Coming from the Land of Droughts and flooding rains one of the things that I noticed immediately when arriving in New York was the use of water. As I walked to my accommodation early on the morning of our arrival we dodged puddles and hoses as the sidewalks out the front of buildings where hosed and scrubbed. Such a thing is almost abhorrent to me as currently in a great deal of Australia one can not even water their lawn let alone water down the side walk. Any such efforts can result in a fine.
Obviously there is a need to maintain a level of cleanliness is an area as densely populated as Manhattan and the New Yorker that I was staying with was quick to point out is that if the sidewalk isn't kept clean then the building can get 'cited' for not maintaining it. While a few of the buildings where using high pressure cleaning systems which by there very nature use less water, a great deal of the cleaning that I saw was being down with hoses that didn't even have nozzles on them.
The second thing that I noticed was sprinklers running all over the place, in the middle of the day, quite often spraying water into puddles or big pools of mud, indicating that they had been running quite a while. I guess to most people that this wouldn't seem weird or even particularly wasteful. But again, it is one of those things that you just wouldn't see in Australia at the moment. I live in Melbourne and until a couple of months ago the only time I was allowed to water with a sprinkler system was between Midnight and 2 AM on two days of the week. This has since been relaxed to being able to water between midnight and 8AM on two days of the week. Otherwise watering was to be done by hand held hose, again only on two days of the week and never between 8 AM and 8 PM. So to see giant puddle forming displays of sprinklers all over the place in the middle of the day struck me as odd.
The third thing I noticed is the ridiculous amount of water that is present in an American toilet, to the point of making the passing of a large meal from the night before dangerously likely to incur splash back and an over enthusiastic wipe can result in a handful of soggy paper. I did not see one half flush toilet anywhere in New York. Also, the majority of urinals that I visited flushed on approach and often departure, each flush taking at least a gallon of water. No where in New York did I see a waterless urinal or seemingly even a timed flush urinal.
Now I contrast this to Boston, the first bathroom I used has waterless urinals and a sign on the wall explaining why the new taps that where fitted where good (sensor activated, temperature controlled) at conserving both energy and water. This theme was reflected across the town, never did I see a sidewalk or pavement getting hosed down, nor did I see sprinklers running during the day. I did see some sprinklers running at night. There where many water less urinals and there seemed to be an awareness across the city of the need to conserve water and energy. An awareness that I didn't see any where in New York. Indeed the only energy conservation awareness that I saw was the news discussing shops being fined for having doors open with their air conditioning on. They where using it as a gimmick to pull in customers during the heatwave conditions.
I shall finish this post with a disclaimer, I am sure that there are people and venues in New York that are concerned about their water usage, I just didn't see them.
Showing posts with label Water. Show all posts
Showing posts with label Water. Show all posts
Friday, July 23, 2010
Friday, July 2, 2010
Why we should recycle instead of Desalinating!
So previously I discussed the links between energy and water in modern society, in particular the costs of desalination.
Today I just wanted to give a short comparison between recycling water (and yes recycling sewage) and desalination. Basically the only reason that Australia's major cities have desalination plants is because people are a little squeamish. Or to put it another way because people are stupid. If you tell someone that the resulting output is cleaner and less contaminated than regular water they still won't touch it, the problem is that it is psychologically dirty. People think that it is dirty and can't drink it.
The problem is people don't think further than that. The reality is that if you live in a country town (or Adelaide for that matter) then you'll probably be drinking 'recycled' water and not really think about it. The difference here is that somewhere further upstream some towns "output" has been cleaned etc and then squirted into the river, then the downstream town pumps this out of the river, processes it etc and pumps it around town as its water supply.
The difference with places like Sydney and the Gold Coast is that that process would be short circuit the "psychological cleansing" that shoving the water into a river and pumping it out again is removed. What people don't understand is that it makes no difference. What is equally silly if you think about it is that this is what is happening in Sydney anyway, they pump the shit out the "deep water outlet" and then suck in sea water for the desalination plant....
I'd love to think that if people knew a few things about it they would want to chose recycling water over desalination anyway. One it is a heap more efficient to recycle water than to desalinate it and two the recycled water is actually a lot cleaner.
To take the first point the efficiency of recycling lets consider Singapore, arguably the most advanced country in terms of both desalination and water recycling technology. Their most efficient desalination plant uses 3 MWh/ML where as their most efficient recycling plant uses 0.7MWh/ML to produce drinking water.
To the second point, again using Singapore as an example, several Silicon processing companies have relocated operations to Singapore because of the reduced costs that surround using the recycled water output. Silicon processing, specifically the production of wafers for semiconductors, requires very pure water. Singapore supplies this companies with output direct from their recycled water plants that is so clean they can vastly cut down on the amount of processing that they do on the water before it is used in their processes.
Finally, and this applies to both Sydney and South East Queensland the power requirements of desalination place such an additional burden on the power systems that we will not be able to meet it without considerable investment in power supply and generation infrastructure. When you factor in the increased water bill to subsidize the construction and then operating costs of the new water plant and the increased power costs for the infrastructure and new generation capacity there will be a serious impact of the desalinized water on the consumer.
Perhaps this hip pocket impact will make people rethink the "Desalination is King" mantra and reconsider both recycled water and storm water capture technologies.
