Toluene vapor remediation in a continuous packed bed loop bioreactor

An external loop airlift bioreactor with a small amount (99% porosity) of stainless steel mesh packing inserted in the riser section was used for bioremediation of a toluene polluted air stream. The packing enhanced VOC and oxygen mass transfer rates and provided a large surface area for cell immobilization. Using a mixed culture, fed‐batch and continuous runs at five different dilution rates were completed with toluene in the polluted air as the only carbon source. Above 99% and 93.6% toluene removals were achieved at toluene loading rates up to 88.1 and 149.1 g/(m3 h), respectively. The bioreactor responded quickly to a toluene load shock of 33 g/(m3 h) at high inlet toluene loadings. After 185.8 days operation, no plugging problems were observed in the column. A mathematical model is shown to accurately predict transient and steady state data. © 2008 American Institute of Chemical Engineers Environ Prog, 2008