Fall 2008 Semester Summery and Conclusions

Fall 2008 Semester Summery and Conclusions

As time progressed this fall, we began to understand more fully the problem that was presented to us. It became apparent that adding another chemical to the current Aguaclara water treatment system was not a reasonable solution to the precipitation problem. While adding hydrochloric acid (HCl) to the solution of calcium carbonate (CaCO3) would be an effective way to reduce pH and prevent the CaCO3 from forming, it would not be very cost effective. Using HCl would not only add to the cost of water treatment in terms of money spent, but also in terms of complicating plant operation. As a result, a different solution was pursued.

Next, the thought of settling out the CaCO3 before it enters the hypochlorinator was investigated. If the precipitated CaCO3 could be removed or reduced from solution before it comes into contact with the flow control device (FCD), this would ideally solve the problem. The fact that this chlorination treatment process will be expanding to many more communities, made investigating these problems more crucial, especially in communities that do not operate with full Aguaclara water treatment plants. We began by examining the flow restrictions that may arise in the Honduran communities that expressed interest in adding an Aguaclara FCD to their chlorine treatment systems. The first solution proposed was to design a settlement basin that could be implemented into the system which would allow the CaCO3 to precipitate out before it entered the FCD like the one that can be observed in (Figure 1).