The Uasb-fixed Activated Sludge Treatment Of Coke Plant Wastewater Research

The UASB reactor and immobilized activated sludge process was applied to the treatment of pre-treated coking wastewater.Trace elements and co-substrate were added in order to decrease the start-up time during the start-up of UASB reactor.The total start-up time was 133 days.The optimum volumetric loading rate,pH and reflux ratio of UASB reactor for coking wastewater treatment were 2.5 Kg/m³ d,7.2 and 1.5 respectively.The COD,ammonia and phenol of effluent were about 1100 mg/L,90 mg/L and 20 mg/L,respectively.The simultaneous removal of carbon and nitrogen activated sludge was cultured by SBR technology.The total culture time was 54 days.The PVA-SA embedded system was used in the immobilization of activated sludge and saturated H₃BO₃+2%CaCl₂ solution was used as crosslinking agent.Further,the immobilized activated sludge was hardened by 1 mol/L KH2PO4 solution.The immobilized activated sludge was good balling property,high strength,resistant to aeration performance.And it was intact after used 1 year.The optimum HRT,pH,aeration volume,Liquid-solid ratio for coking wastewater treatment by immobilized activated sludge were 24h,8.5,40 L/h,4:1, respectively.The effluent concentration of COD,ammonia,nitrate and phenol were about 140 mg/L,2 mg/L,8 mg/L and0.4 mg/L respectively.The effluent can meet the secondary standards in "Integrated Wastewater Discharge Standard GB8978-1996"Kinetic analysis shows that the degradation of organic compounds of UASB was accorded with the Grau model and the equation was T/E=0.01483×T+0.017.The organic compounds degradation model of immobilized sludge was T/(S₀-S_e)=1.96402×1/S_e+0.00587.The simultaneous nitrification and denitrification of immobilized sludge was determined by the nitrification process.There was not accumulation of nitrate during the removal of nitrogen process.The model of nitrogen removal was Ln(S₀/S_e)/(S₀-S_e)=0.12648×T/(S₀-S_e)+0.00192.