Comparison of Biodegradation of Nonylphenol Propoxylates with Usage of Two Different Sources of Activated Sludge

Aerobic biodegradation behaviour of nonylphenol propoxylates was investigated in two tests with different sewage sludge as inocula. The samples containing target compounds were pre-concentrated using dispersive liquid–liquid microextraction and analysed with the use of high performance liquid chromatography with tandem mass spectrometry. Both primary biodegradation and formation of different biodegradation by-products were studied. Primary biodegradation of nonylphenol propoxylates was relatively slow and reached only about 70 % in over 70 days from the start of the tests. The biodegradation by-products from both oxidative and non-oxidative pathways were found. In the non-oxidative route, shortening of the propoxy chain was observed. In the oxidative pathway carboxylic acids and ketones were identified. The biodegradation by-products identified with the use of mass spectrometric detection also persisted for many days.