Recycling water
Think the answer to Australia's chronic water shortage is to build desalination plants? Think again - we can reclaim huge amounts of water by being smarter with our use of it and building recycling plants at a fraction of the cost.
A few days ago on ABC radio Margaret Throsby interviewed Associate Professor Greg Leslie about water recycling. If you click on the title of this blog entry it will start the Windows Media stream of the one hour long interview.
After listening to the interview I wouldn't have any hesitation about using recycled water.
There's a lot of emotion in the community about acceptance of using recycled water, with many people assuming that if something went wrong in the process instead of having clean drinkable water coming from the taps that there would chunks of someone else's turds plopping out.
Very much not the case, according the AP Leslie.
The economics of water recycling are so much better than 'making' drinkable water by desalination. He makes the point that Singapore, which is very largely dependant on Malaysia for its water supply, had done a study and budgeted for building something like 6 desalination plants to meet its water requirements. After building one desalination plant at a cost of something like one billion dollars, Singapore has met much of its clean water requirements by building recycling water treatments plants for much less cost than building desalination plants.
Recycled water can be used not only for domestic consumption but also for business and industry. The recent South Australian government water restrictions limiting for how long and when people can water their gardens and use sprinklers is somewhat of a joke. I don't know the figures, but do domestic sprinklers and garden watering tip the balance of water use in this state? I'm thinking that commercial, industrial, and agricultural users make much more of an impact on use of our water supplies. But we are doing our little bit - I figure the bucket of water collected in the shower must put, what, about 9 litres of water back into the system daily. Just think if everyone in Adelaide collected a bucket of shower over spray and dumped it onto their lawn or garden. Heck, within, I don't know, a few years, we might equal what one golf course uses in a day or two.
AP Leslie said that in Singapore industry there actually loves using recycled water as it is so clean. The silicon chip in your mobile phone takes something like 200 litres of water in the process of making the chip. Using recycled water is a great application for this industry.
A long time ago when I was in the Navy I did temporary duty on a submarine tender, operating a 'pure distilled water' plant that supplied very clean water to submarines for use in their batteries (diesel boats) or reactors (nuke boats.) In this case it was normal 'tap' water used that was forced through a serious filtration system to remove all minerals and salts. The result was water that would make you sick if you drank it as everything except 'the water' was taken out from it. I'm guessing that as that water had no salts or minerals in it that if you drank it the water in your body would give-up those salts and minerals in an effort to equalise the pure water, leaving your body depleted of those salts and minerals.
In the interview with AP Leslie he makes the point that the filtration process used in treating waste water to become recycled water is already widely used by beverage makers who need to make a consistent taste of their product. For example, a maker of beer like CUB has a product called Victoria Bitter that derives a part of its ultimate taste by the characteristics of the water used to make it. The water in Melbourne tastes different than the water in Brisbane because the mineral content varies between the two waters. So companies like CUB filter the water they use to make beer and before the water is used exact amounts of calcium, sodium and other salts and minerals are added back to make it taste exactly the same as how it would be in Melbourne, for example.
So when someone does a public display of drinking recycled water and claims that they can't tell the difference in taste between the recycled water and tap water that's why - the recycled water has been treated after filtration, disinfection and cleaning so that its mineral content matches that of the tap water. Thank heavens that the operators of Adelaide's water supply have cleaned-up our tap water to the extent that they have - back in the mid 1990's the bath tub was brown with sediment from the tap water, our water smelled nasty, and tasted very bad. Not so now. Well done Adelaide's water operators.
Even Dr Karl makes that point that all of the water we use on the planet is 'recycled' in that there is a finite amount of water in our global ecosystem and we just keep reusing it (rain falls, we collect a little of it, use it, flush it down the drain, it gets treated, then fed back into the water system: put back into a river for inland communities, or dumped to the sea for coastal communities; it evaporates into the atmosphere, comes back to us as rain or snow, and the cycle repeats.) Can we 'make' new water by combining hydrogen and oxygen? Yes, but the energy cost to do so is prohibitive.
If we build desalination plants but only 'use' the water once before returning it to the sea we are really not being smart. Apparently a number of years ago the aluminium industry realised that to be cost competitive with other packaging technologies that they had to use recycling in their manufacturing mix. It costs something like 14 times as much to make a new chunk of aluminium than it does to make the same chunk by recycling aluminium scrap. Water provide a similar story - recycling costs less.
< soapbox>
Recycling costs less. Listen to the interview, learn the facts about recycling water. We can be a lot smarter with our resources.
< /soapboax>
So, chattering politicians, what are you doing for us with water recycling projects and plans? I can only carry that bucket of shower water down to the garden so often!
