ESTIMATION OF VOC EMISSIONS FROM WASTE-WATER FACILITIES BY VOLATILIZATION AND STRIPPING

Emissions of volatile organic chemicals (VOCs) from wastewater collection and treatment facilities are a potential concern to treatment plant operators, downwind receptors and regulatory personnel. The purpose of this paper is to present and review current methods to estimate VOC emissions from wastewater collection and treatment systems where the major removal mechanisms are volatilization and stripping. Many of the current methods to predict the rate at which VOCs are stripped or volatilized from wastewater are related to previous studies on oxygen transfer in wastewater. This paper reviews fundamental principles which describe liquid-gas equilibrium and mass transfer, and important parameters which may influence them. It also reviews methods to predict stripping/volatilization from sewers and conveyance channels, preliminary and primary treatment, weirs and drops, and aeration basins. The results indicate that although methods are available to estimate VOC emissions from collection and treatment facilities, further work is required to develop better models and validate existing models in order to provide better predictive tools.