Sewage treatment process

Abstract

The invention relates to the technical field of sewage treatment, in particular to a sewage treatment process which comprises the following steps: constructing a biological bed filter dam, a pretreatment tank, a microorganism module and photocatalytic treatment equipment, firstly removing suspended solids in a water body by using the pretreatment tank, improving the biodegradability, removing suspended solids in the water body by using the biological bed filter dam, and treating the water body by using the photocatalytic treatment equipment. The aquatic plants are planted in the to-be-treated water area, the aquatic plants are matched with the microbiological treatment module, the microbial activity is improved, the efficiency of microorganisms for absorbing and degrading harmful substances in the water body is improved, the photocatalytic treatment equipment is arranged to filter algae in the water body, kill bacteria in the water body and the like, and the water body treatment effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and specifically relates to a sewage treatment process and its equipment. Background Art

[0002] Water is an essential resource for the survival and development of human society. With the development of human society, sewage is generated in all aspects of human life, such as rural sewage, urban sewage, and industrial park wastewater. The sewage discharged from various environments must meet the national discharge standards before being discharged into nature. Some sewage is directly discharged into nature, and the self-adjustment and purification ability of nature is used to degrade the sewage. Usually, a relatively large water area will be formed in the area where the sewage is discharged. The water body capacity of such water areas is limited, and the water bodies are mostly water bodies with a single power source and closed slow-flow (static) water. Due to poor fluidity and poor hydrodynamic conditions, such water bodies are prone to water environment problems. The treatment efficiency of sewage in this water area by natural degradation alone is slow, and water algae will grow and stench will be emitted in the water area.

[0003] Therefore, a sewage treatment process is proposed to treat sewage in the water area where the sewage is discharged to ensure the improvement of the water quality of this water area. Summary of the Invention

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] (1) A sewage treatment process, in which a biological bed percolation dam is built in the water area to be treated to divide the water area into two parts. A pretreatment pool is built on one side of the biological bed percolation dam, and a sewage collection pipe is set to connect the pretreatment pool. A microbial module and a photocatalytic treatment device are installed on the other side of the biological bed percolation dam, and ecological plants are planted at one end of the microbial module far from the biological bed percolation dam

[0006] (2) The sewage is introduced into the pretreatment pool, and the pretreatment pool removes suspended solids and oils in the sewage to improve the biodegradability of the sewage;

[0007] (3) The water body treated by the pretreatment pool is discharged to one side of the biological bed percolation dam, so that the water body passes through the biological bed percolation dam to remove solid suspended solids, ammonia nitrogen, phosphorus and other substances in the water body;

[0008] (4) The water body treated by the biological bed percolation dam is discharged into the side close to the microbial module, and the microorganisms inside the microbial module adsorb and degrade the pollutants in the water body;

[0009] (5) The water body treated by the microbial module is introduced into the ecological plants, and the photocatalytic treatment device extracts the water body at the ecological plants for photocatalytic treatment.

[0010] Further, the aquatic plant is one of emergent plants, floating-leaved plants, floating plants, and submerged plants. Among them, the emergent plants can be lotus and calla lily; the floating-leaved plants can be Nuphar pumila; the floating plants can be water hyacinth and azolla; and the submerged plants can be Ceratophyllum demersum and Myriophyllum spicatum.

[0011] The aquatic plants have an oxygen secretion effect on the water body, use plant shading to inhibit the overgrowth of algae, maintain the balance between bacteria and algae, and form a self-sustaining purification ecosystem.

[0012] The microbial module is provided with microbial cells, which contain multifunctional bacterial groups such as organic matter decomposing bacteria, nitrifying bacteria, denitrifying bacteria, and photosynthetic bacteria, forming a synergistic metabolic network. The microbial colonies are used to remove phosphorus, nitrogen, ammonia and other substances in the water body. The combination of microbial colonies and aquatic plants can form an oxygen secretion effect and optimize the activity of microorganisms.

[0013] Perform pretreatment on the water body. Pass the sewage into the pretreatment tank for hydrolysis acidification reaction. The hydrolysis acidification reaction time is 2 - 15h to remove the suspended solids and oils existing in the water body and improve the biodegradability of the water body.

