(Part of the No Sweat Solutions series.)
Before discussing water savings, we need to define what we mean by "use." The EPA refers to withdrawal and consumption. Withdrawal is the amount taken from surface water and the water table. Consumption refers to the amount chemically combined with something (so that it is no longer fresh water) or evaporated. Water discarded instead of consumed is referred to as "returns," because it is supposedly reusable. This does not even approximate the impact of water use.
One example the EPA gives is power plant cooling. The water is withdrawn and used to cool the plant. A little evaporates, and the rest returned (still more or less clean) to the source. This overlooks a certain amount of impact (fish killed during withdrawals, aquatic plant, fungal, and microbial growth encouraged by the change in water temperature), but is basically correct. However, they apply the same logic to water used for irrigation. With very few exceptions, irrigation water "returns" are loaded with fertilizer salts, growth hormones, microbes, and often pesticides and herbicides as well. Even runoff from organic farms usually contains salts from the manure and composts used.
So the proper way to count water is consumption plus polluted returns -- in most cases, all withdrawals.
The table below translates standard EPA figures into real consumption numbers[1] for the U.S.:
| EPA Classification | Withdrawals (%) | Consumption (%) | Withdrawals (millions of Gallons) | Consumption (millions of gallons) | Consumption + polluted returns = use (millions of gallons) | % total use (excludes clean returns) |
| Irrigation | 40% | 81% | 137,000 | 76,200 | 137,000 | 66.38% |
| Thermoelectric cooling | 39% | 4% | 131,000 | 3,500 | 3,500 | 1.70% |
| Industrial + mining | 8.2% | 5% | 27,800 | 4,500 | 27,800 | 13.47% |
| Domestic | 7.5% | 6% | 25,300 | 5,900 | 25,300 | 12.26% |
| Commercial | 2.4% | 1% | 8,300 | 900 | 8,300 | 4.02% |
| public uses and losses (clean returns) | 1.6% | 5,500 | 0 | 0 | 0.00% | |
| Livestock | 1.3% | 3% | 4,500 | 3,000 | 4,500 | 2.18% |
Note that by any classification, the single largest use of water in the U.S. is irrigation -- around two thirds of total water consumed or polluted. Internationally, the figures are different: rainy climates use less for irrigation, dry more. At any rate, for all categories we have no-hair-shirt ways to greatly reduce water use, with the exception of public use and direct consumption by livestock.
Irrigation
My previous suggestions on food sustainability would save water by default.
To the extent that grazed cattle are substituted for lot cattle (fed irrigated grain and soybeans) you reduce water consumption by about 75 percent, basically to the water the animals drink directly.
Similarly a biodiverse, no-till, low-input approach to growing row crops would save between 30 percent and 50 percent of irrigation water. Soil with good structure holds water better than poor soil; less runoff means more available to plants. Further, good soil structure allows plants to access more of what water is there. So the water goes even further. This also allows better utilization of dissolved nutrients, and if you absolutely need small amounts, to herbicides and pesticides. That means what runoff you get is less polluted; remember, polluting water less is another way to use less. If conventional farming is like hooking soil on heroin, and organic farming is supporting the soil entirely without artificial help, low-input no-till biodiverse farming is like giving the soil an aspirin when needed and letting it have an occasional beer with dinner.
Another huge saving can come from simply growing crops in vaguely appropriate places. I'm not talking about growing native plants only, or even perfectly climate-appropriate imports only. With our current population, we are way past the point where that is possible. But certainly we can avoid certain extremes -- like growing cotton in the Arizona Desert. (Cotton is one of the world's most water-intensive plants in net output ratio to water consumed.)
The combination of rotational grazing, no-till, and avoiding extremes of climate inappropriateness can cut water per unit of output by well over half, when reduced water pollution is taken into consideration.
Convert all less efficient irrigation to low-energy, precise-application micro-sprinkler, drip irrigation, subsurface irrigation, and other ultra-efficient irrigation methods[2]. This can save an additional 33 percent in the U.S., which already uses such means more than most nations -- meaning that worldwide, the untapped potential for high-efficiency irrigation is even higher than in the U.S. There is even a kind of bucket-based drip irrigation, which has low capital costs but high labor costs -- and thus is economic in poor nations where capital is expensive and labor cheap. (In the long run, we hope this won't stay the same.)
