28 Aug We have enough water. How to make it potable?
As populations grow, it’s getting harder and harder to ensure sufficient safe water supplies for everyone. And with climate change and the degradation of nature, we cannot simply take more water from lakes, rivers and aquifers. We need to actively manage the full water cycle from a water sustainability perspective. From fresh water abstraction, pre-treatment, distribution, use, collection and post-treatment, to the use of treated wastewater and its eventual return to the environment, ready for the cycle to start over.
Repurpose our wastewater
One way to manage our fresh water better is to be smarter about managing wastewater. Globally, 80% of wastewater goes back into the ecosystem without being treated or reused. The drinking water of some 1.8 billion people puts them at risk of cholera, dysentery, typhoid and polio. But suppose that instead of flushing raw wastewater into drains and channels, we repurposed it to help us meet the growing demand for water in our increasingly urbanising society? Wouldn’t that be a huge step forward? Well, we can.
Wastewater, intelligently managed, can play a major role in meeting the growing water demand in our rapidly expanding cities. It can be used to enhance energy production and industrial development. It can support sustainable agriculture.
Take cities. Why use drinking water for irrigating public spaces and cleaning streets, when we could be using clean but not potable wastewater instead? Treating wastewater according to intended usage can make recovery more cost effective.
Then there’s industry. Industry accounts for 22% of global water use. But that average hides some dramatic differences. Industry’s share of water use is roughly 50% in developed countries, but only 4-12% in developing countries. The latter figure is expected to rise quickly. The more businesses reuse their wastewater internally, or share it with other industries nearby, the better for everyone. Opportunities include using process water for heating or cooling, and rainwater for toilet flushing, irrigation or washing vehicles.
And finally, there’s agriculture. The growing use of chemical fertilizers and pesticides makes agriculture an increasing source of potential environmental pollution. Pollution of ground and surface water caused by the release of untreated or inadequately treated agricultural wastewater is a major issue in many developing countries. But, with the appropriate treatment, wastewater can supply both much-needed water and valuable nutrients. This would improve food security and standards of living.