The Effect of Time of Ultraviolet Sterilization on the Killing of Bacteria in Water

The purpose of this experiment was to determine what effect time has on the effectiveness of killing E. coli bacteria inside of water. This is a significant question to ask because water reservoirs are becoming more limited and an effective method for cleaning water has to be established (Greenemeier). Ultraviolet sterilization is one of the most popular methods of eliminating bacteria inside of water, therefore, it is important that the process is done with efficiency and effectiveness. It was hypothesized that the four and a half minute exposure time, the longest amount of time, will be the most effective in reducing the bacteria concentration in water. A spectrometer was used in order to measure the bacteria concentration within the water sample, which was then run through an ultraviolet sterilizer for varied amounts of time depending on the trial. A spectrometer would then be used once more in order to measure the bacteria concentration within the water sample after it had been exposed to ultraviolet rays. According to the data, the longer the amount of time the bacteria was exposed to the ultraviolet rays, the more bacteria was killed within the water sample at a significance level of 0.017128. It was also found that the water only needed to be exposed for a very brief period of time in order for the ultraviolet rays to have a serious impact on reducing the amount of bacteria within it.

Research Conducted By:

Mahir Ahmed
Center Line High School

Rani Brikho
Sterling Heights High School

 

 

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