The Rise of Nature-Based Solutions
As the world grapples with the pressing issue of wastewater management, a growing trend has emerged that holds immense promise – the integration of nature-based solutions (NbS) into conventional treatment systems. These innovative approaches leverage the power of natural ecosystems to address societal challenges effectively and adaptively, while simultaneously providing benefits for human well-being and biodiversity.
I’ve been fascinated by the potential of NbS ever since I came across a fascinating article that delved into the practical experiences of integrating these nature-inspired solutions into wastewater treatment. It’s truly remarkable how these sustainable, low-cost, and low-impact methods can transform the way we manage our water resources.
Rediscovering the Power of Nature
For centuries, communities across the world have been discharging wastewater directly into surface waters, which has led to the natural development of wetlands. These wetlands, formed by the accumulation of biosolids and nutrients, have an incredible ability to reduce pollutant loads to receiving waters. It’s a testament to the inherent resilience and purification capabilities of natural ecosystems.
However, as populations have grown and landscapes have changed, we’ve seen a shift towards more conventional wastewater treatment plants that rely on a combination of physical, chemical, and biological processes to remove solids, organic matter, and nutrients. While these technologies have become increasingly sophisticated, they often operate as an “end-of-the-pipe” solution, overlooking the potential of integrating nature-based approaches.
Unlocking the Advantages of NbS
The potential of nature-based solutions is becoming increasingly recognized, and for good reason. These approaches, which utilize plants, soil bacteria, and other natural elements and processes, offer a range of benefits that go beyond just treating wastewater.
In the context of wastewater management, NbS such as treatment wetlands, ponds, lagoons, and soil infiltration processes have been actively used as reliable and economically efficient technologies for decades. These systems not only deliver the primary function of treating wastewater, but they also offer a wealth of co-benefits that can generate greater overall societal advantages.
These co-benefits include:
– Improvement of water quality: NbS can effectively remove pollutants and improve the quality of the treated wastewater, protecting downstream water bodies.
– Social and environmental benefits: NbS can provide recreational areas, enhance urban microclimates, mitigate floods and storms, and support biodiversity.
– Biomass production: Some NbS, like willow systems, can produce valuable woody biomass that can be used for energy or soil amendment purposes.
– Water reuse: Treated wastewater from NbS can be safely reused for irrigation, toilet flushing, and other non-potable applications, reducing the demand on freshwater resources.
The versatility of NbS is truly remarkable, as they can be tailored to meet the specific needs and conditions of a particular location. Whether it’s a dense urban area, a peri-urban setting, or a rural community, there are NbS options that can be effectively integrated into the wastewater management infrastructure.
Innovative NbS Approaches in Action
Let’s explore some real-world examples of how NbS are being integrated into wastewater treatment systems:
Slow-Rate Soil Infiltration in Lubbock, Texas
In the city of Lubbock, Texas, slow-rate soil infiltration has been used as a cost-effective treatment method since the 1930s. By applying municipal wastewater to agricultural lands, the system not only treats the water but also reduces the demand on freshwater resources from surface water and groundwater. This approach has demonstrated the potential of NbS to improve climate resilience in the face of increasing water scarcities.
Vertical-Flow Treatment Wetlands in Shenzhen, China
In Shenzhen, China, a vertical-flow treatment wetland was designed as a polishing step to meet environmental standards. The treated wastewater is intermittently loaded onto the surface of the filter, where it percolates vertically through the system. This low-cost option not only improves water quality but also provides a green recreational area for the local residents and increases biodiversity along the Pingshan River. The wetland system also helps regulate floods, control stormwater, and sequester carbon.
Green Walls and Green Roofs in Urban Areas
In dense urban areas, innovative NbS like green walls and green roofs are being used to treat greywater, which can then be reused for irrigation and toilet flushing. These systems not only provide water treatment and reuse benefits but also offer heat mitigation, building insulation, and improved aesthetics. A demonstration project in Tilburg, the Netherlands, combined a green roof and a treatment wetland to reuse wastewater locally, while also regulating the building’s temperature and reducing urban flooding.
Willow Systems in Peri-Urban and Rural Settings
Another NbS approach suitable for peri-urban or rural settings is the use of willow systems, which are treatment wetlands dominated by willows. These systems are designed to treat all inflow water through evapotranspiration, resulting in zero discharge. The biomass produced by the willows can be used for energy purposes or as a soil amendment, while the system also provides habitat for flora and fauna and flood mitigation. An example of a successful application is on Zeeland Island, Denmark, where a zero-discharge willow system has been treating wastewater for a community of 190-250 person equivalents since 2017.
Navigating the Pathway to NbS Integration
While the benefits of integrating NbS into wastewater management are clear, it can still be challenging for wastewater utility managers to determine the best approach. Factors like the type or combination of NbS, the quantity and quality of water to be treated, and local conditions like climate and precipitation patterns all need to be carefully considered.
To help navigate the options, a web-based tool is under development that includes information on different NbS technologies, as well as case studies from around the world. This tool can raise awareness and deepen understanding of the viable NbS options and the requirements for their implementation.
The Policy Landscape and the Future of NbS
The integration of NbS into wastewater management is not just a grassroots movement; it’s also gaining traction at the policy level. Within the European Commission, NbS have been a part of the Horizon 2020 program, a financial instrument that promotes the alignment of biodiversity and ecosystem services with goals of innovation, growth, and job creation.
The World Bank has also integrated NbS into more than 100 projects across 60 countries, demonstrating a growing commitment to these nature-based solutions. And according to a recent UN working paper, the infrastructure of the future – three-quarters of which doesn’t yet exist – provides a prime opportunity to explore how to include nature in its design.
As we look ahead, the COVID-19 recovery plans offer a chance to build back better in a way that protects and restores the natural environment, addresses climate change, and supports livelihoods. Coupled with the growing need for infrastructure, this is an opportune time to integrate NbS as part of a sustainable and resilient future.
Embracing the Future of Wastewater Management
As I’ve delved deeper into the world of nature-based solutions, I’ve been captivated by the immense potential they hold for transforming the way we manage our wastewater. These innovative approaches not only treat the water effectively but also deliver a wealth of co-benefits that can enhance our communities, our environment, and our overall well-being.
From slow-rate soil infiltration in Lubbock to vertical-flow treatment wetlands in Shenzhen, and from green walls and green roofs in urban areas to willow systems in peri-urban and rural settings, the diversity of NbS options is truly remarkable. And with the growing support at the policy level and the untapped opportunities in future infrastructure, the future of wastewater management is poised to become more sustainable, more resilient, and more in harmony with the natural world.
As we navigate this exciting journey, I encourage you to explore the wealth of resources available, from the web-based tools that can help you identify the best NbS for your needs to the comprehensive wastewater treatment services that can guide you through the implementation process. By embracing the power of nature-based solutions, we can unlock a more sustainable and prosperous future for our communities and our planet.