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Desalination Plants

DetectableNinja
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8/17/2011 9:39:54 PM
Posted: 5 years ago
What with the gradual rise in sea levels, as well as the rapid consumption of fresh water for things such as food production, hygiene, etc, would you think it to be wise for coastal cities to invest in desalination plants for the future, a la Australia?
Think'st thou heaven is such a glorious thing?
I tell thee, 'tis not half so fair as thou
Or any man that breathes on earth.

- Christopher Marlowe, Doctor Faustus
Greyparrot
Posts: 14,249
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8/17/2011 9:40:43 PM
Posted: 5 years ago
At 8/17/2011 9:39:54 PM, DetectableNinja wrote:
What with the gradual rise in sea levels, as well as the rapid consumption of fresh water for things such as food production, hygiene, etc, would you think it to be wise for coastal cities to invest in desalination plants for the future, a la Australia?

Takes a lot of nuclear power to do that.
Lasagna
Posts: 2,440
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8/18/2011 10:15:44 PM
Posted: 5 years ago
Desalinization plants use micro-filters and pumps to force the water through while leaving salt behind. It's an energy-intensive process. The holy grail of environmental technology is using less energy. It doesn't matter how you get the energy, whether it's nuclear, fossil fuel, or some futuristic super-energy source - there are always serious drawbacks. The only way towards sustainability is using less energy, and that involves lowering consumption and planning smarter communities.

In order of importance, these are the goals of environmentalism:
Goal 1: Reduce
Goal 2: Reuse
Goal 3: Recycle
There are subordinate goals below these, but they are not recommended.

It is my opinion that desalinization plants should generally not be employed. There is no technological silver bullet for water pollution or any other environmental concern, and I firmly believe that this will be the case 1,000 years from now as well.
Rob
Ore_Ele
Posts: 25,980
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8/19/2011 10:17:43 AM
Posted: 5 years ago
At 8/17/2011 9:39:54 PM, DetectableNinja wrote:
What with the gradual rise in sea levels, as well as the rapid consumption of fresh water for things such as food production, hygiene, etc, would you think it to be wise for coastal cities to invest in desalination plants for the future, a la Australia?

Water is not "used" in the sense that once it is used you can't use it again. When a plant (for food) takes in water to grow, and turns that water (along with other chemicals) into sugar. When sugar is burned (like in the human body after digesting), it turns back into water. Water just keeps going in a loop, it isn't created nor destroyed (while it can be, it isn't for 99.9% of uses).

That's one of the things that has always bugged me. People say "don't waste water by water the elusive concrete flowers" but that water is simple evaporated and it rains down somewhere else, it isn't destroyed.

Anyway, if there is the goal of making more water, I've always liked boiling methods and steam capture, since you use use a steam generator to recapture much of the energy spent. Then it just comes down to cleaning all the salt deposits that will form in the boiler (making modules that can be easily removed and replaced by another while that one is being cleaned is one idea).
"Wanting Red Rhino Pill to have gender"
Lasagna
Posts: 2,440
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8/19/2011 12:13:07 PM
Posted: 5 years ago
At 8/19/2011 10:17:43 AM, Ore_Ele wrote:
At 8/17/2011 9:39:54 PM, DetectableNinja wrote:
What with the gradual rise in sea levels, as well as the rapid consumption of fresh water for things such as food production, hygiene, etc, would you think it to be wise for coastal cities to invest in desalination plants for the future, a la Australia?

Water is not "used" in the sense that once it is used you can't use it again. When a plant (for food) takes in water to grow, and turns that water (along with other chemicals) into sugar. When sugar is burned (like in the human body after digesting), it turns back into water. Water just keeps going in a loop, it isn't created nor destroyed (while it can be, it isn't for 99.9% of uses).

That's one of the things that has always bugged me. People say "don't waste water by water the elusive concrete flowers" but that water is simple evaporated and it rains down somewhere else, it isn't destroyed.

Anyway, if there is the goal of making more water, I've always liked boiling methods and steam capture, since you use use a steam generator to recapture much of the energy spent.

