Assessment of integration options of hybrid biological reactor in a petrochemical wastewater treatment plant

Abstract

Petrochemical industrial wastewater presents a challenge when treated, employing the conventional activated sludge process, such as in the activated sludge process, the loss of biomass due to the harsh wastewater conditions and the inhibition caused by the elevated levels of industrial compounds. Hybrid biological reactors may present a resource to be tapped in the operation of an industrial wastewater treatment facility if integrated optimally in the treatment sequence. This paper examines possible integration scenarios of hybrid reactors in a petrochemical wastewater treatment plant in order to improve its organic removal efficiency. A pilot hybrid biological reactor was constructed using high surface area biological carrier and was operated using real wastewater streams from a wastewater treatment plant at two flow rates (400 ml/min and 240 ml/min), two dissolved oxygen levels (2.0 mg/l and 4.0 mg/l), and anaerobic conditions. The reactor was tested using raw, primary, secondary, and effluent streams from the wastewater treatment plant. The reactors were primed with wastewater from the aeration tank of the wastewater treatment plant and was operated for 10 d afterward (total 24 runs). The chemical oxygen demand cumulative removal was used to identify best integration scenario and to benchmark its performance against domestic wastewater. The best performing scenarios were identified as anaerobic (400 ml/min) for raw wastewater treatment and [(400 ml/min and dissolved oxygen (DO) 2.0 mg/l)] for secondary wastewater polishing. The results reflected the unfavorable conditions for biodegradation after the primary chemical treatment. This conclusion was confirmed upon benchmarking the hybrid reactor performance using domestic wastewater.