A hollow-fiber membrane bioreactor for the removal of trichloroethylene from the vapor phase

A hollow-fiber membrane bioreactor was used to separate trichloroethylene ( TCE) from a gaseous waste stream with subsequent cometabolic biodegradation by a pure culture of Methylosinus trichosporium OB3b PP358. The two-stage bioreactor system was successfully operated for 20 days. PP358 was grown in a continuous-flow chemostat and circulated through the fiber lumen of a ho llow-fiber membrane module (HFMM), while TCE contaminated air (141 to 191 m u g/L) was pumped through the HFMM shell. Between 54% -84% TCE transfer and 92%-96% TCE cometabolism were obtained in the HFMM reactor loop. Short she ll-residence times, 1.6 to 5.0 minutes, demonstrated quick throughput of TC E contaminated air. Best-fit computer modeling of the biological experiment s estimated mass transfer coefficients between 2.0 x 10(-3) cm/min and 5.6 x 10(-3) cm/min. The average pseudo-first-order biodegradation rate constan t for the biological experiments was 0.46 L/mg TSS/d. These results demonst rate that the hollow-fiber:membrane bioreactor represents an attractive tec hnology for the bioremediation of gaseous waste streams. (C) 2000 John Wile y & Sons, Inc.