[Stoves] Water Disinfection - Mix Boiling Water and Unheated Water to Pasteurize

Sun Sep 22 19:18:07 CDT 2019

How big are spores?

We used to use 2 micron filters for rural water supply, but it is easy to get 0.01 micron filters these days.

Anyone remember the chalk filters with an upper and lower tank?  In Nigeria we boiled the water and it went slowly through the chalk filter and then into bottles in the fridge.

I think those are well below 1 micron.

Regards
Crispin

From: vovers1 at gmail.com
Sent: September 22, 2019 7:44 PM
To: stoves at lists.bioenergylists.org
Reply to: stoves at lists.bioenergylists.org
Subject: Re: [Stoves] Water Disinfection - Mix Boiling Water and Unheated Water to Pasteurize

Andrew

The previous site also has a nice list of what temp kills what during pasteurisation:
https://solarcooking.fandom.com/wiki/Water_pasteurization<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsolarcooking.fandom.com%2Fwiki%2FWater_pasteurization&data=02%7C01%7C%7C264aa27fa73d4edc164308d73fb6dcde%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637047926925108266&sdata=eOpmtgj2mxKr4dIjxMn88xcewQ6cEJCNtRvUk1sJmyM%3D&reserved=0>

My understanding of the spore thing is it is a bacteria defense mechanism developed to survive low water state. Almost impossible to kill in dormant state without killing everything else but can be killed when 'live' by pasteurisation. The spores can 'live' for years (50 years has been found). It's what makes risks like anthrax very hard to fight. High levels of chlorine are effective.
Filtering is used to detect the spores but I could not find any filter claiming to remove spores. I imagine RO would

Some fun reading:
https://www.purewaterproducts.com/articles/anthrax-treatment<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.purewaterproducts.com%2Farticles%2Fanthrax-treatment&data=02%7C01%7C%7C264aa27fa73d4edc164308d73fb6dcde%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637047926925118270&sdata=zFYMz1MMBJIW4Nl75paWgnjpAgYVyG6tSTOd6MSBdCM%3D&reserved=0>

On Mon, Sep 23, 2019, 06:04 Andrew Heggie <aj.heggie at gmail.com<mailto:aj.heggie at gmail.com>> wrote:

On Sun, 22 Sep 2019 at 16:14, Anthony Vovers <vovers1 at gmail.com<mailto:vovers1 at gmail.com>> wrote:
Thanks for interesting discussion.

Due to inconsistencies in application a boil 3 add 1 recommendation is often used.

https://solarcooking.fandom.com/wiki/Boil_3,_Add_1_Method<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsolarcooking.fandom.com%2Fwiki%2FBoil_3%2C_Add_1_Method&data=02%7C01%7C%7C264aa27fa73d4edc164308d73fb6dcde%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637047926925128275&sdata=SyJP4YB%2FE5LQHT9irsu%2BC5sSXCVHJVFpPQZbEPFndgw%3D&reserved=0>
Solar stills often have to deal with <boil  situation.

Low cost WAPI's wax indicators can tell you 70C is achieved visually

Thanks for that Tony, I too find this interesting and having a means of indicating the certainty of adequate treatment  would reassure me, who drinks, bathes and cleans with water supplied by a pipe with guaranteed levels of hygiene.

We had a  potter who used to contribute, now deceased , his name escapes me, who made pottery filter jugs which he precipitated a thin late of silver in as a bactericide

On Sun, Sep 22, 2019, 06:38 Crispin Pemberton-Pigott <crispinpigott at outlook.com<mailto:crispinpigott at outlook.com>> wrote:
Dear Kevin

I like the idea, but the temperature will not be high enough for long enough, or both at 70. Here is a time and temperature chart to guide you (attached).

Interesting chart Crispin but it doesn't show what each of those treatments achieve, or do they all do the same thing to all microbes?

The higher the temperature the more rapidly it will cool. It is fair to assume the lid will be off because of the stirring.

Yes the higher the rate of cooling will be but not that it will get cooler than a less hot vessel in the same time.

This site has what saw would call practical advice

https://www.offgridweb.com/preparation/survival-science-minimum-water-boiling-time/<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.offgridweb.com%2Fpreparation%2Fsurvival-science-minimum-water-boiling-time%2F&data=02%7C01%7C%7C264aa27fa73d4edc164308d73fb6dcde%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637047926925138286&sdata=DUrMHN4NADFLABi5ObX901UVe%2BarJrO%2FeD5UJji1uTQ%3D&reserved=0>

Yes that seemed sensible

Neither reference mentions that spores of several diseases are not killed at 100 C including anthrax, tetanus, gangrene and botulism.

What temperature does kill anthrax, tetanus and botul;sm spores?

I thought botulism killed by a toxin that stayed in infected meat after cooking?

Gangrene is more a condition of bad blood flow and I think is often caused by bacteria we already carry in us which take advantage of the causal injury. Clostridium Difficule is one such which is normally controlled by other gut flora but being antibiotic resistant gets away when the benign gut bacteria are killed off.

Andrew

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