Thanks for posting this link, I wasn’t aware of this study. BTW all the test sites for this study were in the urban environment of Newcastle city, with lots of coal mines and coal fired power stations in the adjoining rural bioregion (Hunter Valley) so one would anticipate a reasonable degree of airborne pollutants.
Bill Mollison talked about positive effect of biofiltration processes in the watertank, good to see this researched and confirmed. Now I feel even better about my lovely fresh rainwater supply.
Robyn
On 27/05/11 9:29 AM, “Neil Bertrando” wrote:
> Here’s a link to a review article from Australia, which includes the concept > of the rainwater treatment train that occurs throughout the process from > collection to utilization (including drinking). I think it reinforces many > of the comments above.
>
> http://www.hydropolis.com.au/Papers/SIA_Coombes1.pdf
>
> We’re installing a > painted metal roof this summer from which we plan to harvest drinking water. >
> Does anyone have advice re: tanks for cold climates (we hit below 0 F (-20 > C) for a couple of days each of the past two winters)? My main concern is > freezing cracking the tank and interrupting our water availability. We’ll > have a groundwater well backup supply, so it won’t be devastating, but I’d > prefer not to have to rebuild or re-buy a tank due to their cost. >
> We’re looking for 1000 – 1500 gallon capacity. Currently I’m looking at > ferrocement or steel culvert style tanks as preferred options. >
> For site design, I’m considering putting it on a concrete pad or > underground. I would prefer not to have it underground for access and > maintenance issues. If on the pad, we’re considering putting it inside a > small passive solar storage structure to prevent freezing and utilize the > thermal mass, but this adds significantly to the cost. another option might > be to plum the downspout directly into the garage where we could insulate > the tank as well (no solar gain though).
>
> any thoughts or experiences with this type of scenario? references, etc? >
> thanks,
> Neil
>
> On Sat, May 14, 2011 at 5:31 PM, Gene Monaco wrote: >
>> Does anybody have any long-term experience with Galvalume. >> I have three concerns and no answers:
>> 1) Since it is 55% Aluminum-Zinc alloy-coated sheet steel, the aluminum >> might leach into the water giving us Alzheimer’s.
>> 2) How does it weather over time. There are a lot of raggy looking metal >> roofs out there. It might be good for a while, and I know that nothing >> lasts forever, nor should it, but what does it look like after 20 years? >> What happens as it deteriorates?
>> 3) Seems like a lot of embodied energy (high carbon footprint). Aluminum >> from far away…
>> -Gene
>>
>> Date: Sat, 14 May 2011 07:57:13 +0100
>> From: harry byrne wykman >> Subject: Re: [permaculture] Roofing materials and water collection >> To: permaculture@lists.ibiblio.org
>> Message-ID: <20110514075713.59a55dbf@humilis>
>> Content-Type: text/plain; charset=UTF-8
>>
>>
>> Here’s a quote from a write-up of a recent study:
>>
>> Cockrell School faculty and students conducted an in-depth study — >> recently published in the academic journal Water Research -examining >> the effects of conventional and alternative roofing materials on the >> quality of harvested rainwater. The study, led by civil, architectural >> and environmental engineering Assistant Professor Mary Jo Kirisits, >> showed that, of the five roofing materials tested, metal (specifically >> Galvalume??), concrete tile and cool roofs produce the highest >> harvested rainwater quality for indoor domestic use. The study also >> showed that rainwater from asphalt fiberglass shingle roofs and >> increasingly popular “green” roofs contain high levels of dissolved >> organic carbon (DOC). Although other potential pollutants can be >> significantly lower on green roofs (turbidity and aluminum), the high >> DOCs are significant where these roofs would be used for potable >> rainwater collection.
>>
>> Source: Rainwater harvest study finds roofing material affects water >> quality : www.sciencedaily.com
>>