Vapor-phase bioreactors: Avoiding problems through better design and operation

Vapor-phase bioreactors are an efficient method to treat air contaminated with volatile organic compound. To ensure stable long term performance, several design and operating factors must be considered. Common problems include nutrient limitations, biomass clogging, inactive biomass, low moisture content and reductions in pH. Based on several bioreactor studies, the underlying cause of each of these problems is identified, monitoring requirements are outlined and a range of appropriate response actions are presented. These solutions range from modification of bioreactor design and operation (e.g., step feed configuration and directionally switching operation) to the use of alternative types of microorganisms (e.g., fungi).