This document provides an overview of common effluent treatment plants (CETPs) in India. It discusses how CETPs were originally promoted to reduce wastewater treatment costs for small and medium industries. It then describes the typical wastewater treatment processes used at CETPs, including preliminary treatment, primary treatment, secondary treatment and tertiary treatment. The document also discusses advantages and disadvantages of CETPs, different disposal methods for treated wastewater, and provides case studies of three CETPs in India.