A recent roundup of field microbiological water testing systems....<div><br></div><div><a href="https://www.engineeringforchange.org/news/2013/01/28/wanted_an_easy_test_for_bacteria_in_drinking_water.html">https://www.engineeringforchange.org/news/2013/01/28/wanted_an_easy_test_for_bacteria_in_drinking_water.html</a></div>
<div><br></div><div>See especially:</div><div><a href="http://www.mdpi.com/1660-4601/9/5/1609">http://www.mdpi.com/1660-4601/9/5/1609</a></div>A Summary Catalogue of Microbial Drinking Water Tests for Low and Medium Resource Settings<br>
<br><font class="Apple-style-span" size="1">Microbial drinking-water quality testing plays an essential role in measures to protect public health. However, such testing remains a significant challenge where resources are limited. With a wide variety of tests available, researchers and practitioners have expressed difficulties in selecting the most appropriate test(s) for a particular budget, application and setting. To assist the selection process we identified the characteristics associated with low and medium resource settings and we specified the basic information that is needed for different forms of water quality monitoring. We then searched for available faecal indicator bacteria tests and collated this information. In total 44 tests have been identified, 18 of which yield a presence/absence result and 26 of which provide enumeration of bacterial concentration. The suitability of each test is assessed for use in the three settings. The cost per test was found to vary from $0.60 to $5.00 for a presence/absence test and from $0.50 to $7.50 for a quantitative format, though it is likely to be only a small component of the overall costs of testing. This article presents the first comprehensive catalogue of the characteristics of available and emerging low-cost tests for faecal indicator bacteria. It will be of value to organizations responsible for monitoring national water quality, water service providers, researchers and policy makers in selecting water quality tests appropriate for a given setting and application.</font><br>
<div><br></div><div><br></div><div><br></div><div><br><div class="gmail_quote">On Sat, Feb 16, 2013 at 12:03 PM, Tom Carter <span dir="ltr"><<a href="mailto:tom@aguapuraparaelpueblo.org" target="_blank">tom@aguapuraparaelpueblo.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div style="font-size:12pt;font-family:tahoma,new york,times,serif"><div><span>Bruce-</span></div><div style="font-style:normal;font-size:16px;background-color:transparent;font-family:tahoma,new york,times,serif">
<span>I often sell WAPI's at $5.00 each to outdoor groups and others who want to use them for camping or emergencies to help finance the free ones we distribute through our programs. </span></div><div style="font-style:normal;font-size:16px;background-color:transparent;font-family:tahoma,new york,times,serif">
<span>Rotary Clubs sponsor WAPI's world wide and provide supplies to make them yourself. One contact is: <a href="http://www.integratedsolarcooking.com/makewapis" target="_blank">http://www.integratedsolarcooking.com/makewapis</a><br>
</span></div><div>I think the wax they use has a somewhat higher melting temp than the green colored
wax that Solar Cookers and I use. It's not a problem for those cooking over fires, but makes a big negative difference with solar reflector stoves because they heat more slowly and may not reach the higher temperature before sunset.</div>
<div>There is also a quality control issue with the Rotary WAPI's. Because they are put together by volunteers, they are sometimes poorly made and leak wax. Bob Tait of Portland has a large, well trained staff who make excellent quality WAPI's and distribute them for free to other non-profits. His organization is Wapi's for the World and his email is <a title="niteowl12@hotmail.com" href="http://us-mg4.mail.yahoo.com/yab-fe/mu/MainView?.src=neo&themeName=fresh&bn=7161&s=0&isFresh=1&bucketId=0&stab=1361033768309#" rel="nofollow" target="_blank">niteowl12@hotmail.com</a> <br>
</div><div style="font-style:normal;font-size:16px;background-color:transparent;font-family:tahoma,new york,times,serif">Tom<br></div><div style="font-style:normal;font-size:16px;background-color:transparent;font-family:tahoma,new york,times,serif">
<span style="font-size:9.000000pt;font-family:'GillSans';font-weight:700;color:rgb(100.000000%,100.000000%,100.000000%)"><a href="http://www.integratedsolarcooking.com/makewapis" target="_blank">http://www.integratedsolarcooking.com/makewapis</a>
