Monitoring biodegradation of VOCs using high speed gas chromatography witha dual point sampling system

A new sampling system has been designed and interfaced with high-speed gas chromatography (HSGC) to monitor and assess the performance of a trickle-be d bioreactor designed for the removal of volatile organic compounds from ai r. A portion of a gas stream containing styrene and toluene was sampled bot h before and after passing through the bioreactor by means of a dual-loop s ampling system. With a frequency of as high as 2 per minute, treated and un treated samples were alternately transferred on-line to the cryofocusing in jection system of a HSGC and analyzed. This analytical system generated dat a with less than 2% relative standard deviations for standard samples, and residual contamination of subsequent analyses from a highly concentrated sa mple (2000 mug/L) was not observed. A bench-scale bioreactor with a fiber m at support was used in these studies, resulting in residence times for anal ytes in the bioreactor of as little as 1 s. Rapid monitoring of this system detected subtle changes in the concentration of analytes with 30 s tempora l resolution. Measurements showed a statistically significant increase in t he removal of styrene from 22% to 27% when water was sprayed over the immob ilized bacteria for 30 min. Overall, the bioreactor removed styrene from th e air stream with a specific elimination capacity of 1700 g of styrene (m(3 ) of biocatalyst)(-1) h(-1) at a spacevelocity of 3400 h(-1)