THERMAL SCIENCE

International Scientific Journal

AN ENVIRONMENTAL LCA OF ALTERNATIVE SCENARIOS OF URBAN SEWAGE SLUDGE TREATMENT AND DISPOSAL

ABSTRACT
The majority of pollutants that affect wastewater are concentrated by treatment processes in sludge; it is therefore critical to have a suitable evaluation methodology of sludge management options to analyze if pollution is redirected from water to other media, such as air and soil. Life cycle assessment is one of the most widely known and internationally accepted methodologies to compare environmental impacts of processes and systems and to evaluate their sustainability in the entire life cycle. In this study the methodology was applied to assess and compare three scenarios of urban sewage sludge treatment and disposal: sludge anaerobic digestion followed by dedicated incineration, sludge incineration without previous digestion, and sludge anaerobic digestion followed by composting. The potential benefits of spreading the compost to soil were not included in the system boundaries even if, due to its nutrients contents and soil improving features, compost could partially replace the use of commercial products. The study was aimed at finding out the environmental critical points of the treatment alternatives selected and at providing a technical and scientific contribution for further debates with national and local authorities on the environmental optimization of sewage sludge management. Life cycle assessment results confirmed the major contribution of electricity and methane consumption on several environmental impact categories. Incineration contributes more than sludge composting to almost all categories, although the heavy metals content of urban wastewater sludge raises substantial concerns when composted sludge is spread to soil. In this paper the models adopted, the hypotheses assumed and the main findings of the study are presented and discussed. .
KEYWORDS
PAPER SUBMITTED: 2007-01-31
PAPER REVISED: 2007-04-07
PAPER ACCEPTED: 2007-04-10
DOI REFERENCE: https://doi.org/10.2298/TSCI0703153T
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2007, VOLUME 11, ISSUE 3, PAGES [153 - 164]
REFERENCES
  1. ***, Directorate-General Environment of European Commission, 2005, http://europa.eu.int/comm/environment/waste/sludge/index.htm
  2. Suh, Y., Rousseaux, P., An LCA of Alternative Wastewater Sludge Treatment Scenarios, Resources, Conservation and Recycling, 35 (2002), 3, pp. 191-200

© 2019 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence