Trace Organic Degradation in Biofilm Processes

摘要

The hypothesis that some trace organic compounds have a threshold below which the concentration cannot be reduced by bacterial action was examined. Also studied were environmental factors that might affect the rate and lower concentration limits for bacterial decomposition of organic materials by biofilms. Batch and continuous flow-column studies were performed, using aerobic and anaerobic conditions and mixed and pure cultures. Under aerobic conditions, a group of chlorinated benzenes and aromatic hydrocarbons was found to be biodegradable, and under anaerobic conditions, several chlorinated aliphatic compounds were biotransformed. Radiotracer studies indicated that the chlorinated benzenes were oxidized to carbon dioxide; no indication of intermediate compound formation was obtained. The lower limits for acetate and propionate when used as primary substrates were investigated. Findings suggest that methanogenic conditions required to transform halogenated organic compounds can be developed even with relatively low substrate conditions. In another study in which a Pseudomonad that used both methylene and acetate was isolated, the rates of decomposition were found to be similar. There was evidence of substrate interactions.