Water is essential to life, making it one of the most valuable resources on the planet. We drink it, use it to grow food and stay clean. However, water is of increasingly short supply and the Earth’s population only continues to expand. Many of the countries with the largest populations are also ones that use the most water. For instance, in the United States, the average person uses 110 gallons of water each day. Meanwhile, three-fourths of those living in Africa don’t have access to clean water.
To ensure we have enough water to survive — and share with those in need — the best approach is to conserve this resource and find sustainable ways of recycling it. Currently, conventional methods or water purification use about three percent of the world’s energy supply. This isn’t sustainable long-term and can have adverse effects on the environment.
Recently, however, major steps have been made to reduce both the collective water and carbon footprint. Now, there are multiple, sustainable ways to both save energy and reuse water using renewable energy.
1. Anaerobic Digestion
Anaerobic digestion — or AD — is the natural process in which microorganisms break down organic materials like industrial residuals, animal manure and sewage sludge. This process takes place in spaces where there is no oxygen, making it an ideal system for cleaning and reusing wastewater. This recycled water can provide nutrients for forest plantations and farmland alike.
For example, in Yucatan, Mexico, the successful implementation of AD systems has provided water to promote reforestation efforts. This system has also helped accelerate the search for a sustainable solution to water-sanitation issues in rural Latin American communities.
Additionally, anaerobic digestion also reduces adverse environmental impacts. As the system filters water, it creates two byproducts — biogas and sludge. The biogas can be used as energy to supply electricity or even fuel vehicles. And the sludge is used as fertilizers and bedding for livestock. In poor countries, like Peru, 14 percent of primary energy comes from biogas, providing heat for food preparation and electricity to homes that would not have access to it otherwise.
2. Vapor Compression Distillation
In this process, the vapor produced by evaporating water is compressed, increasing pressure and temperature. This vapor is then condensed to water for injection — highly purified water that can be used to make pharmaceutical-grade solutions.
Vapor compression distillation is incredibly sustainable because it can produce pure water on combustible fuel sources like cow dung — no chemicals, filters or electricity necessary. This makes it water accessible to even the most rural communities.
The system only needs enough energy to start the first boil and a small amount to power the compressor. This energy can be easily supplied by a solar panel, producing roughly 30 liters of water an hour using no more energy than that of a handheld hairdryer.
3. Solar Distillation
Utilizing solar energy for water treatment may be one of the most sustainable solutions to the water crisis, without sacrificing the environment or non-renewable resources. Between 80 and 90 percent of all energy collected through commercial solar panels is wasted, shed into the atmosphere as heat. However, recent advancements in technology have allowed scientists to capture this heat and use it to generate clean, recycled water.
By integrating a solar PV panel-membrane distillation device behind solar panels, researchers were able to utilize heat to drive water distillation. This panel also increases solar to electricity efficiency. This device can even be used to desalinate seawater, providing a sustainable solution to generating freshwater from saltwater.
Environmental and Economic Benefits
Finding sustainable methods of recycling water is essential to reducing energy consumption and helping the planet, and all those dependent upon it, thrive. Using methods like anaerobic digestion and environmentally-friendly distillation processes can reduce toxic emissions and provide purified, recycled water to those who need it most.
Sustainable reuse of water can also benefit the economy. The financial costs of constructing and operating desalination and purification systems are often high compared to the above solutions. Furthermore, using recycled water that is of lower quality for agricultural and reforestation purposes saves money by reducing treatment requirements.