Environmental Effects of Sewage Sludge Carbonization and Other Treatment Alternatives

Ning-Yi Wang, Chun-Hao Shih, Pei-Te Chiueh and Yu-Fong Huang
Additional contact information
Ning-Yi Wang: Graduate Institute of Environmental Engineering, National Taiwan University, No.71 Chou-Shan Road, Taipei 106, Taiwan
Chun-Hao Shih: Graduate Institute of Environmental Engineering, National Taiwan University, No.71 Chou-Shan Road, Taipei 106, Taiwan
Pei-Te Chiueh: Graduate Institute of Environmental Engineering, National Taiwan University, No.71 Chou-Shan Road, Taipei 106, Taiwan
Yu-Fong Huang: Graduate Institute of Environmental Engineering, National Taiwan University, No.71 Chou-Shan Road, Taipei 106, Taiwan

Energies, 2013, vol. 6, issue 2, 1-13

Abstract: Carbonization is a newly developed process that converts sewage sludge to biocoal, a type of solid biomass that can partially substitute for coal during power generation. This study presents an assessment of the environmental effects of various sewage sludge treatment processes, including carbonization, direct landfills, co-incineration with municipal solid waste, and mono-incineration in Taiwan. This assessment was conducted using the life cycle assessment software SimaPro 7.2 and the IMPACT2002+ model. Results show that carbonization is the best approach for sewage sludge treatment, followed in descending order by co-incineration with municipal solid waste, direct landfills, and mono-incineration. The carbonization process has noticeable positive effects in the environmental impact categories of terrestrial ecotoxicity, aquatic ecotoxicity, land occupation, ionizing radiation, aquatic eutrophication, non-renewable energy, and mineral extraction. For the emission quantity of greenhouse gases, landfilling has the greatest impact (296.9 kg CO 2 eq./t sludge), followed by mono-incineration (232.2 kg CO 2 eq./t sludge) and carbonization (146.1 kg CO 2 eq./t sludge). Co-incineration with municipal solid waste has the benefit of reducing green house gas emission (–15.4 kg CO 2 eq./t sludge). In the aspect of energy recovery, sewerage sludge that has been pretreated by thickening, digestion, and dewatering still retains a high moisture content, and thus requires a significant amount of energy use when used as a substitute solid fuel. Therefore, the carbonization of sewage sludge would be a more sustainable option if the energy delivery and integration processes are made more efficient.

Keywords: sewage sludge; carbonization; life cycle assessment; biocoal; environmental impact (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2013
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (7)

Downloads: (external link)
https://www.mdpi.com/1996-1073/6/2/871/pdf (application/pdf)
https://www.mdpi.com/1996-1073/6/2/871/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:6:y:2013:i:2:p:871-883:d:23498

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().