Lastly, because low-input biodiverse no-till requires drainage in any case, and produces much cleaner runoff than other forms of agriculture, we can capture and recycle that runoff[3], saving another 27 percent. That means we can save around 75 percent of the total water required by no-till agriculture per capita.
Buildings
In residences, toilet flushing and showering alone can be responsible for about 70 percent of water use. Dual flush toilets like the Caroma, which use different amount of water depending on whether dealing with solids or liquid, can cut flushing use by half or more. Advanced compressed-air toilets, like the Microphor can cut this in half again, but at a cost that takes about seven years to pay for itself at 5.5 percent interest in a typical household. Low-flow showerheads such as the Bricor B100Max can cut bathing costs in half at a price from $30-$75.
Washing machines and dishwashers are also major water users in homes that have them. There are many high-efficiency washers out there these days; the LG WM1814c is an example of a comparatively inexpensive one; the LG Tromm Steam Washer of a pricier one with fancier features. Similarly, you can find a long list of dishwashers that get much better results than the U.S. EnergyStar standard from the U.S. D.O.E.
Sink aerators can cut the flow in bathroom sinks by 60 percent, at cost of $4-$15. This can be combined with a hands-free faucet conversions kits for kitchen and bathrooms sinks at around $50 each. (Kick or knee-pedal conversion are more expensive manual alternatives in the $130-$600 ranges.)
Commercial buildings can gain similar savings. Because commercial bathrooms are used more intensively than homes, they get payback from things like one quart compressed air driven standard toilets, and waterless urinals.
Yards and landscaping can follow many of the principles outlined under row crops -- choosing plants suitable to the environment, biodiversity, soil preservation.
Rainwater capture can provide a high percentage of domestic and commercial needs, both at the individual building level (PDF) and the neighborhood scale. Treatment is comparable to that required for well water, though often rain water is higher quality. Separation of blackwater (toilet water and possible garbage disposal water) and greywater (everything else) allows treatment of greywater for reuse. Sewage can be treated on the neighborhood level with living machines, which will have a much easier time processing pure blackwater, with none of the toxins often found in greywater added.
Industrial Water Use
There is a similarly huge potential for water savings at the industrial level: a good example is the computer chip industry, where more efficient filters[4], reduction in output waste combined with recycling[5], and slowing the speed of rinse processes[6] can reduce water consumption by 80 percent or more. There are hundreds, perhaps thousands of techniques that can reduce water use in industry. To name a few: counter-current washing uses waste water from the cleanest process as rinse for the next cleanest, and so on. Some industries can reuse the same water five times. Quite often, dry processes can be substituted for wet ones, such as pigging or super-critical carbon dioxide. On the lower tech, cleaning can start with dry or damp cloths (applied by automated processes, not manually) with rinse steps following. Similarly, spray processes can substitute for bath processes. Other tricks include shaping and sizing vessels in baths to minimize the ratio of rinse water to stuff being rinsed. Mini-reactors can isolate steps requiring ultra-clean or ultra-pure environments from those that can use normal atmosphere and rinse water.
Overall, we can cut water input per unit of production by around three quarters. However, this is not quite enough to make water use sustainable. Population growth would reduce savings to about half. Providing clean drinking and washing water and waste treatment to everyone on the planet instead of letting people die miserably due to lack of it would increase water consumption a bit. (Not a lot; domestic use is not where most water goes.)
Now, if it were not for climate chaos, that would be the end of it; but in the face of it we will probably need to expand irrigation in certain parts of Africa (and as we have seen Australia). It is hard to put a hard number on how much of the savings this will lose. But my intuition is that combining efficiency increases with new demand will give us a 30 percent technically and economically feasible overall reduction in draws on water tables and snow melt. This is unsustainable in at least as many areas as it sustainable, but it takes a bite out of part of the problem. Also, since water is used more efficiently in this scenario, because we squeeze more GDP out of each acre-foot of water, it also allows us to pay more per acre-foot.
And that lets us fill the gap with desalinization. There are well known techniques for desalinating seawater: reverse osmosis driven by electricity and more old-fashioned low-pressure distillation techniques driven by waste heat from various processes. In a renewable scenario, I'd suggest the electricity be produced by wind plants at a time when electrical demand is low (the wind equivalent of off-peak) and that the waste heat be from solar thermal electric plants in the desert. Even with that, desalinated water will cost about twice water from conventional sources (unless major breakthroughs in the technology occur). But if we are using that water four times as efficiently, paying double for it won't be a great hardship. And if we have already reduced absolute demand by 30 percent, then such desalinated water will be providing around another 30 percent, cutting draws on groundwater and snowmelt in half.
