump with a valved drainage pipe, and the bottom of the sump is provided with a drainage pipe connected to three horizontal flow constructed wetlands, and each horizontal flow constructed wetland is equipped with a valved drainage pipe and connected to the sump. Clean water pool connected.

字形，设在水平流床底部，并设有阀门，控制污水的排出速度和水平流床的储水量。另外，使部分未经处理的污水直接沿污水进水管18进入集水池9，然后利用垂直流人工湿地和水平流人工湿地的落差进入水平流床，以补充碳源。The present invention is realized in this way: the domestic sewage first passes through the grid 1 to remove impurities in the sewage, the sewage enters the sedimentation tank 2, the sewage from the sedimentation tank 2 is extracted by the clean water pump, and enters the water distribution main pipe 4 and the water distribution branch pipe 5 along the sewage pipe 3 In the vertical flow constructed wetland, the sewage flows downward in the vertical flow constructed wetland, passes through the high-efficiency dephosphorization matrix layer 6 and the gravel cushion layer 7, and after the sewage passes through the vertical flow constructed wetland, due to the adsorption of the matrix and the uptake of plant roots The complete removal of oxygen organic matter and complete nitrification, the sewage in the vertical flow constructed wetland utilizes the height difference between the vertical flow constructed wetland bed and the sump, the sewage flows into the sump through the drain pipe 8, and the drain pipe is equipped with a valve to control the flow and vertical flow of the sewage. The water storage capacity of the flow constructed wetland, the sewage in the sump 9 utilizes the height difference between the vertical flow constructed wetland and the horizontal flow constructed wetland, flows through the gravel water distribution area 12 of the horizontal flow constructed wetland, the high-efficiency phosphorus removal matrix layer 13 and the gravel water collection area 15. After the sewage passes through the horizontal flow constructed wetland, the SS in the sewage is removed by using the filtering effect of the gravel pores in the horizontal flow constructed wetland. The sewage passes through the horizontal flow constructed wetland, and the adsorption of the slag matrix in the horizontal flow constructed wetland and the uptake of plant roots are used to remove COD, BOD ₅ and most of the ammonia nitrogen in the sewage. The sewage in the horizontal flow artificial wetland enters the clear water pool 17 through the drain pipe 16, and the drain pipe 16 is

Glyph, located at the bottom of the horizontal fluidized bed, and equipped with valves to control the discharge speed of sewage and the water storage capacity of the horizontal fluidized bed. In addition, part of the untreated sewage directly enters the sump 9 along the sewage inlet pipe 18, and then enters the horizontal flow bed by using the difference between the vertical flow constructed wetland and the horizontal flow constructed wetland to supplement the carbon source.

Inventions and creations have the following advantages:

① Use vertical flow constructed wetland to remove part of SS, COD, BOD ₅ and complete nitrification of wastewater, and use horizontal flow constructed wetland to complete most of the removal function of COD, BOD ₅ and SS and denitrification of wastewater, so as to complete the nitrification and denitrification of wastewater Denitrification, and the removal function of the vertical flow and horizontal flow constructed wetlands have been brought into play to a great extent, shortening the hydraulic retention time of the horizontal flow constructed wetlands, and reducing the area occupied by the vertical flow and horizontal flow composite constructed wetlands.

② Sewage enters the horizontal flow constructed wetland after being nitrified in the vertical flow constructed wetland. In the horizontal flow constructed wetland, the anoxic condition formed by the low oxygen supply capacity of vegetables and the nitrification of the vertical flow constructed wetland are used to treat the BOD ₅ , COD and horizontal flow in the water. The organic matter accumulated in the flow constructed wetland is used as the carbon source to complete the denitrification and denitrification process of domestic sewage. When the carbon source in the nitrification water is insufficient or the DO content is high, a part of the untreated sewage is directly entered into the horizontal flow constructed wetland. As a carbon source or under anoxic conditions, it can not only complete the denitrification and denitrification of domestic sewage, but also increase the removal capacity of horizontal flow constructed wetlands for BOD ₅ and COD.

③ Vertical flow and horizontal flow composite constructed wetlands do not require reflux for nitrification treatment of effluent, thus solving the problem of horizontal flow-vertical flow composite constructed wetlands, reducing power consumption and treatment costs, and improving the removal rate of total nitrogen, shortening the The hydraulic retention time and the floor area are reduced, and at the same time, it also prevents the reduction of phosphorus removal rate caused by the reflux of nitrification treatment effluent.

