Skip to Content.
Sympa Menu

permaculture - Re: [permaculture] any biologists out there?

permaculture@lists.ibiblio.org

Subject: permaculture

List archive

Chronological Thread  
  • From: Kevin Topek <ktopek@att.net>
  • To: permaculture <permaculture@lists.ibiblio.org>
  • Subject: Re: [permaculture] any biologists out there?
  • Date: Sun, 20 Dec 2009 08:59:21 -0600

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@lists.ibiblio.org
[mailto:permaculture-bounces@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

_______________________________________________
permaculture mailing list
permaculture@lists.ibiblio.org
Subscribe or unsubscribe here:
http://lists.ibiblio.org/mailman/listinfo/permaculture
Google command to search archives:
site:https://lists.ibiblio.org/sympa/arc/permaculture searchstring



_______________________________________________
permaculture mailing list
permaculture@lists.ibiblio.org
Subscribe or unsubscribe here:
http://lists.ibiblio.org/mailman/listinfo/permaculture
Google command to search archives:
site:https://lists.ibiblio.org/sympa/arc/permaculture searchstring







Archive powered by MHonArc 2.6.24.

Top of Page