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Re: [APD] Thoughts on RO and the environment


I applaud your desire for conservation. [I'm a believer, and I'm even Conservation Editor of the Journal of the American Killifish Assn.] Please forgive me if I try to poke a small hole in your advocacy of DI over RO. OK? ;-)

BoiseBobD at aol_com wrote:

I keep seeing references to RO. It bothers me knowing that some of the people posting these references and even recommendations to use RO come from people living in places like Las Vegas and Los Angeles. I think you people need to take a drive about 20 miles from civilization and look around. You'll quickly notice that you live in a desert.

Perhaps you need to observe how we actually use RO water! The so-called "waste" water is almost indistinguishable from the tap water (do the arithmetic) and works great in harder-water tanks, drip-irrigation systems, etc. In water-scarce regions, we sure as hell don't just dump it down the drain! The stuff is way to precious to do that.

I used to live in Western NY, next to the largest fresh water reserve in the world. Plenty of water, plenty of non-irrigated farms. Water everywhere. My neighborhood was built on a seasonal wetland, and there was a swamp behind my house where the northern pike fishing was great. RO there makes perfectly reasonable sense.

And dumping the "waste" back into the aquifer involved minimal loss and cost. Likewise, using it to irrigate a few patio plants in Las Vegas is cheap, too, if they were going to use the tap water, originally.

But not in Phoenix, Tucson, Santa Fe or San Diego. The Los Angeles River is a concrete trench that movie makers like to use for chase scenes and car races, most recently in "The Italian Job". By the time the Colorado River reaches the end of its course in the Gulf of California, it's only a fraction of the flow that enters the reservoir behind Hoover Dam, and most of it comes from tributary rivers along the way. Because L.A. is a thirsty place with a growing population, there is occasional talk about diverting the Snake from Idaho down to Utah to give LA even more of the water it needs for critical issues like washing cars.

Nice emotional stuff, but has no bearing on the fact that RO water, in desert areas, produces little or no "waste." Only that which gets evaporated and blown away gets out of the system. [It then falls back as rain in NV, CO and NM. That puts it mostly right back into LA's watershed. :-)]

Ten years ago I moved to Idaho, and found that litigation lawyers here make more money on water rights disputes than anything else including ambulance chasing, and most of that is disputes between states protecting their agriculture and the tree-huggers trying to get more water for the fish. Just because there is water coming out of the tap every time I go to the kitchen sink, that doesn't mean I should abuse the water supply. There are alternatives. Like De-ionization.

Whoa there Bob! Ever look at what it takes to first make, then charge and rinse those resins?

I live in the Owens Valley, the high desert created when LA won the first of the big water wars. Bishop sewage water goes directly into the water treatment plant and then into the Owens River, where it then becomes the LA Aqueduct! [Flushing the toilet, here, is not without its small sense of satisfaction, when we see those old orchard stumps in the rabbit brush out south of town. :-)]

Likewise, even dumped RO would be reused, the same way, if we actually used it (we don't need it, here).

The reason we should use DI instead of reverse osmosis in water-challenged areas like the American West (Washington and Oregon rain-forest areas excluded) is because RO units can generate up to five gallons or more of "Waste" water for every gallon of purified water. And that waste water just runs to the nearest water-treatment plant. Most of them still use DI secondary stages to finish the job of purification anyway.

The *only* aquarist reason for DI that can be justified is the needs of certain reef tanks for freedom from trace contaminants like copper -- tolerable by humans and most animals, but not by polyps. They are never justified for freshwater tanks, IMO.

Except for the reef folks, I don't know *any* fresh-water aquarists stupid enough to do that to their fish. [There probably are some out there, getting their word from TFH, the LFS $ales guru, o/e. :-)]

DI water is too poor and dead to sustain life. It gives "dead soft" its true meaning! Great for batteries, but poor for plants and fish.

Even modern RO must usually be tempered with *some* tap water to provide the essential minerals to keep it from being dangerous. Some folks buy expensive reconstituting minerals from the LFS, when a bit of good potable tap water would do better (more useful trace elements, usually).

The waste is not lost. If it doesn't go down the drain and back into the aquifer, it gets used for irrigation, hard-water tanks and a host of other things water is useful for. Too expensive to waste in most arid areas.

Yes, there is maintenance with DI units, but there is with RO, too. If using rechargeable resins, the DI will cost about the same per gallon as changing filters in the RO unit.

Not by a very long shot!

I have scrapped old RO units due to general plumbing failure before ever replacing the main cartridge. If you use the right one, it never wears out, IME. The other filters (carbon, particle) you likely will need, with *either* the DI or RO unit. No really significant difference, there.

Believe me, the cost of RO is far, far below the cost of replacing/recharging ion-exchange resins. It's a more efficient process. That's exactly why it is used around the world for desalinization plants.

With a little effort, it isn't hard to find a water treatment company that will swap you resins for a fee and do the recharging to give to another customer.

And probably use far *more* water than 5X the useful resin output to recharge and rinse, each time, too! [Waste is waste, even if invisible to you.]

A couple years ago the state of Idaho decided that the water coming from certain rivers was "Water-to-die-for" for tropical fish farmers, and actually sponsored a couple breeders with grants for facilities and equipment. But when these lucky individuals starting requesting more water because they needed to do 10-20% daily water changes in their discus fry tanks, the state had a hissy and shut the whole thing down.

Since I moved here, I not only don't need an RO unit, our water is so dead I may even have to sometimes add stuff to get it up to livable levels for plants and fish. Failure to have enough Ca and Mg in the water can cause poisoning with tiny amounts of sodium (from salt in food, for example). It runs about 30ppm total dissolved solids in the city of Bishop, and zero Ca and Mg. That will kill even Discus!

In Modesto (50 ppm) I killed Java Moss with tiny additions of salt! Java Moss is a salt-tolerant, even estuarine/brackish plant that still has to have Ca for proper cell metabolism. Imbalances between Na and Ca/Mg has killed a lot of plants and fish.

I'm lucky here on the outskirts of town, as mine is 80 ppm and probably ideal for most rainforest killies and Amazonian fishes.

[No store in town carries GH and KH kits, so I'll have to get them mail order to be sure I have adequate divalent ions and buffering. Meanwhile a little "Equilibrium" is good insurance, but I'm pretty sure I have more CaCO3 than in the town water. The hard scale ring in the toilet encourages me. :-) They get iron stains.]

If you live in Pennsylvania, ignore this posting, but if nearby farmers are running irrigation systems, think twice about your RO unit. We in the aquarium hobby are generally ecology-sensitive and concerned with issues like bio-diversity and environmental conservation, but we use electricity and water like our actions have no impact on the planet whatsoever. Please, all I'm asking is that you think and act responsibly.

No disagreement with that, at all. All I'm asking is that you don't do something that could be worse than what you are already doing. Instead, use conservation on *all* your use of the resources required for civilized life, but with a bit of sound knowledge.


Wright Huntley - Rt. 001 Box K36, Bishop CA 93514 - whuntley at verizon_net
                    760 872-3995

Eschew obfuscation and bloviation!

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