Optimization of SAR Mongstad Biological Wastewater Treatment Plant with Mass Balance Analysis and Bioprocess Modelling

Abstract

This study focuses on process optimization for the largest polluted industrial wastewater treatment facility in Norway, which belongs to SAR Gruppen AS at Mongstad. The wastewater composition includes a mix of hazardous pollutants such as heavy metals and petroleum hydrocarbons, which are challenging for process optimization. Given the environmental implications, continuous monitoring and optimization of the facility are crucial for maintaining efficiency and sustainability. The study’s methodology involves a multi-faceted approach, encompassing a literature study on fundamental principles of industrial wastewater treatment and industries’ best practices, mass balance analysis, experimental analysis, and bioprocess modeling using SUMO to offer the most reliable and realistic optimization. Modeling results suggest that lowering the operational sludge retention time (SRT) below 20 days could enhance wastewater treatment by reducing effluent COD concentrations, facilitating better aeration performance, and easing mixing. Nonetheless, the high inorganic content and soluble bound COD in the sludge necessitate maintaining a higher SRT to address salt and inorganic removal during pretreatment, alongside investigating additional methods for persistent surfactant issues. If the SRT value is selected as 20 days, the sludge wasting flow rate should be lowered based on the calculated results. Operational improvements are recommended, including upgrading DO sensors for real-time monitoring and installing a more resilient disk filter system to enhance TSS and colloidal removal efficiency. Adjustments to the aeration regime and F/M ratio are also necessary to eliminate foaming filamentous organisms. Furthermore, automated OUR tests are suggested for future research to enhance precision and minimize human error. The anticipated outcome is a comprehensive report presenting the study's findings, with recommendations to optimize the facility. This study’s significance lies in its potential to enhance performance stability, operational efficiency, and environmental protection, contributing to advancing knowledge in industrial, specifically offshore wastewater treatment.