[0014] More specifically, after the pretreatment tank is built, lake water is introduced. After introducing lake water for 6 - 10 days, a variety of microorganisms are naturally enriched on the inner wall of the pretreatment tank. After 6 - 10 days, sewage is introduced, and the reaction time for introducing sewage is 2 - 15h.

[0015] Preferably, the photocatalytic treatment equipment is provided with an outlet pipe connected to the microbial module equipment. The water body treated by the photocatalytic treatment equipment in step (5) is discharged into the microbial module, and this cycle is repeated multiple times.

[0016] Further, the photocatalytic treatment steps are as follows:

[0017] (1) Algae-water separation. The photocatalytic treatment equipment is provided with a separator. The separator performs centrifugal separation on the extracted water body, uses centrifugal force to separate the clear water and algae water, and the clear water directly enters the outlet pipe and flows into the microbial module.

[0018] By setting like this, the efficiency of the overall sewage treatment process is accelerated.

[0019] (2) Photocatalytic treatment. The photocatalytic treatment equipment is provided with a catalytic converter. The separated algae water flows into the photocatalytic converter, and the ultraviolet light and venturi tube aeration act synergistically to kill the algae in the water body. The water body after passing through the photocatalytic converter flows into the microbial module through the outlet pipe.

[0020] Specifically, the water inlet of the photocatalytic treatment device is located at the water surface layer, and the water outlet pipe of the photocatalytic treatment device is connected to the bottom of the microbial module. Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] 1. Aquatic plants are planted to cooperate with the microbial degradation module to treat the water body. The microbial degradation module degrades harmful substances in the water body, and a photocatalytic treatment device is set to further catalytically filter the water body, so that the water body can obtain a good catalytic treatment effect.

[0022] 2. Water lilies are selected as aquatic plants for sewage treatment and planted in the water area to be treated. Since the comprehensive performance of water lilies in water body treatment is better than that of other aquatic plants in sewage treatment, the oxygen secretion effect is carried out by using water lilies in cooperation with the microbial treatment module, which can optimize the activity of microorganisms, enhance the activity of microbial colonies in the microbial treatment module, improve the sewage treatment effect, and at the same time, the microbial activity in the planting area of aquatic plants is also improved, and the water treatment effect of microorganisms here is enhanced.

[0023] 3. The photocatalytic treatment device and the microbial treatment module are set to cooperate. After the water body is photocatalytically treated, it flows back into the microbial treatment module, and then the remaining pollutants are adsorbed and degraded by the microbial treatment module. In this way, the water quality can be improved and meet the sewage discharge standard.

[0024] 4. The upper layer of the water area is pumped by the water inlet of the photocatalytic treatment device and sprayed from the bottom of the microbial module. The upper layer water and the bottom layer water are exchanged by the water pump on the photocatalytic treatment device, which improves the dissolved oxygen level in the lower layer, promotes the aerobic degradation of organic pollutants, and brings the nutrients (such as total nitrogen, total phosphorus, etc.) in the lower layer water to the upper layer to provide nutrients for the growth of aquatic plants and algae. The dissolved oxygen and organic matter in the upper layer water enter the lower layer, promote the metabolic activities of microorganisms, accelerate the degradation of organic pollutants, realize the recycling of nutrients, reduce the excessive accumulation of nutrients in the lower layer water, prevent it from causing eutrophication pollution to the water body, and improve the water quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic cross-sectional structure diagram of the process layout of the present invention;

[0026] Figure 2 is a schematic plan structure diagram of the process layout of the present invention;

[0027] Figure 3 is a process flow chart of the present invention;

[0028] Figure 4 is the removal effect of COD by two different bacterial agents;

[0029] Figure 5The removal effects of different bacterial agents on NH4 + -N;

[0030] Figure 6 The removal effects of different bacterial agents on NO3--N;

[0031] Figure 7 The removal effects of different bacterial agents on TN;

[0032] Figure 8 The removal effects of different bacterial agents on TP.

