title: Role of primary sedimentation on plant-wide energy recovery and carbon footprint.
abstract: The goal of this paper is to show the effect of primary sedimentation on the chemical oxygen demand (COD) and solids fractionation and consequently on the carbonaceous and energy footprints of wastewater treatment processes. Using a simple rational procedure for COD and solids fraction quantification, we quantify the effects of varying fractions on CO2 and CO2-equivalent mass flows, process energy demand and energy recovery. Then we analysed two treatment plants with similar biological nutrient removal processes in two different climatic regions and quantified the net benefit of gravity separation before biological treatment. In the cases analysed, primary settling increases the solid fraction of COD that is processed in anaerobic digestion, with an associated increase in biogas production and energy recovery, and a reduction in overall emissions of CO2 and CO2-equivalent from power importation.
authors.affiliation: Department of Civil and Environmental Engineering - DICEA, University of Florence, Via S. Marta 3, 50139 Florence, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Gori
authors.forename: Francesca
authors.initials: F
authors.lastname: Giaccherini
authors.forename: Lu-Man
authors.initials: LM
authors.lastname: Jiang
authors.forename: Reza
authors.initials: R
authors.lastname: Sobhani
authors.forename: Diego
authors.initials: D
authors.lastname: Rosso
mesh_terms: D002244:Carbon / Q000737:chemistry; D058572:Carbon Footprint; D011232:Chemical Precipitation; D003246:Conservation of Energy Resources / Q000379:methods*; D025341:Principal Component Analysis; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D002244:Carbon