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    Dry Water- How Can Water Purify Effluents!
    By Raghuveer Ramacha... | September 26th 2010 02:29 AM | 1 comment | Print | E-mail | Track Comments
    This whole week there are write-ups all over the internet about something called dry water. Ben CarterWell, originally the idea was patented in 1968, so its not out of the blue.

    But there is a new use to it. Tiny water droplets are coated with water repelling silica (abundant in beach sand) to make it dry.

    That way each drop is distinct particle and can not recombine with other droplets to form liquid. It is more than 90% water yet in the form of dry powder!

    Having a coating changes properties of water and gives it a capacity to combine with other chemicals to form something called hydrates. When improved, 'Dry' water can go through multiple cycles of uptake-release thereby making it recyclable. For a gas like methane, which is dangerous to be transported as-is, a hydrate may be much safer and easy to handle.

    Also, as an alternative to fossil fuels, methane hydrate can be used wherever gas/petrol is used! Hydrates of a lot of gases can be prepared with dry water, which will make them useful in many industries such as food, pharmaceutical and consumer products. 

    Same is possible for other gases, especially CO2. Same amount of water can hold three times more CO2 when made 'dry'. Now that global warming is a serious topic of discussion, scientists are thinking of using dry water to trap some of the green house gases, especially carbon dioxide. 

    Many industries use expensive technologies to trap certain gases. For example, ammonia in fertilizer industries, hydrogen in chemical&aerospace industries, methane in industrial production and so on. It would change the way these gases are shipped and trapped. Some of the industries spend up to 25% of their costs on effluent treatment. If same technology can be applied to make hydrates of dangerous gases in say industrial wastes, that would be great.

    Imagine a reactor where sewage is made to pass through a tank full of dry water and what comes out is recyclable water without toxic wastes, how much money would be save? How green would that be? Industrial waste water contains ammonia, hydrogen sulphide like gases and trapping them would cut the costs by half, to say the least. 

    Toxic gases like H2S or methane are the most important components in household sewage. Trapping these gases would cut costs there too. I am just waiting to see sewage treatment plants that emit no odor when you pass by them!

    Best part is that it is neither cumbersome nor expensive to make 'dry' water. So we might see a sea-change in how we store/transport hazardous gases especially because the patent is ~40 years old!

    Original Story here and here


    "A dry liquid (either pure water or a solution of something dissolved in water) can be separated back to liquid + silica by either of two methods. You can centrifuge it at high speed to force the two apart, or you can add an alcoholic solvent like methanol or ethanol. This reduces the water surface tension as the alcohol penetrates the water droplets, causing the dry liquid to fall apart.
    If you've stored a gas in DW as a gas hydrate, all you have to do to release it is warm up the material to melt the hydrate (hydrates normally form at 0 degrees C under pressure, and can be stored at -20 degrees C without the need to be kept under further pressure)"
    Ref: http://io9.com/

    So, big centrifuges, and plenty of methanol/ethanol, then....?

    or we could try alternate methods of [effluent] waste collection and treatment

    The options for dealing with our rubbish are described in the "waste hierarchy" - with those towards the top of the list more desirable than those towards the bottom.

    (image reproduced courtesy of Sligo County Council)

    Alternate sewage systems suitable for domestic use are part of the 'prevention/minimisation' end of the scale

    Industry has long needed to clean up its act, and health and safety legislation and enforcement, or lack of it, are major contributors to the current problems requiring such high tech, dry water solutions
    EU Legislation on waste water/effluent treatment (since 1991)