GC-MS analysis of odorous emissions from the dissolved air flotation units treating surplus activated sludge at a wastewater treatment works

Odorous air from the dissolved air flotation (DAF) unit of a wastewater treatment plant was scrubbed through an activated carbon column and air samples analysed by gas chromatographic-mass spectrometric techniques. Chromatographic profiles of the gases emitted at the DAF units were obtained. Compounds identified included mainly the aliphatic hydrocarbons from C 9 to C 14 . The odorous compounds detected were toluene, meta-, para- and ortho-xylenes, phenol, dimethyl disulphide and dimethyl trisulphide, alkyl benzenes and chlorinated hydrocarbons such as chloroethylene and chlorobenzenes. Phenol and toluene were found to be the most dominant compounds detected.