SOURCE: IEEE Spectrum 6.10
Today I just wanted to give a short comparison between recycling water (and yes recycling sewage) and desalination. Basically the only reason that Australia's major cities have desalination plants is because people are a little squeamish. Or to put it another way because people are stupid. If you tell someone that the resulting output is cleaner and less contaminated than regular water they still won't touch it, the problem is that it is psychologically dirty. People think that it is dirty and can't drink it.
The problem is people don't think further than that. The reality is that if you live in a country town (or Adelaide for that matter) then you'll probably be drinking 'recycled' water and not really think about it. The difference here is that somewhere further upstream some towns "output" has been cleaned etc and then squirted into the river, then the downstream town pumps this out of the river, processes it etc and pumps it around town as its water supply.
The difference with places like Sydney and the Gold Coast is that that process would be short circuit the "psychological cleansing" that shoving the water into a river and pumping it out again is removed. What people don't understand is that it makes no difference. What is equally silly if you think about it is that this is what is happening in Sydney anyway, they pump the shit out the "deep water outlet" and then suck in sea water for the desalination plant....
I'd love to think that if people knew a few things about it they would want to chose recycling water over desalination anyway. One it is a heap more efficient to recycle water than to desalinate it and two the recycled water is actually a lot cleaner.
To take the first point the efficiency of recycling lets consider Singapore, arguably the most advanced country in terms of both desalination and water recycling technology. Their most efficient desalination plant uses 3 MWh/ML where as their most efficient recycling plant uses 0.7MWh/ML to produce drinking water.
To the second point, again using Singapore as an example, several Silicon processing companies have relocated operations to Singapore because of the reduced costs that surround using the recycled water output. Silicon processing, specifically the production of wafers for semiconductors, requires very pure water. Singapore supplies this companies with output direct from their recycled water plants that is so clean they can vastly cut down on the amount of processing that they do on the water before it is used in their processes.
Finally, and this applies to both Sydney and South East Queensland the power requirements of desalination place such an additional burden on the power systems that we will not be able to meet it without considerable investment in power supply and generation infrastructure. When you factor in the increased water bill to subsidize the construction and then operating costs of the new water plant and the increased power costs for the infrastructure and new generation capacity there will be a serious impact of the desalinized water on the consumer.
Perhaps this hip pocket impact will make people rethink the "Desalination is King" mantra and reconsider both recycled water and storm water capture technologies.
SOURCE: IEEE Spectrum 6.10
Tuesday, June 29, 2010
Water vs Energy: The Balancing Act
Water and Energy are very tightly integrated in modern human society.
You can not create energy without water, whether it is directly driving hydroelectric turbines or being boiled to drive a steam turbine or more likely being used to cool the systems.
You can not get water without using energy, if you're lucky enough to live next to a pristine stream you're going to need to pump it out, otherwise you have to process it, or pump it great distances.
A great example of this in Australia, that has received a lot of attention is desalination (particularly if you are a Sydney sider). Desalination requires A LOT of energy and when I say a lot I mean a lot! Currently it takes around a top of the line efficient reverse osmosis filtering plant around 5 MWh of electricity to generate 1 ML of water, or around 1.25 Wh to get your glass of water filtered. And if you consider an old school thermal desalination plant it takes around 80MWh/ML or around 20 Wh per glass of water.
Now when you consider that the majority of energy in Australia is generated using coal fired power stations, cooled with cooling towers then we need to factor in the water cost of generating the electricity it takes roughly 1900 L of cooling water to generate a MWh of electricity.
Further to the water cost of the electricity we need to consider the waste water from the desalination plant. The most efficient RO plants have water usage efficiencies of around 48% (which means 52% of the water that enters a desalination plant leaves as waste water) and generally the efficiency is more likely to be down in the mid to high 30s. So if we take the most efficient plant around then for every ML of clean water that is produced there is 1.083 ML of dirty water produced.
So basically for your glass of water you'll be using 1.25 Wh and 273 mL if you're getting it via desalination. If you don't happen to live at the desalination plant then there'll be additional energy that is required to pump the water to your location and further if the desalination plant isn't co-located with the power plant then transmission losses of around 20% need to be factored into the equation as well.
SOURCE: IEEE Spectrum 6.10
A great example of this in Australia, that has received a lot of attention is desalination (particularly if you are a Sydney sider). Desalination requires A LOT of energy and when I say a lot I mean a lot! Currently it takes around a top of the line efficient reverse osmosis filtering plant around 5 MWh of electricity to generate 1 ML of water, or around 1.25 Wh to get your glass of water filtered. And if you consider an old school thermal desalination plant it takes around 80MWh/ML or around 20 Wh per glass of water.
Now when you consider that the majority of energy in Australia is generated using coal fired power stations, cooled with cooling towers then we need to factor in the water cost of generating the electricity it takes roughly 1900 L of cooling water to generate a MWh of electricity.
Further to the water cost of the electricity we need to consider the waste water from the desalination plant. The most efficient RO plants have water usage efficiencies of around 48% (which means 52% of the water that enters a desalination plant leaves as waste water) and generally the efficiency is more likely to be down in the mid to high 30s. So if we take the most efficient plant around then for every ML of clean water that is produced there is 1.083 ML of dirty water produced.
So basically for your glass of water you'll be using 1.25 Wh and 273 mL if you're getting it via desalination. If you don't happen to live at the desalination plant then there'll be additional energy that is required to pump the water to your location and further if the desalination plant isn't co-located with the power plant then transmission losses of around 20% need to be factored into the equation as well.
SOURCE: IEEE Spectrum 6.10
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