Oil refinery wastewater treatment using coupled electrocoagulation and fixed film biological processes

Publication date: Available online 11 November 2015 Source:Physics and Chemistry of the Earth, Parts A/B/C Author(s): Laura S. Pérez, Oscar M. Rodriguez, Silvia Reyna, José Luis Sánchez-Salas, J. Daniel Lozada, Marco A. Quiroz, Erick R. Bandala Oil refinery wastewater was treated using a coupled treatment process including electrocoagulation (EC) and a fixed film aerobic bioreactor. Different variables were tested to identify the best conditions using this procedure. After EC, the effluent was treated in an aerobic biofilter. EC was capable to remove over 88% of the overall chemical oxygen demand (COD) in the wastewater under the best working conditions (6.5 V, 0.1 M NaCl, 4 electrodes without initial pH adjustment) with total petroleum hydrocarbon (TPH) removal slightly higher than 80%. Aluminum release from the electrodes to the wastewater was found an important factor for the EC efficiency and closely related with several operational factors. Application of EC allowed to increase the biodegradability of the sample from 0.015, rated as non-biodegradable, up to 0.5 widely considered as biodegradable. The effluent was further treated using an aerobic biofilter inoculated with a bacterial consortium including gram positive and gram negative strains and tested for COD and TPH removal from the EC treated effluent during 30 days. Cell count showed the typical bacteria growth starting at day three and increasing up to a maximum after eight days. After day eigh...

Source: Physics and Chemistry of the Earth, Parts ABC - November 11, 2015 Category: Science Source Type: research