Rain water harvesting

dryan

Hey,

I have decided to install the rain water harvesting tank on my site and together with the well, they will both supply the house.
Was thinkling last night about what areas/taps to connect up the rain water system to.
The rain water tank should supply the electrical appliances (dish washer, washing machine), toilet cisterns, showers and all taps from the cylinder (all hot water taps?).

Am i right here?
Should i also have the cold taps from the bathrooms connected?
What taps are then connected to the well water for drinking?? Just the kitchen??

Another point that was brought up was in relation to the quality of water from the Rain water tank. I was advised to install a UV filtering system to kill off any bacteria present in the water.

Any advice would be greatly appreciated.

anon1

www.bel.ie do a system

10-10-20

My personal opinion is that the rainwater if filtered but untreated should only feed the cisterns.
If you treat it with a UV filter (and maintain the UV bulb!!), then use it for for all that you mentioned above.
If you are storing the treated water for any period of time - in an attic tank or such, be aware of the risks of legionaires disease in warmer temperatures.

You should find out whether there is the possibility of the treated & stored rain-water becoming a breeding ground over time as it will not have had chlorine added.

If this is so, I suppose the ideal solution would be to treat the water on demand.

Don't forget that the rain-water run-off will contain bacteria and other nasties - read this quote from Wikipedia relating to grey-water - "Given that greywater may contain nutrients (e.g. from food), pathogens (e.g. from your skin), and is often discharged warm, it is very important not to store it before using it for irrigation purposes, unless it is treated first."
http://en.wikipedia.org/wiki/Greywater

While the definition of grey-water differs from what you aim to collect (rain-water) the handling and treatment should be similar.

hobie

After the dry summer last year and being a keen gardener I decided to start collecting rain water just for external use ......

I selected a 600 sq foot roof area and assembled a 350 gallon storage tank system ....

water is fed through a simple net filter to the storage tanks and all water is used in the garden ...

Some conclusions so far ......

it's either feast or famine !!!! ..... I could easily fill the total 350 gallon storage tanks in a day when it rains hard, so lots of water goes to waste via overflows .....

the water smells ..... which is fine for the garden but it would need some very serious treatment before it could ever be used in-house

I do feel good about not drawing pure water from the mains for garden use but I would have serious doubts about using roof water anywhere else .....

10-10-20

I have a similar setup - 350l tank on nearly the same roof space. I'd like to setup a hosepipe to the system, but I haven't got around to it yet.

antoinolachtnai

Why would the rain water smell?

GreeBo

could be washing crap off the roof, or just sitting around waiting to be used.
I assume once full any "new" rain is dumped via overflow, could you set it up so that if you get more rain the old stuff is removed and the new stuff replaces it?

hobie

antoinolachtnai wrote:

Why would the rain water smell?

The problem seems to be what it picks up after hitting the roof/gutters ..... bird droppings ... leaves ... I found a dead bird in the gutter once ..... add all these ingredients and then pop it in a 350 gallon tank for maybe days or weeks on end and you get a nice (watery) soup!!!! .... :rolleyes:

but .... on the bright side the plants seem to thrive on it ...

anon1

There are systems to divert the first flush after a dry spell so that it doesn't enter the tank. google it

davidoco

hobie wrote:

bird droppings ... on roof

The Germans put a thin wire pulled tight about 4 inches up along their ridges to keep birds off.

10-10-20

I had a look into my rain-water tank yesterday. It's in an exposed location getting the full sun in the morning to mid-evening and doesn't have a circulation system like GreeBo mentioned (It's the 'Wall Water Storage' unit here: http://perso.orange.fr/bellijardin/Bellijardin.htm).
I saw bubbles rising to the surface and I suspect that it's methane from the breakdown of leaf matter. So, it's an ideal environment for the growth of bacteria.
There is a flush system available alright, but it's only plausable when you have a larger storage system, such as >1000l.

antoinolachtnai

If you mixed grey water in there as well, it would probably reduce this problem, I guess?

10-10-20

It's likely that it would increase.
Depends on the source of the water of course!

antoinolachtnai

Well, it would result in

- more consistent cycling of water (you run the dishwasher whether it rains or not)
- chlorine in the water (which would kill the bacteria)
- other chemicals in the water (which would kill the bacteria)

Of course there are negative factors as well as pointed out in wikipedia article.

(My idea of grey water is runoff from sinks, baths, dishwashers, etc.)

The problem is certainly the storage as much as, or maybe more than, the source of the water.

Just a thought.

10-10-20

The amount of chlorine in the flow wouldn't be enough to negate the additional bacteria that is added through the kitchen sink. Add to this the food particles and other small solids. 'Other chemicals' such as dishwasher tablets are going to be very harsh, and aren't going to be healthy if the water is to be used for garden work...

dryan

Hmmm, plenty of points there to consider alright...
Its just rain water i intend collecting and not the Grey water.

