Treatment of high-strength, complex and toxic chemical wastewater: End-of pipe 'best available technology' vs. an in-plant control program

A case study is presented, in which two approaches to the treatment of complex chemical wastewater are experimentally compared: an end-of-pipe 'best available technology' option and an in-plant source segregation program. Both options proved to be feasible. Application of the powdered activated carbon treatment (PACT®) process for the combined end-of-pipe stream yielded up to 93% reduction of dissolved organic carbon, with complete toxicity elimination. In order to examine the potential for applying a conventional activated sludge process, a simplified laboratory screening procedure was devised, aimed at establishing baseline data of removability potential, defined either by biodegradation, activated carbon adsorption or volatilization. Using this procedure, the major source of the non-biodegradable fraction in the combined park's wastewater was traced to a single factory, from which twelve individual source streams were screened. The results allowed the division of the tested sources into three groups: degradable, volatile, and problematic. A modified wastewater segregation and treatment program was accordingly proposed, which should allow an efficient and environmentally acceptable solution. This program is presently at its final testing stages, at the conclusion of which a full comparison between the two approaches will be carried out.