Low-Cost Desalination Technologies?

First, what you need to do is create a method of assessing all available technologies for the production and management of fresh water on a comparative basis.

You do not want to choose systems simply because they are low cost, because a poor system will probably cost more in the long run. What you want to ask yourself is "What is the best way to produce and keep the most freshwater, so that the total cost of investment, operation and management will be the least in the long run, and the best for the people and the environment, and especially the land of India?

This means looking at every gallon/litre of fresh water you currently have, and understanding methods of conservation, reuse, best use, and control that can be applied. A gallon of water that you save or conserve is worth more than a gallon you filter and deliver, as it is already in hand. It therefore has the most value.

After you have done all these things, you will have enough knowledge to choose the best technologies for desalinization. What is cost of processed water that simply gets dumped in the sewer? First create a massive government initiative to conserve fresh water that you have. Clean up all the waste waters that are entering the rivers. You will have less disease as a byproduct.

Find, download and watch the PBS show on water infrastructure. availabe here as a torrent.

http://dl.btjunkie.org/torrent/PBS-Special-Liquid-Assets-The-Story-of-Our-Water-Infrastructure-2008-HDTV-SoS/37967de8146e269d5a13b4a951039edcaad57175b692/download.torrent

It talks about everything I've said and more.

Chris.

Have a technology that will produce drinking water from virtually anything, and from Seawater at 50 US cents a M3. Low pumping and energy costs.

Are you saying you have this and are selling it?

Dear friend.

your system may be more suitable to get rid of Arsenic.Iron/Fluoride from water,which is also a huge problem in various parts of India

1.West bengal/Bangladesh-the water contains arsenic which leads to darkening of skin and twisting of bones

2.High fluoride content in water leds to darkening of teeth/twisting of back bone leading to early aging

3.Please send details if your system acn help these unfortunate human beings

H.S.Sharma M0-09873020599/E amil:-huda1921@gmail.com

The simplest and straight forward way in a low budget environment is not to go after Desalination but to get a barrage built and few shutters erected quickly.See pictures of a 1958 project abandoned due to sea corosion but rebuilt recently....somewhere in India itself

Fig.1 Barrage view Fig 2 Shutter view inside the well

Shutter wells (4 nos.),at the farthest end where the boat is

Left is River side -Right is Sea side

Dear bala,

your suggestion is well taken.But who will pay? the high cost.You have given a cure which is worse than the disease.Are you not aware of the fiasco of FARRAKKA BARRAGE in west Bengal.

Please give a worakble solution

H.S.Sharma,FAO(UNO) Consultant

M-09873020599/E amil:-huda1921@gmail.com

In Calcutta river Ganges merges with sea. During high tide sea water gushes in the river and mixes with river water. As sea level is rising the content of the sea water is increasing. We have to control the inflow of sea water in the river.

Hello Mr. Hari,

If this were happening any place other than India I would be much more concerned. The reason that I say this is that I have had broad experience with a number of very good engineers that were educated in India. The barrage sounds like a good idea and would probably work well if you consider siltation and a lock for river traffic. The government of Iraq built a series of barrages in Kirkuk many years ago. Unfortunately they were not designed to be periodically purged of silt and are now all useless.

My dear friend from Iraq,the cradle of civilisation,

The problem is not so simple.The barage are no solution.If only we could increase the flow in ganges ,the salinity would be washed out.It is not possible WHY???

1.The chinese are building a dam on Brahamputra in Tibet to irrigate land in their parched province.The river originates from Tibet

2.Due to global warming after initial flood (due to melting of ice) the flow would decrease and reduce to zero by 2030 A.D. due to disappearance of glaciers

3.We do not have seeds which grow in saltish water

WHAT DO WE DO????????????????

Intuitvely my first response would be to build a series off dams along the length of the Ganges....Cover the outflows in flat areas with shade cloths miles and miles long that can be rolled up quickly if cyclones threaten the cloth strucutures....Grow food etc under these shaded structures...Control flow from upstream down to ensure continuous velocity available at the huge mouth of the Ganges,the delta area.to keep salinity at bay..Perhaps massive weirs in the delta to utilize the tidal surges etc in a positive way(energy,fish farming pools etc.) instead of the negative continuously increasing salination of the waters in that area....Manage the entire river system...creatively and pray for rain regularly once the mountain glacier sources turn to a trickle....Then the shade cloth structures will be seen to be vital indeed...A difficult situation that requires broad thinking and action...and no doubt will be viewed as an insult to historical spiritual conections to this great river.Remind people that history is ongoing.Previously in humanities shared histories knowledge was hoarded by the spiritual leaders and others in power being shared grudgingly..Same with money or its equivalent of wealth declinator...To share freely of both of these commodities methinks is the way forward not just for your issue but for many that face a humanity whose back appears to be coming to a wall....Marty Wolf

Something else, we have found in our predesign of desalination plants, is that many times the cost for the safe disposal of the brine concentrate can be as expensive or more expensive than the water treatment to reover safe potable water. Also, improper disposal practices have been found, in those countries that have limited oversight and control, to damage the environment locally. You really have to consider how you do the disposal process.

there is a cheap and green technology of water desalination, i remember it since i came across it in my university days while doing a project on waves. desalination could be done by use of wave energy. if you have fairly good waves then a floating wave absorber pump can be used to push seawater against a membrane to get fresh water. the process is a bit more complicated than just that. you can also use this system to generate electricity.

http://www.topnews.in/wave-powered-water-desalination-electricity-generation-now-closer-reality-23873

in India, there were some groups building such systems.

http://www.hindu.com/2004/01/14/stories/2004011408460400.htm (dont kno how it went)

i dont have much data on this, but you can always google up "wave powered desalination plants" to get more info. this system not only allows desalination, it has zero input cost aside from initial construction and maintenance, it can also be used to generate electricity and wel you can extract the salt from the concentrated brine for other uses.

Cheers!

RAM.

Here's a way to get cheap distilled water.

Reference US patent 5,832,728 (wet compressed air or WCA). It is a means for transmitting and storing energy, as for coupling wind turbines to the users of the energy: vehicles, factories, heating and air conditioning, electric generators, etc. The turbines (or other source of energy, possibly tides, solar, whatever) compress air, which can be easily stored, unlike electricity, and used as needed. Compressed air systems are historically inefficient, about 15 per cent, but that is because they are poorly designed and air cool the compressors. The trick is to cool the compressor with water, generating steam, and the steam is used to reheat the expanding compressed air, so the thermal efficiency is nearly 100%, more efficient than an electric generator, batteries, electric motor. That was demonstrated experimentally; a diesel-pneumatic locomotive used 26% less fuel that a diesel-electric locomotive, pulling the same train over the same route on the same schedule.

Anyway, the input is mechanical energy, air, and water, which can be dirty water. The output is mechanical energy, air, and droplets of distilled water (condensed steam) which can be filtered out and used "for free." The solid residues left behind are an inconvenience, but if you want to drink the water, instead of recycling it through the compressor, it's a tolerable inconvenience.

Dear Sir,

I would recommend to look the following link (if you have the ability to dispose dry salt):

http://www.freepatentsonline.com/5598661.pdf

I can help you with contact information for the inventor.

Sincerely,