CN103880244A - Comprehensive treatment method for liquid dung of livestock and poultry and domestic wastewater in country - Google Patents

Abstract

A technical process and method for treating rural livestock and poultry manure and domestic sewage generated by humans, which solves the problems of arbitrary discharge of comprehensive wastewater from farmers and lack of supporting treatment facilities. The technical scheme adopted is: after mixing the domestic sewage of farmers and livestock and poultry feces and sewage at a weight ratio of 1:1, they are pretreated through coarse screens, sump tanks, and fine screens in sequence, and then pass through anaerobic biological filters, two Stage biological aerated filter and artificial wetland for treatment. The anaerobic biological filter degrades macromolecular organic matter into small molecular organic matter, increasing the biodegradability of wastewater, and the effluent from the secondary aerated biological filter is returned to the anaerobic biological filter for denitrification and denitrification; the two-stage aeration mainly It is used to remove most of the organic matter, and convert most of the ammonia nitrogen into nitrate nitrogen through the action of nitrifying bacteria; the artificial wetland is mainly used for further purification of wastewater, so that the effluent can meet the discharge standards.

Description

A comprehensive treatment method for livestock and poultry manure and domestic sewage in rural areas

technical field

The invention relates to a treatment method for comprehensive rural wastewater, that is, livestock and poultry wastewater and human domestic sewage, and belongs to the field of wastewater treatment technology and rational utilization.

Background technique

With the rapid development of the rural economy, the discharge of comprehensive rural wastewater has gradually increased, which has deteriorating the environmental conditions in rural areas, and the environmental quality has declined significantly, directly threatening the living environment and health of the broad masses of farmers, and restricting the healthy development of the rural economy. .

Rural households often raise 2 to 5 pigs. Compared with humans, livestock and poultry produce more wastewater. The amount of sewage produced by a pig is 7 times that produced by a person. At the same time, due to the small scale and wide scope of the aquaculture industry, it is difficult to implement unified collection and treatment, so that the comprehensive wastewater from farmers cannot be effectively treated, and most of the wastewater will eventually flow into rivers and rivers. At present, rural comprehensive wastewater has become one of the main sources of water pollutants.

At present, the main modes of domestic sewage treatment in rural areas are: 1. Building traditional septic tanks. Traditional septic tanks have disadvantages such as poor ability to remove organic matter, non-compliance with hygienic standards, regular excrement pumping, large transportation volume, and inconvenient management. 2. Build biogas digesters and build a large number of biogas digesters, but the treatment efficiency of biogas digesters for comprehensive wastewater is greatly affected by temperature, and the wastewater generated by farmers is directly discharged. 3. New rural sewage treatment methods, such as artificial wetland treatment, land treatment, activated sludge method, etc. However, it is mainly aimed at the rural domestic sewage generated by people. So far, there is no treatment method for the comprehensive wastewater produced by individual farmers, livestock and poultry. For example, the patent "A Low Energy Consumption Self-Circulating Rural Sewage Treatment Method", patent application number 201310006853.1, is a treatment method mainly aimed at domestic sewage generated by humans, and the comprehensive wastewater generated by farmers cannot be effectively treated by this method. At present, there are relatively few studies on comprehensive rural wastewater treatment. Compared with the maturity and diversification of unified collection and treatment technologies, there is still a lack of research on decentralized sewage treatment, and the technology for rural comprehensive wastewater is even more scarce. Therefore, according to the characteristics of rural comprehensive wastewater pollution, it is very necessary to study appropriate rural comprehensive wastewater treatment processes and methods. the

Contents of the invention

In order to overcome the problems of low comprehensive wastewater treatment rate in rural areas and easy pollution to the environment, the present invention proposes an anaerobic biological filter-primary biological aerated filter-secondary biological aerated filter-ecological wetland treatment process for Treatment of comprehensive wastewater generated by rural farmers.

The present invention achieves the above object like this:

A comprehensive treatment method for livestock and poultry manure and domestic sewage in rural areas, including wastewater pretreatment, pre-denitrification biological filter treatment and wetland treatment, pre-denitrification biological filter treatment includes upflow anaerobic biological filter treatment, Two-stage upflow aerobic biological filter treatment.

