The world’s wastewater – 80 percent of which is released into the environment without adequate treatment – is a valuable resource from which clean water, energy, nutrients, and other resources can be recovered, according to a recent World Bank report released.
The report, Wastewater: From Waste to Resource, calls for smarter wastewater management, including reuse and resource recovery, and looks at wastewater projects around the world which have paid dividends for people, the environment, and economies in the short and long-term.
Efficiently investing in wastewater and other sanitation infrastructure is crucial to achieve public health benefits, improve the environment, and enhance quality of life. Safely managed water, sanitation and hygiene (WASH) services are an essential part of preventing disease and protecting human health during infectious disease outbreaks, including the current COVID-19 pandemic.
Efficiently investing in wastewater and other sanitation infrastructure is crucial to achieve public health benefits
“At a time when 36 percent of the world’s population lives in water-scarce regions, wastewater treatment for reuse is part of the solution to water scarcity and pollution problems,” said Jennifer Sara, Global Director, World Bank Water Global Practice. “Once treated, it can be used to replace freshwater for irrigation, industrial processes, or recreational purposes. It can also be used to maintain the environmental flow and by-products from its treatment can generate energy and nutrients.”
Wastewater treatment offers a double value proposition, the report says. In addition to environmental and health benefits, wastewater treatment can bring economic benefits through reuse in different sectors. Its by-products, such as nutrients and biogas, can be used for agriculture and energy generation. And additional revenues generated from this process can help cover water utilities’ operational and maintenance costs.
“In this sense, wastewater should not be considered a ‘waste’ anymore, but a resource. This is at the core of a circular economy, an economic system aimed at minimizing waste and making the most of resources. As cities continue to grow, future urban development requires approaches that minimize resource consumption and focus on resource recovery, following principles of the so-called circular economy,” said Diego Juan Rodriguez, the report’s author and a Senior Water Resources Management Specialist at the World Bank. “One of the key advantages of adopting circular economy principles in wastewater management is that resource recovery and reuse could transform sanitation from a costly service to one that is self-sustaining and adds value to the economy. This will help countries bridge the funding gap in sanitation to achieve the Sustainable Development Goals.”
Wastewater treatment for reuse is part of the solution to water scarcity and pollution problems
The report casts a light on wastewater management experiences in the Latin America and Caribbean (LAC) region, which are already reaping benefits. For example:
By using treated wastewater instead of groundwater, the San Luis Potosi power plant in Mexico cut costs by 33 percent, leading to US$18 million in savings over six years for the power utility. For the water utility, the additional revenue from selling treated wastewater helped cover operations and maintenance costs.
A wastewater treatment plant in Cusco, Peru, saves US$230,000 a year in transporting biosolids (nutrient-rich organic materials resulting from the treatment of domestic sewage in a wastewater treatment facility) and landfill fees due to an agreement with the local compost producer. The compost produced with the plant’s biosolids is then used as part of the water management project to preserve the Piuray Lake.
The Brazil-based CAESB water and wastewater utility’s use of biosolids for corn production led to higher-than-average grain yields and was 21 percent more efficient than mineral fertilizers.
The operator of the La Farfana wastewater treatment plant in Santiago, Chile, after investing US$2.7 million to retrofit the plant, was able to sell biogas, accounting for an annual net profit of US$1 million for the business.
The report recommends incorporating wastewater interventions as part of river basin planning, and pairing them with policies, institutions and regulations that foster this paradigm shift. Wastewater treatment plants need to be gradually repurposed as water resource recovery facilities, while also exploring and supporting innovative financing and sustainable business models that leverage the potential revenue streams of resource recovery from wastewater.
The report shows what’s possible when governments at all levels apply circular economy principles to their wastewater challenges
Only 30 to 40 percent of the LAC region’s collected wastewater is treated, resulting in negative impacts on both human health and the environment.
The report shows what’s possible when governments at all levels apply circular economy principles to their wastewater challenges. For example, in the city of La Paz, Bolivia, the national and municipal governments, as well as the water utility, with support from the World Bank and other development partners, are working together to incorporate circular economy principles in the design of the La Paz wastewater treatment plant. The goal is to address water pollution and public health issues caused by low levels of wastewater treatment and unregulated use in agriculture.
“We are happy to see that the necessary transformation is well under way – wastewater policies in many countries already include reuse and resource recovery, and we hope more countries will follow suit. Countries need to scale up action,” said Rodriguez.