Volatilisation processes in wastewater treatment plants as a source of potential exposure to VOCs

The results of a survey estimating volatilisation rates (as gas exchange constants and flux rates) of a range of hazardous alkane, aromatic, organohalogen, organosulphide, ketone and alcohol volatile organic compounds (VOCs) from a water bay are presented. More than 73 experimental test runs were carried out over a year under varying seasonal conditions to measure the simultaneous concentrations of VOCs in air and water phases. The data were processed employing new advances in 'surface renewal' volatilisation models. Based on the experimental data, estimates of theoretical equilibrium constants, gas exchange constants and flux rates for each VOC were made. Within the ranges of concentration which may reasonably be encountered by process workers, the fluxes for a broad range of VOCs ranged from approximately 0.04x10(-8) to 9.0x10(-1) g cm(-2) h(-1). The results were used to make predictions about the relationship between volatilisation processes and their implications for occupational hygiene risk assessment. (C) 1997 British Occupational Hygiene Society. Published by Elsevier Science Ltd.