title: Comprehensive Numerical Modeling of Greenhouse Gas Emissions from Water Resource Recovery Facilities.
abstract: A numerical model was developed to comprehensively predict greenhouse gas (GHG) emissions from water resource recovery facilities. An existing activated sludge model was extended to include a nitrifier-denitrification process and carbon dioxide (CO₂) as a state variable. The bioreactor model was coupled to a process-based digester model and an empirical model of indirect CO₂emissions. Direct emissions were approximately 90% of total GHG emissions for a plantwide simulation using the Modified Ludzack-Ettinger process. Biogenic CO₂, nitrous oxide (N₂O), and methane (CH₄) represented 10, 43, and 34% of total emissions. Simulating a dissolved oxygen controlled closed-loop system reduced both sensitivity and uncertainty of GHG emissions. Nitrous oxide emissions were much more sensitive under different design and operating conditions compared to CH₄and CO₂, indicating a significant mitigation potential. An uncertainty analysis found that the uncertainty in GHGs emissions estimates could be significant. Nitrous oxide emissions dominated in both magnitude and uncertainty.
authors.affiliation: Department of Civil and Environmental Engineering, University of North Carolina at Charlotte, Charlotte, North Carolina, USA.
authors.forename: Dongwook
authors.initials: D
authors.lastname: Kim
authors.forename: James D
authors.initials: JD
authors.lastname: Bowen
authors.forename: David
authors.initials: D
authors.lastname: Kinnear
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis*; D017752:Greenhouse Effect; D008697:Methane / Q000032:analysis*; D008962:Models, Theoretical; D009609:Nitrous Oxide / Q000032:analysis*; D062065:Wastewater / Q000737:chemistry*; D018508:Water Purification
chemical_list: D002245:Carbon Dioxide; D008697:Methane; D009609:Nitrous Oxide; D062065:Wastewater