title: Sludge-Drying Lagoons: a Potential Significant Methane Source in Wastewater Treatment Plants.
abstract: "Sludge-drying lagoons" are a preferred sludge treatment and drying method in tropical and subtropical areas due to the low construction and operational costs. However, this method may be a potential significant source of methane (CH4) because some of the organic matter would be microbially metabolized under anaerobic conditions in the lagoon. The quantification of CH4 emissions from lagoons is difficult due to the expected temporal and spatial variations over a lagoon maturing cycle of several years. Sporadic ebullition of CH4, which cannot be easily quantified by conventional methods such as floating hoods, is also expected. In this study, a novel method based on mass balances was developed to estimate the CH4 emissions and was applied to a full-scale sludge-drying lagoon over a three year operational cycle. The results revealed that processes in a sludge-drying lagoon would emit 6.5 kg CO2-e per megaliter of treated sewage. This would represent a quarter to two-thirds of the overall greenhouse gas (GHG) emissions from wastewater-treatment plants (WWTPs). This work highlights the fact that sludge-drying lagoons are a significant source of CH4 that adds substantially to the overall GHG footprint of WWTPs despite being recognized as a cheap and energy-efficient means of drying sludge.
authors.affiliation: Department of Environmental Science and Engineering, School of Architecture and Environment, Sichuan University , Chengdu, Sichuan 610065, China.
authors.forename: Yuting
authors.initials: Y
authors.lastname: Pan
authors.forename: Liu
authors.initials: L
authors.lastname: Ye
authors.affiliation: Australian Water Quality Centre , Adelaide, 5000 South Australia, Australia.|Health and Environment Group, School of the Environment, Flinders University , Bedford Park, 5042 South Australia, Australia.|Centre for Water Management and Reuse, School of Natural and Built Environments, University of South Australia , Mawson Lakes, 5095 South Australia, Australia.
authors.forename: Ben
authors.initials: B
authors.lastname: van den Akker
authors.affiliation: LEQUIA, Institute of the Environment, University of Girona , Girona, Catalonia, 17071 Spain.
authors.forename: Ramon
authors.initials: R
authors.lastname: Ganigué Pagès
authors.forename: Ronald S
authors.initials: RS
authors.lastname: Musenze
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Yuan
mesh_terms: D008697:Methane; D012722:Sewage; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater
chemical_list: D008697:Methane; D012722:Sewage; D062065:Wastewater