Organic compounds in sludges 231
10.4.3 Nitrosamines
A gas chromatographic chemifluorescent detection procedure described by Richardson
et al [134, 135] has been applied to the determination of microgram levels of
nitrosamine (N-nitrosodimethylamine, N-nitrosopyrrolidine, N-nitrosopiperidine,
and N-nitroso-5-methyl-1,3-oxazoldine) imputs to sewage plants.
10.4.4 Guanidines
These substances have been determined in sewage effluents by thin layer chromatography [136]. Thin layer chromatography was carried out on 2.5 mm layers of Adsorbasil1 that had been activated at 100
◦ C for 1 hour. The best results were obtained with
butanol-acetic acid water (8:1:1) as solvent (Rf 0.6); iodine vapour was used as locating
reagent. The sensitivity was equivalent to 0.5 mg l
−1 of dodecylguanidine.
10.4.5 Miscellaneous nitrogen compounds
Gas chromatography coupled to mass spectrometry has been used to determine
nitro musks and their amino metabolites [137] and azarenes, nitroazarines and
4-nitrophenol in sewage sludge [138].
10.5 SULPHUR CONTAINING COMPOUNDS
10.5.1 Alkyl sulphides
Gas chromatography
Bailey and Viney et al [139] have applied gas chromatography to the investigation
of odours produced at sewage treatment plants. Samples of ambient air at a sewage
treatment works were taken using Tedlar bags and also by using traps containing Tenax
GC on site.
Their studies showed that methyl mercaptan found in the headspace of these
samples was produced by aerobic decomposition of hexyl mercaptan.
The methods described by Jenkins et al [140] involves gas chromatography coupled with the sulphur-specific flame photometric detector which can detect 0.25 ng
hydrogen sulphide and 0.5 ng methyl mercaptan. The method has been used to trace
sources of odour due to mercaptans in the air surrounding a sewage works and in
waste waters and sewer gases. They used these techniques to study the fate of various
organosulphur compounds in raw sewage and activated sludge.
Jenkins et al [140] used a gas chromatograph equipped with a Melpar flame
photometric detector and a Perkin-Elmer 3920B gas chromatograph equipped with a
linearized Perkin-Elmer flame photometric detector. Each instrument also had a flame
ionisation detector. An FEP Teflon column (18 in × 0.625 in i.d. (0.56 m × 15 mm)
containing acetone-treated Poropak QS was used for all analyses. The PE 3920B
chromatographer used a glass-lined vaporiser injector and the interface lines were
in stainless steel. For the Tracor 550, the Poropak QS column was connected to glass
capillary tubing which was inserted into the injector and outlet barrels. Teflon-backed
septa were used for sample injection in both instruments.
10.4.3 Nitrosamines
A gas chromatographic chemifluorescent detection procedure described by Richardson
et al [134, 135] has been applied to the determination of microgram levels of
nitrosamine (N-nitrosodimethylamine, N-nitrosopyrrolidine, N-nitrosopiperidine,
and N-nitroso-5-methyl-1,3-oxazoldine) imputs to sewage plants.
10.4.4 Guanidines
These substances have been determined in sewage effluents by thin layer chromatography [136]. Thin layer chromatography was carried out on 2.5 mm layers of Adsorbasil1 that had been activated at 100
◦ C for 1 hour. The best results were obtained with
butanol-acetic acid water (8:1:1) as solvent (Rf 0.6); iodine vapour was used as locating
reagent. The sensitivity was equivalent to 0.5 mg l
−1 of dodecylguanidine.
10.4.5 Miscellaneous nitrogen compounds
Gas chromatography coupled to mass spectrometry has been used to determine
nitro musks and their amino metabolites [137] and azarenes, nitroazarines and
4-nitrophenol in sewage sludge [138].
10.5 SULPHUR CONTAINING COMPOUNDS
10.5.1 Alkyl sulphides
Gas chromatography
Bailey and Viney et al [139] have applied gas chromatography to the investigation
of odours produced at sewage treatment plants. Samples of ambient air at a sewage
treatment works were taken using Tedlar bags and also by using traps containing Tenax
GC on site.
Their studies showed that methyl mercaptan found in the headspace of these
samples was produced by aerobic decomposition of hexyl mercaptan.
The methods described by Jenkins et al [140] involves gas chromatography coupled with the sulphur-specific flame photometric detector which can detect 0.25 ng
hydrogen sulphide and 0.5 ng methyl mercaptan. The method has been used to trace
sources of odour due to mercaptans in the air surrounding a sewage works and in
waste waters and sewer gases. They used these techniques to study the fate of various
organosulphur compounds in raw sewage and activated sludge.
Jenkins et al [140] used a gas chromatograph equipped with a Melpar flame
photometric detector and a Perkin-Elmer 3920B gas chromatograph equipped with a
linearized Perkin-Elmer flame photometric detector. Each instrument also had a flame
ionisation detector. An FEP Teflon column (18 in × 0.625 in i.d. (0.56 m × 15 mm)
containing acetone-treated Poropak QS was used for all analyses. The PE 3920B
chromatographer used a glass-lined vaporiser injector and the interface lines were
in stainless steel. For the Tracor 550, the Poropak QS column was connected to glass
capillary tubing which was inserted into the injector and outlet barrels. Teflon-backed
septa were used for sample injection in both instruments.