New discussion on R.O. water

[Ross]

Reverse Osmosis water has been discussed here, nearly to death. But one factor that comes up a lot is that it may be "wasteful", in some folks eyes.

I did a pretty exhaustive search on the web this afternoon, and based on what I came up with, plus my personal knowledge having used R.O. water for years, I came up with:

1) RO is wasteful - well it appears, that may or may not, be the case depending on where you live and the type of unit you install. According to this web site: About.com: http://www.osmonics.com/products/page833.htm , reverse osmosis systems are often pressure systems that appear (to me) to have little waste. That is the case with Culligen systems and lots of commercial Home Depot style systems as well.

2) "Waste" may be a relative thing, depending on where you live. I personally live in one of the Great Lakes States where water seems to be in abundance. If I am not in error, several of the lower mid-west states' Governors recently tried a maneuver to get a canal dug to drain water from Lake Michigan to the Mississippi River to allow barges to float! This might be a definition of waste. So if water is pressed though a membrain and a certain amount is cast off to "go down the drain" - where does that water go? In my case (and most others) it goes back to the source. In my case, that is back to ground water. In the case of the Floridians enjoying RO water, that is the gulf or the Atlantic - slightly higher in salt.

3) Lots of people here seem to be struggling with how to best get water to their orchids in the highest quality within their means. RO is very affordable and very earth friendly. I only hope this thread serves to start a meaningful discussion with backed-up evidence.

[FinnBar]

Thanks for all the info, i'm glad you brought it up.

also it's not that hard to think of uses for that "waste" water around the house. especially during summertime..

i think a bigger environmental issue in orchid growing is
lighting.
i'm encouraging everyone to contribute and choose energy efficient lighting when possible.
there are several options to choose from which put out more light,less heat and use less energy. they also come out with spectrums very useful for the plants.
in short, they are the best!

sorry Ross..


kind regards,
Antti

[shakkai]

Ross, I'm not swayed. The best ratio I've found for any RO system was 3:1 - that means you need to use 4 gallons of water in to produce 1 gallon of RO water, and you 'waste' 3 gallons of water. And that's the best! Most other systems I have found information on are more like 5:1, 7:1, and even on 10:1!!

I cannot agree that 'returning water to its source' makes it okay. What you are 'returning' has a much higher concentration of dissolved solids, a higher salinity, etc. That's what makes it 'waste' water.

While I agree that freshwater is a renewable resource - the water we use on our plants evaporates, and the plants themselves give off water in their respiration - the amount of fresh water available in the world is still a finite resource.

Environmentally, water is our most precious resource. It is also the one that we (as in, the Earth) are beginning to run desperately short on in some areas of the globe. If problems around the globe don't worry you - say in China, Africa, and India:

In India, home to 1.002 billion people, key aquifers are being overpumped, and the soil is growing saltier through contamination with irrigation water. Irrigation was a key to increasing food production in India during the green revolution, and as the population surges toward a projected 1.363 billion in 2025, its crops will continue to depend on clean water and clean soil.

Then maybe just look at the US South West to bring the situation a bit closer to home.

International water politics play a role in the Southwestern United States, where the Colorado River is shared by many states before its dregs trickle into Mexico. All along the river, water is diverted for irrigation and urban water -- with Arizona and California the biggest users. Because Mexico uses the dribble of water that reaches it for irrigation, virtually nothing reaches the river's once-fertile -- and now parched and polluted -- delta on the Sea of Cortez.

The Colorado may be completely allocated, but the Southwest continues booming. According to one estimate, five of the 10 fastest-growing U.S. states are in the river's drainage. The water the newcomers drink is likely to come from farmers who now receive subsidized river water.

This article raises some interesting points and talks specifically about the recent California wild fires: Thirst refusal | Environment | The Guardian

One other point to make about environmental factors... though this may not directly affect you on Lake Michigan just yet. Most of the worlds major rivers are fed by melting snow from mountains such as the Rockies. As average temperatures rise - even just a degree or two - more precipitation falls as rain instead of snow. This means that the snow in those mountains melts earlier and floods are more likely. But by the time it is summer downstream, there is no snow left to melt and the river runs dry.


On top of the cost to the environment, which might be difficult to feel personally responsible for... there is the personal cost of increased water bills, and for those who are charged a variable rate for waste water, a direct increase in those costs. Think about it. If, prior to using an RO system, you were watering with tap water and using say 5 gallons a week to water your plants. You would now be 'using' up to 55 gallons a week to do the same amount of watering. (Of course, I chose the 10:1 ratio! But even with the "best" 3:1 ration, that same 5 gallons would cost you 20 gallons of water coming in.)

