Urea and Ammonia Influent Limits to Sequencing Batch Reactor Using Wastewater Plant Simulator in a Chemical Fertilizer Plant

A wastewater treatment plant at a petrochemical facility in Malaysia was simulated to assess and improve nitrogen removal performance. The study aimed to identify safe influent limits for urea and ammonia to ensure compliance with discharge standards and to optimize molasses dosing in the sequencing batch reactor (SBR) system. Using the BioWin Process Simulator 6.2, a model of the SBR was developed and calibrated with 6 months of operational data, and achieved results within 10% accuracy. A step change and a gradual increment were applied for urea and ammonia, individually, to investigate the limits. Results showed that the SBR could handle influent urea and ammonia levels up to 300 and 75 mg/L, respectively, without compromising performance. However, the system exhibited low denitrification efficiency, indicated by high nitrate levels in the effluent. This can be improved by increasing molasses injection to enhance microbial activity. This study provides valuable insights for model-based methods for optimizing wastewater treatment plant operations, ensuring compliance with environmental standards and enhancing environmental sustainability.