Rangelands as Nature-Based Solutions to Wastewater

Categories: Student Blogs

by: Kendall Hays

What is Wastewater and Where Does it Go?

Wastewater is any water that is a byproduct of industrial or normal living processes from homes and businesses. According to the Environmental Protection Agency, the average person in the United States uses 82 gallons of water a day (US EPA) but the amount of wastewater varies from person to person and household to household. This water may contain soaps, chemicals, human waste, or even food scraps. While it may seem that there is nothing but sludge and bacteria in this type of water, it contains some very useful elements for plant growth. Nitrogen (N) and phosphorus (P) are two of the most important nutrients that plants need to grow and reproduce. Wastewater is typically released into two different areas: bodies of water or croplands. Before it can be released there is a removal of biosolids and potentially pathogenic bacteria. However, even with the removal of harmful substances, the nutrients in the water can cause algal blooms in the bodies of water or may run off cropland if the soil is not very porous, therefore, wastewater is often treated to remove nutrients too. The third level of treatment to get rid of the nutrients is expensive, but, what if there was a system that needed plant nutrients, could do the final treatment of wastewater, and reduce runoff? This is where rangelands, specifically in the Great Plains, can come into play.

The Great Plains region of the United States stretches from Texas to Montana and consists of 1.081 million mi² in land area. This region contains fertile and porous soils that could potentially help with excess wastewater mitigation. The soils in rangeland are deeper and filled with more organic matter, this facilitates for more percolation of water and an increase in the recharge of water basins. The plants on these lands consist of annuals and perennials so each year, nutrients are utilized in different amounts by the multitude of plants. Instead of further treating the wastewater to remove nutrients, how about applying them to rangelands? The added nutrients contribute to higher production on these lands and the rachers that graze on native grasslands would benefit from the increased production.

What is Needed?

It is well known that the population is rapidly increasing (Figure 2) and that there is a general trend of increased urbanization. This increase means more mouths to feed and more wastewater to treat. When wastewater is not treated properly, it can potentially contaminate drinking water sources and recreational bodies of water (Preisner 2020). This is due to the previously mentioned nutrients that cause eutrophication and pathogenic bacteria like Escherichia coli. When wastewater undergoes primary treatment it removes many of the biosolids and harmful bacteria from the water leaving the nutrients behind. These nutrients are important for plant growth and function.

One of the biggest water consumers is agriculture (Figure 3). In Oklahoma alone, 215 billion gallons of irrigation water is used annually (Mehata and Taghvaeian 2020). The water used by farmers tends to come from irrigation rather than precipitation events. Irrigation draws from groundwater and surface water bodies. Groundwater irrigation can become very harmful because the rate of recharge into these systems is far slower that the rate at which they are used. While the increase in population and cities can be viewed as a bad thing if we can properly utilize natural cycling by returning waste byproducts and adding extra water to our semi-arid rangelands we can better mitigate the excess waste from our cities. Industrial treatment is not the only process by which we can treat wastewater. It is time for us to begin looking at nature-based solutions to our human-made problems.

What are Nature-Based Solutions?

Nature-based solutions (NBS) are efficient and economically viable options for issues from urbanization. The European Union (EU) defines NBS as actions inspired by the natural ecological functions of an environment (Bauduceau 2020). They may be used to sequester carbon or to help with water quality. Some examples of NBS are constructed wetlands to mitigate flooding and clean water from city runoff or the creation of a rooftop garden to sequester carbon and deflect heat from buildings. Nature-based solutions are what natural resource managers have been working towards. The natural world runs on cycles, it can handle floods, droughts, excess nutrients, and lack of nutrients but only in a natural system does any proper cycling occur. We have a tendency to disrupt these cycles but they still exist and we can fix the parts that we have broken. Before major cities and civilizations, the first farmers would return waste from animals back to the lands they farmed. This was part of the natural cycle that existed. When cities came about, the natural flow was disrupted because the waste would remain in the city and not return to the farm. This natural system of waste cycling has been a part of Earth’s life cycles for eons and can be remade by bringing the waste back to the areas it was removed from.

What Makes Rangelands a Better Choice?

