INTEGRATION OF CHEMICAL AND BIOLOGICAL OXIDATION PROCESSES FOR WATER-TREATMENT - REVIEW AND RECOMMENDATIONS

The literature of studies which used a combination of chemical and bio logical degradation (usually oxidative) of organic contaminants in wat er is reviewed. Beneficial effects of such two-step treatments are com monly reported; these results, primarily for laboratory studies, sugge st potential advantages for water treatment via process integration ra ther than single technology processing. Four wastewater contaminant ty pes are identified which can benefit form combined processes; 1.) reca lcitrant compounds 2.) biodegradable wastes with small amounts of reca lcitrant compounds 3.) inhibitory compounds and 4.) intermediate dead- end products. The design key for such two-step systems lies in choosin g processes that complement each other and lead to a synergistic effec t. Predicting this performance outcome requires knowledge of the physi cal, chemical and biological properties of the major reaction intermed iates and their susceptibility to degradation by each process. Economi c, physical and technological limitations of the individual processes should be recognized for design of more effective and economical integ rated processes. The ultimate treatment goal, whether specific polluta nt removal or reduction of a global parameter such as TOC, must be kno wn so that appropriate and complementary processes can be utilized. Mo re work is needed concerning the degradation kinetics within the combi ned process, form initial attack of the primary compound through dynam ics of intermediates and on to total mineralization.