סמינר מחלקתי Limor Nizri
School of Mechanical Engineering Seminar
Wednesday, June 10, 2015 at 15:00
Wolfson Building of Mechanical Engineering, Room 206
A molecular method for testing the effectiveness of UV systems on-site
Limor Nizri
M.Sc Student of Dr. Hadas Mamane
Ultraviolet (UV) disinfection is a barrier to possible contamination of groundwater pollution. The well-water is drawn and treated with UV to meet the Israeli and internationally accepted standards, for protective radius of well water. Activity in the protective radius of well-water may result in microbial contamination and include sewage lines, barns, landfills, wastewater treatment plants, industrial zone and irrigation with wastewater effluent. Due to filtration of water through the soil, groundwater contains a low concentration of bacteria. Enumerating the bacterial concentration in water via the standard method of ”plate count enumeration” can only quantify bacteria that exist in water and are culturable on nutrient media.
Consequently, it is not possible to examine the effectiveness of UV disinfection of well-water operating in the field via standard culturing methods due to the insufficient concentration of indicator bacteria in the raw water, as determined by conventional methods. In this study, we examined the feasibly of a molecular method for determining the efficacy of UV disinfection systems operating on-site. We have developed a method of using the total DNA from a full array of bacterial species in the water sample without any need of growing or isolating a specific type of bacteria, and succeeded to correlate the total DNA of bacteria to the UV dose in the lab (spiked) in buffered water and in natural well-water without growing or isolating a specific type of bacteria. The "DNA damage" can bridge the gap for water without bacterial counts and may be used to validate the efficacy of full commercial-scale systems. Developing methods for evaluating UV disinfection on-site may serve as the stepping stone for wide acceptance of UV disinfection, especially in such waters.