Water has a high heat-energy so boiling it, especially in large amounts, is highly energy intensive. I'm not sure what the return is on the steam generators, but I imagine it can't be more than 20%.

Then it just comes down to cleaning all the salt deposits that will form in the boiler (making modules that can be easily removed and replaced by another while that one is being cleaned is one idea).

I would suspect that if the energy needs were taken care of properly, the cleaning could be figured out easily enough.
Rob
Ore_Ele
Posts: 25,980
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8/19/2011 12:58:46 PM
Posted: 5 years ago
At 8/19/2011 12:13:07 PM, Lasagna wrote:
At 8/19/2011 10:17:43 AM, Ore_Ele wrote:
At 8/17/2011 9:39:54 PM, DetectableNinja wrote:
What with the gradual rise in sea levels, as well as the rapid consumption of fresh water for things such as food production, hygiene, etc, would you think it to be wise for coastal cities to invest in desalination plants for the future, a la Australia?

Water is not "used" in the sense that once it is used you can't use it again. When a plant (for food) takes in water to grow, and turns that water (along with other chemicals) into sugar. When sugar is burned (like in the human body after digesting), it turns back into water. Water just keeps going in a loop, it isn't created nor destroyed (while it can be, it isn't for 99.9% of uses).

That's one of the things that has always bugged me. People say "don't waste water by water the elusive concrete flowers" but that water is simple evaporated and it rains down somewhere else, it isn't destroyed.

Anyway, if there is the goal of making more water, I've always liked boiling methods and steam capture, since you use use a steam generator to recapture much of the energy spent.

Water has a high heat-energy so boiling it, especially in large amounts, is highly energy intensive. I'm not sure what the return is on the steam generators, but I imagine it can't be more than 20%.

If well insulated, you can get very efficient, as the steam cools and releases heat, that released heat is used to heat up other water into steam. Saltwater has a lower boiling point and a lower heat capacity than fresh water, the equation is in your favor.


Then it just comes down to cleaning all the salt deposits that will form in the boiler (making modules that can be easily removed and replaced by another while that one is being cleaned is one idea).

I would suspect that if the energy needs were taken care of properly, the cleaning could be figured out easily enough.

Yeah, though there is a risk. If you've ever boiled salt water down to where there is no water left (lol, it gets fun).

Another option is the electrolysis of brine. You can break the water into Oxygen and Hydrogen, and burn it to make fresh water (the salt is still left behind).
"Wanting Red Rhino Pill to have gender"
innomen
Posts: 10,052
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8/19/2011 1:20:02 PM
Posted: 5 years ago
I don't know anything about this stuff, but wouldn't simple distilation of sea water produce fresh water? I understand that it would be a major effort to make a river of the stuff, but still wouldn't that process create it? Versus say condensation, which yeah would need a lot more energy, and probably wouldn't be so clean.
Ore_Ele
Posts: 25,980
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8/19/2011 1:25:04 PM
Posted: 5 years ago
At 8/19/2011 1:20:02 PM, innomen wrote:
I don't know anything about this stuff, but wouldn't simple distilation of sea water produce fresh water? I understand that it would be a major effort to make a river of the stuff, but still wouldn't that process create it? Versus say condensation, which yeah would need a lot more energy, and probably wouldn't be so clean.

Distillation uses condensation. You boil the water (to make steam) and have to condense it back into water.
"Wanting Red Rhino Pill to have gender"
Lionheart
Posts: 520
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8/19/2011 4:44:07 PM
Posted: 5 years ago
At 8/19/2011 10:17:43 AM, Ore_Ele wrote:
At 8/17/2011 9:39:54 PM, DetectableNinja wrote:
What with the gradual rise in sea levels, as well as the rapid consumption of fresh water for things such as food production, hygiene, etc, would you think it to be wise for coastal cities to invest in desalination plants for the future, a la Australia?

Water is not "used" in the sense that once it is used you can't use it again. When a plant (for food) takes in water to grow, and turns that water (along with other chemicals) into sugar. When sugar is burned (like in the human body after digesting), it turns back into water. Water just keeps going in a loop, it isn't created nor destroyed (while it can be, it isn't for 99.9% of uses).

