...
The water chemistry in our system also contributes greatly to the unexpected results. (were the results unexpected except for 45 mg/L?) The water in the lab is much more alkaline than the water in Honduras. As a result, the pH of the water in Honduras is more sensitive to changes in alum dose. There is an ideal range of pH values where flocculation occurs most effectively, and this range is harder to achieve in Honduras. Thus, the water in the lab allows the system to be more robust and able to achieve acceptable effluent turbidity even with a large range of alum dosages. This observation means that even though the system appears to work successfully regardless of the ranges of alum doses that we tested), the same will most likely not be true in Honduras. We must modify our findings for the plant in Honduras because the same results will not be achieved with a different water chemistry. A future study could include changing the alkalinity of the water to make the water pH more sensitive to changes in alum dose to confirm the applicability to Honduras.