ANALYZING FACTORS INFLUENCING BACTERIAL GROWTH IN FINAL WASTEWATER EFFLUENT WITH CHLORINE AND OZONE DISINFECTANT

The objective of the experiment was to find if ozone or chlorine disinfects effluent filter waste water better and if other various factors such as contact time, temperature, humic acid, and alkalinity also have a positive effect on the disinfection. Various amounts of chlorine, ozone, humic acid, alkalinity solution were added to waste water samples and heated or cooled to specific temperatures. The samples were quenched after a certain period of time to stop the reaction. Membrane filtration was performed on each treated sample to find the number of bacterial colonies left in each sample after disinfection. The samples were incubated for a twenty-four hour period to let the bacterial colonies grow. The fewer bacterial colonies in each sample, the better the disinfection. Only twenty trials were needed because a six-factor fractional factorial design of experiment was used to find that only chlorine had a significant effect on disinfecting waste water. Humic acid also had an effect on the disinfection. The hypothesis was rejected which stated that ozone, with a high contact time, would disinfect the water better than chlorine. The experiment helped to determine which method would be most effective in waste water treatment plants. Treatment plants have been doing research to find if they should begin using ozone or UV light disinfection methods to treat the water more efficiently. However, this experiment showed that chlorine is more effective.

Research Done By:

Chelsea Paga
Cousino High School

Brice Jurban
Sterling Heights High School

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