1. With regard to your response to question 3 in your previous email, what other new technologies have not yet been developed to be sustainable? You noted that the recurring problem is that they aren’t sustainable (i.e. filters need changing, parts need repair/are not available, etc).

Units like LifeStraw for example. We actually tried the LifeStraw family units on the Tonle Sap but the just did not last and the turbidity of the water clogged them quickly.

2. What are the biggest problems you are facing with the bio-sand filters for the boating communities?

Lack of ability to easily follow up, weight of filter, locating families.

3. What portion of the problem of drinking water in Cambodia do boating communities take up? (i.e. How important is it to make this technology available and is it pertinent to the overall goal?) We work with The Lake Clinic (www.lakeclinic.org).

They had come to us asking to work on a light version of our biosand filter and experimented with and helped design our Light Biosand Filter. At this point most of our filters are not on the Tonle Sap but there is a huge community (80,000 people) that need clean water there. Families are difficult to follow up with so any technology has to be sustainable for it to be worthwhile. We mainly work on the rural villages of Siem Reap Province

4. Have you considered floating your Biosand Filters on the water, just as houses and boats do so as well? If so, what problems have you run into? Also, what alternate materials to concrete has Water for Cambodia looked into for making Biosand Filters suitable for Tonle Sap?

Our light biosand filter uses PVC. It has not been as effective as our concrete filters mainly due in part to the decreased surface area and therefore biolayer. There is also a plastic bucket model but that is heavy. We have not tried floating the filters. The risks with that are storms, theft, and mobility. These homes are always relocating. Access might also be an issue.

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