Treatability of strong wastewaters from polyester manufacturing industry

In this paper, the treatability of strong wastes originating from an organi c chemicals industry was studied. Literature data were evaluated to assess the applicability of conventional and advanced methods of treatment to high ly concentrated wastewaters. A derailed treatability study was conducted on the wastewater, which was provided from a small-scale polyester manufactur ing plant. The manufacturing process involved only esterification reactions , generating a wastewater with a COD content of over 200,000 mgl(-1). The a pplicable treatment methods to be tested were determined as biological trea tment of activated sludge process with low organic loading and chemical oxi dation with H2O2. Results Of the biological treatability study indicated th at 80% COD removal could be obtained with 10 days retention time, provided that the system was fed with a 1/100 diluted raw wastewater. Chemical oxida tion of raw wastewater with H2O2 in acid conditions and using ferric chlori de as catalyst yielded 70% COD removal. However, the dosage required to obt ain this efficiency was about 1 kg H2O2 per m(3) of wastewater. With these applications the wastewater was treated to yield a COD of lower than 2000 m g/l, Results of the study were discussed and evaluated considering complexi ty and cost of treatment. (C) 1999 Published by Elsevier Science Ltd on beh alf of the IAWQ. All rights reserved.