title: Characterization of sulfur in raw and anaerobically digested municipal wastewater treatment sludges.
abstract: A microwave-enhanced acid digestion method that was integrated with inductively coupled plasma-atomic emission spectrometry was developed and validated for determining total, soluble, and precipitated sulfur in wastewater treatment sludges. The coefficient of variation of this method was less than 4.0%. The recovery of dosed sulfur from sludge samples was between 97.1% and 100.5%. The composition of sulfur in primary and waste-activated sludge (WAS) before and after anaerobic digestion at 35 and 55 degrees C was characterized by employing this developed method. There was not an apparent relationship between the precipitated sulfur and nonsoluble iron concentrations in sludges. Raw WAS had a more consistent organic sulfur fractionation because of its relatively homogeneous composition. The organic-sulfur-containing components (proteins) of WAS had reduced degradability as compared with that in primary sludge during anaerobic digestion. Digestion at 55 degrees C increased solubilization but not ultimate conversion of organic sulfur in sludge.
authors.affiliation: Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario, Canada. wdu@engmail.uwaterloo.ca
authors.forename: Weiwei
authors.initials: W
authors.lastname: Du
authors.forename: Wayne
authors.initials: W
authors.lastname: Parker
mesh_terms: D012722:Sewage / Q000032:analysis*; D013455:Sulfur / Q000032:analysis*; D013457:Sulfur Compounds / Q000032:analysis*; D018505:Waste Management; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D012722:Sewage; D013457:Sulfur Compounds; D014874:Water Pollutants, Chemical; D013455:Sulfur