Experimental Study On Treatment Of Aquatic Product Processing Wastewater By Coagulation Sedimentation +A/O Process

In 2015,the State Council issued a document calling for special treatment of wastewater discharge in China's top ten key industries.Among them,the problem of wastewater discharge from aquatic products processing industry,which is developing rapidly in the food processing manufacturing industry,is particularly prominent.Discharge of wastewater from aquatic products processing is an important part of wastewater discharge from food processing manufacturing.The state will strictly address the issue of wastewater discharge from aquatic product processing enterprises.Therefore,this thesis is based on the current "Water Quality Standards for Sewage Discharged into Urban Sewers" and "Water Pollutant Discharge Standards for Food Processing and Manufacturing Industries" in the process of being formulated by the country.The coagulation sedimentation + A/O process was used to treat wastewater from different aquatic product processing enterprises.Directly or indirectly discharge wastewater from aquatic product processing enterprises in the standard.Objective To provide technical reference for the construction and reconstruction of sewage treatment stations of aquatic product processing enterprises after the implementation of the standard.The main research contents are as follows:First of all,three coagulants,PAC,PFS,and Fe Cl3,were used to conduct coagulation precipitation experiments.Treatment of wastewater from three aquatic product processing enterprises respectively.And add appropriate amount of coagulant PAM to improve the treatment effect.During the coagulation test,a suitable coagulant was selected and the effect of the amount of the coagulant added on the coagulation effect was studied.Research indicates.When Fe Cl3 is used as the coagulant,under appropriate stirring and precipitation conditions.The dosage of coagulant was 650 mg/L.and the dosage of coagulant PAM was 2 mg/L.The coagulation test treatment effect was the best.The average removal rates of COD,SS and TP can reach 62.0%,90.7% and 92.8%,respectively.But the average removal rate of NH3-N and TN is less than 10%.Except for NH3-N and TN,the coagulated effluent water quality indicators can meet the indirect discharge standards of aquatic product processing wastewater.Secondly,the experimental research on the treatment of aquatic product processing wastewater by A/O process is carried out.The effects of the HRT,DO,and internal and external reflux ratios on the A/O system were discussed.According to the influence of the system on the removal rate of COD,NH3-N,TN,SS and TP under different conditions,a single factor experiment was carried out.During the test,the A/O process has a better treatment effect on aquatic product processing wastewater.The COD removal rate was 86.6%,the NH3-N removal rate was 86.0%,the TN removal rate was 74.9%,the SS removal rate was 79.1%,and the TP removal rate was 39.8%.Water quality: COD = 147.0 mg/L,NH3-N = 14.1 mg/L,TN = 30.2 mg/L,SS = 66.9 mg/L,TP = 6.5 mg/L.The effluent water quality can meet the indirect discharge standards for aquatic product processing wastewater,but cannot meet the requirements for direct discharge standards for aquatic product processing wastewater.Finally,coagulation sedimentation combined with A/O treatment process was used to treat wastewater from different aquatic product processing enterprises.The aquatic product processing wastewater after the coagulation treatment is allowed to enter the A/O treatment process.The HRT of the hypoxic and aerobic tanks in the control reactor were 2 h and 6 h,the dissolved oxygen content was 3 mg/L,and the internal and external reflux ratios were r = 100% and R = 300%.Under this system,the wastewater of the three aquatic product processing enterprises has a good treatment effect,and all of them can meet the requirements for direct discharge of aquatic product processing wastewater.The test results show that the coagulation and sedimentation treatment process has a better effect on the treatment of COD,SS and TP in aquatic product processing wastewater,but the coagulation test has a general effect on the treatment of nitrogenous pollutants.The effluent nitrogen-containing pollutants index cannot meet the indirect discharge standard of aquatic product processing wastewater;the A/O process treats aquatic product processing wastewater in the experimental study.The HRT,DO and reflux ratios in the optimized process are three factors that affect the treatment effect.The effluent quality of the system can reach the indirect discharge standard.But cannot handle direct emission standards;The coagulation sedimentation + A/O treatment process is used to treat the aquatic product processing wastewater.The test results show that the combined process has a good treatment effect on aquatic product processing wastewater.The aquatic product processing wastewater after treatment by the system can basically reach the direct discharge standard.The average removal rates of COD,NH3-N,TN,TP and SS in this system were 94.5%,91.9%,83.4%,93.4% and 94.2%,respectively.