Application Research On Anaerobic And Aerobic Treatment Process Of Silicone Wastewater

The silicone manufacturing in China is developing rapidly.At the end of 2021,China ’s silicone production capacity was 1.88 million tons,accounting for 62 % of the world.At the same time,the pressure of wastewater treatment in silicone production enterprises is increasing.The organic silicon wastewater contains a variety of pollutants,which is difficult to be discharged directly by biochemical treatment,and the feasibility of complete physical and chemical treatment is poor.Silicone wastewater treatment generally needs to be pretreated by physical and chemical pretreatment and then discharged by biological treatment.In this paper,the ’ UASB(up-flow anaerobic reactor)+ A / O(aerobic / anaerobic)’biological treatment process is used to treat the pretreated silicone production wastewater.(1)In this paper,the effects of different OLR lifting methods and influent water quality on the start-up of UASB were analyzed by UASB start-up experiment and A/O optimization operation experiment.The effects of different operating parameters DO,nitrification liquid reflux ratio,sludge reflux ratio and sludge age on the actual A/O process were analyzed.The results showed that the UASB reactor started fastest when the influent COD concentration was increased and the HRT was reduced.The OLR was increased to 5.09 COD/(m3·d)and the COD removal rate was 92.8 %.The influent was mixed wastewater(actual wastewater + simulated wastewater),and the COD removal rate of the system reached 94.9 % and the start-up was completed 10 days in advance.The impact of operating parameters on A/O was ranked as: sludge reflux ratio > DO >nitrification liquid reflux ratio > sludge age.DO = 3.0 mg/L,nitrification liquid reflux ratio = 150,sludge reflux ratio = 80,sludge age = 21 d is the best combination of operating parameters.(2)Referring to the experimental results and analysis,the influent water quality was changed by adding nutrients in the UASB commissioning work.The OLR was increased to the design value by increasing the influent COD concentration and reducing the HRT,and the proportion of actual wastewater in the influent was increased by stages until 100 %.After 82 days of debugging,the influent COD concentration was about 5500~6000 mg/L,the effluent COD concentration was about 1200 mg/L,and the COD removal rate finally reached about 80 %.The commissioning of the A/O pool lasted 58 days.When the commissioning was completed,the influent COD concentration of the system was 1000~1100 mg/L,the ammonia nitrogen concentration was 110~120 mg/L,and the total nitrogen concentration was 120~135 mg/L;the effluent COD,ammonia nitrogen and total nitrogen concentrations were stable at about250 mg/L,23 mg/L and 30 mg/L,respectively.The removal rate of COD was 75~80 %,and the removal rates of ammonia nitrogen and total nitrogen were close to 80 %.After debugging,the water quality was monitored for 60 days.After biochemical treatment,the effluent COD,ammonia nitrogen and total nitrogen concentrations were stable at about 220 mg/L,20 mg/L and 30 mg/L,and the removal rates were 96 %,82 % and80 %,respectively,which met the park takeover standards.The average annual emission reductions of COD,ammonia nitrogen and total nitrogen reached 569.42 t,10.21 t and 12.27 t,respectively,with good environmental benefits.