Gee Chandler, i don't know. Biochemists on this list please help answer
On 5/10/2014 4:30 PM, Chandler Davis wrote:
> 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?
> 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.
>> 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.
>> Jim West
>> 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.
>> On Thu, May 8, 2014 at 8:28 PM, herb fox <[log in to unmask]>
>> 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
>> 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
>> 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.