[0033] In the figure: 11, inlet pipe; 12, photocatalyst; 13, microbial module; 14, biological bed percolation dam; 15, pretreatment tank; 16, outlet pipe. Specific implementation manners

[0034] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] Embodiment 1

[0036] In this embodiment, the steps of microbial sewage treatment are simulated in the laboratory. The microbial agents selected in this experiment are the same as those at the construction site, and the experimental results are obtained.

[0037] 1. Prepare microbial agents and microbial colonies

[0038] The microbial agents used in this experiment are two indigenous microbial agents, agent A and agent B, cultured in this laboratory. Among them, agent A is nitrifying bacteria (Rhodococcus sp), and agent B is phosphorus-accumulating bacteria (Pseudomons sp). The two agents are configured on-site to ensure microbial activity. The test water is laboratory-prepared water, and the composition of the laboratory-prepared water refers to the elemental composition of sewage.

[0039] Table 1 Simulated sewage quality and composition in the laboratory

[0040]

[0041]

[0042] 2. Experimental method

[0043] Set up a control group, an agent A group, and an agent B group, prepare experimental water, place it in a conical flask and put it into a constant temperature shaker, set the temperature to 30.00 °C, and the rotation speed to 130 r·min -1. Sampling was carried out at 0h, 8h, 16h, 24h, 48h, and 72h at the start of the experiment to measure the removal effects of nitrogen, phosphorus, and COD in each conical flask within 72h, as well as the removal effects of pollutants in sewage under hydraulic retention times of 12h, 24h, and 48h for the two types of bacterial agents, and to explore the optimal hydraulic retention time for the operation of the microbial treatment unit.

[0044] 2.1 Experimental Results

[0045] 2.1.1 Removal Effects of Different Bacterial Agents on COD

[0046] Through the above experimental process, the removal effects of two different bacterial agents on COD are as Figure 4 shown.

[0047] At 72h, the degradation rates of COD in the control group, bacterial agent A group, and bacterial agent B group were 49.70%, 88.90%, and 86.20% respectively. The treatment groups with the addition of bacterial agents could increase the COD removal rate by 36.50% - 39.20%. When operating for 72h with an influent COD concentration of 307.00mg / L, bacterial agent A could degrade COD to 34.10mg / L, and bacterial agent B could degrade it to 42.50mg / L. The addition of bacterial agents could remove a large amount of COD in the water body.

[0048] It can be seen that putting nitrifying bacteria and phosphorus-accumulating bacteria into the microbial module (13) to treat the sewage in the water area to be measured can effectively remove the COD component in the water body.

[0049] 2.1.2 Removal Effects of Different Bacterial Agents on NH4 + -N

[0050] The removal effects of two different bacterial agents on NH4 + -N are as Figure 5 shown.

[0051] It can be seen that the removal effect of the control group on NH4 + -N is not ideal. When the influent NH4 + -N concentration is 21.60mg / L, the effluent NH4 + -N concentration is 19.70mg / L, and the degradation rate within 72h is only 8.70%; in the test groups with the addition of bacterial agents, the degradation of NH4 + -N is significantly accelerated. After 72h, the effluent NH4 + -N concentration of bacterial agent A is 2.30mg / L, and the removal rate is 89.10%; the effluent NH4 + -N concentration of bacterial agent B is 3.20mg / L, and the removal rate is 85.10%. Both bacterial agents can effectively degrade the concentration of NH4 + -N in the water body. Bacterial agent A has a better effect on NH4+ The degradation effect and degradation rate of -N are better than those of microbial agent B.

[0052] It can be seen that putting nitrifying bacteria and phosphorus-accumulating bacteria into the microbial module (13) to treat the sewage in the water area to be measured can effectively remove NH4 in the water body. + -N component.

[0053] 2.1.3 Removal effect of different microbial agents on NO3 - -N

[0054] The removal effect of two different microbial agents on NO3 - -N is as Figure 6 shown. In the control group, the NO3 - -N only decreased by 0.90 mg / L, while in the microbial agent A group and microbial agent B group, the NO3 - -N concentration can be degraded to 2.40 mg / L and 1.20 mg / L respectively at 72 h. It can be seen that the degradation efficiency of microbial agent A on NH4 + -N between 48 h and 72 h is higher than its degradation of NO3 - -N, resulting in the conversion rate of NH4 + -N to NO3 - -N being higher than the degradation rate of NO3 - -N.

