World without Water: The Dangerous Misuse of Our Most Valuab

[mistermack]

First, the drop in temperature (courtesy of the Gas Laws) causes the water to freeze, and become ice.

That didn't sound right to me, I thought that the water boiled first, and then froze, because it was using up the latent heat of evaporation, taking it directly from the water. Like in a fridge. Evaporate a liquid, and you chill it.

I found this on youtube which seems to be doing just that :



The water froze because it was a small quantity, so the temperature drop was high.
If you wanted to produce vapour, you wouldn't want it to freeze, so you would use a bigger quantity, that was as warm as possible.
Or maybe pump in warm water to keep it from freezing.

[JimC]

Solar evaporation can certainly work without expensive energy inputs, particularly in a dry, sunny region on the coast, but requires a large area to provide significant quantities of potable water.

How does that work? I can see that it's easy enough to evaporate salt water, but how do they condense it?

Evaporation is the most expensive way to treat water.
Most of the water that is discharged is lightly contaminated.
You take out the poo and the condoms, filter it, add ozone, put it through activated carbon and then back into the taps.

Not rocket science.

In our state, they are developing a system of recycling water from sewage, but it is connected to a separate reticulated system, with purple pipes and taps in new suburbs, only to be used for watering the garden.

[Calilasseia]

First, the drop in temperature (courtesy of the Gas Laws) causes the water to freeze, and become ice.

That didn't sound right to me, I thought that the water boiled first, and then froze, because it was using up the latent heat of evaporation, taking it directly from the water. Like in a fridge. Evaporate a liquid, and you chill it.

I found this on youtube which seems to be doing just that :



The water froze because it was a small quantity, so the temperature drop was high.
If you wanted to produce vapour, you wouldn't want it to freeze, so you would use a bigger quantity, that was as warm as possible.
Or maybe pump in warm water to keep it from freezing.

My mistake. I was thinking of freeze drying, but that process involves freezing the water before applying the vacuum. Which then undergoes sublimation under reduced pressure.

But the vacuum pump idea for reducing the boiling point would still work, as your video clip clearly demonstrates. And would still have the same end effect. It's just that I got my wires crossed temporarily whilst thinking about freeze drying, which involves a separate, prior refrigeration operation.

[mistermack]

I reckon in a hot climate, you might be able to combine it with air conditioning.

Circulate the cold brine through a grid and fan, to warm it back up for more evaporation, and blow the cooled air into the room.
So you cool the house, and produce fresh water in one system. Or just use radiators for heat exchange, like in winter.

[rainbow]

Solar evaporation can certainly work without expensive energy inputs, particularly in a dry, sunny region on the coast, but requires a large area to provide significant quantities of potable water.

How does that work? I can see that it's easy enough to evaporate salt water, but how do they condense it?

Evaporation is the most expensive way to treat water.
Most of the water that is discharged is lightly contaminated.
You take out the poo and the condoms, filter it, add ozone, put it through activated carbon and then back into the taps.

Not rocket science.

In our state, they are developing a system of recycling water from sewage, but it is connected to a separate reticulated system, with purple pipes and taps in new suburbs, only to be used for watering the garden.

Why not straight into the drinking water?

[mistermack]

Solar evaporation can certainly work without expensive energy inputs, particularly in a dry, sunny region on the coast, but requires a large area to provide significant quantities of potable water.

How does that work? I can see that it's easy enough to evaporate salt water, but how do they condense it?

Evaporation is the most expensive way to treat water.
Most of the water that is discharged is lightly contaminated.
You take out the poo and the condoms, filter it, add ozone, put it through activated carbon and then back into the taps.

Not rocket science.

In our state, they are developing a system of recycling water from sewage, but it is connected to a separate reticulated system, with purple pipes and taps in new suburbs, only to be used for watering the garden.

Why not straight into the drinking water?

I think the answer might be two things. One is that you have to treat it to a much higher standard for drinking, which costs more money. And two is that people wouldn't fancy drinking piss and shit water, even if it had been treated.

[rainbow]

I think the answer might be two things. One is that you have to treat it to a much higher standard for drinking, which costs more money. And two is that people wouldn't fancy drinking piss and shit water, even if it had been treated.

The expensive part is the ozonation and filtration, which you have to do whether the water is used for drinking or not.

On the psychological aspect, well I think that people need to get over this little neurosis.
Every drop of water you drink has been through the digestive system of someone else. Fact.
Do you think the water you flush simply disappears?

