Impact of drying and composting procedures on the concentrations of 4-nonylphenols, di-(2-ethylhexyl)phthalate and polychlorinated biphenyls in anaerobically digested sewage sludge
Por:
Gibson R.W., Wang M.-J., Padgett E., Lopez-Real J.M., Beck A.J.
Publicada:
1 ene 2007
Resumen:
Enhanced treatments of sewage sludge produce a more manageable product for agricultural use by stabilizing the material, removing water, and reducing the possibility of pathogen transfer. We investigated the impact of pilot-scale composting and drying of sludge on physicochemical characteristics and on the concentrations of some organic contaminants. During the 143 day composting procedure, organic matter fell 22% and moisture by half. Concentrations of 4-nonylphenols (4-NPs) fell by 88% and di-(2-ethylhexyl) phthalate (DEHP) by 60%; losses continued throughout the procedure. Losses of total polychlorinated biphenyls (PCBs) were 11%, mostly from the lower molecular weight congeners, suggesting volatilization as the most likely loss mechanism. The drying process was much shorter, 40 days, yet organic matter content decreased by 27% and moisture by 85%. Losses of 4-NPs (39%) and DEHP (22%) were less than in composting and stopped when moisture content became constant. There were no losses of PCBs. Both treatments are simple, practical procedures that reduce the volume of waste and are applicable in situ on farms. Composting would be the method of choice for reducing organic contaminants but requires much longer times than drying. © 2007 Elsevier Ltd. All rights reserved.
Filiaciones:
Gibson R.W.:
Instituto de Geografía, UNAM, Ciudad Universitaria, 04510 México, DF, Mexico
Wang M.-J.:
Department of Agricultural Sciences, Imperial College London, Wye Campus, Ashford, Kent TN25 5AH, United Kingdom
Padgett E.:
Department of Agricultural Sciences, Imperial College London, Wye Campus, Ashford, Kent TN25 5AH, United Kingdom
Lopez-Real J.M.:
Department of Agricultural Sciences, Imperial College London, Wye Campus, Ashford, Kent TN25 5AH, United Kingdom
Beck A.J.:
Department of Agricultural Sciences, Imperial College London, Wye Campus, Ashford, Kent TN25 5AH, United Kingdom
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