[0055] It can be seen that the application of nitrifying bacteria and phosphorus-accumulating bacteria in sewage treatment can accelerate the conversion speed of NH4 + -N in sewage.

[0056] 2.1.4 Removal effect of different microbial agents on TN

[0057] The removal effect of two different microbial agents on TN is as Figure 7 shown. After operating for 72 h under the condition that the initial influent TN concentration is 39.70 mg / L, the TN effluent concentration of the control group is 36.80 mg / L, and the removal rate is 7.20%; the TN effluent of microbial agent A.

[0058] The concentration is 6.30 mg / L, and the removal rate is 84.20%; the TN effluent concentration of microbial agent B is 5.80 mg / L, and the removal rate is 85.10%. It can be seen that the removal efficiencies of the two microbial agents on TN are similar and there is no obvious difference.

[0059] 2.1.4 Removal effect of two different microbial agents on TP

[0060] As Figure 5 shown, the removal rate of microbial agent A on TP is 88.10%, that of microbial agent B is 82.10%, and that of the control group is 28.40%. At 72 h, the effluent TP concentration of the microbial agent A test group is

[0061] The effluent TP concentration of the test group with B microbial agent was 1.20 mg / L, while that of the test group with A microbial agent was 0.80 mg / L. Comparatively speaking, microbial agent A could better degrade TP in the water body, and the effluent concentration could reach the requirement for TP effluent in the first-class A discharge standard of "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002) at 72 h.

[0062] Example Two

[0063] In this example, according to the different sewage qualities of the application scenarios, hydrolysis acidification treatment was carried out for application scenarios such as urban sewage and industrial wastewater at normal temperature, and the hydrolysis acidification treatment was carried out in the pretreatment tank.

[0064] Table 2 Pollutant removal rates of the hydrolysis acidification reactor

[0065]

[0066] Example Three

[0067] Based on Example One and Example Two, in this example, plants were planted in the water area to be measured, and the plant effects generated by the plants and the microbial module (13) were used to absorb and degrade the pollutants in the water body. The water inlet pipe of the photocatalytic processor was placed in the plant planting area, the water body at the plant planting area was extracted, and the water body was filtered and subjected to photocatalytic disinfection and algae removal treatment.

[0068] The planting method is as follows: the selected aquatic plants are cultivated in the open air, and then the cultivated aquatic plants are planted around the microbial module, showing a surrounding trend around the microbial module. The types of aquatic plants shown in Table 3 can be selected.

[0069] Table 3 Varieties of experimental aquatic plants

[0070]

[0071] To clearly show the sewage treatment effect of the selected aquatic plants this time, the following experiment was carried out:

[0072] Experimental method: Select aquatic plants in the vigorous growth period, conduct open-air rain-sheltered pot experiments in coarse pottery water tanks, select fine sand as the culture medium, and set a control without plants. Select the water body in the septic tank as the detection object. The TN in the water body is 31.76 - 31.97 mg / L, TP is 3.89 - 3.94 mg / L, COD Cr is 178.87 - 178.98 mg / L, NH3-N is 23.58 - 23.69 mg / L, SS is 166.65 - 166.77 mg / L, and pH is 6.96 - 7.01.

[0073] Pour the water body into the pottery water tank planted with aquatic plants and let it stand for 1 to 80 days. Test the water body drawn from the tank every 15 days.

[0074] 3.1 Experimental results

[0075] 3.1.1 Comparison of the purification ability for solid suspended matter. The plant effect of water lily on suspended solids is 9.75%.

[0076] Table 4 Purification ability of six aquatic plants for SS

[0077]

[0078] 3.1.2 Chemical oxygen demand comparison

[0079] The plant effect of water lily on chemical oxygen demand (COD) is 17.06%, lower than that of water hyacinth (18.62%), but it performs better among plants with medium purification ability.

[0080] Table 5 Comparison of chemical oxygen demand of various plants

[0081]

[0082] 3.1.3 Total phosphorus

[0083] The plant effect of water lily on total phosphorus (TP) is 22.25%, significantly lower than that of cattail (23.03%) and reed (28.13), but higher than that of most plants with medium purification ability (such as Salvinia natans, Myriophyllum verticillatum, etc.).