That's one of the things that has always bugged me. People say "don't waste water by water the elusive concrete flowers" but that water is simple evaporated and it rains down somewhere else, it isn't destroyed.

Anyway, if there is the goal of making more water, I've always liked boiling methods and steam capture, since you use use a steam generator to recapture much of the energy spent. Then it just comes down to cleaning all the salt deposits that will form in the boiler (making modules that can be easily removed and replaced by another while that one is being cleaned is one idea).

This.

I agree with desalinization plants being employed. Think of all the extra water that could be channeled to areas that have no clean water to drink. Energy production is not much of a problem, scientists just need to quit wasting time and start getting really serious about developing alternative energy sources. It is in my opinion that Tesla has this all figures out, but a conspiracy covered up his work. I could be wrong though.
"Knowing others is intelligence;
knowing yourself is true wisdom.
Mastering others is strength;
mastering yourself is true power."


- Lionheart -
Ore_Ele
Posts: 25,980
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8/19/2011 5:11:04 PM
Posted: 5 years ago
At 8/19/2011 4:44:07 PM, Lionheart wrote:
At 8/19/2011 10:17:43 AM, Ore_Ele wrote:
At 8/17/2011 9:39:54 PM, DetectableNinja wrote:
What with the gradual rise in sea levels, as well as the rapid consumption of fresh water for things such as food production, hygiene, etc, would you think it to be wise for coastal cities to invest in desalination plants for the future, a la Australia?

Water is not "used" in the sense that once it is used you can't use it again. When a plant (for food) takes in water to grow, and turns that water (along with other chemicals) into sugar. When sugar is burned (like in the human body after digesting), it turns back into water. Water just keeps going in a loop, it isn't created nor destroyed (while it can be, it isn't for 99.9% of uses).

That's one of the things that has always bugged me. People say "don't waste water by water the elusive concrete flowers" but that water is simple evaporated and it rains down somewhere else, it isn't destroyed.

Anyway, if there is the goal of making more water, I've always liked boiling methods and steam capture, since you use use a steam generator to recapture much of the energy spent. Then it just comes down to cleaning all the salt deposits that will form in the boiler (making modules that can be easily removed and replaced by another while that one is being cleaned is one idea).

This.

I agree with desalinization plants being employed. Think of all the extra water that could be channeled to areas that have no clean water to drink. Energy production is not much of a problem, scientists just need to quit wasting time and start getting really serious about developing alternative energy sources. It is in my opinion that Tesla has this all figures out, but a conspiracy covered up his work. I could be wrong though.

It wasn't a conspriacy, his warehouse caught fire, and he never thought his generator was good enough to bother making a new one afterwards. Unless he was part of the conspriacy, he could have made more.

Anyway, his generator wasn't what people think it was. It was more of a battery, than a power source. By constantly putting in a little energy over a long period of time, you could build up momentum of a spinning disk (building rotational energy), then release it all at once to get a big surge of energy. We can already do this on a small scale via capasitors in electronics, and they are more efficient.

But his could be employed large scale to make things like massive thunderbolts (that go all the way to the sky).
"Wanting Red Rhino Pill to have gender"
Tiel
Posts: 1,500
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8/19/2011 6:19:50 PM
Posted: 5 years ago
At 8/19/2011 5:11:04 PM, Ore_Ele wrote:
At 8/19/2011 4:44:07 PM, Lionheart wrote:
At 8/19/2011 10:17:43 AM, Ore_Ele wrote:
At 8/17/2011 9:39:54 PM, DetectableNinja wrote:
What with the gradual rise in sea levels, as well as the rapid consumption of fresh water for things such as food production, hygiene, etc, would you think it to be wise for coastal cities to invest in desalination plants for the future, a la Australia?

Water is not "used" in the sense that once it is used you can't use it again. When a plant (for food) takes in water to grow, and turns that water (along with other chemicals) into sugar. When sugar is burned (like in the human body after digesting), it turns back into water. Water just keeps going in a loop, it isn't created nor destroyed (while it can be, it isn't for 99.9% of uses).