[mistermack]

I think the answer might be two things. One is that you have to treat it to a much higher standard for drinking, which costs more money. And two is that people wouldn't fancy drinking piss and shit water, even if it had been treated.

The expensive part is the ozonation and filtration, which you have to do whether the water is used for drinking or not.

On the psychological aspect, well I think that people need to get over this little neurosis.
Every drop of water you drink has been through the digestive system of someone else. Fact.
Do you think the water you flush simply disappears?

It wouldn't bother me. But if the general public don't like it, good luck with getting them over their neuroses.
In any case, you are asking them to accept that the water treatment will never fail. Good luck with that too.

I think they would just buy bottled water.

[cronus]

Make some into a cheap beer and let people overcome their unfounded anxiety that way? Once the beer is in circulation the drinking water will lose its negative stereotyping as piss water.

[cronus]

Make some into a cheap beer and let people overcome their unfounded anxiety that way? Once the beer is in circulation the drinking water will lose its negative stereotyping as piss water.

[rainbow]

I think the answer might be two things. One is that you have to treat it to a much higher standard for drinking, which costs more money. And two is that people wouldn't fancy drinking piss and shit water, even if it had been treated.

The expensive part is the ozonation and filtration, which you have to do whether the water is used for drinking or not.

On the psychological aspect, well I think that people need to get over this little neurosis.
Every drop of water you drink has been through the digestive system of someone else. Fact.
Do you think the water you flush simply disappears?

It wouldn't bother me. But if the general public don't like it, good luck with getting them over their neuroses.
In any case, you are asking them to accept that the water treatment will never fail. Good luck with that too.

I think they would just buy bottled water.

Let the stupid pay for their stupidity.

Why should the others pay for it?

They have been doing this for 40 years in Namibia: http://m.wpi.edu/Pubs/E-project/Availab ... Report.pdf

San Gabriel, California
San Gabriel Valley is located in southern California. It is a very arid region in California, having encountered several droughts in its history. The idea of a water treatment plant became a reality when, during a drought in the region, the aquifer was not holding enough water for the community. To gain community support, the San Gabriel Valley took several steps to inform the public. Newspaper articles and letters were mailed out to residents with a brief overview of the process and a questionnaire. The area also got support from local organizations and industries in the area that would be using the treatment plant water. Public tours of the facility were held to show that there are no secrets as to where the water is coming from, how it is being treated and
- 15 -
where it is going. The government also distributed a survey for community members to take; most of the respondents replied that they do not want to drink water that once had feces in it, even if it has been properly cleaned and purified (Zimmerman, 2008). Then, weeks before the plant was to officially open, a group of hostile residents placed an article in the newspaper and highlighted that the project contained unnecessary processes. Even though the public was aware of potential health risks associated with the reclaimed water, the government failed to disclose the specifics of these risks. The people declared the project ―Toilets to Tap‖ which ceased all desire to complete the project (Po et al., 2003). This project was defeated by members of the public who were against drinking reclaimed water and who managed to reframe the issue in ways that played upon public concerns. This defeat spread to other Californian communities, including San Diego and Los Angeles. In 2000, people in the Los Angeles area forced their city to stop a $55 million dollar project that would have provided enough water for 120,000 homes and helped with the lack of water in the area. Similar reluctance among San Diego residents led the mayor to veto the City council's approval of a pilot program to use recycled water to supplement their city drinking water, because the mayor did not want to see uproar of the citizens like in other cities throughout California (Zimmerman, 2008).

Do we Africans have to take the burden of educating the Merkins?

[mistermack]

Yeh, but in Namibia, they eat lizards and snakes and locusts too.

You might as well wash it down with a glass of piss.

[laklak]

You might as well wash it down with a glass of piss.

SNAP. I was just about to mention Bear Grylls. If you don't like piss there's always air conditioning condensate.

[JimC]

A large amount of water is used in cities parks and gardens. A reasonable compromise is to use recycled sewage (properly treated) and/or stored stormwater run-off for this, therefore saving a lot of water without causing psychological angst in the citizenry. Add some rainwater tanks for homes, and you've gone a long way towards a sustainable future.

[mistermack]

We drink plenty of Welsh piss in Gloucester.
All of the sewage treatment works upstream from Gloucester, in the Severn catchment area, put their treated water back in the Severn. Then we take it out again somewhere near Tewkesbury.

Nobody minds, once it's been mixed back into a river. If the fish can live in it, we can drink it.