title: Advanced solid-state carbon-13 nuclear magnetic resonance spectroscopic studies of sewage sludge organic matter: detection of organic "domains".
abstract: Two novel solid-state 13C nuclear magnetic resonance (NMR) spectroscopic techniques, PSRE (proton spin relaxation editing) and RESTORE [Restoration of Spectra via T(CH) and T(1rho)H (T One Rho H) Editing], were used to provide detailed chemical characterization of the organic matter from six Australian sewage sludges. These methods were used to probe the submicrometer heterogeneity of sludge organic matter, and identify and quantify spatially distinct components. Analysis of the T1H relaxation behavior of the sludges indicated that each sludge contained two types of organic domains. Carbon-13 PSRE NMR subspectra were generated to determine the chemical nature of these domains. The rapidly relaxing component of each sludge was rich in protein and alkyl carbon, and was identified as dead bacterial material. The slowly relaxing component of each sludge was rich in carbohydrate and lignin structures, and was identified as partly degraded plant material. The bacterial domains were shown, using the RESTORE technique, to also have characteristically rapid T(1rho)H relaxation rates. This rapid T(1rho)H relaxation was identified as the main cause of underrepresentation of these domains in standard 13C cross polarization (CP) NMR spectra of sludges. The heterogeneous nature of sewage sludge organic matter has implications for land application of sewage sludge, since the two components are likely to have different capacities for sorbing organic and inorganic toxicants present in sewage sludge, and will decompose at different rates.
authors.affiliation: Dep. of Soil and Water, Waite Agricultural Research Institute, Univ. of Adelaide, Glen Osmond, South Australia 5064, Australia. ronald.smernik@adelaide.edu.au
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Smernik
authors.forename: Ian W
authors.initials: IW
authors.lastname: Oliver
authors.forename: Graham
authors.initials: G
authors.lastname: Merrington
mesh_terms: D001419:Bacteria; D002244:Carbon / Q000032:analysis; D002247:Carbon Isotopes / Q000032:analysis; D004785:Environmental Pollutants / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009930:Organic Chemicals / Q000032:analysis; D011506:Proteins / Q000032:analysis; D012037:Refuse Disposal; D012722:Sewage / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D004785:Environmental Pollutants; D009930:Organic Chemicals; D011506:Proteins; D012722:Sewage; D002244:Carbon