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[1] United States Environmental Protection Agency, How We Use Water In These United States. 18/March 2003, United States Environmental Protection Agency, 06/Jul/2005.
[2] Micro-irrigation system (drip + sprinkler) about 5.7% of total irrigated acreage.
Various gravity forms (at 50 percent) are about 43.9 percent of total irrigated acreage.
Other sprinklers irrigate about 51.2 percent of total irrigated acreage.
United States Department of Agriculture National Agricultural Statistics Department, 2003 Farm & Ranch Irrigation Survey (2002 Census of Agriculture| Volume 3, Special Studies, Part 1)(PDF). Nov 2004. United States Department of Agriculture National Agricultural Statistics Department, 28/Oct/2005. p8.
Table 4. Land Irrigated by Method of Water Distribution: 2003 and 1998.
Micro irrigation systems average around 82.5% irrigation efficiency.
Gravity irrigation systems average around 50% irrigation efficiency.
Other sprinkler average around 70% irrigation efficiency.
Michael D. Dukes, Types and Efficiency of Florida Irrigation Systems(PDF), (Note: Data used was from national sources). Dec 2002. University of Florida - Agricultural and Biological Engineering Dept, 28/Oct/2005. p8.
So applying the efficiency numbers from the second source to the acreage in the first, we can calculate that current average irrigation efficiency is around 62 percent. If that average efficiency was upgrade to micro-irrigation levels we would reduce water use for irrigation nationally by an average of one third, internationally by substantially more.
[3] I. Broner, Irrigation: Tailwater Recovery for Surface Irrigation. Crop Series, 4.709. 1998. Colorado State University Cooperative Extension, 17/Sep/2005.
[4] Pacific Northwest Pollution Prevention Resource Center, Topical Reports, "Energy and Water Efficiency for Semiconductor Manufacturing," Pollution Prevention (P2) Pays - N.C. Division of Pollution Prevention and Environmental Assistance, Feb 2000, Pacific Northwest Pollution Prevention Resource Center, 17/Sep/2005.
[5] Hidetoshi Wakamatsu, Akira Mayuzumi, and Norio Tanaka, Effective Utilization Technology for Ultra Purewater, Chemical Liquids and Waste Materials on Semiconductor Manufacturing Plant (PDF), OKI Technical Review 68, no. 188: Special Edition on the Environment Dec 2001, Oki Industry Co. Ltd - Environment Division, 23/May/2004. pp23 - 27.
[6] Stanford University News Service, Can Computer Chip Makers Reduce Environmental Impact? 5/Jun 1996, Stanford University News Service, 4/Jun/2004.
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Comments
View as Flat
BernardBrown Posted 8:54 am
08 May 2007
Bernard Brown
Change the world one lunch at a time. Find out how at http://www.pbjcampaign.org
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Sam Wells Posted 10:05 am
08 May 2007
Irrigation projects in California, Florida, Texas, and some strange states like New Mexico and Arizona require huge amounts of water and you're already paying for it and have been for decades. The farming industry is extremely strong and as the numbers tell you, they are the Number One consumer of water in the United States. The industry is so heavily subsidized that your tax dollars might pay an equal amount in taxes as to the true societal cost of the product.
Most of the water ends up evaporating, leaching into the groundwater, ot simply running off somewhere. The problem is that this irrigation water once applied contains massive amounts of fertilizers, namely nitrogen, potassium, and phosphorus compounds (N-P-K). It really screws up the recieving waters when in over moderate concentrations.
I'd put this issue up there along with global warming as far as likely threats to our future. Perhaps you could explore the farmland just west of Phoenix where not only has the aquifer been sucked nearly dry, but the salts from fertilizers have rendered whatever is left almost useless. Honest, the locals simply do not know what to do.
It's that bad, mon.
/sammie
Onward through the fog
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GreyFlcn Posted 10:37 am
08 May 2007
We just don't have enough fresh water to have our cars chugging more than we do.
As Bill Reinert, Toyota's chief U.S. engineer in charge of advanced vehicle planning, puts it:
"If we replace 30% of the nations gasoline with ethanol, the amount water required for irrigation, and process water, would be the same as goes over Niagara Falls each year. Believe me, water quality and water availability is going to be a bigger issue in years to come than climate change."