</span>
<span style="font-size:9.000000pt;font-family:'GillSans';font-weight:700;color:rgb(100.000000%,100.000000%,100.000000%)"><a href="http://www.integratedsolarcooking.com/makewapis" target="_blank">http://www.integratedsolarcooking.com/makewapis</a>
</span> </div> <div style="font-family:tahoma,new york,times,serif;font-size:12pt"> <div style="font-family:times new roman,new york,times,serif;font-size:12pt"> <div dir="ltr"> <font face="Arial"> <hr size="1"> <b><span style="font-weight:bold">From:</span></b> Bruce Stahlberg <<a href="mailto:bruce@affordableenergysolutions.com" target="_blank">bruce@affordableenergysolutions.com</a>><div class="im">
<br> <b><span style="font-weight:bold">To:</span></b> Tom Carter <<a href="mailto:tom@aguapuraparaelpueblo.org" target="_blank">tom@aguapuraparaelpueblo.org</a>>; Discussion of biomass cooking stoves <<a href="mailto:stoves@lists.bioenergylists.org" target="_blank">stoves@lists.bioenergylists.org</a>> <br>
</div><b><span style="font-weight:bold">Cc:</span></b> Crispin Pemberton-Pigott <<a href="mailto:crispinpigott@gmail.com" target="_blank">crispinpigott@gmail.com</a>>; Jeff Holiman <<a href="mailto:jeff.holiman@gmail.com" target="_blank">jeff.holiman@gmail.com</a>> <br>
<b><span style="font-weight:bold">Sent:</span></b> Friday, February 15, 2013 2:00 PM<br> <b><span style="font-weight:bold">Subject:</span></b> Re: [Stoves] A simple water sterilization technique<br> </font> </div><div><div class="h5">
<br><div>Thanks Tom for the
information. Do you know the wax that is used in a WAPI? Is it easily, readily available in other countries? Any other wax that also melts at or just above the same temperature? <br><br>I believe SCI, like many organizations, uses the costs to the general public of the USA to help subsidize their programs internationally. Fairly common practice and seems appropriate. At $7 - 9 per WAPI, the average citizen that wants one is not as likely to make one. The additional cost is for convenience and to help with programs to provide clean water, clean cooking. <br>
<br>Can you check with Bob to see what materials he uses? Might be useful for others on this list to be able to make them locally too.<br><br>Bruce<br><br><div>On Thu, Feb 14, 2013 at 6:45 PM, Tom Carter <span dir="ltr"><<a rel="nofollow" href="mailto:tom@aguapuraparaelpueblo.org" target="_blank">tom@aguapuraparaelpueblo.org</a>></span> wrote:<br>
<blockquote style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div style="font-size:12pt;font-family:tahoma,new york,times,serif">All-<br>No, No, No! Storing water in a dark container does NOT kill pathogenic bacteria or other organisms! Nor does refrigeration or even freezing. E Coli and other bacteria can survive for weeks in a cold dark environment. Heating, filtration, UV disinfection and chemical treatment (chlorine or other) are the only recommended methods I'm aware of for drinking water decontamination. <br>
Bacteria tend to cling to particles in the water so allowing it to settle or adding a flocculating agent can sometimes help a little. Particulate material in the water also blocks UV penetration and thus makes solar (UV) disinfection less effective.<br>
Part of the problem with bore wells and similar systems is that they become readily contaminated by misuse and need to be monitored. I'm aware of a diarrheal outbreak in Kenya
caused by a contaminated well, and so we recommend frequent testing of community water sources. We supply the testing materials to trained health workers and others at no cost so that they can safely and accurately monitor local water supplies. For the average family it's better to just assume contamination and develop the habits of drinking water purification. <br>
The WAPI's (Water Pasteurization Indicator's) that Jeff Holiman and others mentioned cost $7.00 each on the Solar Cookers International website, but really only cost about $.05 to manufacture. Where the rest of the money goes, I know not. Bob Tait of Clackamas, Oregon makes and distributes thousands of them for free to various missionary groups and other non-profits. My only point with Bob is that I believe they should used as part of a general program that supports various health and sanitation practices including safe latrines, hand washing and
