title: Distribution of trace metals (Cu, Pb, Ni, Zn) between particulate, colloidal and truly dissolved fractions in wastewater treatment.
abstract: The distribution of Cu, Pb, Ni and Zn between particulate, colloidal and truly dissolved size fractions in wastewater from a trickling filter treatment plant was investigated. Samples of influent, primary effluent, humus effluent, final effluent and sludge holding tank returns were collected and separated into particulate (i.e. > 0.45 μm), colloidal (i.e. 1 kDa to 0.45 μm), and truly dissolved (i.e. < 1 kDa) fractions using membrane filters. In the influent, substantial proportions of Cu (60%), Pb (67%), and Zn (32%) were present in the particulate fraction which was removed in conjunction with suspended particles at the works in subsequent treatment stages. In final effluent, sizeable proportions of Cu (52%), Pb (32%), Ni (44%) and Zn (68%) were found within the colloidal size fraction. Calculated ratios of soluble metal to organic carbon suggest the metal to be adsorbed to or complexed with non-humic macromolecules typically found within the colloidal size range. These findings suggest that technologies capable of removing particles within the colloidal fraction have good potential to enhance metals removal from wastewater.
authors.affiliation: Cranfield Water Science Institute, Cranfield University, College Road, Cranfield, Bedford, MK43 0AL, United Kingdom.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Hargreaves
authors.affiliation: Severn Trent Water, 2 St John's Street, Coventry, CV1 2LZ, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Vale
authors.affiliation: Severn Trent Water, 2 St John's Street, Coventry, CV1 2LZ, United Kingdom.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Whelan
authors.affiliation: Atkins, Chilbrook Oasis Business Park, Eynsham, Oxford, OX29 4AH, United Kingdom.
authors.forename: Carlos
authors.initials: C
authors.lastname: Constantino
authors.affiliation: Cranfield Water Science Institute, Cranfield University, College Road, Cranfield, Bedford, MK43 0AL, United Kingdom.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Dotro
authors.affiliation: Cranfield Water Science Institute, Cranfield University, College Road, Cranfield, Bedford, MK43 0AL, United Kingdom. Electronic address: P.campo-moreno@cranfield.ac.uk.
authors.forename: Pablo
authors.initials: P
authors.lastname: Campo
authors.affiliation: Scottish Water, Castle House, 6 Castle Drive, Carnegie Campus, Dunfermline, KY11 8GG, United Kingdom.
authors.forename: Elise
authors.initials: E
authors.lastname: Cartmell
mesh_terms: D000327:Adsorption; D003102:Colloids / Q000032:analysis* / Q000737:chemistry; D004784:Environmental Monitoring; D005374:Filtration; D019216:Metals, Heavy / Q000032:analysis* / Q000737:chemistry; D052638:Particulate Matter / Q000032:analysis* / Q000737:chemistry; D012995:Solubility; D014865:Waste Disposal, Fluid; D062065:Wastewater; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D003102:Colloids; D019216:Metals, Heavy; D052638:Particulate Matter; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Colloids; Membrane filtration; Particle fractions; Trace metals; Wastewater