Dr. Lester R. Brown, author of "Plan B 2.0", talks about how ethanol water usage is causing falling water tables in ground water reserves.
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Zarkov Posted 10:40 am
08 May 2007
A very good analysis on water, Gar
but wonder why ?
The world will run out of water sooner than you think, and there are no ways to stop this. Fresh water housekeeping seems a bit late, IMO.
Like in Australia, the talk will go on until there really is no water left ... LOL
And yet the number of cars is growing as their future shrinks.
WATER, whats that ? They have had excess water for so long they forgot it comes from pesky cold and miserable rain; clear sunny skies are so nice. NO Rain No rain, they used to chant, now the the only rain they get are tears.
Human beings are the craziest creatures I have ever come across. Don't you ever wonder WHY, it is so ?
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GreyFlcn Posted 10:54 am
08 May 2007
Well there's always the age old solution
"Save water, drink beer!"
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Gar Lipow Posted 1:51 am
09 May 2007
I think I showed we have do both. Reduce demand is the immediate solution, and the majority of the long term solution. Some desalinization as supplementary measure. And yes you are absolutely right, it is a huge argument against ethanol. I thought the main argument against hydrogen was thermodynamic--that is an immensely wasteful storage method compared to alternatives. I wasn't aware it was a water hog. Does it really take anything like as much water per BTU as fossil fuels?
And yeah, Bernard Brown. I should have mentioned reducing meat consumption also. Mind you even if we raise the same amount of meat we do now, if world incomes grew more equal, and population increases, most people in the rich nations will see meat consumption drop drastically.
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zcorrigan Posted 2:49 am
09 May 2007
http://foodandwaterwatch.org/water/desal/oceantotap/from- ....
Zach Corrigan, Food & Water Watch
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SustainableGreen Posted 3:07 am
09 May 2007
I don't remember if it was Bolivia or a nearby country, and if it was World Bank or other similar agency, but as part of a major loan to the country the agency wanted the country to privatize ALL water resources, making even stream and mud puddle water property of a private entity! Cost of daily household water would be the equivalent of weeks of work--so the headline is quite appropriate.
I am disappointed though that not more attention is given to rooftop water collection systems. I put together my own and it collects, depending on annual rainfall, 40-100% of my water needs. And, since I live in a climate with 100% nighttime relative humidity 75% of the nights, I can hear water dripping into my tank at night. The City of Austin TX has excellent guidelines for these systems and recommends a 4000-gal water tank for typical family use. $1,000-5,000 up front is all that is needed for long-time water insurance coverage.
Regarding the demand for agricultural water, this is another strike against biofuels, and also the the research into fast-growing GMOs which increase water demands for each crop, and increase the likelihood of double cropping in a season. [A chill, like what you would get upon seeing Frankenstein walk into the room, interrupted me.] Another reason to bring up the point with regard to science: 'we are so busy asking the question 'can we?', no one is asking the question 'should we?''.
Also, ironic how we complain about floods, but no one bothers to hold their hand out to the rain, looking forward to the inevitable drought.
David
Sustainability For Life
Messages done with sustainable energy, with Wind and Sun!
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Gar Lipow Posted 3:35 am
09 May 2007
Alternatively, desalinization can be part of water recycling--using polluted land sources rather ocean water as the source.
Agreed that you don't want our current corporate system to be one who implements desalinization. In general we are going to be dealing with scarcer resources; either they are distributed more evenly or people will die. Either they are distributed more evenly or the majority will oppose reducing resource use to sustainable levels. If you want wiser resource use, you have to support more social and economic equality. Because we will have enough for everyone, but enough for everyone to outbid
Anyway I'm open to alternatives. It looks like, because of warming locked in, multiplying water use efficiency by 4 only decreases absolute use by 30% in any scenario that ends poverty. Are withdrawals from existing sources at 66% to 70% of current levels sustainable.
Note that I did not give short shrift to rainwater; rainwater capture can supply all or almost all of our domestic use; then discarded treated domestic water can supply part of agricultural and industrial use as well. But we are not going to be able to stop irrigation; we are going still want industry which means some industrial use of water. And that is not going to come from rainwater capture on or near the industrial or agriculture sites. It means dams, in are era when we are goin to have less snowmelt cause more water will fall as rain. It means withdrawal from groundwater, in an era when we are currently withdrawing groundwater at a much faster rate than it discharges.
