title: Energy and carbon footprints of sewage treatment methods.
abstract: The paper presents energy and carbon footprints of sewage treatment plants (STPs) operating at different scales and using different technology options based on primary data from 50 STPs operating in India and the UK. The study used a combination of fundamental mass-balance approach for energy consumption and the methodology defined by IPCC for the carbon emissions. Small-scale institutional STPs consume twelve times the energy consumed by large-scale municipal STPs, the corresponding energy intensities being 4.87 kWh/m(3) and 0.40 kWh/m(3) respectively. Embodied energy from construction material and chemicals accounted for 46% and 33% of the total energy intensity of the municipal and institutional STPs respectively. The average carbon footprint of large-scale STPs is 0.78 kgCO2eq/m(3) and for small-scale STPs it is 3.04 kgCO2eq/m(3). However, fugitive emissions from large-scale STPs constituted 74% of the total carbon emissions whereas the figure was only 0.05% for small-scale STPs. Average electrical energy intensity in STPs in India is much lower (0.14 kWh/m(3)) than that in the UK (0.46 kWh/m(3)). This is due to the reason that STPs in India do not have resource recovery processes and use solar heat for sludge drying. The paper offers information and insights for designing low carbon strategies for urban waste infrastructure.
authors.affiliation: Department of Natural Resources, TERI University, New Delhi, India. Electronic address: prati.singh@gmail.com.
authors.forename: Pratima
authors.initials: P
authors.lastname: Singh
authors.affiliation: Coca-Cola Department of Regional Water Studies, TERI University, 10 Institutional Area, Vasant Kunj, New Delhi 110 070, India. Electronic address: akansal@teri.res.in.
authors.forename: Arun
authors.initials: A
authors.lastname: Kansal
authors.affiliation: Department of Civil Engineering, University of Birmingham, UK. Electronic address: c.m.carliell@bham.ac.uk.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Carliell-Marquet
mesh_terms: D002244:Carbon / Q000032:analysis; D058572:Carbon Footprint / Q000706:statistics & numerical data; D004560:Electricity; D007194:India; D012722:Sewage; D013672:Technology; D006113:United Kingdom; D014865:Waste Disposal, Fluid / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data
chemical_list: D012722:Sewage; D002244:Carbon
keywords: Carbon emissions; Energy consumption; Large-scale municipal STPs; Sewage treatment technologies; Small-scale institutional STPs