Study On Treatment Of Swine Wastewater By Biological Coagulation Combined With SBR

In recent years,with the rapid development of China’s pig breeding industry,the substandard discharge of swine wastewater has seriously affected the rural ecological environment.How to quickly treat piggery wastewater has become a major problem in rural environmental governance.There are many industrial methods for the treatment of swine wastewater,but these methods often have long technological process,strong technicality,high construction and operation costs,and cannot flexibly adapt to the changes in the quality and quantity of swine wastewater,so they are not suitable for the use of rural small pig farms.In this paper,the combined process of Biological Coagulation and SBR was used to treat swine wastewater.The optimal dosage of bacteria and Cao was found.The treatment effect of Biological Coagulation on swine wastewater was analyzed.The operation conditions of SBR reactor,such as aeration rate and sludge concentration,were optimized.The effect and feasibility of Biological Coagulation with SBR in treating swine wastewater were studied.The C/N、pH and metal ions in the effluent of Biological Coagulation were discussed in order to provide theoretical guidance for practical engineering application and provide a new idea for the simple and rapid treatment of piggery wastewater.The results show that:（1）bacteria and Cao have different removal ability for different pollutants in swine wastewater,and they are not suitable for treating swine wastewater alone.The results showed that the effect of compound flocculation was much better than that of single flocculation,and the optimal dosage of compound flocculation was 8%bacteria+0.4%Cao.（2）After sludge acclimation,the optimal water filling ratio and aeration rate were 1/10and 100 ml/min,respectively.The optimal operation mode was aerobic12h-anaerobic10h.When MLSS was about 4000 mg/L,SBR had the best effect on the treatment of swine wastewater.The average removal rates of COD,NH₄⁺-N and TN were 89.1%,87.9%and 52%respectively.The effluent COD of SBR was about 55 mg/L and the concentration of NH₄⁺-N was only 35 mg/L.（3）With the increase of C/N,the removal rate of NH₄⁺-N decreased slightly,while the removal capacity of TN increased significantly.When the C/N was 20,the TN of SBR effluent was only 26 mg/L;when the pH was too high or too low,the removal rate of COD and TN of SBR would be reduced;when the pH of influent was increased,the removal capacity of NH₄⁺-N would be improved.When the pH of influent was 11,the NH₄⁺-N concentration of SBR effluent was close to 0 mg/L;With the increase of NH₄⁺-N concentration,the nitrification and denitrification processes in the system were inhibited to varying degrees,and the removal capacity of NH₄⁺-N and TN in the system decreased to varying degrees.Compared with the traditional aerobic anaerobic operation mode,the removal rates of NH₄⁺-N and TN were increased by 4.1%and 12.6%respectively.（4）The results show that trace Zn²⁺can promote the denitrification process to a small extent;when the influent concentration of Cu²⁺is low,the system will not be greatly affected in the short term,but the pollutant removal capacity of the long-term operation will be reduced;when the concentration of Zn²⁺and Cu²⁺is too high,the nitrification and denitrification process will be inhibited in varying degrees,and the higher the influent concentration is,the more obvious the inhibition effect is.The stronger the inhibition of Zn²⁺and Cu²⁺on denitrification is than that on nitrification.Compared with Zn²⁺,microorganism is more sensitive to Cu²⁺and has more obvious influence on the stable operation of activated sludge system.All kinds of pollutants were effectively removed,and the concentration of pollutants in the effluent was far lower than the relevant national discharge standards.The combined process has the advantages of fast operation and low cost,which is very suitable for rural small pig farms.The combined process has good application value in livestock wastewater treatment.