We need a robust circular economy for #water, our most useful resource — GreenBiz

El Torno treatment plant. Photo credit: FutureENVIRO

Here’s an in-depth look at how a circular economy for water would look from GreenBiz (Nick Jeffries & Tansy Fall). Click through and read the whole article. Here’s an excerpt:

Water is a vital resource that has fueled human progress. It transports solids, dissolves minerals, chemicals and nutrients and stores thermal energy. This “carrier characteristic” allows for countless industrial, agricultural and transport processes that enable our society to thrive.

But water is also key to life. The water in our oceans is home to phytoplankton that produce 70 percent of the oxygen we breathe. The lakes and rivers, and the groundwater beneath our feet, are our sources of drinking water without which we would soon perish. The food we eat relies on fresh water to grow.

In nature, water purifies and renews itself endlessly as it flows through the planet’s hydrological cycle. But nature’s capacity to renew on her own is being disrupted. In the last century, intensive industrial activities and urbanization have significantly affected our water supplies.

To make just one pair of jeans, for example, requires around 1,981 gallons of water and produces difficult-to-clean wastewater. With the number of clothes produced annually doubling from 50 billion to 100 billion units in the last 15 years, industrial water use in the clothing industry alone also has increased dramatically.

Extrapolating this growth across the economy, and factoring in an expanding population, it is easy to understand why the United Nations estimates that water demand will exceed easily accessible supply by 40 percent in 2040.

To make things more complex, the evolving climate emergency is leading to more unpredictable rainfall and greater frequency of extreme and unusual weather events. This has manifested as floods in South East Asia, droughts in California and Australia and wildfires in Greenland. The recent U.N. Water Policy Brief on Climate Change and Water is unambiguous on such effects: “The global climate change crisis is inextricably linked to water.”

Water is never waste

With more unpredictable weather events and increased demand for fresh water, the ways in which we use and reuse water resources have never been more important. Reimagining wastewater not as a costly problem but as a valuable resource is a good illustration of this.

One example is the El Torno wastewater treatment plant in Cadiz, southern Spain. Like thousands of similar treatment facilities across the world, El Torno receives wastewater flows from surrounding businesses and homes, which it purifies so the water can be safely discharged into the nearby river. However, an aerial view of the El Torno site shows this plant to be different from the rest.

Extending from the North West corner of the facility is a pair of very straight emerald green channels, each about 328 feet long. In these “raceways,” algae are cultivated that produce oxygen to fuel the biological treatment of the wastewater, thus almost eliminating the need for an energy supply to the facility.

To avoid suffocating the water flow, dead algae constantly are harvested and pumped to an anaerobic digester where they are converted into biogas. The gas is then scrubbed of impurities, leaving pure biomethane, which is pressurized and used to fuel a fleet of cars. Results from the full-scale pilot facility indicate that just one hectare of algae can treat the effluent of 5,000 people and produce enough biofuel to power 20 cars driving 18,600 miles a year. Although the burning of biomethane produces carbon dioxide, it releases only the same amount of CO2 that the algae absorbed while it grew. Carbon also remains in the byproducts of this process, which can be returned to the soil of local farms, meaning that the process has the possibility of being net carbon positive.

When we connect systems such as this and think of them as a whole, it is possible to transform a costly carbon emitting process into both an economic opportunity and a means of addressing a number of global challenges. The implications are significant. Wastewater treatment consumes about 3 to 4 percent of U.S. energy demand. In India, inadequate wastewater treatment, due to unreliable or expensive power, costs the Indian economy more than $50 billion a year. Imagine the positive impact that could be made if all future new wastewater treatment facilities in Africa, for example, were designed as power plants…

Regenerative action

Regenerating the environment by redesigning systems is a critical element of the circular economy. It advocates that economic activities should go beyond doing less harm, and strive for a regenerative or net-positive impact on nature. Natural systems provide us with food, oxygen and clean water, regulate our climate, absorb floods, provide recreation and much more. The WWF Living Planet Index estimates these “ecosystem services” provide humans with more than $120 trillion of benefits each year. Our current extractive and polluting economic model drastically diminishes the ability of ecosystems to provide these services.

No sector of the economy illustrates the potential for circular economy to regenerate natural systems more than agriculture. And, as farming consumes 70 percent of the planet’s freshwater, no part of the circular economy offers more to the conservation of water resources than regenerative agriculture.

Regenerative agriculture describes a broad set of food production methods with two complementary outcomes: the production of high quality food and the improvement of the natural environment. It recognizes that farms are part of a larger ecosystem, which farming activities must not just extract from, but also support. Farming in this way shifts from monoculture practices heavily reliant on chemical inputs, towards a more holistic way of thinking that cherishes diversity, encourages virtuous cycles of renewal and focuses on the health of the system as a whole.

The specifics vary, or as soil expert David Montgomery puts it: “What works for temperate grasslands may not work so well in tropical forests.” However, there are common regenerative practices that can be applied across all soil farming. These include the use of cover crops, wider crop diversity, minimizing soil disturbance and, most important, the building up of soil organic matter. For every 1 percent increase in organic matter in the top 7.9 inches of topsoil, 90 metric tons of carbon can be sequestered and an additional 38,000 gallons of water stored. This shows that regenerative agriculture is a powerful tool for climate mitigation and adaptation, while at the same time meeting demand for food.

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