④ Use the blast furnace slag matrix filled in the vertical flow artificial wetland to complete the removal of most of the phosphorus in domestic sewage; use the slag and blast furnace slag matrix filled in the horizontal flow artificial wetland to fix phosphorus to complete the removal of phosphorus in the wastewater Remove function. At the same time, the uptake of terrestrial flowers, fresh-cut flowers and vegetable roots planted in vertical flow and horizontal flow constructed wetlands is used to remove part of the phosphorus, so that the removal rate of total phosphorus in domestic sewage by composite constructed wetlands can reach more than 85-95%. , the concentration of total phosphorus in the treated effluent is less than 1 mg/L, reaching the first-level discharge standard of urban sewage treatment plants, and the service life of the inventive technology for phosphorus reaches more than 8 to 10 years.

⑤Using vertical flow constructed wetlands to remove most of the oxygen-consuming organic matter COD and BOD ₅ in domestic sewage, and solve the problem of anoxic and rotten roots of vegetables planted in horizontal flow constructed wetlands; The nitrification of nitrogen provides a large amount of nitrate nutrient solution that can be directly used for planting vegetables in horizontal flow constructed wetlands; the use of vertical flow constructed wetlands removes most of the pathogenic microorganisms and bacteria, and provides food safety for the cultivation of vegetables in horizontal flow constructed wetlands. a reliable guarantee.

Example:

The daily designed water treatment volume is 0.9～3.0m ³ /d.

Design Parameters:

Grille: Use 2cm×2cm barbed wire, stand upright in the inspection well where the outlet of the septic tank is connected with the underground water diversion pipe.

Sedimentation tank: The design size is 2.0m×1.8m×2.0m, the effective water depth is 1.0m, the effective volume is 3.6m ³ , and the brick structure is plastered with cement.

Constructed wetland with vertical flow: the designed outer diameter is 3.35m×3.67m×0.9m in length×width×height, divided into three grids, and the practical size of a single pool is 2.9m×1.1m×0.9m in length. The actual usable area is 12m ² . The vertical flow bed bed layer is composed of limestone with a diameter of 8cm and 4cm, and a thickness of 10-15cm; the thickness of the high-efficiency phosphorus removal matrix layer is 75-80cm. The practical size of the sump is 0.4m x 3.37m in length x width. The sump collects three vertical fluidized beds to treat the effluent and mixes them, and distributes water to the three horizontal fluidized beds by means of hydrostatic pressure through pipes and valves.

Constructed wetland with horizontal flow: a rectangular pool whose inner diameter is designed to be 2.7m×3.37m×0.9m in length×width×height. The horizontal fluidized bed is divided into three pools for parallel operation, and the practical size of a single pool is 2.7m x 1.1 x 0.9m in length x width x height. The horizontal flow bed is divided into gravel water distribution area, high-efficiency phosphorus removal matrix layer and gravel water collection area, each accounting for 1/5, 3/5, and 1/5 of the bed length, filled with limestone or marble, slag, limestone or marble respectively . It is covered with a layer of blast furnace slag with a thickness of 10 cm.

Operation time and operation mode: Trial operation began in March 2004, with HRT of 1, 2 and 3 days. On 3 vertical flow beds, the 1st block (VF1) is a control without plants, the 2nd block (VF2) is planted with roses, and the 3rd block (VF3) is planted with cannas. On three horizontal flow beds, the first block (HF1) is a control without plants, the second block (HF2) is planted with green vegetables, and the third block (HF3) is planted with watercress and leek.

Treatment effect (mg/L, %): as shown in Table 1, Table 2, Table 3 and Table 4.

Table 1 shows the change of COD concentration in sewage after domestic sewage is treated by vertical flow-horizontal flow composite constructed wetland for nitrogen and phosphorus removal;

Table 2 shows the change of BOD ₅ concentration in the sewage after the vertical flow-horizontal flow compound wetland denitrification and phosphorus removal treatment;

Table 3 shows the changes in the concentration of TN in the urban sewage after the nitrogen and phosphorus removal in the composite constructed wetland;

Table 4 shows the change of TP concentration in urban sewage after nitrogen and phosphorus removal by vertical flow-horizontal flow composite constructed wetland.

