Study On Treatment Of High COD Acetamiprid Wastewater

In this paper,acetamiprid wastewater produced by a chemical company in Lanzhou New District was the research object.According to its characteristics of high-salinity,high organic,and low biodegradability,it follows the principles of low-cost and high-efficiency treatment,Vacuum distillation,Fe/C micro-electrolysis,and Fenton oxidation were used to pretreat the high COD acetamiprid wastewater,and the best experimental conditions of each process were explored through experiments.By comparing the pollutant removal performance and wastewater treatment costs of combined processes,a plan for pretreatment of the acetamiprid wastewater was determined.And with the help of GPS-X software platform,the biological treatment process was compared,simulated and parameter optimized,so as to provide data reference for the acetamiprid wastewater and similar wastewater.The main contents of this paper are as follows:（1）The single-factor experiment of vacuum distillation show that 37.04%of COD_Crcan be removed when the distillation temperature is 50℃ without adjusting the pH of the original wastewater.The distillation process removes most of the hard-to-degrade organic pollutants such as acetamiprid.Meanwhile,reduces the ammonia nitrogen,total nitrogen and salt.When the condensate after distillation is used for subsequent pretreatment,a better pollutant removal performance can be obtained,and the costs of wastewater treatment can be reduced.（2）The single-factor experiment and response surface optimization experiment of Fe/C micro-electrolysis show that the mass ratio of Fe/C is 0.96,the dosage of Fe/C is 210.01 g/L,the pH is 3,and the reaction time is 90 min,44.64%of COD_Crcan be removed.（3）The single-factor experiment and response surface optimization experiment of Fenton oxidation show that the dosage of H₂O₂is 1.28Q_th（243.38 m L/L）,the pH is4,n（H₂O₂）:n(Fe²⁺)is 8.90,and the reaction time is 95 min,61.93%of COD_Crcan be removed.（4）By comparing the COD_Crremoval performance and wastewater treatment costs of different combined processes,the first vacuum distillation is determined in this study,followed by the combined process of Fe/C micro-electrolysis and Fenton oxidation as the pretreatment process of the acetamiprid wastewater.The single-factor experiment and response surface optimization experiment of the combined process show that:the dosage of H₂O₂is 0.77Q_th（80.93 m L/L）,the number of dosages is 3,the pH is 4,and the reaction time is 98 min,80.52%of COD_Crcan be removed,and the B/C value can be increased to 0.425.The combined process has better COD_Crremoval performance and biochemical performance on the acetamiprid wastewater than a single treatment process.Meanwhile,can save the costs of wastewater treatment.（5）Use GPS-X software platform for modeling and comparison,choose hydrolysis acidification and IFAS as the wastewater treatment plan.The single-factor simulation study of process parameters show that the residence time of the hydrolysis acidification tank is 1 day,dissolved oxygen concentration of the IFAS tank is 3 mg/L,the sludge reflux ratio is 60%,and the sludge discharge is 3 kg/d.The quality of the effluent after the optimization of the process parameters can not only be far lower than the low-concentration wastewater of the sewage treatment plant,but also can save the wastewater treatment costs.