Assessing the Effectiveness of Common Effluent Treatment Plants (CETPs) in the State of Gujarat, India Using Reliability Analysis

Common effluent treatment plants (CETPs) are integrated wastewater treatment systems meant to function as a consolidated process for several industrial units from a single industrial area. CETPs are installed as a common treatment plant to provide a uniform treatment system along with space and cost effectiveness and play an important role in industrial wastewater treatment and management. However, due to several reasons, including the varied nature of influent pollutants, the inability of CETPs to effectively treat wastewater can lead to contamination of water bodies in the city. Ahmedabad is an industrialized city in the state of Gujarat in India, where currently seven CETPs discharge their wastewater into the Sabarmati river. Due to the increased pollution in the Sabarmati river, it is necessary to evaluate the performance of these CETPs for their quality of wastewater treatment. The aim of this study was to present a reliability analysis of these CETPs using statistical data obtained from official Government websites. An established methodology was used to calculate the coefficient of reliability in terms of compliance of effluent chemical oxygen demand, biochemical oxygen demand, ammoniacal nitrogen, and phenolic compounds. The results revealed significant variations in the reliability levels across all CETPs. The reliability levels ranged from 7 - 99.99 % for COD, 25.5–99.99 % for BOD, 46.8–99.4 % for SS, 41.2–99.8 % for NH₃-N, and 85.2–98.1 % for PC. These discrepancies can be attributed to improper functioning in majority of CETPs. Further, the required operating mean concentrations for the studied parameters were obtained to improve the reliability level to 95 %. This study should definitely help the wastewater community as it can be applied to individual wastewater treatment plants to achieve optimum treatment performances.