TY - JOUR
T1 - Feasibility analysis of anaerobic digestion of excess sludge enhanced by iron
T2 - A review
AU - Wei, Jing
AU - Hao, Xiaodi
AU - van Loosdrecht, Mark C.M.
AU - Li, Ji
PY - 2018/6/1
Y1 - 2018/6/1
N2 - The Paris Climate Treaty implies the coming of a new era towards carbon-neutral operation in wastewater treatment plants (WWTPs), and thus energy self-sufficiency from biosolids and/or heat in the form of wastewater temperature has to be considered. In this regard, anaerobic digestion (AD) of sludge should be paid renewed attention to resolve a low conversion efficiency of biosolids. As a potential way to energy positive operation, exogenous iron has been proposed to enhance methane production in recent years. In this review, the authors provided a deep insight into the feasibility of iron-enhanced AD system. Hydrogen evolution from iron corrosion and its effects on CH4 production is firstly reviewed; then the roles of iron in reducing ORP was illustrated with regard to its impact on fermentation type; serving as an essential element and potential electron donor, the stimulating effects of iron on microorganisms and enzyme activities were also elaborated, and thus the technical feasibility of iron-based AD could be evaluated. In regards of the environmental and economic impacts of iron-based AD, life cycle assessment (LCA) was employed to calculate its economic feasibility, and the results revealed that iron-based AD system could reduce both operational costs and carbon emissions. Conclusion was drawn that iron-based anaerobic digestion is promising on technical level as well as economic perspective, and is expected to contribute to carbon-neutral operation of WWTPs. Iron-based anaerobic digestion is such a promising and sustainable strategy towards circular economy that it could be applied to many cross-disciplinary fields.
AB - The Paris Climate Treaty implies the coming of a new era towards carbon-neutral operation in wastewater treatment plants (WWTPs), and thus energy self-sufficiency from biosolids and/or heat in the form of wastewater temperature has to be considered. In this regard, anaerobic digestion (AD) of sludge should be paid renewed attention to resolve a low conversion efficiency of biosolids. As a potential way to energy positive operation, exogenous iron has been proposed to enhance methane production in recent years. In this review, the authors provided a deep insight into the feasibility of iron-enhanced AD system. Hydrogen evolution from iron corrosion and its effects on CH4 production is firstly reviewed; then the roles of iron in reducing ORP was illustrated with regard to its impact on fermentation type; serving as an essential element and potential electron donor, the stimulating effects of iron on microorganisms and enzyme activities were also elaborated, and thus the technical feasibility of iron-based AD could be evaluated. In regards of the environmental and economic impacts of iron-based AD, life cycle assessment (LCA) was employed to calculate its economic feasibility, and the results revealed that iron-based AD system could reduce both operational costs and carbon emissions. Conclusion was drawn that iron-based anaerobic digestion is promising on technical level as well as economic perspective, and is expected to contribute to carbon-neutral operation of WWTPs. Iron-based anaerobic digestion is such a promising and sustainable strategy towards circular economy that it could be applied to many cross-disciplinary fields.
KW - Anaerobic digestion (AD)
KW - Enzyme activity
KW - Life cycle assessment (LCA)
KW - Oxidation-reduction potential (ORP)
KW - Scrap iron
UR - http://www.scopus.com/inward/record.url?scp=85043510077&partnerID=8YFLogxK
U2 - 10.1016/j.rser.2018.02.042
DO - 10.1016/j.rser.2018.02.042
M3 - Review article
AN - SCOPUS:85043510077
SN - 1364-0321
VL - 89
SP - 16
EP - 26
JO - Renewable & Sustainable Energy Reviews
JF - Renewable & Sustainable Energy Reviews
ER -