[0084] Table 6 Comparison of the purification ability of 6 aquatic plants for TP

[0085]

[0086] 3.1.4 Total nitrogen

[0087] The plant effect of water lily on total nitrogen (TN) is 24.97%, lower than that of plants with high purification ability such as reed (26.29%), water hyacinth (25.54%) and cattail (26.66%), but significantly higher than that of water chestnut with low purification ability (6.21%).

[0088] Table 7 Comparison of the purification ability of various aquatic plants for NH3-N

[0089]

[0090]

[0091] Note: The plant effect represents the additional pollutant removal capacity of the plant treatment group compared to the control group without plants (natural degradation). The calculation formula is as follows:

[0092] Plant effect = (Initial pollutant concentration - Final concentration of the plant treatment group - Final concentration of the control group) / Initial pollutant concentration × 100%.

[0093] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A sewage treatment process, characterized in that: It includes the following steps: (1) Build a biological bed percolation dam (14) in the water area to be treated to divide the water area into two parts. Build a pretreatment tank (15) on one side of the biological bed percolation dam (14), set up a sewage collection pipe to connect the pretreatment tank (15), install a microbial module (13) and a photocatalytic treatment device on the other side of the biological bed percolation dam (14), and plant ecological plants at one end of the microbial module (13) far from the biological bed percolation dam (14). (2) Introduce the sewage into the pretreatment tank (15) to remove suspended solids and oils in the sewage by the pretreatment tank (15) and improve the biodegradability of the sewage; (3) Drain the water treated by the pretreatment tank (15) to one side of the biological bed percolation dam (14) so that the water passes through the biological bed percolation dam (14) to remove solid suspended solids in the water; (4) Drain the water treated by the biological bed percolation dam (14) into the side close to the microbial module (13), and the microorganisms inside the microbial module (13) adsorb and degrade the pollutants in the water; (5) Introduce the water treated by the microbial module (13) into the ecological plants, and the photocatalytic treatment device extracts the water at the ecological plants for photocatalytic treatment.

2. A sewage treatment process according to claim 1, characterized in that: The aquatic plants are emergent plants, floating-leaved plants, floating plants, and submerged plants.

3. The sewage treatment process according to claim 1, characterized in that: The microbial module (13) is provided with microbial cells, and the microbial cells contain multifunctional microbial populations such as organic matter decomposing bacteria, nitrifying bacteria, denitrifying bacteria, and photosynthetic bacteria to form a synergistic metabolic network.

4. A sewage treatment process according to claim 3, characterized in that: Introduce the sewage into the pretreatment tank (15) for hydrolysis acidification reaction, and the hydrolysis acidification reaction time is 2 - 15h.

5. The photocatalytic treatment process according to claim 4, characterized in that: The photocatalytic treatment device is provided with a water outlet pipe (16) connected to the microbial module (13) device. In step (5), the water treated by the photocatalytic treatment device is drained into the microbial module (13), and this cycle is repeated multiple times.

6. The photocatalytic treatment process according to claim 4, characterized in that: The photocatalytic treatment steps are as follows: (1) Algae-water separation. The photocatalytic treatment device is provided with a separator, and the separator centrifugally separates the extracted water to separate the clear water and the algae-water by centrifugal force. The clear water directly enters the water outlet pipe (16) and flows into the microbial module (13). (2) Photocatalytic treatment. The photocatalytic treatment device is provided with a catalytic device. The separated algae-water flows into the photocatalytic device (12), and the ultraviolet light and Venturi tube aeration are used together to kill the algae in the water. The water after passing through the photocatalytic device (12) flows into the microbial module (13) through the water outlet pipe (16).

7. A sewage treatment process according to claim 1, characterized in that: The equipment used in the sewage treatment process is directly built in the landscape lake.

8. A sewage treatment process according to claim 6, characterized in that: The water inlet of the photocatalytic treatment device is located on the water surface layer, and the water outlet pipe of the photocatalytic treatment device is connected to the bottom of the microbial module.

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