Estimating Emissions of 20 VOCs. I: Surface Aeration

The emission rates of semivolatile organic compounds during surface aeration can be estimated from the oxygen mass‐transfer coefficient $K_L{a}_{O_2}$ and a modified coefficient ${\Psi }_M$, which incorporates the fraction of liquid‐phase mass‐transfer resistance to total resistance. In order to verify this method, the mass‐transfer coefficients for oxygen and 20 volatile organic compounds (VOCs) were simultaneously measured in a laboratory‐scale surface‐aerated reactor. Using these measurements, the ratios of gas‐phase and liquid‐phase mass‐transfer coefficients were determined by nonlinear regression. These ratios then were used to estimate the fraction of liquid‐phase resistance to total resistance. The method was validated by excellent agreement between observation and theory. The correlation between the ratios of gas‐ and liquid‐phase transfer coefficients and specific power input was also studied.