I raised the question regarding bacteria building up in the tank over time alright. Got a few second opinions on it too and the main conclusion i gathered is that once the tank is sealed from daylight, bacteria will not thrive/survive.
I still intend installing some sort of filtering system - its just a matter of finding out what best suits my needs - as outlined above.

antoinolachtnai

Going back to your original post -

If you connect the hot water and cold water to different tanks, I think you will have a problem with mixer tanks in your bathroom. The water won't mix properly, because the pressures will be slightly different.

You should check this with an experienced plumber (or physicist). I think I had a problem like this once because of my pathetic efforts to balance the load between two tanks in a house.

My own view would be to just take any water that makes regular contact with human skin from the well. No point in taking a chance on that for all the reasons mentioned above.

But I'm sure other people will have better informed views.

hobie

Going back to my 350 gallon storage system for a sec ..... I needed a 100 gals or so to top it up ..... we had a cloud burst this afternoon and a 100 gallons was dumped into the tanks in less than 15 minutes !!!! .... :eek:

I raised the question regarding bacteria building up in the tank over time alright. Got a few second opinions on it too and the main conclusion i gathered is that once the tank is sealed from daylight, bacteria will not thrive/survive.

Bad advice in my opinion .... Algae (the stuff that turns water green) will certainly die off/not grow atall without light ..... but bacteria? ..... no way Jose (pronouced Hosay )

Bacteria need food (the crap that gets washed in with the water) and oxygen (Aerobic organism's) ..... some don't even need oxgen (anaerobic organism's) ..... give them a nice dark warm tank and they will happily P$$$ and F$$$ all day long .....

10-10-20

Quite correct Hobie. If anything the UV in sunlight will kill the bacteria. But, most plastics and glass either block the UV or reduce it to a state of non-existance.

old boy

a couple of bags of charcoal dumped in the bottom of the tank is said to be benefecial,

hobie

old boy wrote:

a couple of bags of charcoal dumped in the bottom of the tank is said to be benefecial,

..... and a bottle of Gin too ....

old boy

son, been smart does not suit you, have you researched my answer, no you have not,if you think your funny post on the humour fourm.

hobie

old boy wrote:

son, been smart does not suit you, have you researched my answer, no you have not,if you think your funny post on the humour fourm.

Adding a bottle of Alcohol to a rainwater storage system will be as beneficial as "dumping a couple of bags of charcoal in the bottom of the tank" I can assure you ....

As to my own experience on water filtration ....

I currently employ the following concepts on a water treatment system ....

Vortex primary filtration ....

brush .... Biological filtration ...

Trickle tower ...... Biological filtration ....

Foam Fractionator .... DOC removal (Dissolved Organic Carbon)

U.V. light exposure .... sterilization

this system runs 24/7 on a 2000 gal/hour system and has been in use for a number of years .... but I confess a bit over the top for the average rainwater harvester ......

apart from the above I know nothing about water filtration ....

Rain water harvesting requires sophisticated systems and concepts of filtration, if the final product is to be employed within the house ..... if not it may well put you in hospital ....

hobie

I've posted below a photo of the product extracted by my Foam Fractionator (just part of the filtration system) ..... this concentrate is produced at the rate of approx. one(1) gallon per day (every day) from water that for all intentions and purposes looks relatively clean ....

Put even a small amount of this product anywhere near your internal organs and I promise you .... you will be walking up the street with your pants in your hands ..... :eek:

Water harvesting requires serious filtration for household use ....

old boy

im on about water for the kitchen and flower garden, the old ways cannot be beaten, your on about what you have, all you have is dosh, why not try the ols ways there hundread of years old and they work, new fanfled ideas are taken from the old ways, just costing people with dosh, have you got self heal growing for emergencys,

hobie

The subject we are discussing ....

dryan wrote:

Hey,

I have decided to install the rain water harvesting tank on my site and together with the well, they will both supply the house.
Was thinking last night about what areas/taps to connect up the rain water system to.
The rain water tank should supply the electrical appliances (dish washer, washing machine), toilet cisterns, showers and all taps from the cylinder (all hot water taps?).

Am i right here?
Should i also have the cold taps from the bathrooms connected?
What taps are then connected to the well water for drinking?? Just the kitchen??

Another point that was brought up was in relation to the quality of water from the Rain water tank. I was advised to install a UV filtering system to kill off any bacteria present in the water.

Any advice would be greatly appreciated.

This is serious use of Harvested water and demands much more than water for garden use ....

im on about water for the kitchen and flower garden,

for garden use all you need is perhaps a net for collecting leaf material .... the plants will love all the nutrients etc that flow into your tank ....