A MODELING APPROACH FOR VOC EMISSIONS FROM SEWERS

Experimental and computational studies were completed to assess volatile organic compound (VOC) emissions from wastewater collection systems. Deuterated chloroform solutions were released into two operating collection systems as a VOC tracer. Downstream sampling of the sewer headspace and wastewater was performed and samples were analyzed by mass spectrometry. Results were used to evaluate a two-phase finite volume model for VOC interphase mass transfer and emissions for uniform reaches in sewers. Differences between predicted and experimental average steady-state concentrations were less than 30%, quite adequate for emission estimation purposes given other uncertainties in wastewater characteristics. The model described in this paper is intended to serve as a screening tool to identify conditions leading to emissions of VOCs from collection systems. The modeling approach can also serve as a basis for more advanced computational solutions as the knowledge base associated with VOCs in sewers improves.