PERFOMANCE EVALUATION OF SEWAGE TREATMENT PLANT

ABSTRACT

‘This research work was done to evaluate the performance of the wastewater treatment plant of Omotosho Power Plant, Ondo state, Nigeria.’ The sewage treatment plant is an underground type which combines both anaerobic and aerobic (Activated Sludge Process) treatment methods. It has a design capacity of 5m3 /d. Wastewater samples were collected at the inlet and outlet of the treatment plant using standard procedures and analyzed for the major water quality parameters such as five-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids (TSS), Dissolved Oxygen (DO), et cetera, from July 2020 to June 2021. The Biodegradability Index (BI) of the raw and treated sewage was also determined in order to investigate the reduction in organic load in the raw sewage. By calculating the removal efficiencies of key biological parameters provided insight to the overall performance of the STP. The attained degree of purification for BOD5 was an average of 49.39 % while COD and TSS had mean values of 53.14% and 62.44% respectively. The mean BI obtained for the raw and treated sewage are 0.50 and 0.54, respectively, indicating that the effluent still contains a high organic load since the BI remained relatively unchanged. It is advisable to seed the raw sewage to improve the activities of the bacteria in the biological chamber for better results. The findings in this research indicate that Omotosho Power Station is not polluting Oluwa river and its environment because the water quality criteria as stipulated by NESREA for wastewater has not been exceeded. Again, the overall performance of the STP of Omotosho Power Plant is average when compared with most other STPs reviewed in this project and therefore needs further investigation to isolate the causes of its performance so that it can be optimized.’