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| The release characteristics of phenol in sewage sludge and its risk assessment and control. |
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Abstract The phenol contents in several types of sewage sludge were determined. The characteristics of phenol release under natural condition and at various temperatures, as well as factors that impact this process were assessed. The carcinogenic risks due to the phenol release were evaluated, based on which a number of potential control measures were proposed. Phenol content in the sewage sludge ranged from 0.17 to 3.22μg/g. The phenol release decreased as the aerial exposure of sewage sludge prolonged. When dried at low temperature, the released phenol was mainly derived from the phenol pre-dissolved in the sewage sludge. When dried at higher temperature, the primary phenol release was resulted from the pyrogenation of organic matters contained in the sewage sludge. The current sewage sludge drying protocol adopted by the Hangzhou municipal sewage management required a drying temperature at 350℃, which exerted high carcinogenic risks to workers with exposure potentials. By lowering the temperature of sewage sludge drying, it could effectively lower the health harm risks due to the phenol release in this process.
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Received: 15 January 2010
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