That's one of the things that has always bugged me. People say "don't waste water by water the elusive concrete flowers" but that water is simple evaporated and it rains down somewhere else, it isn't destroyed.

Anyway, if there is the goal of making more water, I've always liked boiling methods and steam capture, since you use use a steam generator to recapture much of the energy spent. Then it just comes down to cleaning all the salt deposits that will form in the boiler (making modules that can be easily removed and replaced by another while that one is being cleaned is one idea).

This.

I agree with desalinization plants being employed. Think of all the extra water that could be channeled to areas that have no clean water to drink. Energy production is not much of a problem, scientists just need to quit wasting time and start getting really serious about developing alternative energy sources. It is in my opinion that Tesla has this all figures out, but a conspiracy covered up his work. I could be wrong though.

It wasn't a conspriacy, his warehouse caught fire, and he never thought his generator was good enough to bother making a new one afterwards. Unless he was part of the conspriacy, he could have made more.

Anyway, his generator wasn't what people think it was. It was more of a battery, than a power source. By constantly putting in a little energy over a long period of time, you could build up momentum of a spinning disk (building rotational energy), then release it all at once to get a big surge of energy. We can already do this on a small scale via capasitors in electronics, and they are more efficient.

But his could be employed large scale to make things like massive thunderbolts (that go all the way to the sky).

I don't really agree with you on this point, but that is ok. I will create a forum about it at a later time.
"Only the inner force of curiosity and wonder about the unknown, or an outer force upon your free will, can brake the shackles of your current perception."
innomen
Posts: 10,052
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8/21/2011 4:08:14 PM
Posted: 5 years ago
At 8/19/2011 1:25:04 PM, Ore_Ele wrote:
At 8/19/2011 1:20:02 PM, innomen wrote:
I don't know anything about this stuff, but wouldn't simple distilation of sea water produce fresh water? I understand that it would be a major effort to make a river of the stuff, but still wouldn't that process create it? Versus say condensation, which yeah would need a lot more energy, and probably wouldn't be so clean.

Distillation uses condensation. You boil the water (to make steam) and have to condense it back into water.

Well, i meant refridgeration condensation.
Ore_Ele
Posts: 25,980
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8/22/2011 9:45:54 AM
Posted: 5 years ago
At 8/21/2011 4:08:14 PM, innomen wrote:
At 8/19/2011 1:25:04 PM, Ore_Ele wrote:
At 8/19/2011 1:20:02 PM, innomen wrote:
I don't know anything about this stuff, but wouldn't simple distilation of sea water produce fresh water? I understand that it would be a major effort to make a river of the stuff, but still wouldn't that process create it? Versus say condensation, which yeah would need a lot more energy, and probably wouldn't be so clean.

Distillation uses condensation. You boil the water (to make steam) and have to condense it back into water.

Well, i meant refridgeration condensation.

Oh, I'm not really sure what refridgeration condensation is.
"Wanting Red Rhino Pill to have gender"
RoyLatham
Posts: 4,488
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8/23/2011 11:41:05 PM
Posted: 5 years ago
Desalinization is accomplished using very high pressure with a ceramic "membrane." It's never done on a large scale by distillation. The process has no relation to sea levels.

Currently, the costs of water are about $1 for ground water (wells). $2 for reservoirs, and $4 for desalinization. Saudi Arabia has large cities supplied by desalinization. In the US, Tampa uses a lot of recovered water. The price seems perfectly reasonable for many places, where the cost of water is small compared to other development costs.

One reason it isn't done is too artificially control population. In California coastal areas, the cost of water is trivial compared to the land value, but local governments restrict water to prevent development.
DirkBergurk
Posts: 32
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8/26/2011 9:16:01 PM
Posted: 5 years ago
At 8/18/2011 10:15:44 PM, Lasagna wrote:
...It doesn't matter how you get the energy, whether it's nuclear, fossil fuel, or some futuristic super-energy source - there are always serious drawbacks....

