| Abstract: | Ozone pretreatment studies of organic compounds that are difficult to biodegrade were conducted to evaluate the effects of ozonation on biodegradability of these compounds. Initial testing was conducted in batch activated sludge experiments with and without preozonation to evaluate the impacts of ozonation on the ultimate BOD/COD and ultimate BOD/TOC ratios of these compounds. Experimental results indicated wastewater preozonation to be an effective pretreatment step for some compounds, ineffective for other compounds and detrimental to biological treatment of still other compounds. These same compounds were then investigated in continuous flow, complete–mix activated sludge systems. Complete material balances, including influent, effluent, waste sludge and off–gas specific compound analyses, were conducted so that the actual fate of the compound could be determined. Removal mechanisms of the ozonated or unozonated compound were then determined to be biodegradation, stripping, or sorption to the biomass. Three compounds were investigated: acrylonitrile, 2,4 dinitrophenol, and 1,2 dichloropropane. |
