Affiliation: | a Faculty of Science and Technology, Science University of Tokyo, 2641 Yamazaki, Noda-shi, Chiba 278, Japan b Institute of Colloid and Interface Science, Science University of Tokyo, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162, Japan |
Abstract: | This study describes the effect of temperature on the behavior of bacteria viable in ultrapure water and the contamination of ultrapure water by bacteria. Three species of bacteria were isolated from ultrapure water (total organic carbon, 60 ppb and 5 ppb; effluent resistivity > 18 MΩ cm at 25°C) and identified by morphological and physiological characteristics. The three isolates were incubated in water for injection and PYG broth to check the growth profile at various temperatures. In PYG broth, temperature influenced the behavior of bacteria directly; however, it did not in water for injection. By checking both viable and non-viable bacterial numbers and endotoxin concentration in pure water, the water was found to be contaminated with non-viable bacteria and newly generated endotoxins besides viable bacteria. A column treatment, a mixed bed of fully regenerated strong acid cation exchange resin (SACER) and strong base anion exchange resin (SBAER), was used to remove bacteria from pure water. Bacteria could not grow on the surfaces of ion exchange resins in the mixed bed. The removal of bacteria was more effective as pure water was circulated through the mixed bed more rapidly. |