Experimental Study On Treatment Of Secondary Effluent Of Petrochemical Industry By Ozone-Biological Activated Carbon Combined Technology

The petrochemical wastewater has characteristics of large fluctuation,complex composition and high toxicity.The traditional secondary process is difficult to meet the strict discharge standards and wastewater reuse requirements.In this paper,the removal of organic matter in petrochemical secondary effluent by ozone-biological activated carbon was studied.In this paper,the original treatment process and characteristics of the secondary effluent from a petrochemical wastewater treatment plant in Tianjin were studied.The secondary effluent was characterized by large fluctuation in quality and quantity and poor biodegradability.According to the characteristics of the secondary effluent,ozone oxidation was used for pre-treatment,the main role of pre-oxidation was to oxidize macromolecular organic matter and improve the biodegradability of the wastewater.Considering the economic indexes such as floor area and operating cost,the ozone dosage and contact time were 20 mg/L and 40 min,respectively.The adsorption characteristics of activated carbon used in wastewater treatment were studied.Through the adsorption kinetics experiment,the equilibrium of activated carbon adsorbing organic matter was reached within 60 min.Freundlich isotherm equation could describe the adsorption process of the activated carbon,taking into account the role of biological activated carbon removal of organic matter and economic factors,the contact time of biological activated carbon column was 90 min.Under the condition of the optimal test parameters,the pilot scale test was carried out.The effluent of the biological activated carbon column could meet the discharge standard of Tianjin petrochemical company,COD ? 30 mg/L,the COD removal rate was more than 50%.The effluent quality was stable and the economic performance was good.