Performance evaluation and upgrade options for existing sequencing batch reactor for nutrient removal

Abstract

Assessment and upgrade of existing sewage treatment plants (STPs) are necessary due to the revision of the existing effluent regulations which now monitors nutrients including ammonia, nitrate and phosphates. The aim of this study is the performance evaluation of four sequencing batch reactor (SBR) type of STP based on the following parameters: biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), nitrates, ammonia, phosphates and pH; and their potential upgrade based on the revised regulations stated in DAO 2016-08. Four sequencing batch reactor (SBR) type of STP were assessed for 12 weeks for this study. Results showed noncompliance with nutrient levels, thus upgrade is necessary. Analytical Hierarchy Process (AHP), a Multi-Criteria-Analysis (MCA) tool, was used to select the best option for upgrade among options that include (1) additional SBR tank, (2) diverting wastewater to another treatment facility, and (3) converting the SBR into membrane bioreactor (MBR). Considering the criterion for upgrade, option 2 was the most preferred decision followed by option 1 then option 3.