Environmental Science: Water Research & Technology blog

“Think you need 8 glasses of water a day? Think again.” reads an infographic on The Nature Conservancy website. All the things we consume – the food in our pantries, the clothes in our closets, the appliances in our homes and the gadgets in our pockets – have gallons of embodied water in them.

Save water by turning off lights and unplugging unused chargers

The average light bulb consumes 1.4 gallons of water per hour (Last Call at the Oasis). “Water is needed for energy production and energy is needed for water supply.” say Mekonnen et al. in their recent paper on the consumptive water footprint (WF) of electricity and heat. “The consumptive WF of electricity, expressed as the total volume of water consumed over the supply chain, per unit of gross electricity produced, primarily depends on the energy source.”

Water and energy are intimately interlinked

Recent research shows that the energy can also be produced during water treatment [1,2,3,4]. At the same time, reducing our energy consumption would also reduce our water footprint. But how much would our reduced energy consumption absolve us of our environmental sins depends on what keeps our lights on – fossil fuels, solar energy, hydroelectricity, wind energy or biofuels.

How green is renewable energy?

Renewable energy sources such as solar and hydropower are often promoted as low-carbon alternatives to fossil fuels. But Mekonnen et al. deliver some sobering news: “The WF of solar energy from CSP [concentrated solar power] is in the same order of magnitude as the WF of electricity from fossil fuels and nuclear energy, because of the need for cooling.” What does this say about massive fields of solar panels in deserts and other water stressed areas?

Wendy Wilson, Executive Director of Advocates for the West has said, “[E]ach day, enough water to meet the demands of more than 50 million people evaporates from reservoirs behind hydroelectric dams.” So what is the carbon footprint of water?

Rethinking green

Buying green and installing solar panels on our rooftops may give us the warm fuzzies, but we need to reassess what we mean by ‘green’. Of course, a single metric (such as carbon footprint or water footprint) cannot capture the complexity of the life cycle impacts of a product or a process. We need an array of complementary metrics and life cycle assessment to analyse the sustainability of renewable energy [5]. Nonetheless, Mekonnen et al. have provided ample fodder for us to chew on and think about the intertwined challenges of sustainable energy and water.

What is your water footprint?

Find out by using this personal water footprint calculator and the statistics and infographics developed by the Water Footprint Network.

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You can read the full paper for free* using the link below:

The consumptive water footprint of electricity and heat: a global assessment
Environ. Sci.: Water Res. Technol., 2015, Advance Article
Mesfin M. Mekonnen, P. W. Gerbens-Leenes and Arjen Y. Hoekstra
DOI: 10.1039/C5EW00026B

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About the webwriter

Paramjeet Pati is a PhD Candidate at the Virginia Tech Center for Sustainable Nanotechnology (@VTSuN).
You can find more articles by him in the VTSuN blog, where he writes using the name coffeemug.

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*Access is free through a registered RSC account.

The top three everyday things that still amaze me after several years of living in the developed world are 1) safe-to-drink water in the tap, 2) near-ubiquitous wireless internet, and 3) microwaveable meals. The next everyday miracle on my list would be public restrooms (or washrooms/ lavatories/ toilets, depending on which city in the developed world you are exploring).

Can’t hang up when nature calls: Let’s take a moment to appreciate that we get to go when we need to go. That the answer to our question, “Excuse me, where’s the restroom?” is usually “That way.”, instead of a potentially terrifying “What’s a restroom?”.

We see our roads, railways, bridges and dams, but the sanitation infrastructure in our “flushed and plumbed world” is quietly tucked away underground, out of sight and out of mind. We are, however, reminded how much we depend on it when we are stuck behind a long queue in front of a porta potty, or when an uncooperative toilet refuses to flush, or rebels by regurgitating its long-forgotten contents.

An “urgent, shameful issue”
Readers of the British Medical Journal chose the ‘sanitary revolution’ as the greatest medical advancement since 1840, rating it above antibiotics and anaesthesia. Despite our phenomenal scientific progress, economic growth and improved living standards in the modern world, nearly 2.5 billion people worldwide lack access to adequate sanitation, which Rose George, in her brilliant TED talk, called an “urgent, shameful issue”.

Nearly 1800 children under the age of five die every day from diarrhoeal diseases due to lack of clean water, sanitation and hygiene. “If 90 school buses filled with kindergartners were to crash every day, with no survivors, the world would take notice. But this is precisely what happens every single day because of poor water, sanitation and hygiene.”, said Sanjay Wijesekera, the Chief of Section for Water, Sanitation and Hygiene at UNICEF. Improved sanitation can decrease the occurrence of diarrhoeal diseases and reduce diarrhoea-related deaths by 37.5%.

Beyond the ick factor
Sanitation seldom features in polite dinner table conversations. But we need to bring this unmentionable topic into our collective public consciousness. And it goes beyond the direct health impacts. In a recent paper on the challenges related to sanitation, Dr. Michael Templeton said, “Health is not the only intended outcome of improved sanitation, with other objectives including ensuring personal dignity, safety, and a cleaner environment.”

Today, even developed nations face challenges to adequate sanitation. The aging sanitation infrastructures in our cities are vulnerable to financial as well and natural disasters.

Improved sanitation will require not only technological innovations, but also behavioural changes through community-led campaigns and policy innovations.  Which leads to many intriguing questions: What is Community-Led Total Sanitation (CLTS) approach? Why do well-intentioned, but narrowly focused funding programmes for sanitation interventions fail? What are the economic paybacks from improved sanitation?

Here, take my hand – let’s wade through the muck, take a deep breath, and plunge headfirst into these urgent, smelly, and icky topics by reading the full article for free^*. In the end, we will come out smelling like roses.

Pitfalls and progress: a perspective on achieving sustainable sanitation for all
Environ. Sci.: Water Res. Technol., 2015, 1, 17-21
DOI: 10.1039/C4EW00087K

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About the webwriter

Paramjeet Pati is a PhD Candidate at the Virginia Tech Center for Sustainable Nanotechnology (@VTSuN).
You can find more articles by him in the VTSuN blog, where he writes using the name coffeemug.

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*Access is free through a registered RSC account.