Fate of semivolatile organic compounds during heat drying of mixed primary and waste-activated sludge
Abstract:The fate of semivolatile organic compounds was studied during heat drying of mixed primary and waste-activated sludge. Selected organic compounds were spiked in the sludge collected from a wastewater treatment plant. The thickened sludge samples were heat dried in a tube furnace at different temperatures with a constant airflow rate. The exhaust air from the furnace was condensed in a glass condenser. Methanol was used as the solvent for extraction of compounds from both the dried sludge and the condensate. The concentrations of the organics were determined from high performance liquid chromatography (HPLC) analysis. The selected semivolatile organic compounds showed a high affinity to remain adsorbed in the thickened sludge. Drying sludge to more than 90% solids content caused complete removal of all of the organic compounds. The removal of organics took place in three distinct phases: a high removal in the initial phase, a sudden drop in the intermediate phase, and an increase in the final phase. Removal of phenol was approximately proportional to moisture removal from the sludge. For 4-nitrophenol and nitrobenzene, the removal rate decreased as the amount remaining in sludge diminished. The removal pattern of the individual organics correlated with their respective Henry's law coefficients. At higher temperatures, a faster removal rate was observed for all the compounds.
Document Type: Research Article
Publication date: January 1, 1995
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- Water Environment Research® (WER®) publishes peer-reviewed research papers, research notes, state-of-the-art and critical reviews on original, fundamental and applied research in all scientific and technical areas related to water quality, pollution control, and management. An annual Literature Review provides a review of published books and articles on water quality topics from the previous year. Published as: Sewage Works Journal, 1928 - 1949; Sewage and Industrial Wastes, 1950 - 1959; Journal Water Pollution Control Federation, 1959 - Oct 1989; Research Journal Water Pollution Control Federation, Nov 1989 - 1991; Water Environment Research, 1992 - present.
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