Chlorine Precipitation

Currently in Honduras, there are flow controllers treating water with Calcium Hypochlorite. An issue has arisen however, making it more difficult to effectively continue this type of treatment process. When treating water with Calcium Hypochlorite, especially when the water has a high alkalinity, calcium carbonate precipitates out. This results in clogging or failure at the float valve.

This summer, the late Demo Plant team spent time mixing similar concentrations of water/Calcium Hypochlorite solution and running this solution through the flow controller, in order to observe this precipitate forming.

The next step is treating the problem. To prevent failure at the float valve, the Chlorine Precipitation team has two proposed solutions that they are currently exploring:

• Creating an additional element in the hypochlorinators that would allow the precipitate to form elsewhere in the set up. This would make cleanup a lot easier and prevent the flow from stopping at the float valve.

• Figuring out an additional chemical solution to add to the hypochlorinator that would result in a lower pH and prevent the precipitate from forming at all. This would mean finding the exact concentration and amount of acid to add into the stock tank, which would result in the desired pH and alkalinity.

FCM Chlorine Precipitation goals and meeting minutes.