Extraction of nonylphenol and nonylphenol ethoxylates from sewage sludge using the pressurized fluid extraction method and the supercritical fluid extraction method

Abstract

To establish endocrine disruptor (ED) monitoring and control methods for wastewater treatment plants, it is necessary to clarify the fate of EDs in each process of a sludge treatment system. However, the ED analysis method for sewage sludge containing large quantities of organic matters has not been established. So, a highly reliable analytical method that accurately measures EDs in sewage sludge must be developed. This paper reports on the results of applying the Pressurized Fluid Extraction (PFE) method and the Supercritical Fluid Extraction (SFE) method to the extraction of nonylphenol (NP) and nonylphenol ethoxylate (NPnEO) existence of which has often been confirmed in past surveys. To clarify the quantity of EDs in sludge specimens and the fate of EDs in the sludge treatment process, appropriate analytical methods should be developed. In this study, the PFE method and the SFE method were tested to extract NP and NPnEO from sewage sludge specimens. The findings indicate that the extraction from dried sludge by the PFE method can extract a larger quantity of NP and NPnEO in a shorter time than the widely used heating reflux method. Regarding the extraction by the SFE method, conditions for extraction of NP and NPnEO at a higher rate than the heating reflux method were not found.