Calcium Hypochlorite Experiments

Introduction

In Honduras, a Calcium Hypochlorite solution is used in the Agua Clara flow controllers to chlorinate the drinking water. Unfortunately, due to the precipitation of calcium carbonate, the system clogs, which leads to large decrease in the flow rate (and thus dosing) of the chlorinating solution. The goal of these experiments were to find the contributing factors to failure (significantly decreased flow rate) by modeling a hypochlorinator in use in Honduras.

Procedure

The experimental model is displayed below. The five gallon stock tank consists of a calcium hypochlorite solution at a concentration of 17.435 g/L. In Honduras, the stock tank consists of a 55 gallon tank that runs for approximately three days. In order to model this, the stock tank was run at 8 hour intervals and refilled when it was depleted, and then run again. The target flow rate used 48.1 mL/min, the same as 55 gallons/ 3 days. Overnight, the flow rate was to be slowed down to approximately a third of the flow rate by decreasing the change in head by a third. It would be evident that the system had reached failure when the flow rate had decreased significantly. Steps would then be taken to determine which portion had failed.

Procedure

The experimental model is displayed below. The five gallon stock tank consists of a calcium hypochlorite solution at a concentration of 17.435 g/L. In Honduras, the stock tank consists of a 55 gallon tank that runs for approximately three days. In order to model this, the stock tank was run at 8 hour intervals and refilled when it was depleted, and then run again. The target flow rate used 48.1 mL/min, the same as 55 gallons/ 3 days. Overnight, the flow rate was to be slowed down to approximately a third of the flow rate by decreasing the change in head by a third. It would be evident that the system had reached failure when the flow rate had decreased significantly. Steps would then be taken to determine which portion had failed.