 |
|
|
|
|
|
 |
|
Green Building Discussion
Topic: Rainwater Storage Systems
Discussion Participants:
- Buzz Burrell lays out the problem
- Bion Howard likes stainless
- Bruce Sullivan looks in the REDI database
- Marc Rosenbaum with some experience
- Marc Richmond-Powers with a correction
- John Alderman has his own system
- Buzz Burrell recaps the problem
- Rob Tom suggests a silo
- Bion Howard on concrete tanks
- Alex Wilson on embodied energy choices
- Egidio Reale is concerned about concrete
- Norbert Senf on cement contents
- Bill Christensen on cisterns in Texas
All postings are the opinion of the writer, and BuildingGreen can take no responsibility for their accuracy or appropriateness.
Buzz Burrell lays out the problem
From: Buzz Burrell
Sent: Monday, November 25, 1996 4:23 PM
I need to buy a 20,000 gallon cistern (for drinking water) for a small rural subdivision. I don't know what type of material this should be made of. The desire is to have a practical storage medium that reduces contaiminants leaching into the water, if this is even a problem at all. The storage will be above ground. The choices seem to be:
1. Steel tank lined with epoxy - most expensive, durable, but what if the epoxy flakes off? I looked at a used tank recently, and it had 3 rust spots where the epoxy was gone.
2. Plastic tank - Much much cheaper, not sure about durability. They are FDA approved, but I don't want the water to taste like that of a plastic canteen.
3. Concrete tank - Also expensive, very durable, also not sure about various compounds leaching into the water.
IOW, I am quite lost on this subject and would greatly appreciate feedback, preferably of the non-theoretical variety. As long as it it FDA approved, our engineers offer no advice.
This also relates to the use of PVC pipe for drinking water. I've heard that PVC leaches into the water, and have also heard that this isn't true but the manufacturing process gives off plenty of VOC into the atmosphere. With our system of wells and cisterns, we're going to have a MILE of pipe (in total) before water even gets to the houses, so the type of material is of great interest, both for economic and health reasons. PVC, copper (forget it), Steel, Iron - any comments?
Buzz Burrell Geneva Development Corporation Boulder, CO buzz@diac.com
Bion Howard likes stainless
From: Bion Howard
Sent: Monday, November 25, 1996 9:44 PM
If you can afford it I would go with stainless steel (a common piping material in Europe, the Swiss especially love it).
I would really like to see some data on contaminants that slough-off from piping into potable water. Anybody have any?
Mr. Bion D. Howard bhoward2@sprynet.com (business)
Bruce Sullivan looks in the REDI database
From: Bruce Sullivan
Sent: Monday, November 25, 1996 4:45 PM
Buzz
I suggest you start your search with companies listed in the REDI database under "Rainwater Collection." You'll find several companies listed. I've talked several times with the nice folks at Rainwater Collection over in Texas. You can find REDI at:
http://oikos.com/redi/
You might also visit the Green Building Sourcebook at:
http://www.greenbuilder.com/sourcebook/SourcebookContents.html
Bruce
Marc Rosenbaum with some experience
From: Marc J. Rosenbaum
Sent: Monday, November 25, 1996 6:08 PM
Hello Buzz -
As regards pipe - are you really going to have PVC as opposed to polyethylene, which is the black stuff which is standard around here in small systems. I would prefer polyethylene to PVC (although I'm making this decision on a gut level and from the little I have read about chlorinated compounds being not so great for us)
As regards cistern: the best system I have seen (and I am far from an expert, just curious) was ferro-cement. The man who is building the ones I saw is Duncan Echelson PO Box 698 Dripping Springs, TX 78620
512 476-3030
Finally, another anecdotal piece of info - my friend who has a block cistern coated with Thoroseal to make it waterproof has noticed that the alkalinity of the materials used to make the cistern make the rainwater less acid than when it fell from the sky - so maybe all leaching isn't bad?
How's that for a bunch of non-facts?
Marc
Marc Richmond-Powers with a correction
From: Marc & Wendy Richmond-Powers
Sent: Tuesday, November 26, 1996 12:31 AM
Marc,
Duncan Echelson's telephone number you quoted is actually 512/419-4555 at this time. I work for his firm and find our ferro-cement cisterns quite good, durable, cost-effective and safe. Thanks for the plug.
Marc Richmond-Powers Supervisor Bowerbird Construction Straw Bale Homes and Rainwater Cisterns
John Alderman has his own system
From: John H. Alderman III
Sent: Tuesday, November 26, 1996 4:16 PM
Buzz, Id appreciate you sending me email on your final solution. I have been considering a huge drain pipe (concrete or galvanized) which are made here locally. I mean some big enough for a garage for multiple cars! A much smaller one I considered to catch my rainfall for use in my garden,..because of the missing water treatment chemicals. I have considered the use of "INSTEEL" for a larger tank. It consists of styrene or urethane insulation inside a metal mesh grid . You spray both sides with concrete. I was going to put a couple of reinforcing cables around and make a tank. The liner was to be by a urethane truck bed system that is sprayed on. Extra foam insulation could be added externally. The result is a concrete insulated steel reinforced tank with a very strong liner. with a reverse galvanic system the tank could last for a very long time perhaps over 50 years (or more) with out serious maintenance. If you are interested I could fold costs into my own flow and get you a good price. I need to know how much volume you need.