Mix domestic sewage and poultry manure 1:1 and filter it through a 50 mm grid, equalize wastewater in the sump, and filter with a 3 mm grid to remove suspended solids in the comprehensive wastewater, on the one hand prevent debris from clogging the water inlet pipe and biological The filter tank realizes the uniform distribution of air and water. On the other hand, the 50 mm grid filter, the water collection tank equalizes the waste water, and the waste residue generated by the 3 mm grid filter can be organically composted to provide organic fertilizer for farmers' crops. The pretreated wastewater is sent to an upflow anaerobic biofilter containing cinder filler at a flow rate of 90 mL/min, and the hydraulic retention is 4 hours. The dissolved oxygen concentration in the upflow anaerobic biofilter is lower than 1 mg/L , where the filter material accounts for 1/5~1/3 of the volume of the filter tank. Due to the large specific surface area of cinder, microorganisms are easy to grow on the surface of cinder, which improves the biodegradability of wastewater, and can remove part of COD at the same time. The total COD removal rate up to 40%. The wastewater after anaerobic treatment is sent to the first-stage upflow biological aerated filter containing cinder filler for treatment, and the hydraulic retention is 3h. The dissolved oxygen concentration in the first-stage upflow biological aerated filter is higher than 4 mg/L , where the filter material accounts for 1/4~1/3 of the volume of the filter tank, the comprehensive wastewater concentration in the first-stage biological aerated filter is relatively high, and there are a large number of bacteria and ciliates in the biological filter tank that are suitable for high-concentration wastewater Most of the organic matter and ammonia nitrogen are removed here. After this stage of treatment, the removal rate of total COD can reach 67.76%, and the removal rate of ammonia nitrogen is 89.02%. Then pass through the secondary upflow biological aerated filter with coal cinder as the filler. There are a large number of microorganisms such as caterpillars, rotifers, and nematodes in the biological filter that are suitable for low-concentration wastewater. The comprehensive wastewater is further treated, and the hydraulic retention is 3h. , the dissolved oxygen concentration in the first-stage upflow biological aerated filter is higher than 4 mg/L, wherein the filter material accounts for 1/4~1/3 of the filter volume, and the total COD removal rate after the second-stage aeration Reached 75%, ammonia nitrogen removal rate reached 99.32%. The secondary aeration effluent flows back into the anaerobic biological filter for denitrification and denitrification, and due to the dilution of the reflux water, the pre-denitrification process has higher stability in removing COD and NH ₃ -N. The treated water finally flows into the artificial wetland treatment system to further purify the effluent. The filler of the constructed wetland treatment system is divided into three layers, which are soil, cinder and gravel from top to bottom.

The advantages of this rural comprehensive wastewater treatment process and method: (1) Low power consumption and small footprint. The power system of the present invention is a peristaltic pump and two electromagnetic air pumps; the sump pool, anaerobic pool, and aeration pool in the treatment device are all replaced by plastic barrels or plastic boxes, which occupy a small area. (2) The operation of the treatment process is simple, the input cost, operating capital and maintenance cost are relatively low, the daily maintenance and management are simple, and the equipment can be operated intermittently. If it is not used for a long time, the facility can resume normal operation within a few days . Once the equipment is running, there are no additional costs other than proper management. (3) Effectively remove organic matter, nitrogen, phosphorus and other pollutants. Since the wastewater has undergone four stages of hydrolysis, acidification, acid production and methane production in the anaerobic biofilter, the macromolecular organic matter can be degraded into small molecular organic matter, which improves the biodegradability of the wastewater and improves the treatment effect of the wastewater .

Description of drawings

The method will be further described below in conjunction with the accompanying drawings.

Figure 1 is a flow chart of the rural wastewater treatment process.

Figure 2 is a diagram of the removal efficiency of comprehensive wastewater by the treatment process.

Detailed ways

Below in conjunction with accompanying drawing, this treatment technological process and method are described in detail

Figure 1 is a flow chart of the rural comprehensive wastewater treatment process. After the livestock and poultry wastewater is mixed with the domestic sewage generated by humans, it is pretreated through coarse screens, sump tanks, and fine screens in sequence, and then the comprehensive wastewater is treated through anaerobic biological filters and two-stage aerated biological filters, and part of the treated water Return to the anaerobic biological filter for denitrification and denitrification, and the wastewater after aeration treatment flows into the constructed wetland system for further treatment of the wastewater to purify the water quality. The role of the coarse grid is to remove large suspended matter and floating matter; the sump has the function of a grit chamber to remove larger particles; the fine grid is mainly used to remove smaller suspended matter in the wastewater to prevent clogging of the peristaltic pump water inlet pipe. Anaerobic biological filter is mainly used to degrade macromolecular organic matter into small molecular organic matter through hydrolysis and acidification, improve the biodegradability of wastewater, and simultaneously perform denitrification and denitrification; two-stage biological aerated filter is mainly used to remove Most of the organic matter, and under the action of nitrifying bacteria, ammonia nitrogen is converted into nitrate nitrogen. The artificial wetland is mainly to further treat the effluent from the aeration tank to purify the water quality again. The mechanism of the wetland treatment system for wastewater purification is multifaceted, including physical settlement, chemical precipitation, soil adsorption, and microbial metabolism. effect. The effluent of the wetland system can meet the standard discharge.

