Biological Decomposition of Trace Organic Compounds

Biological decomposition of trace organic compounds was investigated to apply to the reclamation system of the rinse water recovered from semiconductor manufacturing processes. First, growth characteristics of microorganisms grown at low concentrations of organics were examined and extremely low saturation constants for acetate and methanol were obtained. Based on the growth characteristics, a biological fluidized bed reactor was operated to remove low concentrations of organics in a laboratory scale. One milligram per liter of acetate carbon was degraded to less than 10µg/l carbon with 10 minutes of hydraulic retention time. Low concentrations of methanol and isopropanol, which are main organics contained in the recovered rinse water, were also decomposed effectively. For a full scale operation, a pilot study was also carried out to examine treatability and stability of a fluidized bed reactor. Effluent organic concentrations decreased gradually and had been stable below 5µg/l carbon during 5 month operation.