By Matt Scholz of the Sustainable Phosphorus Alliance
While the recycling of many products has only taken hold in the past few decades, people have been recycling phosphorus for thousands of years through the collection and land application of animal and human wastes. Ancient Romans used manure as fertilizer, and ancient Athenians are said to have used sewage to fertilize groves and gardens around the city. Jump forward to 19th century New York, where night soil men would collect human waste from homes either to be land applied on farms or hauled to the city dump. (This makes me appreciate my job.)
We still land apply treated human waste (a.k.a. biosolids) to farms, but much of it is still sent to the city dump—45% according to a 2007 report from NEBRA—thereby wasting our phosphorus resources. Annually, we generate about 350,000 tons of phosphorus as biosolids in the US alone (c.f. Chris Peot’s Phosphorus Forum 2017 talk), so we estimate that about 157,500 tons of phosphorus is lost to landfills.
Land application of biosolids from wastewater, as well as manure from animal feeding operations and composted or digested biomass from farms and cities, is an important means of providing nutrients to crops and restoring soil carbon while diverting wastes from landfills. However, it can also result in over-application of nutrients, especially phosphorus, which can lead to adverse impacts on water quality. Most notably, the US produces upwards of 1.9 million tonnes of phosphorus in animal manure annually (US EPA, 2007) that is spread across more and more geographically constrained areas as consolidation of animal agriculture into concentrated animal feed operations (CAFOs) continues. Manure, especially wet, is heavy and expensive to transport, and that tempts its over-application. Yet over-applied phosphorus is carried by rains and other mechanisms to nearby waterways, resulting in harmful algal blooms and dead zones.
If only we could teleport manure.
A New Initiative
If there’s a global theme in phosphorus management, it’s resource misallocation. We have too much in some regions, too little in others, and too much wasted throughout the value chain. We want to encourage more efficient use of phosphorus, and we want to encourage its recycling in the food system through the sustainable land application of biosolids and manure, for example.
Recognizing this, the Sustainable Phosphorus Alliance has been asking industry and regulatory stakeholders to help us vet project proposals on sustainable use of organic residuals for the better part of a year, and we thank those of you who’ve provided feedback on those proposals. We are pleased to announce that we have decided to conduct a comparative landscape analysis of the regulations and policies affecting land application of biosolids and manure at the US federal and state levels and, resources permitting, at the Canadian federal and provincial levels. The work will be led by our own Dr. Rebecca Muenich with the help of some graduate student support.
Application of both biosolids and manure in the US is regulated under the Clean Water Act, but each is regulated under different sections. Namely, biosolids are regulated under 40 CFR Part 503, “Standards for the Use or Disposal of Sewage Sludge” and manure generated at CAFOs is regulated under the National Pollutant Discharge Elimination System. Much of the manure that is generated is not produced at CAFOs and isn’t subject to NPDES permitting. How regulations on both biosolids and manure management play out at state and regional levels varies. For example, the state of Michigan does not allow manure application on soils with greater than 150 ppm of P, whereas Indiana allows application on soils up to 200 ppm of P. Likewise, states treat biosolids variably. For example, Pennsylvania and Maryland permit use of the water extractable phosphorus test to determine a site-specific application rates, but other states regulate based on total phosphorus.
What consequences do these disparate treatments have for application of biosolids and manure and how might we develop policies that increase sustainable land application? The first step to addressing this question is understanding the regulatory landscape, and that’s precisely the goal of our work. We’ll be developing a white paper and webinar over the coming months on this topic. More exciting to me is our development of an ArcGIS Story Map that will allow users to navigate these regulations geographically through a web interface. This dataset can then serve as a scaffold upon which we can layer other relevant datasets, including such things as locations of CAFOs and wastewater utilties, soil test P levels, known areas of land application, etc. We hope this becomes a great tool for managers and policy makers to develop more sustainable scenarios.
To ensure relevancy and leverage past work on this topic, we’re reaching out to industry and regulatory partners to join an oversight board for the project. This board will provide feedback on a draft of our white paper and on the first rollout of the ArcGIS tool. If you think that your organization can lend expertise or other valuable resources, please contact me. We expect this first phase of the project to take about nine months to complete.
And if you would like to support our work more broadly, please join us as members.