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Tankers may ship water to parched cities of future (pg. 2)
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| Lilith |
I don't see tankers being very efficient, they carry about 1/4million tons for the large oil tankers up to 500,000 for the biggest (thanks google) which is only a small fraction of what you'd need to even keep a large town of 100,000 from dehydration, for about 2 days.
(Add to that they use immense quantities of diesel to do it)
Desalination plants use a lot of energy too dont forget so thats going to have to come from somewhere, thinking that solar would be the best choice at least in places like Australia.
What do they do with all the salt from these things anyway because you can't just dump that anywhere without locally killing fish or leaving it on the ground where it'll kill the plants? |
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| Sunsnail |
Google ftw
| quote: | Waste Discharges
Desalination plants produce liquid wastes that may contain all or some of the following constituents: high salt concentrations, chemicals used during defouling of plant equipment and pretreatment, and toxic metals (which are most likely to be present if the discharge water was in contact with metallic materials used in construction of the plant facilities). Liquid wastes may be discharged directly into the ocean, combined with other discharges (e.g., power plant cooling water or sewage treatment plant effluent) before ocean discharge, discharged into a sewer for treatment in a sewage treatment plant, or dried out and disposed of in a landfill. Desalination plants also produce a small amount of solid waste (e.g., spent pretreatment filters and solid particles that are filtered out in the pretreatment process).
For example, the capacity of the City of Santa Barbara's desalination plant is 7,500 AF/yr (about 7.16 MGD). In May 1992, the plant produced 6.7 MGD of product water and generated 8.2 MGD of waste brine with a salinity approximately 1.8 times that of seawater. An additional 1.7 MGD of brine was generated from filter backwash. Assuming that concentrations of suspended solids in the seawater feed range from 10 to 50 ppm, approximately 1.7 to 5.1 cubic yards per day of solids were generated, which is equivalent to one to two truck-loads per week. (Source: Woodward-Clyde Consultants, EIR for the City of Santa Barbara and Ionics, Inc.'s Temporary Emergency Desalination Project, March 1991.) |
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| ogvh5150 |
Lilith:
Dump all that salt back into the ocean. The water you've just consumed makes it back to the ocean by way of evaporation in one form or another.
The world is seventy-five per cent covered in water. Just complaining that the salty "residue" might do to plants and other forms of life is irresponsible disposal.
If it came from the water it'll go back to the water. After all you've just drank a water molecule that most likely made it's journey through some guy in Australia. Or some elephant in India. Or some animal food. Or some plant. Or some iceberg. |
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| Omega_M |
| quote: | Originally posted by Lilith
Desalination plants use a lot of energy too dont forget so thats going to have to come from somewhere, thinking that solar would be the best choice at least in places like Australia.
What do they do with all the salt from these things anyway because you can't just dump that anywhere without locally killing fish or leaving it on the ground where it'll kill the plants? |
The article on desalination does refer to the use of nuclear energy for this purpose.
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A number of factors determine the capital and operating costs for desalination: capacity and type of facility, location, feed water, labor, energy, financing and concentrate disposal. Desalination stills now control pressure, temperature and brine concentrations to optimize the water extraction efficiency. Nuclear-powered desalination might be economical on a large scale, and there is a pilot plant in the former USSR.
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BN-350 (1973) was the first full-scale Soviet FBR. Constructed on the Mangyshlak Peninsula in Kazakstan and on the shore of the Caspian Sea, it supplied 130MW of electricity plus 80,000 tonnes per day of desalinated fresh water to the city of Aktau.
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| Lilith |
| quote: | Originally posted by ogvh5150
Lilith:
Just complaining that the salty "residue" might do to plants and other forms of life is irresponsible disposal. |
I wasnt complaining, I was just simply asking what the methods of responsible disposal are, Australia has terrible salinisation problems in large amounts of its arable land. |
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| Magnetonium |
I think that the desalination of water will have its reprocussions. It will damage the water cycle, as the salt dumped back into the ocean will saturate the water and with higher salt levels it will negatively affect life. Thats just my opinion, as I am not an expert on this issue by any means. |
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| venomX |
| Well too little salt water in the ocean is bad, so removing the salt out of the ocean is not good. The effect of dumping extra salt and metals from the process of desalinization is also bad. The conditions that would allow to use a desalinization plant effectively should be thoroughly studied before large scale implementation IMO. We don't want to go around creating more problems that we're solving. I think by now we should've learned to test before doing eh? |
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| Omega_M |
Any solution to this problem will end up creating multitude of other problems. Desalination has it's own issues and so does super tankers.
The best solution probably is to minimize the environmental damage and use alternative water delivery concepts in moderation. |
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| ogvh5150 |
| quote: | Originally posted by Magnetonium
I think that the desalination of water will have its reprocussions. It will damage the water cycle, as the salt dumped back into the ocean will saturate the water and with higher salt levels it will negatively affect life. Thats just my opinion, as I am not an expert on this issue by any means. |
What do you do about lava falling into the ocean from a volcano? Or what about an iceberg melting?
Then why worry about salt that came from the seas going back into it.
People are too worried about what might happen based on what was told to them by tree hugging drug sniffing hippie professors.
If I told people silly things ruining the oceans people would jump on that bandwagon just because I sound like a person authority as soon as I add PhD to my sigs.
ogvh5150
PhD Verbatim University, Microasia |
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| Sunsnail |
| It's not like the salinity of the ocean is hanging on a thin line. The difference in saliny between the 4 different oceans is so great that it'd be virtually impossible for humans to disrupt salinity levels beyond a few miles of the plant, at worst. |
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| Magnetonium |
| quote: | Originally posted by ogvh5150
What do you do about lava falling into the ocean from a volcano? Or what about an iceberg melting?
Then why worry about salt that came from the seas going back into it.
People are too worried about what might happen based on what was told to them by tree hugging drug sniffing hippie professors.
If I told people silly things ruining the oceans people would jump on that bandwagon just because I sound like a person authority as soon as I add PhD to my sigs.
ogvh5150
PhD Verbatim University, Microasia |
Well, then, here's my analogy: humans release a small amount of greenhouse gases into atmosphere compared to natural forces, from glacier retreat, for example. So, if allegedly humans are having an adverse effect with a 0.4% of atmosphere made up of carbon dioxide and greenhouse gases composition, then how come I am supposed to believe that if we dump tons of salt into the oceans the balance is not going to be shifted? |
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| ogvh5150 |
You act as if the water we use doesn't make it way back into the ocean.
Come on man what have you learned in basic biology? |
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