Maybe I'm wrong about us having to cut withdrawals in half in absolute terms. If I am, if a 30% absolute reduction is enough then we won't need desalinization. If I'm right then there is a gap to fill, and I'm interested in how we cut consumption further, or increase supply from some other source.
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amazingdrx Posted 4:27 am
09 May 2007
Compressed air/water showers, faucets, and nozzles in dishwashers and washing machines would save a huge amount of water. That's the bucky fuller dymaxion bathroom solution.
http://amazngdrx.blogharbor.com/blog
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GreyFlcn Posted 5:08 am
09 May 2007
For instance, heat engine systems like OTEC and Geothermal can do passive desalination.
http://www.soton.ac.uk/~trevor/ei/otecnews.php
There's also cool tech like this one.
Wave powered desalination.
http://hardware.slashdot.org/article.pl?sid=06/11/08/0151 ...
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Gar Lipow Posted 5:54 am
09 May 2007
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ConnerE Posted 8:25 am
09 May 2007
I do like the direction of this discussion, though, with reducing demand and Gar's extensive research. There is so much conservation left to do, including the basics of metering and systems losses. If you are interested in learning more about all of this I would recommend Dr. Peter Gleick- interviewed in Grist and the Pacific Institute's reports, Waste Not, Want Not and Desalination, With a Grain of Salt at http://www.pacinst.org and the California Urban Water Conservation Council at http://www.cuwcc.org and finally http://www.desalresponsegroup.org
Conner Everts
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SustainableGreen Posted 8:31 am
09 May 2007
Just a quick note on appliances:
Staber Industries http://www.staber.com/ makes water- and energy-efficient washing machines near Columbus Ohio, saving emergy costs over anything made in Japan/China/Indonesia/India/Taiwan. They use half or a third of the water and electricity of others. I have one, and the speed of the spin cycle whips a lot more of the water out of the clothes. Then I move the clothes to a real old dryer--a clothes line! Hah!
I have a Vestfrost SKF-375 refrigerator/freezer made by VestFrost in Denmark (sorry) http://www.vestfrost.com/ and now marketed as "ConServ".
It uses the same power as a 150 Watt bulb and has two separate doors (one refrigerator and the other the freezer) and a compressor for each, so that when one is opened and the temperature goes up and triggers the compressor only that compartment is affected. And when neither compressor is drawing current, the entire unit is drawing NO power. It has superior insulation and the cooling heat is vented on the outer skin, using no fins to become covered with dust and grunge ("Grunge"--technical term for a combination of dirt, dust bunnies, and lots of unmentionable stuff.).
I have had both Staber and Vestfrost for 8-10 years and they work well. I understood at the time the Vestfrost could not qualify for the U.S. Energy Star labeling although it kicked ass on all the rest, because it was not made in the U.S.! Much like the domestic auto industry, other U.S. producers just aren't cutting it!
I guess the message is that if we only look at the big box stores, we miss out on some lesser known but better products.
David
Sustainability For Life
Messages done with sustainable energy, with Wind and Sun!
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Zarkov Posted 8:42 am
09 May 2007
The rains will completely disappear... water has nothing to do with what you drink.
Water for the fields to grow food is the problem.
No food, and we all have choas.
Look to the bush fires, you talk of CO2 ! LOL
It will all burn and you won't be able to stop that either.
At least get your perspective straight.
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Gar Lipow Posted 8:52 am
09 May 2007
What the report says:
"Is desalination the ultimate solution to our water problems? No. Is it likely to be a piece of our water management puzzle? Yes."
In other words it needs to be a piece of the puzzle, but as a last resort when all other alternatives are exhausted--which is basically what my article says.
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amazingdrx Posted 9:47 am
09 May 2007
I agree though, conservation of water is best. But to reverse global climate change, renewable deslinization could be used to provide very efficient pinpoint irrigation with organic compost and mulch.
It can also save aquifers by preserving rivers and wetlands now drained by human water use.
http://amazngdrx.blogharbor.com/blog
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Gar Lipow Posted 10:36 am
09 May 2007
Sorry, still salt sludge. Salt sludge does not depend on energy source. All RO methods currently known require salt water to be treated with various chemicals in order to pass through the RO filters without damaging them. Even if that was not the case, you pass sal water through an RO filter, you end up with desalinated water in one stream and concentrated salt sludge in other. You can use the greenest electricity on earth to power the process and you still end up with salt sludge you have to do something with.
