Efficiency assessment of aerobic biological effluent treatment plant treating pharmaceutical effluents

The present paper undertakes a study of the physico-chemical properties and toxic heavy metals content in the untreated and treated pharmaceutical effluents in order to evaluate the working efficiency of industrial effluent treatment plants. The treatment efficiency achieved for various parameters was conductivity (79.94%), alkalinity (93.91%), hardness (87.70%), chloride (89.24%), cyanide (79.66%), phosphate (99.19%), total dissolved solids (85.89%), total suspended solids (96.87%), salinity (52.41%), dissolved oxygen (27.32%), biochemical oxygen demand (83.39%) and chemical oxygen demand (72.21%). The removal efficiency achieved for different heavy metals was Cu²⁺ (79.66%), Ni²⁺ (69.22%), Cr⁶⁺ (80.15%), Pb²⁺ (72.14%), Fe³⁺ (92.59%) and Zn²⁺ (90.61%). The level of biochemical oxygen demand (64 mg L^?1) in the treated effluents was above the limit of 30.0 mg L^?1, chemical oxygen demand level (208 mg L^?1) was close to a limit of 250 mg L^?1, while average Pb²⁺ concentration (0.10 mg L^?1) was on the borderline of maximum permissible limit of 0.10 mg L^?1 set by Central Pollution Control Board for safe discharge of industrial effluent in inland surface water. The average concentration of cyanide (0.01 mg L^?1) in the treated industrial effluent of our study is of great concern to the fisheries of freshwater ecosystem in which the effluents finally get discharged. Based on the results of the present study, it is concluded that the pollution level in the discharged pharmaceutical effluent is of the great concern requiring proper treatment and regular scientific monitoring so as to protect the environmental degradation of water resources and facilitate the propagation of the aquatic life.