title: Transformation of molecular weight distributions of dissolved organic carbon and UV-absorbing compounds at full-scale wastewater-treatment plants.
abstract: The molecular-weight distribution (MWD) of wastewater dissolved-organic carbon (DOC) was determined in samples from seven full-scale wastewater-treatment plants (WWTPs) that use different biological treatments (air activated sludge [air-AS], pure-oxygen AS [O2-AS], and trickling filters). The research objective was to determine how different biological treatments influenced the MWD of wastewater DOC. Primary sedimentation effluent DOC from most of the WWTPs exhibited a skewed distribution toward the low-molecular-weight fraction (MWF) (40 to 50%, < 0.5 K Daltons [KDa]). The Air-AS effluent DOC exhibited a centrally clustered distribution, with the majority of DOC in the intermediate MWF (0.5 to 3 KDa). The O2-AS effluent DOC exhibited a skewed distribution toward the high MWF (> 3 KDa). The removal of DOC by air- and O2-AS bacteria followed trends predicted by a macromolecule degradation model. Trickling-filter effluent DOC exhibited a skewed distribution toward the high MWF (50% DOC, > 3 KDa).
authors.affiliation: Centro Interamericano de Recursos del Agua at Universidad Autónoma del Estado de México, Toluca. marioesparza@uaemex.mx
authors.forename: Mario
authors.initials: M
authors.lastname: Esparza-Soto
authors.forename: Peter
authors.initials: P
authors.lastname: Fox
authors.forename: Paul
authors.initials: P
authors.lastname: Westerhoff
mesh_terms: D001673:Biodegradation, Environmental; D001704:Biopolymers / Q000737:chemistry / Q000378:metabolism; D002244:Carbon / Q000737:chemistry / Q000302:isolation & purification*; D008954:Models, Biological; D008970:Molecular Weight; D009930:Organic Chemicals / Q000737:chemistry / Q000302:isolation & purification*; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D014462:Ultrafiltration; D014466:Ultraviolet Rays; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D001704:Biopolymers; D009930:Organic Chemicals; D012722:Sewage; D002244:Carbon; D010100:Oxygen