COD concentration changes date hydraulic retention time sewage VF1 VF2 VF3 HF1 HF2 HF3 3/15/04 1 day Concentration (mg/L) 365.31 292.68 174.53 153.93 100.67 43.62 67.18 Removal rate (%) 19.88 52.23 57.86 72.44 88.06 81.61 4/8/04 1 day Concentration (mg/L) 320.95 124.24 144.20 137.55 94.51 58.42 43.34 Removal rate (%) 61.29 55.07 57.14 70.55 81.80 86.50 5/10/04 1 day Concentration (mg/L) 326.22 104.59 87.41 144.89 60.91 93.84 74.32 Removal rate (%) 67.94 73.21 55.59 81.33 71.23 77.22 3/17/04 2 days Concentration (mg/L) 389.66 243.51 192.45 158.35 190.18 124.03 137.05 Removal rate (%) 37.51 50.61 59.36 51.19 68.17 64.83 4/10/04 2 days Concentration (mg/L) 383.80 133.26 170.83 181.48 118.52 54.32 103.70 Removal rate (%) 65.28 55.50 52.72 69.12 85.85 72.98 5/12/04 2 days Concentration (mg/L) 290.27 55.09 175.15 130.86 58.50 94.62 58.78 Removal rate (%) 81.02 39.66 54.92 79.85 67.40 79.75 3/20/04 3 days Concentration (mg/L) 468.22 260.05 199.69 209.20 102.84 83.82 109.46 Removal rate (%) 44.46 57.35 55.32 78.04 82.10 76.62 4/14/04 3 days Concentration (mg/L) 390.12 166.26 273.25 223.87 73.35 86.17 95.78 Removal rate (%) 57.38 29.96 42.62 81.20 77.91 75.45 5/15/04 3 days Concentration (mg/L) 244.01 22.65 64.52 136.77 21.52 6.55 48.65 Removal rate (%) 90.72 73.56 43.95 91.18 97.32 80.06

Table 1

Changes of BOD ₅ concentration date hydraulic retention time sewage VF1 VF2 VF3 HF1 HF2 HF3 3/15/04 1 day Concentration (mg/L) 227.86 112.46 113.17 178.29 15.75 44.04 7.96 Removal rate (%) 50.64 50.33 21.76 93.09 80.67 96.51 4/8/04 1 day Concentration (mg/L) 207.48 60.24 89.69 76.97 61.01 37.19 24.60 Removal rate (%) 70.97 56.77 62.90 70.59 82.08 88.14 5/10/04 1 day Concentration (mg/L) 230.55 66.67 62.98 96.14 26.75 26.93 24.49 Removal rate (%) 71.08 72.68 58.30 88.40 88.32 89.38 3/17/04 2 days Concentration (mg/L) 134.18 67.77 48.82 98.88 90.24 81.88 81.05 Removal rate (%) 49.49 63.62 26.31 32.75 38.98 39.60 4/10/04 2 days Concentration (mg/L) 164.58 62.76 82.04 2.93 53.62 41.88 41.59 Removal rate (%) 61.86 50.15 98.22 67.42 74.55 74.73 5/12/04 2 days Concentration (mg/L) 108.47 22.80 30.24 30.17 33.24 9.65 1.81 Removal rate (%) 78.98 72.12 72.19 69.36 91.10 98.33 3/20/04 3 days Concentration (mg/L) 222.75 106.70 48.88 120.03 83.36 69.81 57.01 Removal rate (%) 52.10 78.06 46.11 62.58 68.66 74.41 4/14/04 3 days Concentration (mg/L) 114.44 102.04 108.05 134.22 42.61 33.46 34.46 Removal rate (%) 10.84 5.58 - 62.76 70.76 69.88 5/15/04 3 days Concentration (mg/L) 96.65 31.89 36.17 36.09 40.10 40.10 42.05 Removal rate (%) 67.00 62.57 62.66 58.51 58.51 56.50

