Sewage Treatment Plants (STP's) are designed and constructed with an aim to manage wastewaterso as to minimize or remove organic matter, solids and other pollutants before it enters a waterbody. Although a lot of work has been carried out regarding STP Performance evaluation withdifferent technologies by various researchers, but not much emphasis has been given ondevelopment of regression model of Biochemical Oxygen Demand (BOD) removal efficiency forActivated Sludge Process (ASP), Extended Aeration (EA) and Densadeck/BIOFOR. Hence thisresearch work will emphasis on the comparative performance analysis of STP's along with theabove-mentioned technologies used for the treatment of sewage. Development of regression modelfor the same can help in deciding that which technology will be better suited for treatment of whichcomposition of wastewater. The models obtained will further help in deciding the combination ofthe above-mentioned technologies which can be used to optimise the desired output in variousindustries. Different attributes of assessing the performance of the STP's working on differenttechnologies are taken into consideration and at the final stage of the research work.