THE TOXICITY OF 4 ORGANIC-SOLVENTS COMMONLY USED IN THE PHARMACEUTICAL-INDUSTRY TO ACTIVATED-SLUDGE

The ISO activated sludge respiration inhibition test was evaluated as a tool for assessing the treatability of pharmaceutical wastewaters. The EC50 values of four test chemicals: ethylene glycol, methanol, isopropanol and acetone, were determined using different combinations of sludge and substrate types. The coefficient of variation of EC50 results within-batch was found to be 3.7% and between-batch variations ranged from 7.8 to 13.5% using sludge from a municipal treatment plant. Between-source variations were 6.72-54.05% depending on the combination of sludge and substrate used and the test chemical. The method was found to be inexpensive, rapid and accurate in terms of reproducibility and variability.