A wet revolution?

We need the right kind of help to cope with the world’s coming water crisis, says Fred Pearce Water 4.0: The past, present, and future of the world’s most vital resource by David Sedlak, Yale University Press, $28.50 A Journey in the Future of Water by Terje Tvedt, I.B.Tauris, £14.99 EVER wondered what reactivated sludge is? Or what links your local water treatment plant with chemical warfare in the trenches of the Somme? Or why the water closet put paid to sewage farms, or the rivers of Chicago run backwards? If so, David Sedlak’s Water 4.0 is your kind of book. Sedlak is an engineer and proud of it. His journey through the world of modern urban water and sewage systems – how they came about, what their failings are  and where they are headed – is concise, thorough and engaging. A professor at the University of California, Berkeley, Sedlak is unashamedly US-centric, and he is only really interested in complex urban plumbing. But most of the technologies he discusses are widely used around the world, and we all pay water bills. So we can simply substitute London for Chicago or Sydney for Los Angeles.  Sedlak is admirably clearsighted about the problems of a normally secretive and monopolistic industry, especially the drawbacks of its default chemical tool-kit. Dosing water supplies with chlorine is near universal. It has saved more lives worldwide than most technological innovations, by killing a huge range of stomach bugs and other pathogens. But some of the disinfection byproducts created can cause cancer.  To survive water shortages, nations need to rethink their supplies His chapter exploring this “chlorine dilemma” recommends adding activated carbon to water so that it removes the substances that react with chlorine to create the carcinogenic by-products. It ends with the world-weary observation that consumers might pay a few dollars more  for safer water if we were told the truth about what it contained.  But “utilities and regulators continue to insist… our drinking water is safe and healthy”. The book’s title is a simple conceit. So far urban populations have benefited from three water revolutions: the Roman invention of plumbing, chemical water treatment and safe management of sewage. Now we need a fourth water revolution to make far more efficient use of the world’s increasingly limited supplies. Here, Sedlak is realistic about the potential of desalination and other technological advances. But he sees huge potential in doing the simple things better, such as “ A fourth water revolution would help us make far more efficient use of the world’s limited supplies"

recycling roof water, improving urban run-off and routing flood flows back into water supply systems. Here, he concedes, they are much further ahead in Singapore than Santa Monica.  Sedlak’s exemplary study of urban water is too narrow in its focus to be a primer for the coming global water crisis. For a start, he leaves out the billions of people living in poor rural communities, as well as the world’s main user  of water: agricultural irrigation, which consumes two-thirds of  the water we take from nature.  I had hoped to find that global perspective in Terje Tvedt’s A Journey in the Future of Water. Sadly, Tvedt, a Norwegian geographer, promises much but delivers little. He has travelled the world to visit water systems from the Nile to the Ganges and Las Vegas to Lourdes. He has seen the mega projects – the big dams and irrigation schemes, the canals  and flood defences – and spoken to their engineers and puffed-up political backers. But he saw them for a series of  TV programmes he presented – and it shows. The result is a travelogue, with no depth, no analysis and no perspective. This is made all the more irritating by his style of reportage, where he tells us more about his eating habits than what he thinks about the politics of water. Just as we get to the crux of an issue, the chapter is over. Worse, it is out of date. The book is a 2014 translation of one published in Norway in 2007. Surely the publisher could have asked for updates? That isn’t good enough.  ■