Table 2

TN concentration changes date hydraulic retention time sewage VF1 VF2 VF3 HF1 HF2 HF3 3/15/04 1 day Concentration (mg/L) 140.04 123.72 143.44 133.00 113.62 102.23 106.76 Removal rate (%) 11.65 - 5.03 18.87 27.00 23.77 4/8/04 1 day Concentration (mg/L) 190.65 178.73 169.06 167.31 121.12 109.74 124.44 Removal rate (%) 6.25 11.32 12.24 36.47 42.44 34.73 5/10/04 1 day Concentration (mg/L) 136.65 69.77 74.05 81.44 95.58 86.29 86.82 Removal rate (%) 48.94 45.81 40.40 30.05 36.85 36.46 3/17/04 2 days Concentration (mg/L) 120.03 128.70 152.53 139.49 117.37 122.17 112.29 Removal rate (%) - - - - 2.21 - 6.45 4/10/04 2 days Concentration (mg/L) 208.53 181.83 208.60 189.75 128.31 93.36 145.12 Removal rate (%) 12.80 - 9.01 38.47 55.23 30.41 5/12/04 2 days Concentration (mg/L) 106.45 117.53 192.97 147.60 69.07 68.94 92.96 Removal rate (%) - - - - 35.11 35.23 12.67 3/20/04 3 days Concentration (mg/L) 145.32 143.19 176.52 149.53 123.16 133.75 140.83 Removal rate (%) 1.47 - - 15.25 7.97 3.10 4/14/04 3 days Concentration (mg/L) 193.92 156.51 176.77 186.96 73.49 69.26 76.03 Removal rate (%) 19.29 8.85 3.59 62.10 64.29 60.79 5/15/04 3 days Concentration (mg/L) 130.50 88.53 129.24 115.21 58.04 50.71 59.53 Removal rate (%) 32.16 0.97 11.72 55.53 61.14 54.38

table 3

TP concentration changes date hydraulic retention time sewage VF1 VF2 VF3 HF1 HF2 HF3 3/15/04 1 day Concentration (mg/L) 10.96 6.61 0.74 1.13 1.48 1.47 1.22 Removal rate (%) 39.74 93.23 89.70 86.53 86.59 88.88 4/8/04 1 day Concentration (mg/L) 14.49 7.30 1.64 3.09 2.52 1.87 1.83 Removal rate (%) 49.61 88.65 78.66 82.58 87.12 87.34 5/10/04 1 day Concentration (mg/L) 13.68 2.46 1.09 3.1 1.98 3.79 2.12 Removal rate (%) 82.02 92.05 77.33 85.52 72.27 84.52 3/17/04 2 days Concentration (mg/L) 10.97 5.79 1.38 1.56 2.33 2.40 2.37 Removal rate (%) 47.24 87.40 85.74 78.79 78.13 78.37 4/10/04 2 days Concentration (mg/L) 7.12 5.21 2.04 2.69 2.00 1.60 1.72 Removal rate (%) 26.87 71.31 62.18 71.84 77.59 75.90 5/12/04 2 days Concentration (mg/L) 9.59 1.85 1.32 2.03 1.21 1.13 1.27 Removal rate (%) 80.71 86.27 78.86 87.37 88.18 86.79 3/20/04 3 days Concentration (mg/L) 15.30 7.11 0.62 1.94 1.81 1.74 1.40 Removal rate (%) 53.55 95.92 87.34 88.17 88.68 90.87 4/14/04 3 days Concentration (mg/L) 13.41 5.62 4.06 2.66 2.31 2.08 2.20 Removal rate (%) 58.12 69.69 80.16 82.80 84.47 83.58 5/15/04 3 days Concentration (mg/L) 8.83 3.53 1.07 2.10 1.23 1.00 1.03 Removal rate (%) 60.05 87.87 76.18 86.12 88.65 88.35

Table 4

Claims (2)

1. Domestic sewage vertical flow-horizontal flow compound constructed wetland nitrogen and phosphorus removal method is characterized in that the vertical flow constructed wetland is first and the horizontal flow constructed wetland is connected in series to form a composite constructed wetland. The domestic sewage first passes through the vertical flow Constructed wetland, and then pass through the horizontal flow constructed wetland, and let part of the untreated sewage directly enter the horizontal flow constructed wetland to supplement the carbon source, place blast furnace slag in the bed of the vertical flow constructed wetland, and place slag in the bed of the horizontal flow constructed wetland , and use blast furnace slag as the covering material on the surface of the bed; plant terrestrial flowers and fresh-cut flowers on the vertical flow artificial wetland substrate, and plant vegetables on the horizontal flow artificial wetland substrate. 2. The nitrogen and phosphorus removal method according to claim 1, characterized in that: terrestrial flowers are cannas, fresh-cut flowers are roses; vegetables are watercress, water spinach, leeks, lettuce, cucumbers, tomatoes, arrowroot and wild rice stems .

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