DEGRADATION OF NONYLPHENOL ETHOXYLATES DURING THE COMPOSTING OF SLUDGES FROM WOOL SCOUR EFFLUENTS

The aqueous scouring of raw wool produces an effluent that typically h as a pollution toad of at least 10 times that of domestic sewerage. Th e bulk of these pollutants may be removed by the SIROLAN-CF chemical f locculation process to produce a clear effluent and a sludge rich in w ool wax. This sludge also contains practically all of the wool scourin g detergent initially present in the untreated effluent. As the mast c ommonly used detergents for this purpose, nonylphenol ethoxylates (NPE ), are toxic to the environment, their fate must be carefully evaluate d when disposal options for these sludges are considered. This paper e xamines the fate of NPE and the metabolites produced during the compos ting of a mixture of these sludges and municipal greenwaste. Over 14 w eeks the NPE residues were decreased by >96%. The principal degradatio n pathway involved the oxidative hydrolytic shortening of the paly(eth ylene oxide) chain of the hydrophile to produce low levels of the bior efractory metabolites nonylphenol (NP), nonylphenol monoethoxylate (NP EO1), nonylphenol diethoxylate (NPEO2), nonylphenoxy acetic acid (NPE1 C), and nonylphenoxyethoxy acetic acid (NPE2C). Concomitant degradatio n of the nonylphenyl hydrophobe also occurred but at about half the ra te of the degradation of the polyoxyethylene hydrophile. No metabolite s of the breakdown of the hydrophobe were observed.