Figure 2 takes the integrated wastewater from rural retail households in the Three Gorges Reservoir area as the treatment object, and the treatment effect diagram of the integrated wastewater by using this treatment process. The test time is 40 days, and the average values of various indicators of comprehensive wastewater are: COD 745.77 mg/L; ammonia nitrogen 336.97 mg/L; total phosphorus 28.97 mg/L. The effluent indicators are: COD 68.90 mg/L; ammonia nitrogen 1.72 mg/L; total phosphorus 3.46 mg/L. The removal rate of COD, ammonia nitrogen and total phosphorus in rural comprehensive wastewater by this treatment process varies with the monitoring time as shown in Figure 2. The average removal rates of COD, ammonia nitrogen and total phosphorus are 90%, 99.44% and 87.2%, respectively. The treatment process has a good effect on the comprehensive wastewater treatment in rural areas, and the effluent water quality meets the national farmland irrigation water quality standards. The treated water can be used for artesian irrigation water before and after farmers' houses.

Claims (9)

1. A comprehensive treatment method for livestock and poultry manure and domestic sewage in rural areas, including wastewater pretreatment, pre-denitrification biological filter treatment and wetland treatment, characterized in that: the pre-denitrification biological filter treatment includes upflow denitrification Oxygen biological filter treatment, two-stage upflow aerobic biological filter treatment. 2. The comprehensive treatment method of rural livestock and poultry manure and domestic sewage according to claim 1, characterized in that: said wastewater pretreatment is to mix domestic sewage and poultry and livestock manure at a ratio of 1:1 to 3 and then sequentially Filtrate through a grid with a gap of 50 mm, equalize the waste water in the sump, and filter with a grid with a gap of 3 mm. 3. The comprehensive treatment method of livestock and poultry manure and domestic sewage in rural areas according to claim 1, characterized in that: the pre-treated biological filter for denitrification is to treat the pretreated waste water with 90 ~ 100 mL/ The flow rate of min is sent to the upflow anaerobic biological filter with a hydraulic retention time of 4 h; the wastewater after anaerobic treatment enters the first-level upflow biological aerated filter in sequence, with a hydraulic retention time of 3 h, and the second-level upflow biological aerated filter The filter tank has a hydraulic retention time of 3 hours; the secondary aeration effluent flows back into the anaerobic biological filter at a flow rate of 90-100mL/min, and the remaining secondary aeration effluent is used for wetland treatment. 4. the comprehensive treatment method of rural livestock and poultry manure and domestic sewage according to claim 3, characterized in that: the dissolved oxygen concentration in the upflow anaerobic biofilter is lower than 1 mg/L, wherein the filter material accounts for 1 mg/L of the filter. 1/5~1/3 of the volume. 5. the comprehensive treatment method of livestock and poultry manure and domestic sewage according to claim 3, characterized in that: the dissolved oxygen concentration in the first-level upflow biological aerated filter is higher than 4 mg/L, wherein the filter material accounts for 1/4~1/3 of the filter volume. 6. The comprehensive treatment method of livestock and poultry manure and domestic sewage according to claim 3, characterized in that: the concentration of dissolved oxygen in the secondary upflow biological aerated filter is higher than 4 mg/L, wherein the filter material accounts for 1/4~1/3 of the filter volume. 7. The comprehensive treatment method of rural livestock and poultry manure and domestic sewage according to claim 3, characterized in that: the anaerobic biological filter, the first-level biological aerated filter, and the second-level biological aerated filter All are equipped with fillers, and the fillers are cinders. 8. The comprehensive treatment method for rural livestock and poultry manure and domestic sewage according to claim 1, characterized in that: the wetland treatment is to send the secondary aeration water into the wetland treatment system for purification, and the wetland The treatment system is equipped with fillers, which are divided into three layers, which are soil layer, cinder layer and gravel layer from top to bottom. 9. The comprehensive treatment method of livestock and poultry manure and domestic sewage according to claim 8, characterized in that: the thickness of the soil layer is 30cm, the thickness of the cinder layer is 25cm, and the thickness of the gravel layer is 20cm.

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