BIOLOGICAL TREATABILITY OF META-AMINOPHENOL PLANT WASTE-WATER CONTAINING STRUCTURAL ISOMERS OF BENZENE WITH DIFFERENT SUBSTITUENTS

Bench scale studies on treatability of combined waste water from an m-aminophenol (m-AP) manufacturing plant using acclimated activated sludge and an organic loading of 0.12 kg BOD [biological O2 demand] kg MLVSS [mixed liquor volatile suspended solids]-1 day-1 resulted in removal of .apprx. 96% BOD and 59% TOC [total organic C]. Analysis of raw and treated waste waters by HPLC [high pressure liquid chromatography] revealed that resorcinol and m-AP present in the waste water were completely removed, while m-nitrobenzene sulfonate (m-NBS) removal was only partial. In a batch system, preferential utilization of m-NBS was observed when a mixture of m-NBS and resorcinol was fed to m-NBS acclimated activated sludge. Electrolytic respirometric studies showed that O2 uptake rate of m-NBS acclimated activated sludge with m-NBS as the substrate was not affected in the presence of resorcinol. Also m-AP and metanilic acid (m-AA) had no effect on resorcinol or m-NBS removal by respective acclimated activated sludges. The incomplete removal of m-NBS from combined waste water may have been due to the metabolic interaction between m-NBS and an unidentified compound which appeared in the HPLC chromatograms of the raw and treated waste waters.