Laurence Mansuy

Characterisation of sewage sludge-derived organic matter: lipids and humic acids

Abstract The distribution of humic substances and lipids extracted from two sewage sludges (S1 and S2) resulting from different wastewater and sludge processes was studied. The humic acids were investigated using elemental analysis, infrared spectroscopy and thermally assisted hydrolysis and methylation coupled to gas chromatography–mass spectrometry (THM-GC–MS). The influence of lipid extraction prior to humic fractionation was also tested. The main differences between the two sludges are evident from the analysis of lipids and the distribution of carbon in the humic fractions. The results reveal that the carbon is more extractable in the most matured sludge (S2). The chromatograms of the lipids show that the extract from the least matured sludge (S1) consists mainly of fatty acids whereas that from the most matured one is dominated by steroids. THM-GC–MS analyses show the aliphatic nature of the sludge derived humic acids as confirmed by elemental analyses and infrared spectroscopy. The aliphatic character is attributed to the presence of lipids presumably trapped in the humic structure.

Characterization of humic substances in highly polluted river sediments by pyrolysis methylation-gas chromatography-mass spectrometry

Humic substances were extracted from two sediment cores sampled in a river on the outskirts of a large city (Deule near Lille, France) and in its highly polluted oxbow-lake. Humic acids (HA) were characterized by infrared spectroscopy and in situ pyrolysis/methylation–gas chromatography–mass spectrometry. The main results are the substantial aliphaticity of HA in the oxbow-lake at all depths, mainly due to the presence of a lipid fraction associated with the HA structure. The abundance of sterols in this fraction implies that lipids could originate from the accumulation of sewage in the oxbow-lake. Humic acids of the Deule sediments show a different trend ; their evolution is characterized by a decrease of the pollutant inputs with increasing depth. The results demonstrate the efficiency of Py–GC–MS in identifying the different organic contributions to HA and in distinguishing natural from anthropogenic sources.

Characterization of the macromolecular organic content of sewage sludges by thermally assisted hydrolysis and methylation-gas chromatography-mass spectrometer (THM-GC/MS)

Abstract The aim of this study is to determine a methodology enabling us to simplify the information generated by thermally assisted hydrolysis and methylation (THM)-pyrograms of sludges and to provide an insight into the sludges according to their chemical composition. The insoluble organic fractions of 48 sewage sludges originating from industrial (food-processing and paper mill) and domestic (urban, small urban and rural) wastewater-treatment plants (WWTP) of the region of Lorraine (northeast of France) were characterized by THM-GC/MS. A relative quantification of the pyrograms by integration of the major peaks was then carried out. The results of this integration were plotted in a triangular diagram defined by the poles corresponding to the three major families evidenced in the pyrograms (lignin-derived, lipid-derived and nitrogenous compounds). This type of representation enables us to separate paper-mill sludges from the others, because they are characterized by high amounts of lignin-derived compounds. The majority of domestic sludges and food-processing sludges are gathered and characterized by an intermediate composition in lipid-derived, lignin-derived and nitrogenous compounds, but seven urban sludges show an evolution of their chemical composition towards the lipid pole. The domestic sludges can be separated from the others on the basis of their molecular nitrogenous distribution. Such a methodology is complementary with the qualitative analysis of pyrograms and makes it possible to approach the chemical composition of sludges, which governs their reactivity once they are disposed on soil.

A Novel Procedure for the Synthesis of Ether-Bridged Perfluoro Non-Ionic Surfactants

Abstract An efficient procedure is described for the synthesis of perfluoro non-ionic surfactants of the type RF-CH 2 (OC 2 H 4)pOH which involves the use of the principle of solid-liquid phase transfer methodology to simplify the Williamson ether synthesis usually employed in previous procedures (5,7).