h1. ANC CONTROL


h2. Materials and Methods

The ANC experimental setup consists of the water source, a peristaltic pump, the limefeeder, and a pH probe. The water source is either tap water or distilled water, depending on the experiment. Distilled water has a much lower concentration of carbonates compared to tap water and is used to simulate water conditions in Honduras. It can be found in the hydraulics laboratory.

The peristaltic pump is run by [Process Controller|https://confluence.cornell.edu/display/AGUACLARA/Process+Controller]. The file can be found here <put file here>. The tube size is 18 and flow rate can be changed. In the first type of setup (Fig 1), the limefeeder is just a vertical column. In the second setup (Fig 2), the limefeeder is a vertical column attached to a tube with a 22.5 degree angle with respect to the vertical axis. The pH probe measures the pH of the effluent and is calibrated with buffers of pH 4, 7, and 10. The file to set up the probe can be found here <put file here>.

!Limefeeder.jpg!
{float:left}* Figure 1. Type I Setup. Limefeeder was a vertical column.{float}

!Limefeeder2.png!
{float:left}* Figure 2. Type II Setup. Limefeeder was a combined vertical and angled tube.{float}

There were two types of hydrated lime used in these experiments. The first type is Hi-Yield Hydrated Lime. The second is <Enter name of lime here>. 100 grams of lime is measured on the scale and then is introduced from the top of the limefeeder either in powder form or in a lime slurry (lime mixed with water) for the second type of setup. After the lime is in the column, Process Controller turns the peristaltic pump on, starting the experiment.

After the experiment is done, there is an abundance of calcium carbonate settled on the bottom of the lime feeder. To clean the column, the top is uncapped, water is sloshed around, and then emptied. Acid may be needed to clean the column for calcium carbonate residue.