EVALUATION OF BACTERIAL REMOVAL EFFICIENCY OF DOMESTIC WATER PURIFICATION SYSTEMS WITH DIFFERENT TECHNOLOGIES WIDELY USED IN INDIA

摘要

Bacterial disinfection using ultraviolet radiation is a world wide technology for drinking water purification. The efficiency of this technology depends on certain important parameters like the UV intensity, the exposure time, the area, clarity of thewater etc. Ultrafiltration is a membrane technology which removes the bacteria and its porosity is 0.01 micron. Nanofiltration removes the bacteria and this membrane porosity is 0.001 micron size. Reverse osmosis is a high end membrane technology with aporosity of 0.0001 micron removes bacteria. Brominated resin beads bacterial removal efficiency depends upon the clarity of the input water, flow rate, contact time etc.. This paper is indented to assist the reader about the various technology's capabilities to remove the pathogenic bacteria from drinking water. Standardized suspensions of test bacterial strains each having a cell density of approximately 10~5 cfu/mL were mixed with the inlet water in a pre unit reservoir and passed through the system.Samples were collected from the outlet after each passage and tested for bacterial viability. Test procedures were based on internationally accepted principles for the evaluation of point of use water purification units, including a standard test protocol of the United States Environmental Protection Agency. Reduction in numbers of seeded test organisms at several log levels higher than those expected in water for which the unit is intended, was determined by the cultivation of viable organisms.