Energy and carbon footprints of sewage treatment methods. (1st January 2016)

• Record Type: Journal Article
• Authors: Singh, Pratima; Kansal, Arun; Carliell-Marquet, Cynthia
• Is Part Of: Journal of environmental management. Volume 165(2015)
• Page Start: 22
• Page End: 30
• Publication Date: 2016-01-01
• Subjects: Sewage treatment technologies -- Energy consumption -- Carbon emissions -- Large-scale municipal STPs -- Small-scale institutional STPs; AF Anaerobic fermentation -- ASP Activated Sludge Process -- AD Anaerobic digester -- AC Activated carbon -- BT Biological treatment -- BS Bar screen -- BFP Belt filter press -- BOD Biological oxygen demand -- CF Clariflocculation -- CAACO Chemo-autotrophic activated carbon oxidation -- CL Chlorination -- Cf Centrifuge -- CO2 Carbon emission -- CH4 Methane emission -- DAF Dissolved air flotation -- ET Equalization tank -- EA Extended aeration -- En Net energy -- El Electrical energy -- Ed Diesel energy -- EB Biogas energy -- Emt Embodied energy of construction material -- Ech Embodied energy of chemicals -- FST Final settling tank -- FM Flash mixer -- FBR Fluidized bed reactor -- FM Flash mixer -- Ge Carbon emission from use of electricity -- Gd Carbon emission from use of diesel -- Gfugitive Carbon emission due to fugitive gases -- Gbiogas Carbon emission due to biogas flaring -- Gmt Emissions embodied in construction materials -- Gch Emissions embodied in chemicals -- GC Grit chamber -- I1 to I8 Small-scale institutional sewage treatment options -- LCA Life cycle analysis -- M1 to M6 Large-scale municipal sewage treatment options -- MGF Multi grade filter -- MLD Million litres per day -- MB Membrane bioreactor -- N2O Nitrous Oxide emission -- NT Not-for-treatment -- OD Oxidation ditch -- OT Ozonation tank -- PT Primary treatment -- PST Primary settling tank -- RCC Reinforced cement concrete -- RBC Rotating biological contractor -- SC Screen chamber -- STP Sewage treatment plant -- SAGBR Submerged attached-growth biological reactor -- ST Secondary treatment -- Sld. H Sludge treatment -- SF Sand filter -- SDB Sludge-drying beds -- TT Tertiary treatment -- TSD Treated sewage disposal -- TF Trickling filter -- UASB Up-flow anaerobic sludge blanket -- WSP Waste stabilization pond; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2015.09.017
• Languages: English
• ISSNs: 0301-4797

Abstract

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 kgCO2 eq/m 3 and for small-scale STPs it is 3.04 kgCO2 eq/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. Highlights: Scale and technology choices influence energy and carbon footprint. Embodied energy contributes nearly half of the total energy footprint. Fugitive emission from biological process causes 87% of the total carbon emission. Electrical energy use in STPs in India and UK is 0.14 and 0.46 kWh/m 3 respectively. Secondary treatment accounts for about 70%–80% of electrical energy used in an STP.