The normal composition of the effluent samples at Abbott Laboratories is within the maximum tolerated impurity levels as listed in the Illinois State Standards (1968). These tolerances are partially summarized in Table I and do not interfere in the assay. Wiersma (1970) employed 2,3-diaminonaphthalene as a fluorometric reagent for nitrite ion and in addition performed Table I. Illinois Effluent Standards Constituent" Standard Ammonia nitrogen 2.5 ppm Arsenic 1.0 ppm BOD 40 mg/1.

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This article reports on the biodegradation of trichloroethylene (TCE) in a hollow‐fiber membrane biofilter. Air contaminated with TCE was passed through microporous hollow fibers while an oxygen‐free nutrient solution was recirculated through the shell side of the membrane module. The biomass was attached to the outside surface of the microporous hollow fibers by initially supplying toluene in the gas phase that flows through the fibers. While studies on TCE biodegradation were conducted, there was no toluene present in the gas phase. At 20‐ppmv inlet concentration of TCE and 36‐s gas‐phase residence time, based on total internal volume of the hollow fibers, 30% removal efficiency of TCE was attained. At higher air flow rates or lower gas‐phase residence times, lower removal efficiencies were observed. During TCE degradation, the pH of the liquid phase on the shell side of the membrane module decreased due to release of chloride ions. A mathematical model was developed to describe the synchronous aerobic/anaerobic biodegradation of TCE. © 1996 John Wiley & Sons, Inc.

This article reports on the biodegradation of trichloroethylene (TCE) in a hollow-fiber membrane biofilter. Air contaminated with TCE was passed through microporous hollow fibers while an oxygen-free nutrient solution was recirculated through the shell side ofthe membrane module. The biomass was attached t o the outside surface of the microporous hollow fibers by initially supplying toluene in the gas phase that flows through the fibers. While studies on TCE biodegradation were conducted, there was no toluene present in the gas phase. At 20-ppmv inlet concentration of TCE and 36-s gas-phase residence time, based on total internal volume of the hollow fibers, 30% removal efficiency of TCE was attained. At higher air flow rates or lower gas-phase residence times, lower removal efficiencies were observed. During TCE degradation, the pH of the liquid phase on the shell side of the membrane module decreased due to release of chloride ions. A mathematical model was developed to describe t h e sync h ro n ou s a e ro b ic/a n ae ro b ic b i od eg ra dation of TCE. 0 1996 John Wiley & Sons, Inc.*