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In an oxidizing scrubber for odor control, the odorant is absorbed in a scrubber and must be oxidized to allow steadystate operation. The rate of absorption depends on the Henry's law coefficient, the gas-and liquid-phase mass transfer coefficients, and the rate of the oxidation reaction. The effect of a liquid-phase reaction on the liquid-phase mass transfer is often expressed in terms of an enhancement factor. Pseudo-first-order reaction rates were estimated for chlorination reactions for selected odorants. For simple amines and ammonia, the pseudo-first-order reaction rate is very fast, resulting in high enhancement factors for typical values of the mass transfer coefficients and odorant liquid-phase diffusion coefficients. For phenol and toluene, the reaction rate is relatively slow, and the enhancement factor is very close to unity.

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An integrated theory is developed to describe the steadystate operation of a suspended-growth bioscrubber for the control of biodegradable, volatile organic gases. The bioscrubber consists of an N-stage absorber and an oxidation reactor. A biomass slurry is circulated between the absorber and the oxidation reactor, the pollutant is absorbed and partially oxidized in the absorber. Oxidation is completed in the oxidation reactor. Predictions of the theory show that the removal efficiency is a function of Henry's Law constant for the pollutant, the ratio of the liquid flow rate to the gas flow rate, and the number of stages. Since high efficiencies can be achieved for soluble, biodegradable, volatile organic compounds, such systems have the potential to be a low-cost control method.Wet scrubbers can be used to remove water soluble gases including some volatile organic compounds. If the gas is not very soluble in water, its rate of absorption can be enhanced by either neutralization or oxidation. Neutralization is used for acid and alkaline gases. Chemical oxidation with sodium hypochlorite, hydrogen peroxide, or other oxidizing agents has been used for various organic compounds, particularly odorant gases. Biochemical oxidation by microorganisms is a potential alternative to chemical oxidation for biodegradable pollutants. It is attractive for toxic compounds because biochemical oxidation usually results in mineralization, destroying the toxic nature of the pollutant. This paper presents a theory for a biologically enhanced scrubber to remove biodegradable volatile organic compounds from the gas phase. In the scrubber, suspendedgrowth biomass metabolizes the pollutant. This lowers the liquid-phase concentration, allowing continuous operation with minimal requirements for both makeup water and water discharged from the system. ImplicationsTheoretical predictions show that suspended-growth bioscrubbers have potential for high removal efficiency of soluble, biodegradable, volatile organic compounds. In addition, biological oxidation usually mineralizes the compound and destroys the toxic nature of the pollutant without producing toxic byproducts. Such a system has the potential to be a lower cost method than conventional air pollution control technologies.