Rick Clise
P.S. If you don't have Windows Media Player there is a Real Audio version of the interview is found here and details about the interview are found here.
A few days ago on ABC radio Margaret Throsby interviewed Associate Professor Greg Leslie about water recycling. If you click on the title of this blog entry it will start the Windows Media stream of the one hour long interview.
After listening to the interview I wouldn't have any hesitation about using recycled water.
There's a lot of emotion in the community about acceptance of using recycled water, with many people assuming that if something went wrong in the process instead of having clean drinkable water coming from the taps that there would chunks of someone else's turds plopping out.
Very much not the case, according the AP Leslie.
The economics of water recycling are so much better than 'making' drinkable water by desalination. He makes the point that Singapore, which is very largely dependant on Malaysia for its water supply, had done a study and budgeted for building something like 6 desalination plants to meet its water requirements. After building one desalination plant at a cost of something like one billion dollars, Singapore has met much of its clean water requirements by building recycling water treatments plants for much less cost than building desalination plants.
Recycled water can be used not only for domestic consumption but also for business and industry. The recent South Australian government water restrictions limiting for how long and when people can water their gardens and use sprinklers is somewhat of a joke. I don't know the figures, but do domestic sprinklers and garden watering tip the balance of water use in this state? I'm thinking that commercial, industrial, and agricultural users make much more of an impact on use of our water supplies. But we are doing our little bit - I figure the bucket of water collected in the shower must put, what, about 9 litres of water back into the system daily. Just think if everyone in Adelaide collected a bucket of shower over spray and dumped it onto their lawn or garden. Heck, within, I don't know, a few years, we might equal what one golf course uses in a day or two.
AP Leslie said that in Singapore industry there actually loves using recycled water as it is so clean. The silicon chip in your mobile phone takes something like 200 litres of water in the process of making the chip. Using recycled water is a great application for this industry.
A long time ago when I was in the Navy I did temporary duty on a submarine tender, operating a 'pure distilled water' plant that supplied very clean water to submarines for use in their batteries (diesel boats) or reactors (nuke boats.) In this case it was normal 'tap' water used that was forced through a serious filtration system to remove all minerals and salts. The result was water that would make you sick if you drank it as everything except 'the water' was taken out from it. I'm guessing that as that water had no salts or minerals in it that if you drank it the water in your body would give-up those salts and minerals in an effort to equalise the pure water, leaving your body depleted of those salts and minerals.
In the interview with AP Leslie he makes the point that the filtration process used in treating waste water to become recycled water is already widely used by beverage makers who need to make a consistent taste of their product. For example, a maker of beer like CUB has a product called Victoria Bitter that derives a part of its ultimate taste by the characteristics of the water used to make it. The water in Melbourne tastes different than the water in Brisbane because the mineral content varies between the two waters. So companies like CUB filter the water they use to make beer and before the water is used exact amounts of calcium, sodium and other salts and minerals are added back to make it taste exactly the same as how it would be in Melbourne, for example.
So when someone does a public display of drinking recycled water and claims that they can't tell the difference in taste between the recycled water and tap water that's why - the recycled water has been treated after filtration, disinfection and cleaning so that its mineral content matches that of the tap water. Thank heavens that the operators of Adelaide's water supply have cleaned-up our tap water to the extent that they have - back in the mid 1990's the bath tub was brown with sediment from the tap water, our water smelled nasty, and tasted very bad. Not so now. Well done Adelaide's water operators.
Even Dr Karl makes that point that all of the water we use on the planet is 'recycled' in that there is a finite amount of water in our global ecosystem and we just keep reusing it (rain falls, we collect a little of it, use it, flush it down the drain, it gets treated, then fed back into the water system: put back into a river for inland communities, or dumped to the sea for coastal communities; it evaporates into the atmosphere, comes back to us as rain or snow, and the cycle repeats.) Can we 'make' new water by combining hydrogen and oxygen? Yes, but the energy cost to do so is prohibitive.
If we build desalination plants but only 'use' the water once before returning it to the sea we are really not being smart. Apparently a number of years ago the aluminium industry realised that to be cost competitive with other packaging technologies that they had to use recycling in their manufacturing mix. It costs something like 14 times as much to make a new chunk of aluminium than it does to make the same chunk by recycling aluminium scrap. Water provide a similar story - recycling costs less.
< soapbox>
Recycling costs less. Listen to the interview, learn the facts about recycling water. We can be a lot smarter with our resources.
< /soapboax>
So, chattering politicians, what are you doing for us with water recycling projects and plans? I can only carry that bucket of shower water down to the garden so often!
Rick Clise
P.S. If you don't have Windows Media Player there is a Real Audio version of the interview is found here and details about the interview are found here.
posted by Rick's Rambles at 7:22 AM
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