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Fate of phthalic acid esters during composting of both lagooning and activated sludges

Paper ID Volume ID Publish Year Pages File Format Full-Text
36701 45142 2005 8 PDF Available
Title
Fate of phthalic acid esters during composting of both lagooning and activated sludges
Abstract

Among the phthalic acid esters (PAEs) targeted by the United States Environmental Protection Agency (USEPA) as priority pollutants, di-ethyl-hexyl phthalate (DEHP) is the major pollutant identified at high concentration level in lagooning sludge (LS), at about 28.67 mg/kg, and in activated sludge (AS), at about 6.26 mg/kg. Other phthalic acid esters, such as di-butyl phthalate (DBP) and di-methyl phthalate (DMP) show very low concentrations. During sludge composting, after the stabilization phase, the subsequent appearance of DEP and then DMP occurred indicating that microbial metabolism begins by alkyl side-chain degradation before aromatic ring-cleavage. The appearance and accumulation of PAEs with a short alkyl side-chain in the last stages of AS and LS composting is suggested originating from the degradation of phthalates with a much long side-chain. The DEHP showed a rate of biodegradation that follows a first-order kinetic model during composting of both AS and LS. The calculated DEHP half-lives are 45.4 days for LS and 28.9 days for AS. The better DEHP biodegradation rate (2.4 × 10−2 day−1) have been observed in the case of AS composting compared to LS compost (1.53 × 10−2 day−1). The mono-ethyl-hexyl phthalates MEHP has been shown to follow the same order of biodegradation as DEHP indicating that the same mechanism is followed (hydrolysis or dealkylation of each DEHP side-chain). Composting could be suggested as a detoxification process for the removal of PAEs (mainly DEHP) from sludges after a sufficient time of treatment to provide a safe end product.

Keywords
Phthalic acid esters; DEHP; Composting; Lagooning sludges; Activated sludges; Biodegradation rate
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Fate of phthalic acid esters during composting of both lagooning and activated sludges
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Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 40, Issue 6, May 2005, Pages 2183–2190
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us