clean water storage. These practices can be adapted to local cultural practices and should include follow up and support.<br>Our free training programs include teaching accurate testing and interpretation of water samples using the 3M petrifilm methods and a second fluorescent confirmatory assay called Colilert. We also train participants in the use of the WAPI's, and other disinfection methods and in the construction of simple solar and biomass stoves that that families can use to heat their water and to cook. The workshops usually take a day and a half but for efficiency sometimes can be squeezed into a day. If there is enough interest I could organize one here in Portland or in some other site.<br>
Tom Carter<br><br><div><span><br></span></div><div><br></div> <div style="font-family:tahoma,new york,times,serif;font-size:12pt"> <div style="font-family:times new roman,new york,times,serif;font-size:12pt"> <div dir="ltr">
<font face="Arial"> <hr size="1"> <b><span style="font-weight:bold">From:</span></b> Crispin Pemberton-Pigott <<a rel="nofollow" href="mailto:crispinpigott@gmail.com" target="_blank">crispinpigott@gmail.com</a>><br>
<b><span style="font-weight:bold">To:</span></b> 'Tom Carter' <<a rel="nofollow" href="mailto:tom@aguapuraparaelpueblo.org" target="_blank">tom@aguapuraparaelpueblo.org</a>>; 'Discussion of biomass cooking stoves' <<a rel="nofollow" href="mailto:stoves@lists.bioenergylists.org" target="_blank">stoves@lists.bioenergylists.org</a>> <br>
<b><span style="font-weight:bold">Sent:</span></b> Thursday, February 14, 2013 11:59 AM<br> <b><span style="font-weight:bold">Subject:</span></b> RE: [Stoves] A simple water sterilization technique<br> </font> </div><div>
<div> <br><div><div><div><div><span style="font-size:11.0pt;color:#1f497d">Dear Friends</span></div><div><span style="font-size:11.0pt;color:#1f497d"> </span></div>
<div><span style="font-size:11.0pt;color:#1f497d">Keeping water in the total dark for 3 days kills quite a lot of things including Bilharzia. When I worked in Rural Water Supply in Swaziland we provided covered tanks with more than 3 days storage on most systems for this reason (in the lowveld). We also used dosing boreholes with chlorination occasionally (always when new) and precautionary chlorination using bypass jets on pumped systems to get a 2 ppm level at the last standpipe. No one boiled
water to purify it in those days. </span></div><div><span style="font-size:11.0pt;color:#1f497d"> </span></div><div><span style="font-size:11.0pt;color:#1f497d">In contrast, nearly everyone in peri-urban and rural Indonesia boils their drinking water. Completely different situation, for which stoves are required.</span></div>
<div><span style="font-size:11.0pt;color:#1f497d"> </span></div><div><span style="font-size:11.0pt;color:#1f497d">Regards</span></div>
<div><span style="font-size:11.0pt;color:#1f497d">Crispin</span></div><div><span style="font-size:11.0pt;color:#1f497d"> </span></div>
<div><span style="font-size:11.0pt;color:#1f497d"> </span></div><div><div><div style="background:white"><span>Jeff-</span></div>
</div><div><div><span>Thanks for the post. Yes, it's true that pasteurization at 65C kills all pathogenic bacteria and viruses, as well as worms and cysts. I don't recommend "feeling it with your hand" however as even a 10 degree lower temperature will have a much lower effectiveness. As you
note, a wax indicator developed by Dr. Robert Metcalf accurately and safely demonstrates when the water is pathogen free. We distribute them at no cost to families and instruct them on their use. Filtration through a clean cloth probably helps a little, as does letting the water settle, but is not necessary for pasteurization. Some methods that use solar UV disinfection do require clean water and clear PET water bottles for effectiveness. They also take longer, lack an end point and have inconsistent results and for that reason we don't recommend them.</span></div>
</div><div><div><span>The last step is keeping safe water safe, by storing it in clean containers with small openings so that people cannot recontaminate it by dipping in with dirty containers or hands.</span></div>
</div><div><div><span>I'm going to give a water testing and water pasteurization workshop here in Portland in the next months if anyone is interested in being trained.</span></div>
</div><div><div><span>Tom Carter</span></div></div><div><div><span><a rel="nofollow" href="http://us-mg4.mail.yahoo.com/neo/aguapuraparaelpueblo.org" target="_blank">Agua Pura Para El Pueblo</a></span></div>
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