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TRIAL 3. DISTILLED WATER, CHANGED BRAND OF LIME
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INTRODUCTION
This trial was carried out using distilled water to determine how long the experiment would last without the influence of carbonates (present in tap water). In addition, another parameter that was inadvertently changed was the brand of lime, since the previous supply of lime was depleted. The new lime brand had 70% calcium hydroxide compared to the older lime containing 96% Calcium Hydroxide. Thus during this trial, not only was the effect of water quality was evaluated but also the effect of lime quality. For this trial the pH remained stable at 12 for just 3.5 hours.
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OBJECTIVES
• Confirm if the carbonates or other quality characteristics of tap water, have any influence on the lime feeder performance.
• Evaluate the apparatus performance with a different brand of lime.
• Look for improvements for future experiments.
PROCEDURE
For this trial tap water was replaced by distilled water. In addition, the lime was changed, looking for a better quality of the compound. The apparatus was kept the same as for the previous two trials. The procedure adopted was the same as for trial 2, i.e. 100g of lime was made into a slurry and poured into the lime feeder from the top of the column. The flow rate was regulated at 120 mL/min (upflow velocity of 4.42 mm/s) by the peristaltic pump while the pH was recorded using a pH probe. Water supplies were made available from the distilled water tank. A more detailed explanation of the procedure can be obtained in the Materials and Methods section.
Although the change in the brand of lime was not pre-decided for this particular trial, it would allow us to evaluate if the performance of the lime feeder changes on using a different lime brand. This change is important to study taking into account the fact that the operators would have to deal with a different brand(s) in the local Honduran markets.
OBJECTIVES
• Confirm if the carbonates or other quality characteristics of tap water, have any influence on the lime feeder performance.
• Evaluate the apparatus performance with a different brand of lime.
• Look for improvements for future experiments.
RESULTS
For the above trial, the pH remained at 12 for about 3.5 hours but the performance of the apparatus changed drastically. The new lime was much more soluble in water and generally was composed of finer particles. The new lime did not accumulate in clusters at the bottom of the apparatus. This gave an almost perfect and uniform suspension of lime throughout the apparatus leaving no scope of observing the particle movements.
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