Performance of simultaneous carbon, nitrogen, and phosphorus removal from vegetable oil refining wastewater in an aerobic-anoxic sequencing batch reactor (OA-SBR) system by alternating the cycle times

Abstract

Carbon (C), nitrogen (N), and phosphorus (P) pollutants are among the most common environmental contaminants in different types of industrial wastewater, and they are a pollution factor that causes the eutrophication of receiving aquatic systems. An aerobic-anoxic sequencing batch reactor (O/A-SBR) system was studied to enhance the efficiency of vegetable oil refining wastewater treatment (VORW). Reactors were exploited with a total cycle period of 24 h (20 min filling, 17 h aeration, 4 h anoxic, 2 h settling, 20 min draw, and 20 min idle). SBR efficiency was evaluated by measuring pH, turbidity, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), and nutrients such as nitrate, ammonium, and phosphate. The results showed better performance from the start of operation with COD (83%), BOD5 (94%), turbidity (80%), nitrate (93%), ammonium (96%), and phosphate (91%) removal efficiencies. As industrial wastewater treatment is an important and complicated issue regarding environmental pollution, SBR can provide a better solution. The O/A-SBR system is a promising option that the VOR industry may adopt as a pre-treatment due to its more effective, inexpensive, and simple operation for organic matter and nutrient removal.