And it doesn't just cost you more in your water/wastewater bill.

Water subsidies are a fact of life in the western United States. According to de Villiers, they amount to $500 per acre. He alleges that "70 percent of the farmers' profits in California's Central Valley -- which is supposed to be the richest farmland in the world -- came directly through taxpayer subsidization."

Quotes above taken from:
A global shortage

[FinnBar]

Shakkai, though these facts are a concerning read i'm glad you shed more light on the issue.
Thanks,
Antti

[shakkai]

Thanks, Antti. I'm hoping, like Ross, that this will lead to a useful discussion. I know that my view (and the facts that I've chosen) are biased one way.

I'm sure that RO technology will eventually give better yields in pure vs. waste ratios. I am not so sure about using the waste water for watering other plants or with living things. I guess that depends a lot on how high the TDS ratings for your water are to begin with.

Your point about lighting isn't lost either. Lighting and heating are two other areas where major improvements in efficiency can be made. Enjoying this hobby doesn't have to 'cost us the earth' (literally)!

For the record, we do not have a water meter on the house and pay a flat rate for water and sewage regardless of usage (the house was built before they had water meters, and one was never installed as it isn't compulsory here). That said, I collect and use rainwater as much as possible for both the orchids and for the garden outside in general. Fortunately for me rain is usually not in short supply here!

[FinnBar]

I guess that depends a lot on how high the TDS ratings for your water are to begin with.

i see your point. Helsinki gets its water from the lake Päijänne. when i still had a fish tank i had to add calcium carbonate as a buffer against a ph crash
and that was just tap water not r/o..
the whole of Finland gets more or less similar water.
though i wouldn't worry about it here, that certainly won't apply everywhere.

[Brooke]

Ross, your theory that water is not used but just borrowed and returned doesn't really hold water..ha ha! If it did there would be no droughts because all the toilets and RO units would just refill the reservoirs. Ask somebody in Atlanta.

Besides this "recycled" water has to be located, pumped, treated, and pumped...hardly a free proposition. I'm not saying that we "damage", breakup, or destroy the water we use. The sum total of water in the earth and its atmosphere is basically constant. However, it is not as simple as recycling yesterdays usage for today. The water shortage that sometimes develops is just a shortage of treatment capacity. We have that here. However, in many cases it is a shortage of raw water and it's getting worse as humans over populate the earth.

Your theory is too simple to fit the facts.

[Ray]

Shakkai, My particular RO unit is a 1:3 - 1 part waste to three parts pure. I can "get away with" the slim flushing volume because my well water is fairly pure to start with. The waste fills a small fish pond just outside the greenhouse that also provides water for the local fauna, with the outfall reentering the GH and humidifying it, so the minerals must not be too high of a concentration. (Apparently the fish, frogs, and newts don't mind it, anyway. And it's a definite winter watering hole for deer, birds, etc.)

There are "zero-waste" RO units out there, having a pump to force 100% of the water through the membrane. The membrane has been enlarged and redesigned, and must be replaced more frequently than "flushed" ones, but there is truly zero waste water.

I know your climate (and population pressure) has changed since I lived there (early 60's), but GB probably isn't in great danger of running out of water, so vendors have apparently not seen the need to introduce the technology there.

[Ray]

I would like to add a side comment to this thread, and give a bit of friendly chastisement to the "holier than thou" commentary.

Some of you jumped on Ross for the environmental unfriendliness of using an RO system and simply allowing the waste water to reenter the ground. The implication that it was "bad" because it was more highly concentrated with contaminants is really what caught my eye.

If we are trying to be environmentally friendly, then we should stop growing orchids, or any other plant for that matter, that is not native and in-situ.

What do you think we're doing when we ADD fertilizer to our water? Seems to me that we are "contaminating" it more than that RO flush water is likely to be.

And those of you who use high-phosphorus, so-called "bloom boosters" are really at fault, as all of those extra phosphates can find their way into ponds and cause eutrification.

And how about pesticides? In a lot of cases, they become necessary because we are not providing the correct growing conditions, so we are mandating their use.

Each of us has a personal choice to make about our activities, and how they affect the world around us. I strongly suggest that we consider all of them, not just a select one or two, when we get on the soapbox.

[cb977]

Ray...