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In some AguaClara plants, a surface foam develops at the end of rapid mix. The initial focus of the research was on the chemical conditions required for this surface foam to develop then the focus shifted to the mechanical conditions that make this occurrence possible and simple retrofit designs that can ameliorate these conditions. In the initial experiments, different chemical conditions were modeled using a series of jar mixers and one-gallon tanks. The first few trials tests ran a constant supply of clay with varying amounts of alum but these did not exhibit any form of surface foam formation. Subsequent trials included organic matter: humic acid, but these only produced large non persistent bubbles. It was not until a stronger surfactant, liquid soap, was added to the baffle spacing that a surface foam with strong persistent bubbles developed. From these experiments it was concluded that air entrainment along with a surfactant in the raw water are the main chemical factors behind surface foam formation.
The second half of the research was on the mechanical******Knowing the ideal chemical conditions needed for surface foam formation, it was understaood that with the help of the In Honduras, the raw water may contain decaying matter which decays to fatty acids acting as the surfactant while the waterfall at the LFOM creates- the perfect- condition for air entrainment (what about the waterfall does?). The process of air entrainment along with natural surfactants in the water allow for the formation of surface foam. With this in mind, the research is now focused on retrofitting AguaClara's designs so that no air entrainment occurs in the entrance tank and rapid mix chamber by eliminating waterfalls and or implementing hydraulic jumps.*******
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