A systematic study on the VOCs characterization and odour emissions in a full-scale sewage sludge composting plant

• Published in: Journal of hazardous materials Vol. 373; pp. 733 - 740
• Main Authors: González, Daniel, Colón, Joan, Sánchez, Antoni, Gabriel, David
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 05-07-2019
• Subjects: Full-scale composting plant; Gaseous emissions; Odour emission factor; Odour emission rate; Sewage sludge; VOC; Full-scale composting plant; Gaseous emissions; VOC; Odour emission rate; Sewage sludge; Odour emission factor
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2019.03.131

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•Odours and volatile organic compounds emissions depend on the composting time.•Global odour emission factors of 4.42E + 06 and 5.97E + 06 ou·Mg−1 RS–VF were obtained.•Isovaleraldehyde, butyric acid, DMS, DMDS and α-pinene were the major odorants.•Odour activity value is not a good predictor for odour concentration.
Sewage sludge management is known to cause odour impact over the environment. However, an information gap exists about odour emissions quantification from different treatment strategies. In the present work, odorous emissions generated in a full-scale sewage sludge composting plant were characterized, aiming at providing specific odour emission factors (OEF) and to determine their variability depending on the composting time. Additionally, characterization of VOCs emitted during the process was conducted through TD-GC/MS analyses. Odour emission and VOCs characterization considered both (1) a first stage where a raw sludge and vegetal fraction mixture were actively composted in dynamic windrows and (2) a second curing stage in static piles. After increasing the composting time, a reduction of 40% of the maximum odour concentration referred to the dynamic windrow stage was estimated, whereas a reduction of 89% of the maximum odour concentration was achieved after turning of curing piles. However, global OEF increased from 4.42E + 06 to 5.97E + 06 ou·Mg−1 RS – VF when the composting time increased. Finally, different VOCs such as isovaleraldehyde, indole, skatole, butyric acid, dimethyl sulphide and dimethyl disulphide were identified as main potential odour contributors. Results obtained are a valuable resource for plant management to choose an appropriate sewage sludge composting strategy to mitigate odour emissions.