Batch aerobic treatment of a pharmaceutical wastewater

This objective of the study was to determine the effect of temperature on the treatment efficiency of COD (chemical oxygen demand) from pharmaceutical wastewater by batch activated sludge reactors and a two stage activated sludge reactors Batch activated sludge reactors were operated at various temperatures from 30 to 70 UC. Soluble COD removal efficiency decreased from 62% to 38% as temperature increased from 30 UC to 60 UC. When temperature was higher than 60UC the aerobic biological treatment was not effective. For the two-stage biological treatment process better soluble COD removal was achieved when both reactors were operated at 30 UC compared to the 2 stage treatment system where the temperature was maintained at 55 UC and 30 UC for the first and second stage, respectively. The first 2-stage system (30 UC and 30 UC) reduced COD from 2800 to 1450 mg/L, while the second 2-stage system (55 UC and 30 UC) reduced COD from 3650 to 1900 mg/L. The results indicated the maximum temperature for pharmaceutical wastewater treatment was from about 60-65 UC. A two stage aerobic treatment system produced a good quality of effluent when both reactors were operated at 30 UC compared to a system where the 2 stage reactors were consecutively operated at 55 and 30 UC, respectively.