For the past two years we have been doing research into viability of using Ultrasound as replacement for the more common types of disinfection. (i.e. Chlorine, Ultraviolet, etc.) We are also high school students, but have entered our research into the International Science and Engineering Fair for the past two years. This year we placed fourth in the world. We are looking for some feed back on our research.

ABSTRACT:

AN ANALYSIS OF THE EFFECTS OF ULTRASOUND ON FECAL COLIFORM BACTERIA CONTAINED IN DOMESTIC WASTEWATER ACCORDING TO VARYING AMOUNTS OF SUSPENDED SOLIDS

Wilson, James & Rainy, Justin
5525 Holiday Rd, Minnetonka, MN, 55345
5680 Christmas Lake Point, Shorewood, MN, 55435

e-mail: jwilson@minnetonka.org

Minnetonka High School, Minnetonka, MN, USA

Since the middle ages people have had problems disposing of domestic waste water. Current systems breed bacteria to decompose the solids contained in the waste water. The most common form of bacteria used for this process is Fecal Coliform bacteria. Then a disinfection system is used to destroy the bacteria. Problems remain because many of the current systems leave chemicals which can become harmful to the environment. Justin Rainy and James Wilson attempted to resolve this problem by using ultrasound to destroy the bacteria. The EPA is currently studying the effectiveness of ultrasound but is neglecting to test the many variables. A major factor in the sonication [i.e., the use of ultrasound to disrupt cells] of bacteria is the amount of solids present. Current research indicates that solids present in the solution directly influence the effectiveness of the disruption of the bacteria. Therefore, Justin and James hypothesized that increasing the amount of suspended solids will increase the effectiveness of the sonication. Samples of waste water were allowed to settle for 30 min. Then the amount of solids was varied and the samples were sonicated for a constant amount of time and amplitude. Finally, Fecal Coliform membrane tests were performed ten times to determine the amount of bacteria destroyed. The data showed that the hypothesis was wrong and that the amount of suspended solids did not affect the effectiveness of sonication. Further research will be conducted to aid the development of the sonication processes.


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