Produced water was treated to Nigerian Federal Environmental Protection Agency (FEPA) discharge limits using the concept of substrate limiting thermophilic anaerobic digestion with physical adsorption. The percentages of pollutants removed from the produced water shows that the treatment efficiency was approximately 100 % and the percentage error approximately 0 %. The concentration of Total Suspended Solids (TSS) in the produced water was found to be the most potential among the pollutants in the produced water for having a coefficient of variation of 0.998 (99.8 %) followed by Biochemical Oxygen Demand (BOD); Total Dissolved Solids (TDS); Total Hydrocarbon Content (THC); Concentration of oil and Grease (COG); negative of the logarithm of Hydrogen ion concentration (pH) and concentration of Volatile Suspended Solids (VSS) with Coefficients of Variation 0.930; 0.709; 0.380; 0.331; 0.087 and 0 respectively. This shows that the concentration of Total Suspended Solids (TSS) in the produced water is the furthest away from the Nigerian FEPA discharge limit and hence the highest contributor to the pollutant level of the produced water. More so, most suspended solids in the produced water are the most toxic and hence the major aspect in the treatment of produced water is the efficiency in the removal of suspended solids whether by filtration or adsorption. Produced water must therefore be treated so as to remove the Total Suspended Solids, Biochemical Oxygen Demand, Total Dissolved Solids, Total Hydrocarbon Content, Oil and Grease, pH, Volatile Suspended Solids to the discharge limits recommended by the Nigerian Federal Environmental Protection Agency (FEPA) before discharge into the environment (land and/or water bodies) so as to safeguard the environment and ecosystem.