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We will first vary the alum dosage because research supports that surface foam can be attributed to the overdosing of aluminum sulfate. Additionally, the presence of natural organic matter (NOM) has been proven to lower surface tension in water, thus creating a surface foam. The location of the alum addition is also thought to effect the foam formation. This is because in small quantities, aluminum sulfate dissolves in water and the aluminum begins to precipitate as aluminum hydroxide. Air is then entrained in the aluminum hydroxide, forming bubbles which are less dense than water and are persistent on the water surface.

In addition to this information, it is commonly known that surfactants aid in the formation of foam by stabilizing the bubbles. This in turn prevents small bubbles from combining and forming larger bubbles which are easily popped. As a result, many small persistent bubbles or a foam form.

List of Parameters

In our rapid mix experiment we plan to vary the following independent variables:

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