Dump in back in the ocean? Two problems. One is the chemicals that were added to prevent it from fouling the RO filter-now concentrated along with salt. The other is that much more concentrated salt is itself harmful to the sea life.
The first problem can be solved in various ways. Use less toxic pretreatment chemicals. Do some post treatment to remove the toxic chemicals. The second is tougher: the best solution seems to be to dilute the returned stream with untreated salt water back to something close to original salinity. If you use waste heat from solar thermal to power a distillation process instead, that reduces the chemical pretreatment needed (but does not eliminate it: you still have problems with scaling.)
In addition to salt disposal problems, there are also problems with damage to sea life on intake. There are various solutions to that: subsurface intake, filters and so on. Bottom line: sustainable desalinization will be more expensive than highly damaging desalinization.
That is why it has to remain the last resort. That is why you are better off trying desalination of polluted land sources before you turn to the sea.
But it can be done right, and unless my numbers are wrong (which is always possible) it will have to be done to some extent.
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SustainableGreen Posted 12:04 pm
09 May 2007
Sorry about that, got caught up in the description.
But, here is something to consider:
A one inch rainfall on 1000 sq. ft. ~ 623 gallons of water.
How big is your roof? What is your mean annual precipitation (MAP)?
Surface area(sq ft)/1000 X MAP(in) X 623 = gals mean annual water collection potential
The result could be very impressive, and comes with little or no energy use. The emergy of a system can be compensated for very quickly. Purification can be simple or complicated, from using it raw, provided the roof and equipment are clean, or use multi-stage filtration and UV purification. Pumps, UV power can all be done with PV or wind.
Not too terribly high-tech, I am afraid, so maybe it won't appeal to a lot of people. And it is not the huge scale of a mega-bucks desal plant, which will not appeal to still more.
On the other hand, run the water through a greywater setup, water the plants or yard, wash the car, have it do double duty.
Thumb your nose at your city water utility. Make your own ecological footprint smaller. "Simplify, simplify."
David
Sustainability For Life
Messages done with sustainable energy, with Wind and Sun!
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Gar Lipow Posted 4:03 pm
09 May 2007
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amazingdrx Posted 4:18 pm
09 May 2007
I did not know about the chemical pre-treatment used with reverse osmosis. Could pre-filtering with ceramic filters help eliminate the chemicals? The other alternative is low pressure evaporation using wind/wave powered pumps and solar heat. The heat could be recycled from the water condensing cycle too, with an additional heat pump system powered by wind/wave power.
The idea of refining waste water is really great. In most regions with water problems a lot of solar energy is available. Biodigestion, then treatment in a lagoon system that goes through a greenhouse could be very efficient in this case. The water recondensed with geothermal cooling after being distilled by plant transpiration and water evaporation in the greenhouse. Water spray cooling would add to the effect.
This could also reclaim salt and fertilizer contaminated groundwater. Organic fertilizer and biogas would be byproducts of this process. As well as a lot of possibly valuable plant biomass.
http://amazngdrx.blogharbor.com/blog
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GreyFlcn Posted 5:11 pm
09 May 2007
I find it curious that you are posting on a thread about how to conserve fresh water resources.
While at the same time promoting Hydrogen.
A fuel technology which actively uses up fresh water resources by the lakefull.
Ulf Bossel: Director of the European Fuel Cell Forum I have analyzed the situation to illustrate how much water and electricity is needed for certain hydrogen jobs. If you take the Frankfurt Airport and Frankfurt Airport is perhaps comparable to the airport at Montreal. About 50 jumbo jets leave Frankfurt every day, each charged with 130 tons of kerosene. If you replace kerosene by hydrogen on a one-to-one energy base, each plane needs 50 tons of hydrogen. As a side remark: 50 tons of liquid hydrogen occupy 720 cubic meters of space, while 130 tons of kerosene take only 160 cubic meters. We need totally different airplanes for hydrogen. But that is another story. To fill the 50 jumbo jets one needs 2,500 tons of liquid hydrogen every day. 22,500 cubic meters of water, the water consumption of a city of 100,000, must be split by electrolysis. For this one the continuous electricity output of about eight nuclear power plants is needed. Now, if the entire traffic at Frankfurt Airport was all done with hydrogen, one would need the water consumption of the City of Frankfurt plus about 25 nuclear power plants. Using hydrogen for all public air and road transport in Germany, it would take the power output of about 400 nuclear power plants plus enormous amounts of water. You need nine kilograms of water to make one kilogram of hydrogen. The Rhine river and all other rivers would be dry in the summer because the water is used to make hydrogen. greyfalcon. net/ hydrogen
Does that sound sustainable to you?
