Peter (Hostel) Pethoe said:

James Davis said:

Project: Water Filters in Africa

We are planning to send low-cost, efficient water filters to small communities in Africa (and hope to go international in the future). Our goal is that the whole community will eventually have clean water. This would lower the large amount of deaths caused by water-borne diseases and deaths of HIV/AIDS victims who need clean water for their weak immune systems.

Proposal Description: http://www.omidyar.net/group/cmp s80j/ws/Project%3A%20Water%20Fil ters%20in%20Africa/

This discussion is part of the voting process to select a winning proposal. Details here:

http://www.omidyar.net/group/cmp s80j/ws/index/

Mr. Davis: What do you mean by "We are proposing to send low-cost sand filters"??

Aren't all of the materials for producing these filters readily available locally in Africa? Do these filters have to be imported?

Also adding a layer of activated charcoal would improve the taste and smell of the filtered water. Disinfection of the water is still necessary. Here we usally use chlorine because of its residual benefits and ease of testing. If at the far end of the pipe there is no chlorine residual, it means somewhere in the system contamination that used up the chlorine oxidizer is present. Other oxidizers, such as potassium permangenate could be used (before filtering- to remove color).

For those UCSC students that prefer not to consume the beneficial effects of chlorine in water, the solution is simple: Leave an OPEN container of tap water (glass bottles might be the best) by the sink for later consumption. The chlorine gas will evaporate and dissipate. No need to purchase expensive bottled water (that might be worse than our good city water) and to throw away vast quantities of oil-based plastic containers. City water is rechlorinated twice at pump stations and reservoirs on the way up to the top of UCSC.

We're fortunate here in Santa Cruz that (unlike 3/4 of US city water systems) our water is not flouridated. So young students with growing teeth should use flouridated toothpaste, although there's probably sufficient flouride in most foods, soft drinks and beer to keep your teeth from rotting away (not counting the sugar in the gunk). Flouridating city water would be stupid, only a quart/person per day is drunk about 20,000 gallons for Santa Cruz with daily 10 to 15 million gallons production. Flouridation just pollutes the environment with toxic flouride while letting large chemical companies off the hook, they don't have to pay to dump the stuff at toxic landfills, but actually get to sell it to water providers. A big scam. Also most immigrants won't drink tap water, no one south of the border drinks tap water.

Alternate methods of disinfectation include ozone, requiring electricity, or UV which might be accomplished by exposing the filtered water to the sun's ultraviolet rays.

High turbidity drastically shorten filter times between backwash or cleaning, but would be minimal with underground well water sources not affected as much by high stirring effects of rainfall as surface sources. Large clear lakes may be an exception. The earth itself in underground water sources also performs as a filter.

Another disinfectation method very common in Mainland China is heating water to nearly boiling. Electrically heated water containers are used everywhere. However this process uses much electricity, although solar water heating might be a very practical green alternative. Aeration is another practical way to disinfect water, although not as quick as using chemicals.

With above ground water sources and occasional high turbidity, more sophisticated water purification methods such as flocculation, coagulation and sedementation may be required, all complicated and expensive, well beyond the scope of this project.

However such complicated methods require trained personnel, in short supply here in California. Those of you with some math background might want to pursue a career in Water or Wastewater Treatment. Grade 3 operators that can work shifts by themselves (Grade 2 require supervision) are in high demand and get quite well paid. As a new Grade 3 you'll probably work night shifts that give you plenty of time to study towards even higher goals. The requirements issued by the State, are getting stricter, the tests tougher, the pay higher. Once you're a 3 you'll get job offers from all over. I understand some water courses are offered at Hartnell JC in Salinas.

Ask for a tour through our City Water Treatment Plant at 715 Graham Hill Road. The same architect that designed Foothill JC, Cabrillo JC and many other schools also did this very elegant California style building.

Remember, the big battles here in California this century will be over water, or lack of it!

Good luck! PGP

Thanks for all your info Peter. Our main goal is to filter out the most important pathogens that cause diarrheal diseases (which affect adults and cause deaths of too many children) and we would like to do that with a low-cost filter that doesn't require electricity which is a cost we could not endure as of yet. So although the filteration processes you have mentioned that require electricity is important, we need to first get rid of the most important bacteria and parasites in their water at a low-cost to make a better-quality water supply before we can make it the best quality that is up to America's high-cost standards.

As for sending, yes it is made of local materials that can be found in Africa but certain parts (i.e. the pvc pipe) need to be shipped from somewhere, although I've found you can get them in Tunisia or some other countries in Africa. So when we say send, you can take it as making them available there by shipping parts over there and installing them.