HI!

After perusing the ETS info on water purifiers, I realized I do not know enough to make a decision on what to purchase to clean rain water from my roof that I am collecting in rain barrels. I'd like to be prepared to make it into potable water should an emergency arise.


The Miox purifier seemed like a good choice to get buggies out but what would take out particle like fiberglass and asbestos from roof material?


Anyone with suggestions?

We're gathering info and preparing to install a 55 gal rainwater barrel on one corner of our house. This forum re-sparked an old interest and lessons from the past. YOUR post now has me thinking....even though our runoff will be used to water the ducks and chickens, I might need to re-think because of asbestos or asphalt particles. I won;t need to "purify" the water for human consumption like you do, but now I wonder what else I'm missing.

By the way, Welcome tothe forum

If you plan on eating the chickens and ducks, I'd give a lot of thought to purifying their water. I don't know how much "industry" is in New Mexico but traces of heavy metals, chemicals and other toxins can be found in rain water in industrialized areas (or down wind from those areas). I've seen plans for a home built purifier (layers of gravel, sand and charcoal) for rain water somewhere but don't recall where.

Here are a couple of threads from the past:
rain water
acid rain water collection

That last thread has a great link to rain water harvesting from Sue. Awesome information there, though it doesn't look easy or cheap.

One thing I would be concerned about is any pesticides on the roof, such ass moss killer. I know some roofs have that sprayed on when they're new to keep moss from being a problem. I've got some in my garage right now, ready to go on the roof to get rid of some issues I'm having. That might preclude collecting rain water there, with it being a chemical contaminate and not just a particulate contaminate.

Good luck!
Jason

Howdy!!

I'm glad you asked that question. I've been playing with that idea as well.

I'm imagining the water I stored from roof runoff as beings stored in a cistern of some sort (maybe at or below ground level?) for the purpose of watering the garden rather that human consumption.

Though now that I think about it, if it goes into the garden it goes into me and my loved ones.

Rats!! And I just got a new roof too.

Either way, that project is waaaaay down the road. I've got to finish painting the house first and figure out how we're going to pay for college for the offspring.

Howdy Mr. EHiggins,

Currently, I collect my roof water in three 55-gallon Greek pepper plastic barrels but I want to build this system:


1. downspot
2. 20-gal U-shaped tube to collect preflush
3. soaker hose to empty preflush tube
4. spout to sand filter barrel
5. sand with naturally-forming biofilm layer on surface
6. pea gravel
7. perforated pipe surronded by larger gravel
8. final water collection barrel tapped with a hand-pump.

Item #2. is the preflush to collect dirt, bird droppings, etc. It has to fill up before water will flow into the sand filter barrel. A soaker hose attached to the U-tube is used to drain the water after the rain passes. I'll have to play with the soaker hose some to see what gives me fast enough drainage. Also, the bottom of the U-tube needs to be slanted away from the downspot with the soaker hose attached to the lowest point.

Theorectically, the water will be clean enough to drink right out of the final collection barrel, but I'll still treat it by boiling.

-Blast

That design looks good, it should filter out most particulates, however it won't filter out any heavy metals, chemicals and pesticides that were blown into the upper atmosphere and got washed down in the rain. Boiling may work for steralizing creek water, however the rainwater has already been steralized through evaporation and boiling won't remove most of the chemicals and heavy metals that are in the water. You would only need to boil the water if your tank got contaminated somehow. Rain water is pretty clean of organisms and will not grow anything so long as you have a tank that does not let the light in. Oh and it needs to be pretty well sealed to keep out those pesky mozzies. Any parasites that are in bird droppings will probably be killed by the heat and UV from the sun, then flushed down your preflush.

If you want to filter out some of the chemicals you can add crushed charcoal to your filter stack.

As far as the preflush design goes, when the u section is full then some of the contaminants, especially the floating ones will wash into your good water, also your bad water will mix with your good water, I would put a floating ball in a cage at the overflow point, when the U section is full the ball will seal off the opening, then the water will only go where you want.

I have thought about the same problems for when I get my own house in the country. Most of the air is pretty clean over here in Southern Australia (so long as you aren't down wind of a major city like Melbourne), but I am still considering filtering our drinking water at least using a reverse osmosis filter and a pressure pump (they require 60 to 100 psi).

You also have to remember that the body adsorbs more of some chemicals through the skin and breathing in during showering, than through drinking. This is true for chlorine and fluride in city water. Filtering your drinking water does little or no good if you don't have a shower filter.... there isn't an effective one for fluoride.

That having been said, our city water here and almost everywhere else is not filtered at all. They throw in chlorine and then toxic waste from industry called fluoride and then pass it along to us. It has more of the nasties in it than you would get out in the country.

In the country you have fertalizers and pesticides and herbacides, that is the purpose of the preflush, to wash that stuff off the roof. But all in all the water that you get off the roof of your country house is much better than any city service can provide.

In the city... well filter it the best you can, get a big berkey or something like that and it will take most of the junk out. In a major emergency there may be fires which are pumping toxic chemicals into the air and they can eat the coating right off the inside of your tank, I wouldn't drink that even if I had the best filter in the world. It could be good to have a diverter on your tank for the rare occasion that you don't want to have your good water contaminated with toxic smoke residue.

Just a few thoughts to throw in the mix, I hope it helps someone.

Happy drinking,
Macgyver.

Thanks for the suggestions. The ball valve is a good idea to keep any floaties out, even though they'd be trapped by the sand. Same with the heavy metals. The system is basically a condensed version of a natural spring.

The chemicals are decomposed by the biofilm layer. Check Susan's links from the previous thread for more information. Supposedly they are very effective.

Mosquito-proof screens will cover everything! We have a lot of cases of West Nile Disease here.

-Blast

Eventually that sand filter will plug up and its efficiency will diminish. You need a way to backflush the sand filter.

One alternative might be to purchase a sand filter from a pool store. If you have a pump and filter it will run on 120VAC and the valve mechanism allows backflushing of the filter.

About the heavy metals - keep in mind that they could be disolved in solution and difficult to filter out, though it would seem most would come from particles floating in the air, which could be filterable if filtered out quickly after a rain fall.

What kind of roof are you planning to collect the water from? It would seem that a electrostatically painted metal roof would be best.

Overall, I'm not too worried about metals and chemicals from the rainwater or my roof.

To quote from The Texas Rainwater Harvesting Manual

"drinking rainwater, consider the path
taken by the raindrop through a
watershed into a reservoir, through
public drinking water treatment and
distribution systems to the end user.
Being the universal solvent, water
absorbs contaminants and minerals on its
travels to the reservoir. While in
residence in the reservoir, the water can
come in contact with all kinds of foreign
materials: oil, animal wastes, chemical
and pharmaceutical wastes, organic
compounds, industrial outflows, and
trash. It is the job of the water treatment
plant to remove harmful contaminants
and to kill pathogens. Unfortunately,
when chlorine is used for disinfection, it
also degrades into disinfection byproducts,
notably trihalomethanes,
which may pose health risks. In contrast,
the raindrop harvested on site will travel
down a roof via a gutter to a storage
tank. Before it can be used for drinking,
it will be treated by a relatively simple
process with equipment that occupies
about 9 cubic feet of space."

The amount of heavy metals/chemicals the water will leech from my shingles in the short time of contact will be ultra-tiny.

Backflushing is one way of cleaning the sand filter. Removal and replacement of the sand also works and fromn a design point of view is much easier. Lots of good info on slow sand filters here.

-Blast