John Alderman http://www.randomc.com/~mountain/
Buzz Burrell recaps the problem
From: Buzz Burrell
Sent: Tuesday, November 26, 1996 11:31 AM
Thanks for all the comments regarding what kind of material is best for potable water cisterns and pipes. I would like to continue to followup on this subject; it seems this is not well understood by anybody. As Bion H said:
>I would really like to see some data on contaminants that >slough-off from piping into potable water. Anybody have any?
Marc R also wrote: >As regards pipe - are you really going to have PVC as opposed to polyethylene, >which is the black stuff which is standard around here in small systems. I >would prefer polyethylene to PVC (although I'm making this decision on a gut >level and from the little I have read about chlorinated compounds being not so >great for us)
Around here, its the opposite: everyone uses PVC instead of black plastic; I'm not sure why. Both have types of pipe that are FDA approved for drinking water. I don't have a gut feeling about this myself, except that PVC is much stronger, so if anyone has more info, please share it!
I looked in various databases's (as per suggestion), but they contain where to buy products, and my need is to first decide WHAT type of product to buy.
I got positive feedback on ferro-cement cisterns, but since I suspect they need to be buried (we hit solid bedrock at 3'), I'm still considering other materials. My current inclination is for a polyethelene tank (sprayed with foam to keep from freezing).
Thanks again,
Buzz Burrell Geneva Development Corporation Boulder, CO
Rob Tom suggests a silo
From: Robert W. Tom
Sent: Tuesday, November 26, 1996 11:43 PM
Hi Buzz;
I wonder if a few rings of an agricultural silo would do the job ? (Of the enamelled steel exterior + glass-lined interior variety (Harvestore* etc).
They are easily added to, moveable and have a good resale value should your needs change + come with a warranty against leakage.
It would seem that the glass lining would be benign WRT health concerns. Don't ask me how "green" they are. But I do know they're blue.
If you're *really* highly AR, perhaps the concrete pad on which it sits could be tiled with fully vitrified porcelain.
Rob Tom be417@FreeNet.Carleton.ca Kanata, Ontario, Canada
Bion Howard on concrete tanks
From: Bion Howard
Sent: Wednesday, November 27, 1996 8:31 AM
I would recommend calling precast concrete compaines that make products like septic and stock-watering tanks and equipment. Tell them you would like a tank of suitable capacity cast with additive-free concrete. Ask them if they use accelerants or other substances in their mix designs. They may also be willing to cast the tank at your site, with redi-mix so that such a huge and heavy article need not be trucked there. This reduces the transportation factor of the embodied energy of the tank. Concrete has a high embodied energy (96,100 Btu/cu-ft; R.G. Stein, 1981) to begin with so why not cast it there as a "local material." The transportation of the redi-mix truck(s) may be less than transporting the finished article.
Mr. Bion D. Howard bhoward2@sprynet.com (business) Building Environmental Science & Technology Voice:(301)627-2780 FAX:(301)627-4735
Alex Wilson on embodied energy choices
From: Alex Wilson
Sent: Wednesday, November 27, 1996 11:53 AM
I'm not sure I agree, Bion, on the embodied energy issue of ready-mix vs. pre-cast. With a pre-cast concrete cistern, a smaller truck would likely be used in making the delivery, and you would have less waste concrete from the pour. Ready-mix trucks carry around a huge amount of weight that is not in the concrete! Plus, ready-mix concrete generally (I think) has more admixtures in it that pre-cast--because it has to be kept from setting for a longer period of time, for example. Of course, the distance needed to transport the pre-cast tank is an important issue. Pre-cast septic tanks are widely available from fairly local sources--at least in this region. Perhaps cisterns are in arid climates.
Alex Wilson Environmental Building News
Egidio Reale is concerned about concrete
From: egidio reale
Sent: Wednesday, November 27, 1996 8:22 AM
It would seem that everybody agrees on concrete directly touching the water. What kind of cement are you using? Ashes from treatment plants for toxic waste are often mixed with the basic cement. Is Portland cement cleaner? The powder should be white, not gray. If you have some information on this, please answer. Thank you, Egidio Reale
Norbert Senf on cement contents
From: Norbert Senf
Sent: Wednesday, November 27, 1996 4:58 PM
The grey in portland cement is due to iron oxide content --------------------------------------------------------
Norbert Senf email: mheat@mha-net.org
Top of file
Bill Christensen on cisterns in Texas
From: greenbuilding Conference @ txinfinet.com
Sent: Thursday, November 28, 1996 8:10 PM
mountain@randomc.com,Internet SMTP writes: > I got positive feedback on ferro-cement cisterns, but since I suspect > they need to be buried (we hit solid bedrock at 3'),
Nope. Here in the Texas Hill Country, we often hit solid bedrock between 3" and 3mm. I've seen plenty of above ground ferrocement cisterns. You do have to do your calculations so that the thing will stay together without the benefit of an earth berm, of course.
Bill Christensen billc@txinfinet.com Sustainable Building Calendar at http://www.greenbuilder.com
|
|
|
|
|
|
|
|
|