ANAEROBIC DEGRADATION OF XENOBIOTICS BY ORGANISMS FROM MUNICIPAL SOLID-WASTE UNDER LANDFILLING CONDITIONS

The potential for biological transformation of 23 xenobiotic compounds by microorganisms in municipal solid waste (MSW) samples from a labor atory scale landfill reactor was studied. In addition the influence of these xenobiotic compounds on methanogenesis was investigated. All R1 1, 1,1 dichloroethylene, 2,4,6 trichlorophenol, dimethyl phthalate, ph enol, benzoate and phthalic acid added were completely transformed dur ing the period of incubation (> 100 days). Parts of the initially adde d perchloroethylene, trichloroethylene, R12, R114, diethyl phthalate, dibutyl phthalate and benzylbutyl phthalate were transformed. Methanog enesis from acetate was completely inhibited in the presence of 2,5 di chlorophenol, whereas 2,4,6 trichlorophenol and R11 showed an initial inhibition, whenafter methane formation recovered. No transformation o r effect on the anaerobic microflora occurred for R13, R22, R114, 3 ch lorobenzoate, 2,4,6 trichlorobenzoate, bis(2 ethyl)hexyl phthalate, di isodecyl phthalate and dinonyl phthalate. The results indicate a limit ed potential for degradation, of the compounds tested, by microorganis ms developing in a methanogenic landfill environment as compared with other anaerobic habitats such as sewage digestor sludge and sediments.