Petrochemical wastewater treatment with aerated submerged fixed-film reactor (ASFFR) under high organic loading rate

An aerated submerged fixed-film reactor (ASFFR) was developed to treat a petrochemical wastewater with high organic loading rate, where stationary submerged biofilms were attached to net-type media (SARAN 1000D) under diffused aeration. The specific surface area of SARAN 1000D was 400 m2/m3 approximately. The organic removal ability of the reactor was tested in three lab-scale ASFFRs. The reactor demonstrated 91.8-96.6% removal efficiencies of soluble chemical oxygen demand (SCOD) and exhibited efficient and stable performance at organic loadings of 1.02-6.21 kg COD/m3 day. When the media packing ratio increased the COD removal efficiency increased, while the effluent COD and SS concentrations were stable. The organic removal rates were dependent on the effluent SCOD concentration and the reaction orders were the same as or lower than 0.5. Based on the experimental results, the ASFFR should be very suitable for treating petrochemical wastewater with relatively high organic loading rate.