Had a great discussion with a representative from the Department of Health. During our two-hour meeting we discussed our filter, the design, and how it compares to traditional methods of slow sand filtration. We discussed the overall effectiveness of bio-sand filters removing contaminants from water, alternate filtration systems, and contaminants in the water found in the Philippines.
We determined several things from the meeting, the most notable being that we need to determine the filter's flow rate. The flow rate must be correct for proper filtration. The optimal flow rates are unknown currently, but are dependent on the medium used.
We also discussed the problem of nitrates in drinking water in the Philippines. Nitrates come from sewage, and are a major problem as they cannot be filtered out with either our bio-sand filter or our Cascading pre-filter system. Nitrates can be treated through certain ultraviolet light systems, but such systems are expensive and not easy to replicate with our materials.
We discussed other ways to treat for nitrates, and learned that plants can drink the nitrogen compound in the water. We reasoned that we could utilize a locally available, economically useful plant in the Philippines (if we could find one) and implement it into our Cascading filter as an additional stage of pre-treatment. While this is currently still theoretical, it definitely merits further discussion.
Also discussed were testing our water, where the team can find a contaminated source of water, and if we can purposefully contaminate water with bacteria such as E. coli in order to test our filter system's effectiveness on truly contaminated water.
That's all for now. We are possibly meeting this weekend to build a couple more whey pre-filters, but this is dependent on several team member's schedules.