Why use rangelands if wastewater is already being applied to croplands? We might consider this a nature-based solution, however, croplands are not native systems. They are maintained and created using mechanical processes and use amendments to mimic a native system. Croplands are vital to our food production but adding wastewater increases the risk of potentially harmful bacteria being in our crops. Rangelands, however, are fully native and are used mainly by grazers who are less likely to be effected by the bateria. So why not use the native system and its cycles to our own benefit? Rangeland soils are mainly classified as mollisols. Mollisols have high soil organic carbon and tend to have clay loam textures. These properties allow for greater fertility and water infiltration (Xing 2005). There have been long-term studies that show the addition of biosolids to rangelands can improve soil health and plant communities (US EPA 1999). The addition of wastewater can greatly benefit ranchers in providing enough forage for their herds at a lower cost than applying fertilizer or supplementing nutrients. Greater above-ground forage also means greater belowground organic matter in the form of roots. Native grasslands have roots that can reach up to six feet deep. This massive amount of organic turnover is what helps create the large amount of soil organic matter in rangeland soils. Those roots also create macropores that allow for greater water infiltration. Not only will rangelands treat wastewater but that wastewater will also provide the nutrients needed for plants to grow bigger and sequester more carbon. A win-win situation!

Why Does it Matter to You?

Rangelands are slowly being taken over by croplands or being mismanaged by ranchers. Twenty percent of all rangelands have been converted to croplands. This loss may seem small but it makes up an estimated 60% loss in carbon (EDF 2019). Without these native lands, our native birds, mammals, and fish will begin to die out. Recognizing the importance of rangelands not only as a food producer but also for other ecological functions is important for our prosperity. Regulating and creating policies to treat wastewater in rangelands will help remind us of their importance while also creating better native habitats and forage as well as recharging basins that are used for irrigation. If we want to create a world for future generations to be healthy and safe, we need to begin to take steps toward sustainable and environmentally conscious actions. Feeding the world and keeping it clean do not have to be mutually exclusive. If we can utilize nature-based solutions, we may be able to save our lands and water.  

Conclusion

There is no way to completely stop wastewater production but there is no need for it to be a looming threat in the future. Through natural and efficient ways, we can utilize wastewater for the benefit of mankind and planet Earth. We should not be in a constant battle with nature or try to change its ways, rather we should be working with natural cycles to improve our health and environment. Using rangelands as an area to apply wastewater can help prevent algal blooms and bacterial outbreaks, while replenishing the necessary nutrients for our lands to thrive. This is just one of many nature-based solutions that exist but we should continue to strive for newer and better solutions to our problems so that we can better protect natural resources.

Works Cited

• Bauduceau, N., Berry, P., Cecchi, C., Elmqvist, T., Fernandez, M., Hartig, T., Krull, W., Mayerhofer, E., N, S., Noring, L., Raskin-Delisle, K., Roozen, E., Sutherland, W., & Tack, J. (2015). Towards an EU Research and Innovation Policy Agenda for Nature-based Solutions & Re-naturing Cities: Final Report of the Horizon 2020 Expert Group on ‘Nature-based Solutions and Re-naturing Cities’. Publications Office of the European Union. https://doi.org/10.2777/765301

• Environmental Protection Agency. (n.d.). EPA. Retrieved April 24, 2023, from https://www.epa.gov/watersense/statistics-and-facts

• Generation, B. (1999). Use, and Disposal in the United States. US Environmental Protection Agency, Washington, DC.

• Oklahoma State University. 2020. Irrigated agriculture in Oklahoma. Retrieved April 24, 2023, from https://extension.okstate.edu/fact-sheets/irrigated-agriculture-in-oklahoma.html#:~:text=The%20total%20amount%20of%20irrigation,more%20than%20215%20billion%20gallons.

• Preisner, M., Neverova-Dziopak, E., & Kowalewski, Z. (2020). Analysis of eutrophication potential of municipal wastewater. Water Science and Technology, 81(9), 1994-2003.

• Sarah Hamilton Buxton and Rae Powers, & Authors                                                    RaeAnn Powers. Farm Bill Pollinator Conservation Planner. (n.d.). Great Plains Rangelands are important habitat for pollinators. Xerces Society. Retrieved April 24, 2023, from https://xerces.org/blog/great-plains-rangelands-are-important-habitat-for-pollinators

• Xing, B., Liu, X., Liu, J., & Han, X. (2005). Physical and chemical characteristics of a typical Mollisol in China. Communications in Soil Science and Plant Analysis, 35(13-14), 1829-1838.