Thanks Herb. Is Jim right in crediting Legionella with some of the
power of the sand filter to remove noxious bacteria? Does it then
actually damage the efficacy of the filter to allow antibiotics
into it?
Chandler
On Sat, 10 May 2014, herb fox wrote:
> On 1st reading Jim's post appeared to be asserting that Legionella is not to be feared: "Hurray for Legionella. So badly demonized."
> Just to set the record straight:
>
> Legionella bacteria have been found to make up a significant portion of the bacterial population in slow sand filters. Some species of Legionella are human pathogens (Calvo-Bado et al, 2003a). As such, i
> t is recommended that the sand filter not be kept inside the greenhouse where high temperatures can lead to proliferation of Legionella (Calvo-Bado et al., 2003a). As well, levels of Legionella should be
> monitored to prevent harm to workers
>
> Calvo-Bado L.A., Pettitt T.R., Parsons N., Petch G.M., Morgan J.A.W., Whipps J.M. 2003b. Spatial and temporal analysis of the microbial community in slow sand Filters used for treating horticultural irri
> gation water. Applied Environmental Microbiology 69:2116?2125.
>
> Certainly the fears associated with Legionaires Disease have been and will be used to stimulate "the sales of antibiotics for water systems in the industrialized countries." What else would one expect
> from an economic system for which the primary motivation has been reduced to maximizing profit. That in the system in which we are presently compelled to live there are daily insults from big pharma
> does not remove the fact that there are real, dangerous diseases, or even worse that the wanton proliferation of antibiotics enables the evolution to new, antibiotic resistant forms. However, to deny or
> lessen concern with the harmfulness of the responsible bacteria is not an appropriate response.
>
> There can be no widespread Science for the People as long as the profit motive is the underlying basis for the invention, production and distribution of pharmacologicals.
>
> Expressions of passionate hatred of science being used against the people especially those not well armed to understand its threats does not lead to remediation as successfully as it leads to a
> fundamental distrust of science. The offer of, if possible, scientific remediation along with a popular explanation of why the positive science is superior and why the fundamental problem is actually
> science for profit has a better chance of gaining wide spread public support for Science for the People as a movement, and ultimately a change of consciousness that makes possible a humane,
> post-capitalistic society.
>
> herb
>
> On 5/10/2014 11:15 AM, Jim West wrote:
>
> Thanks John,
>
> I too appreciate biosand filters, with their bacteria colonies building gels that filter out other microbes.
>
> Legionella bacteria makes up a "significant proportion" of the bacteria in slow-sand filters. Hurray for Legionella. So badly demonized, increasing the sales of antibiotics for water systems in the indus
> trialized countries.
>
> Ref:
> http://www.ces.uoguelph.ca/water/PATHOGEN/SlowSand.pdf
>
> Jim West
> http://harpub.tk
>
> ==========
> Thanks Herb. The biosand filter is an excellent low cost and appropriate technology. see http://www.howard.edu/kenya for work some of our howard engineers without borders students did in a rural communit
> y in wesern kenya. the team went back last year and installed another eleven filters. when we went back, we visited an orphan house where the team had installed a biosand filter the previous trip. the or
> phan house "mom" told us she hadn't had a single case of water borne stomach ailments in her 20 orphans since we put in the biosand filter and trained her to operate and maintain it.
>
> john
>
> On Thu, May 8, 2014 at 8:28 PM, herb fox <[log in to unmask]> wrote:
> I read the post and ancillary material before Sam posted it and rejected it for other reasons than those raised in the posts.
>
> I found the whole approach paternalistic and disrespectful of those it intended to help. Advanced technology requiring 1st world production techniques is not the way of Science for the People. SftP sho
> uld be of, by, and for the People. As much as possible it should be based on the traditions of the people, be producible by them and use indigenous materials. The issue of potable water is central to i
> mproving and extending the lives of people throughout the world, in Haiti also for example. There a colleague, Bob Giles, with a long experience in Haiti and adequate command of the language worked with
> some young Haitians and USA university students to resurrect a device that could be made entirely with indigenous materials, require existing native skills, and be understood by those who would be using
> it.
>
> The bio-sand filter is a slow filtration system that uses a casing made from cement and filled with three different layers of sand. The system purifies water in four basic steps: mechanical trapping (sus
> pended solids and pathogens are physically trapped), predation (pathogens are consumed by other microorganisms), adsorption (pathogens become attached to other suspended solids in water and the sand grai
> ns) and natural death (pathogens finish their life cycle or die because of oxygen and/or food starvation).
>
> ?Another key aspect of the bio-sand filter is the bio-layer,? she notes. ?This layer removes up to 70 percent of pathogens through mechanical trapping and predation.?
>
> During Giles?s visit to Haiti last summer, he and his HDSC staff hired workers to build the filters and conducted a teachers? science training program for select graduates of College St. Jean in Les Cayes.
>
> ?The young adults in the training program were taught how to test water and develop technical reports detailing water quality before and after filtration,? he says. ?They will be responsible for installing fiv
> e filtration systems within the community.
> Those of you who have read Cliff Conner's book know, as one reviewer put it the triumphs of science rest on a "massive foundation created by humble laborers," he writes. "If science is understood in the
> fundamental sense of knowledge of nature, it should not be surprising to find that it originated with the people closest to nature: hunter-gatherers, peasant farmers, sailors, miners, blacksmiths, folk h
> ealers and others."
>
> Let those who believe in Science for the People and have been privileged to become knowledgeable in a science do their utmost to respect the people they would help by making them integral to the process
> of defining problems and participating from the beginning in obtaining solutions that rely as much as possible on their traditions, materials, and processes of doing and thinking. PhDs might be amazed a
> t how much can be learned from the people they want to help.
>
> herb
>
>
>
>
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