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Nucbuddy Posted 11:41 pm
09 May 2007
"Flushing" a toilet does not necessarily require any water. Feces, urine, vomit and blood can all be freeze-dried.
All household water can be recycled with equipment located inside the house. The International Space Station has proven this concept ("The ECLSS Water Recycling System (WRS), developed at the MSFC, will reclaim waste waters from the Space Shuttle's fuel cells, from urine, from oral hygiene and hand washing, and by condensing humidity from the air. Without such careful recycling 40,000 pounds per year of water from Earth would be required to resupply a minimum of four crewmembers for the life of the station."). Shower water can be recycled (filtered and re-heated) in real-time. Shower steam, of course, is easily condensed.
Growing of crops does not necessarily require any more water than that contained in the resulting yield. Aeroponic agriculture inside hermetically-sealed, windowless concrete domes evaporates no water to the outside. Meat has been grown in laboratories. Perhaps culturing meat would take less water than does raising animals.
There is water in the sky. It does not have any salt in it. Condensing of atmospheric water might be more cost-effective than desalination. A large wind-turbine turned horizontal and circumscribed by a ring might support several nuclear-reactors, several propellers (to spin the ring), and massive condensers raining water down upon anything below -- be it a reservoir or a forest-fire. The ocean might make a convenient place for launching and landing.
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Gar Lipow Posted 1:47 am
10 May 2007
Condensing water from air takes more electricity than desalination as far as I know. And I'm familiar with Aeroponics. Even plain old hydroponics is very water sparing compared to conventional agriculture even with drip irrigation. However both are extremely capital intensive.
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SustainableGreen Posted 4:45 am
10 May 2007
Thanks, Gar, for mentioning these types of toilets. They range from nothing more than a small pit that is shoveled out periodically, to a $20 plastic bin with a lid (which is what I have) to some $2-3000 big, overblown, overkill, over hyped, plastic/fiberglass apparatuses (apparati?) that dry, warm, circulate, and process yer poop better than they do in ICU. That's some expensive shit, dood!
Dry composting toilets have been around, well, ever since. Yes, it is true, there is resistance to the technology (at least on the low end of the cost/complexity spectrum), and when friends/family/associates/visitors come out, and I show them what I have, they instinctively turn up their noses up, but after I show them the plastic bin and the very nice wooden toilet seat (for tradition's sake), and the source of peat (to start the drying process), later on I always ask them "Does it smell?" To the very last one of them, they look a moment then say, "Uh, no." So the noses turning up is strictly social and cultural, and not olfactory. Mine is in a regular bathroom so the surroundings are not foreign, and most pretty much figure it out quickly.
Dry composting toilets act differently from the anaerobic sewage systems we all (well, most of us) grew up with. The stink in typical sewers comes from the anaerobic mechanism. Aerobic digestion is much less offensive, and instead of continuing to provide wet, anaerobic habitat for fecal coliforms, thermophilic bacteria in a much drier (though not completely dry) system pretty much kill all the pathogens.
Recommendations are not to use any of this compost for anything that might be consumed (following official precautions) but it is far less involved than some of the hi-tech, far more energy intensive ideas.
Many people tend to focus on smaller scale solutions to problems, with the viewpoint that if we provide leadership to solve these problems, others will see this and recognize the potential to solve larger ones in much the same way.
I also think that waiting for government or business to act is pure foolishness. Only on the City and State level has anything changed in the U.S., and if there is ANY change on the Federal level it won't be until 2009-10, it even then it will be PATHETIC compared to the need. And "Big Bidness" owns the Federal government, so until there is real, meaningful, I-mean-near-revolutionary campaign finance reform, and equally significant lobbying reform, we are stuck to work things out in the science and environmental and activist community.
From the 1930s: "Government is the shadow cast by business on society." -- John Dewey
Has anything changed?
David
Sustainability For Life
Messages done with sustainable energy, with Wind and Sun!
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