Though tomes of literature on the water-energy nexus and climate change exist, the inherent message of embedded energy is either forgotten or ignored, argues David Pryce
There exists a direct correlation between water, sewage, energy and our climate, and we need to understand this, so that action and decisions are easier made. Let’s first look at particular water use and the resultant sewage creation and, then, the disturbing correlation.
For those of us who live in the Middle East, we reside in an area that includes 10 of the 17 countries in the world suffering from extremely high baseline water stress (www.earth.org). The water stress index is typically defined as the relationship between total water use and water availability (www.indicators.ucdavid.edu).
In the UAE, we are fortunate the government has invested heavily in water technologies, and initiatives and infrastructure, such as cloud seeding, dams, desalination and a good distribution network. However, in a country that has one of the highest per capita consumption of water in the world, little has been done by individuals and commercial organisations to conserve the expensively produced water and reduce unnecessary waste. Wastage and lack of conservation will not improve until such time as corporations and individuals place less importance on petty profits at any cost and greater importance on our collective environment.
Of course, you might be of the opinion that wasting water doesn’t really matter, that the government can easily produce more, but you’d be wrong, and here’s why.
In most commercial facilities, the majority of the water used is in their public bathrooms. In fact, the figure is close to 90%, according to research. Of this, 45-55% is for flush operations, 18-20% in urinals and the rest in spent in washing. Now, simply to put some scale to that, consider this: We each use the bathroom 7-8 times per day, and cistern sizes are 7-9 litres. If we take a conservative low estimate on the UAE population at eight million and a conservative low on both personal number of bathroom visits and the lowest flush of seven litres, we are flushing away 143 billion litres of potable water a year.
This is wasted water, and it comes at a heavy cost, not only to the operator but also to our environment. If commercial operators can reduce water usage, they save water and, therefore, money. However, there is a far greater positive effect on our environment and climate, and that is the reduction in embedded energy.
Almost all of our water comes from desalination, and the very act of desalination is very energy-intensive, consuming oil or gas to create steam and evaporation. But it is not just the cost of desalination itself that should concern us. Desalination plants themselves cost a lot of energy/carbon to construct, as do the distribution network, pumping houses and the large storage facilities. Growing populations put a strain on this, and so more plants and networks are built, creating an even larger carbon footprint.
That’s all upstream, but what about downstream of the bathrooms? Once the waste leaves the toilet or sink, it has to go somewhere, either directly to the sewage treatment plant or indirectly via septic tanks. This is another vast network of pumps, pipes and plants, which again require large-scale, energy-intensive resources; and yet again, the construction and day-to-day operation of this system creates a large carbon footprint.
There’s further damage done to our environment when septic tanks have to be emptied, often several times a week. Diesel-powered tankers are used to pump the sewage out of the tanks and transport it to the treatment plant. This adds to traffic congestion but, more important, harmful emissions.
Furthermore, by the nature of their operations, desalination facilities produce thousands of tons of concentrated brine, which is then pumped back into the sea or ocean, in turn causing immense harm to the delicate marine environment.
It can be seen, therefore, that the cost of the collective embedded energy in constructing and operating desalination and sewage treatment plants is extremely damaging to our total environment and, with it, the climate. It should be clear by now that reducing our water demand – and the subsequent reduction in sewage volumes – will have a significant positive effect on our planet’s health. Conversely, doing nothing about it will produce the opposite result, and a worsening climate will lead to even more water scarcity and ever greater water production and carbon footprint.
So, what, if anything, can we do about it without having to change the basic functions of our bodies or our habits – always a difficult prospect?
Commercial establishments can retrofit high-quality altered tap aerators, flow-control hoses and innovative, low-flush systems that use in the region of only 1.5 litres per flush. Collectively, these solutions will reduce the bathroom consumption by around 75-80%. To put that into perspective, for argument’s sake, let’s say we could replace every seven-litre toilet in the UAE with a 1.5-litre toilet that does the same job or better. The amount of water being flushed away would drop from 143 billion litres to only 30 billion litres, thus creating water and financial savings for the end-users and the government but, far more important, enormous reductions in embedded energy – or, as may be more apt, embedded environmental damage.
For the majority of commercial facilities, including schools, hospitals, malls and labour camps, the cost of the retrofit brings benefits in reduced maintenance and reduced utility costs with a return on investment of usually between two and four years. The government benefits due to reduced water demand and sewage treatment operations, better quality marine environment and less traffic and emissions. And finally, and by far the most important, our environment, our planet benefits immeasurably due to our combined actions on water saving and the resultant reduction in carbon.
The writer is Partner at Tellus. He may be contacted at david.pryce@tellus.ae
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