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In order to overcome the difficulties faced at the end of the second experiment, a new design was considered, which consisted of a diagonal column attached at the top of the vertical column. The design would retain small lime particles while allowing the saturated lime water to exit. Since the velocity in the slanted tube is affected by the angle, its vertical component is lower than the upflow velocity of the primary column.
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Figure 1: Sloping Column Lime feeder //
With the new apparatus, as shown seen in figure-2 below1 above, four sets of trials were carried out and evaluated.
The apparatus was first tested on with tap water in trial 1 and trial 2 and then using with distilled water will be used instead of tap water, in trial 3 and 4.
It had been observed that after a few hours into any experimental run using lime, the lime, instead of remaining in suspension as soluble particles, forms formed a single mass and becomes became insoluble. It is was hypothesized (by the previous research team) that this happens happened because some or all of the lime gets got converted into calcium carbonate(which is insoluble)if tap water is was used since the water received at Cornell is alkaline in nature. This should not be a problem in Honduras because the raw water to be treated will is not be as alkaline. However, under laboratory conditions, in order to get a true estimate of the lime feeder's efficiency (in dissolving lime for a longer period and thereby lasting for a longer time) distilled water will prove to be more accurate was used because it has no alkalinity and has pH that is that of a solution saturated with respect to atmospheric carbon dioxide. In the pictures below, the ANC Control team can be seen carrying the distilled water tank on to the platform where the experiment is to be set up.
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