"The methods used to determine microbial degradability of organic compounds vary with the purpose of the study. River water die-away tests (Gledhill & Saeger, 1978) are effective as screening tools to detect recalcitrant organic compounds. Shake flask and chemostat experiments, either jointly or separately, provide information useful in both degradation screening and in designing treatment systems for compounds as different as surfactants (Soap & Detergent Association, 1965; Rogers & Kaplan, 1970: Gledhill, 1975; Kimerle & Swisher, 1977), plasticizers, rubber curing agents, pharmaceuticals (Gledhill & Saeger, 1978), and effluents from both petroleum refineries (Lindsay & Prather, 1977) and wood treatment plants (Vela & Rainey, 1976). Large trickling filters have proven effective in testing degradation of cresols and cresolbased stripping solvents (Cobb, et al., 1975). And, microcosms have been used to determine biodegradation, environmental uptake and fate, and bioconcentration of DDTl, its analogues, and other pesticides (e.g., Metcalf et al., 1971; Metcalf 1977; Yu et al.1974) and trace metals in sewage sludge (Lu et al. 1975)."