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The apparatus worked well with the established upflow velocity. The movement of particles was clearly visible and in accordance with the hypothesized movements (similar to the particle movements in the tube settler spacing apparatus).
At the top of the sloped column, the water looked clear i.e. sans of visible particles but according to the pH sensor measurements, it was saturated with base (i.e. pH 12), which was in accordance with the main objectives. A great amount of lime remained captured in the middle of the apparatus, although it was held in suspension. This signifies that the upflow velocity was high enough to give good suspension but the sloped column took care that the extra lime did not fall out with the effluent water but remained inside the column. This was a desirable behavior because the lime was still in the apparatus, giving the protons needed by water.
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The design seemed to work as expected and the movement of the particles was desirable. However there were a few some difficulties faced in the running of this trial.
Firstly, As the lime was poured into the apparatus in powder form with very little water inside. This , this resulted in the solidifying of the lime sludge and caused initial pressurizing within the column. It also took up time to clear out the clogging especially since the apparatus was extremely long and difficult to deal with. To overcome this difficulty it was decided that henceforth for all future experiments, lime will first be made into a slurry form and poured into the apparatus.
Secondly, since the experiment lasted for only 20 min, it was necessary to run at least one more trial using tap water using a different (larger) amount of lime.
Hence the next step was to run a second trial using tap water, the same upflow velocity but a larger amount of lime.