[permaculture] any biologists out there?

Kevin Topek ktopek at att.net
Sun Dec 20 09:59:21 EST 2009


Lawrence & Paul,

You have definitely covered some major points and concerns over water  
quality. Here in Houston, Texas we get most of our municipal water  
from Lake Houston in east Texas. During periods of drought a lot of  
folks here come down with viral infections. I have suspected for years  
it is tied to a decreased volume of water supply carrying an increased  
concentration of pathogens. This is why municipalities treat the  
potable water supply with chlorine; inelegant and toxic, but  
effective. I have come to appreciate the trade off of long-term  
poisoning to stop short term death in the public sphere. Domestic  
water can be treated with ozone or more expensive micro filters.  
Filtering water for particulates before treating it for pathogens  
reduces the amount of treatment required and preserves resources while  
decreasing toxicity. As Steve mentions, 140 F kills most bacteria and  
virus'. Unfortunately heating water is not very sustainable and  
usually produces greenhouse gases. If that is not practicable, then  
another method of treatment becomes necessary and preferable for  
continued human health. You could gone on forever on this subject.

Kevin Topek

On Dec 20, 2009, at 7:14 AM, Margaret & Steven Eisenhauer wrote:

> Hello,
>
> Water that is heated above 140 F/ 46 C is going to be free from  
> microbial
> activity, unless you have incubated some very unusual bacteria that  
> make a
> living in very hot sulfur laden water associated with vents in the  
> earth.
> Heating water is the traditional way to sterilize it.  Think about  
> Asia
> where raw human waste is used in agriculture, thus polluting the  
> drinking
> water leading to the practice of heating the water before drinking it
> leading to the tea culture.  Heat kills baby! But domestic hot water  
> should
> not be delivered to the tap above 140 F because it represents a  
> scalding
> hazard.  You can get mixing valves that will cool the water for  
> delivery if
> your system produces water hotter than that. Any system that is open  
> to
> atmosphere is of course open to contamination which is why wells are  
> in well
> casings and why they are drilled into rock, thus preventing  
> contamination
> from surface water, so any system you put together that is supposed  
> to be
> potable should be a closed system utilizing non corrosive materials.
>
> Steven Eisenhauer
> Eisenhauer Design Inc.
>
>
>
>
> -----Original Message-----
> From: permaculture-bounces at lists.ibiblio.org
> [mailto:permaculture-bounces at lists.ibiblio.org] On Behalf Of  
> Lawrence F.
> London, Jr.
> Sent: Sunday, December 20, 2009 6:05 AM
> To: permaculture
> Subject: Re: [permaculture] any biologists out there?
>
> paul wheaton wrote:
>> Well, a year ago I would have never thought to ask about any of this.
>> And when I brought it up before a solar hot water demo about three
>> months ago, I was sorta shamed into shutting up.  Reasoning was:  A)
>> The gub'mint is always trying to take away our liberties and I must
>> have been brainwashed by the gub'mint, and B) Lots of folks have been
>> using this sort of thing for years and not a one has ever complained
>> about anything of the sort.
>>
>> I ain't sore about it.  I just wanna figure out what it takes to do
>> the super simple approach that everybody else is doing without  
>> getting
>> sick.
>>
>> Now we're learning that there are very real things to be concerned
>> about.  And the information appears to suggest that a lot of people
>> are getting sick, but they don't know that it is related to this.
>>
>> I'm glad that we're having this discussion!  Powerfully educational!
>>
>> Once we get our heads wrapped around the particulars, we might be  
>> able
>> to figure out solutions so that existing simple systems can work
>> safely.
>>
>>> Sometimes simple isn't the right solution. The various water borne
>>> diseases are a serious matter. Personally, I would not necessarily  
>>> take
>>> a chance with the popular simple solutions unless I could come up  
>>> with
>>> mods that ensured safety of use. Not to say that they wouldn't be  
>>> safe
>>> as designed and used. HS Tarm wood Danish fired boilers send very  
>>> hot
>>> water into a huge tank for long term storage. Into this is  
>>> immersed a
>>> heat exchanger with cold i and hot out ports for clean DHW. I think
>>> contamination from pathogen growth occurs when the system is  
>>> stagnant
>>> for long periods or successive short periods. during which the  
>>> microbes
>>> can incubate and propagate.
>
> Man, you sure know how to keep discussion alive! It is a lot of work
> sometimes. Now, to figure out how to make best use of this forum and
> permies.com to move this discussion forward toward toward maximum
> usefulness.
>
> As for the approach described in your first paragraph I choose to  
> ignore
> those types who seem not particularly creative or interested in  
> relating
> to the rest of the back to the land community.
>
> Example: the HS Tarm system. large hot water storage unit with heat
> exchanger supplying DHW.
>
> Simple system solution:
> 1) inexpensive conventional hot water heater with cold in and hot out
> plumbing; this is where the DHW will be stored that will be used in  
> the
> house for washing and bathing
> 2) buy a big plastic cistern (often used for water storage these days)
> 3) run plumbing from collector 1) solar or/and 2) coiled black pvc  
> lines
> in compost pile to the plastic cistern; add circulation pump, backflow
> preventer and cleanout drain valve - this probably should go in  
> through
> the top of the tank
> 4) also through the top of the tank, drop your heat exchanger into the
> middle of the tank, attached at the top to its plumbing (cold in, hot
> out and insulated) which is run to the house and into hot water heater
> (no pump needed, relies on line pressure for circulation, on demand).
> This line should be hot water type PEX, 3/4" diameter.
> 5) The heat exchanger consists of 4 foot lengths of 1" straight copper
> water line all connected with simple 90degree elbows and 4-6" straight
> sections for the turns; you make and connect together enough of these
> sections to make a circular "column" of copper tubing; inlet and  
> outlet
> are at the top, connected to your plumbing to house. The copper heat
> exchanger should probably be coated with a water resistant durable  
> paint
> or epoxy to prevent it from being etched by acidic water or undergoing
> other surface damage from the hot water; using black paint will help
> with heat exchange. Of course, there may be leaching of copper from  
> the
> exchanger into the hot water but that might be preferable to bathing  
> in
> hot water that has passed through hot pvc pipe, a known problem with
> toxics given off by pvc at high temperatures. You're probably stuck  
> with
> copper because of its thermal properties. I would not use aluminum but
> that is a remote option. Of course black steel pipe can be used too  
> with
> lower thermal transmission qualities.
> 6) Spray weather-resistant foam insulation all over the tank for at
> least R30 insulation or if the tank is indoors use any other type of
> insulation you choose or put the tank in an insulated closet. Put a
> blanket of insulation around the plumbing (4 pipes) coming out of the
> top of the tank (usually 1-2 feet wide); seal the top to keep dirt  
> out.
>
> Compare the cost of this with that of the system without the heat
> exchanger and consider the longevity of the former, convenient
> maintenance issues and the security of knowing you have clean DHW.
>
> The factors affecting the vulnerability of the cheaper system to
> contamination by pathogenic microbes should be considered with an  
> eye to
> designing and building the more expensive system with the HE; i.e.  
> avoid
> obvious mistakes and pitfalls with the better system. Standing water  
> in
> the cheap system undergoing wide temperature swings and remaining
> stagnant for periods of time may be what creates the environment
> favorable for the pathogenic microbes to incubate and propagate. With
> the better system you have water only in the 3/4" lines and what is in
> the hot water heater which likely presents no more risk for
> contamination than normal use of that type of heater using an electric
> element or natural gas - plus you could hook it up to an energy source
> for backup DHW source.
>
> LL
>
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