Comparison of different measurement methods of odour and odorants used in the odour impact assessment of wastewater treatment plants in Poland.

The aim of this study was to compare sensory and analytical methods used to measure odour and odorants concentrations for odour impact assessment on municipal wastewater treatment plants (WWTPs). A range of sources and odour or odorants concentrations were used to compare the methods. Four different odours and odorants measurement methods were compared: field olfactometry using Nasal Ranger field olfactometer, dynamic olfactometry according to PN-EN 13725:2007 standard, colorimetric assays (hydrogen sulphide, ammonia) and gas chromatography-mass spectrometry (GC-MS) methods (methanethiol, ethanethiol, dimethyl sulphide). Mechanical-biological and mechanical-biological-chemical WWTPs were chosen. Receptor points were selected inside of 'closed' facilities of the technological line (screening rooms, mechanical thickening and dewatering building) and downwind at 'open' facilities (collection chambers, sand trap, mechanical thickeners) which were the most significant regarding the potential for odour nuisance. By the research, it is not possible to specify explicit dependencies between results obtained from different research methods used in the odour impact assessment of WWTPs. A strong correlation (Pearson's correlation coefficient was equal R = 0.79) was determined only once between odour concentrations measured by dynamic olfactometry and methanethiol concentrations in the screen room at the WWTP No. 3.