While I agree reducing consumption should be at the forefront of the water sustainability discussion, I do not agree that all power sources are equally valid. A power plant that uses a Rankine cycle (i.e. boiling water to create power) has to reject heat to the environment. These include your traditional fossil fuels, nuclear, solar thermal, etc. This waste heat is usually a burden (particularly in nuclear) as it can adversely effect the environment. However, this waste heat is especially useful in desalination applications as it can preheat the incoming water, which is a first step in many desalination processes. This can greatly reduce the energy needed.

Nuclear has a particular advantage in this area as it has a low power plant efficiency (which is otherwise a negative) compared to modern coal and gas plants. This means it produces more waste heat per unit of energy than other forms of power. Since nuclear power plants typically are enormous, they have plenty of waste heat to spare. The downside to all of this is that the power plant must be built close to the desalination plant, but at least you have plenty of water. Just watch out for tsunamis.

Wind power and photovoltaics are not useful in desalination in that they don't produce waste heat in significant quantities.

At 8/19/2011 12:58:46 PM, Ore_Ele wrote:
Saltwater has a lower boiling point and a lower heat capacity than fresh water, the equation is in your favor.

This is half correct. The boiling point of salt water is higher than fresh water.
http://en.wikipedia.org...
Lasagna
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8/26/2011 10:22:20 PM
Posted: 5 years ago
At 8/23/2011 11:41:05 PM, RoyLatham wrote:
Currently, the costs of water are about $1 for ground water (wells). $2 for reservoirs, and $4 for desalinization. Saudi Arabia has large cities supplied by desalinization. In the US, Tampa uses a lot of recovered water. The price seems perfectly reasonable for many places, where the cost of water is small compared to other development costs.

The Saudi's use their oil profits to desalinize; that type of spending isn't going to be possible everywhere. Could you imagine how much it would cost if places like L.A., Phoenix, and Vegas switched to desalinization? I suppose it would just drive home my point of reducing consumption that much more...

One reason it isn't done is too artificially control population. In California coastal areas, the cost of water is trivial compared to the land value, but local governments restrict water to prevent development.

That's an interesting perspective. Do you have any articles that go into depth about this?

You're talking about an area that is excessively dry. We've created these cities, like the three I just mentioned, which are sustained by stealing (both literally and figuratively) water from other areas to sustain them. Read up on Lake Mono and how the city of L.A. secretly bought all the property around it so they could drain it dry, nearly destroying the ecosystem before the breaks were put on. People are told not to water their grass and not to light campfires because it is bone-dry out there and water is no small issue; to say the aridity issues out there are engineered purposefully is absurd.
Rob
RoyLatham
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8/27/2011 12:52:24 PM
Posted: 5 years ago
At 8/26/2011 10:22:20 PM, Lasagna wrote:
The Saudi's use their oil profits to desalinize; that type of spending isn't going to be possible everywhere. Could you imagine how much it would cost if places like L.A., Phoenix, and Vegas switched to desalinization? I suppose it would just drive home my point of reducing consumption that much more...

There is no need to imagine it. it's easy to compute. The current cost of water varies in the US, "A family of four using 100 gallons per person each day will pay on average $34.29 a month in Phoenix compared to $65.47 for the same amount in Boston."

Phoenix gets a third of its water from wells, a third from reservoirs in Northern Arizona, and a third from the Colorado river. The Colorado river water has to be pumped for hundreds of miles including an elevation rise of about a thousand feet. So Phoenix is probably about 2 on the 1. 2. 4 scale of wells, reservoirs, and desalinization. So desalinization would about double water costs, to about $70 per month. That's small compared to homeowners costs for mortgage, taxes, and other utilities.

In general it depends how far from the ocean the city is. Phoenix is 244 miles to the Sea of Cortez, closer than Lake Mead. LA is on the ocean, and now its water is pumped for very long distances.

The whole idea of conserving water to save money is not derived from the costs. There is an utterly ridiculous "water footprint" idea circulating based on the idea that if Americans use less water there will be more for people in Africa, or something. Not only is it recycled you can't stop it from being recycled.