Degradation of Nonylphenol Ethoxylates during the Composting of Sludges from Wool Scour Effluents

Abstract

The aqueous scouring of raw wool produces an effluent that typically has a pollution load of at least 10 times that of domestic sewerage. The bulk of these pollutants may be removed by the SIROLAN-CF chemical flocculation process to produce a clear effluent and a sludge rich in wool wax. This sludge also contains practically all of the wool scouring detergent initially present in the untreated effluent. As the most commonly used detergents for this purpose, nonylphenol ethoxylates (NPE), are toxic to the environment, their fate must be carefully evaluated when disposal options for these sludges are considered. This paper examines the fate of NPE and the metabolites produced during the composting of a mixture of these sludges and municipal greenwaste. Over 14 weeks the NPE residues were decreased by >96%. The principal degradation pathway involved the oxidative hydrolytic shortening of the poly(ethylene oxide) chain of the hydrophile to produce low levels of the biorefractory metabolites nonylphenol (NP), ...