| Livestock waste, especially in large-scale pig farms have a high concentration of aquaculture wastewater has become a major source of pollution in many regions, no direct discharge of treated wastewater pollution of breeding water bodies downstream, resulting in the death of biological water so that the next water body loss of self-repair capabilities; farming produce odor of sewage, polluted the air around the plant and the surrounding villages of the living environment; breeding farm dirty water can lead to a large number of compaction, the accumulation of a large number of pollutants in the soil makes the land loss of use value.Despite the high concentration of aquaculture wastewater for return to field use or use of natural treatment systems for processing, but the two processing mode requires a lot of land, most of the breeding factory does not have this condition; in the industrial processing mode, the use of aerobic processes to deal directly with the HRT and aeration for a long time, resulting in project investment and daily operating costs are high, limiting its application; anaerobic an aerobic combined process is the more general method, can be produced by anaerobic digestion after ammonia nitrogen in the aerobic degradation of post-processing is a new problem; direct the use of artificial wetlands can be a better treatment effect, can also have a big problem area, while the design of constructed wetlands there are difficulties in dealing with extremely complex mechanism The actual operation results are unsatisfactory. For this problem, according to a pig farm in Jiangxi field situation, using the UASB, SBR, stabilization pond aquaculture combined process of high concentration wastewater, effluent COD value of the average of 240.8mg/L, ammonia nitrogen value of the average of 46.5mg/L , SS value is an average of 80.7mg/L, the effluent quality meet the national requirements of "emission standards for livestock and poultry", testing the combined process of aquaculture wastewater treatment can achieve better results for the high concentration of aquaculture wastewater processing provides a new treatment ideas.New combined process wastewater aquaculture farms, the main results obtained are as follows:(1) Aquaculture wastewater degradation of COD and ammonia nitrogen from the molecule to a small molecule, and then absorbed by microbial degradation process. Using UASB macromolecules into small molecules in the process of degradation of some organic compounds are; SBR aerobic activity was higher in the aerobic microorganisms and rapid degradation of small molecules; biological stabilization pond in the physical, chemical and biological interaction Most of the nitrogen can be absorbed, these factors make the combination process of high concentration of COD in wastewater aquaculture removal of 98.9%, 95.1% ammonia removal there, SS with 93.7% removal efficiency, better treatment results.(2) Combined process of designing new ideas, the size of the structures and equipment, process operating parameters. Analysis of UASB, SBR, and stability out of the water pond of their own data, get the process on COD removal efficiency of each individual, including UASB reached 74.9%, SBR 73.2%, 34% stabilization pond.(3) Compare the current domestic and international aquaculture wastewater treatment process, to compare the effects of their effluent, aquaculture wastewater derived from a variety of techniques including the advantages and disadvantages. HRT direct aerobic treatment usually takes 15 days, leading to treatment tank doubles investment, high running costs. Anaerobic treatment of the effluent COD is generally 1500mg/l, reach the discharge standards, the general need to be combined with other techniques. Anaerobic and aerobic treatment of ammonia emissions in this process the water content of 164mg/l, reach the emissions standards, of which the main reason is the absorption of microbial nitrogen reach the speed of absorption of carbon, the process of running the treatment of nitrogen is a problem. Combined process of emission of ammonia was 46.5mg/L, to solve this problem.(4) The water treatment process fail to deal with emissions standards, explain the design ideas, the role of the various structures. Construction of the Central Plains anaerobic tank sealing performance is not good, affected the growth of anaerobic microorganisms; no sludge return system. Less than the design of anaerobic treatment efficiency requirements, the subsequent aerobic treatment influent concentration is too high, the treatment effect is not satisfactory, the sewage discharged into the stabilization pond than the design load concentration, COD concentration of the actual emissions of 2264mg/L, not meet emission standards for drainage.(5) High concentrations of aquaculture wastewater in the process can produce methane, toxic and hazardous substances in aquaculture wastewater, PH, temperature. Organic loading are within reasonable limits, in particular through the microbe is the role of bacteria produce large amounts of methane gas, for breeding plant to provide energy and heat, a better economic efficiency.(6) Analog simulation of anaerobic reactor - aerobic process, UASB obtained in the simulation the best control point in the 6.8-7.2 pH, temperature, the best control point 33℃-35℃; SBR process can be in the 25d 87% of aquaculture wastewater COD removal removal; SBR Reactor UASB anaerobic digestion effluent ammonia nitrogen content of 50 mg / L -113 mg / L between the removal rate of 63%-73%. Using UASB, SBR, combined process stabilization pond aquaculture wastewater effluent quality in the experiments meet the national emission standards. |
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