Journey to Improve Water Quality in Powers Lake

By Laura M. Fleming, President and CFO of SRS Crisafulli, Inc.

Outbreaks of blue-green algae in a 1,616-acre natural lake, created an emergent call to action in the 1990’s from the community of Powers Lake, North Dakota. Due to blue-green algae blooms, the recreational value of Powers Lake plummeted and few people gathered or recreated there.

Powers Lake Watershed Committee (PLWC)

In 1998, the local community recognized the importance of Powers Lake and formed the Powers Lake Watershed Committee (PLWC). They initiated the water quality improvement project in Powers Lake which is fed from a 44,458 acre watershed. Improving water quality requires funding, cooperation, and action.


PLWC applied for and received three federal 319 grants of the Clean Water Act in 2003, 2011 and 2016 and the community provided local match requirements with funding, cash and in-kind services. The project also received a grant in 2017 from the North Dakota Outdoor Heritage Fund.


In 1999, PLWC initiated a watershed assessment and Agricultural NonPoint Source (AGNPS) model, which was completed in 2001. The watershed assessment and AGNPS model recommended watershed restoration actions, established pollutant reduction goals, and provided a method for evaluating progress. The watershed assessment revealed the lake received an annual phosphorus load of 11,564 pounds with 6,339 pounds entering the lake and 5,225 pounds within the lake. The water analysis measured Powers Lake as “hyper-eutrophic” with excessive nutrient loadings, specifically, high levels of phosphorous and low dissolved oxygen levels. To meet state water quality standards and improve water quality required reducing nutrient loads entering the lake by seventy-five percent and nutrient cycling within the lake by fifty percent.

Conservation to Prevent Nutrients from Entering the Lake

Agriculture production is the economic foundation of the Powers Lake area community and agricultural pollution was a significant source of pollution entering Powers Lake. Agricultural producers changed practices and adopted Best Management Practices BMP’s for soil and water conservation to prevent nutrient loads from entering the lake. Farmers switched to no-till or minimum till, fallowed fewer acres and reduced the quantity of fertilizers applied across the watershed. Ranchers installed wells, pipelines, tanks, fencing and implemented grass seedings and grazing rotations. The cooperation and actions of the agricultural community resulted in fewer nutrients flowing through the watershed into Powers Lake.


The data indicate the watershed conservation activities are effective at preventing nutrients from entering the lake through erosion and runoff. The water quality measurements between 2001 and 2009 indicate that Trophic State Index (TSI) scores improved. In 2009, the average TSI score for chlorophyll a was 53.24, which met the goal of a total maximum daily load (TMDL) target of 55.02.

Legacy Phosphorus in the Lake

After the conservation activities, phosphorus TSI scores remained high and held steady at 85, which is considered “hyper-eutrophic”. The likely cause was legacy phosphorus within the lake continually cycling from the lake’s sediments. In 2008, PLWC sought solutions on how to reduce the internal nutrient cycling which was feeding blue-green algae blooms. Houston Engineering Inc. was hired and completed the Powers Lake Nutrient Management Alternatives report in October 2009. They recommended dredging as the best remediation method to reduce internal nutrient cycling.

Dredging to Remove Overabundance of Nutrients

In 2015, the City of Powers Lake purchased a Montana made Crisafulli Rotomite hydraulic dredge. The PLWC Coordinator has been dredging sediments from the lake for five seasons. As of 2019, 50,900 cubic yards of sediment which includes 80,273 pounds of phosphorus and 32,020 pounds of nitrogen have been dredged out of the lake.

Results of Conservation and Dredging to Improve Water Quality

Significant declines in total phosphorus levels indicate the combination of conservation activities and dredging are effective actions toward continued water quality improvement. Prior to the initial project in 2001, dissolved phosphorus constituted 45.9% of total phosphorus. During the conservation implementation phase in 2006 and 2007, dissolved phosphorus constituted 50.3% of total phosphorus. During the dredging phase of the project from 2015 to 2019, dissolved phosphorus constituted 72.6% of total phosphorus. Combined with declines in total phosphorus, the significant change in the ratio of dissolved phosphorus to total phosphorus from 50.3% during the conservation implementation phase to 72.6% during the dredging phase indicates removing sediment-bound nutrient sources via dredging is highly effective.

Community Teamwork

The community of Powers Lake followed their motto of A lake is a reflection on the community that lives within its watershed by improving the water quality in the lake. For more than twenty years, people have been contributing to the common goal of improved water quality. They include PLWC, farmers, ranchers, the City of Powers Lake, Mountrail Soil Conservation District(SCD), Burke SCD, NRCS in Mountrail and Burke Counties, US Fish and Wildlife Service, Burke County Extension Service, North Dakota Natural Resource Trust, Upper Dakota RC&D, North Dakota Game and Fish, Ducks Unlimited, and the many volunteers.

Opinions expressed here do not necessarily reflect those of the Sustainable Phosphorus Alliance.

About the author

SRS Crisafulli, Inc. is a manufacturing company located in rural eastern Montana that celebrates and supports resourceful communities and clean water. They specialize in sludge removal systems for municipalities, industries, and lake communities.

Alliance’s Phosphorus Transport Modeling Group Meets

By Dr. Matt Scholz

Sustainable Phosphorus Alliance

Matt Scholz

The Sustainable Phosphorus Alliance hosted its second in-person workshop of what’s been rebranded as its Phosphorus Transport Modeling Group in San Antonio, Texas, on Nov 14-15. The meeting was held nearby, and just after, the meetings of the Soil Science Society of America and SERA-17. Fourteen academics and practitioners met for the workshop with an additional two joining via phone. The meeting was underwritten in part by USDA-ARS.

The working group originally formed in 2018 to address issues of how to better harmonize field-scale hydrological models of phosphorus fate and transport, such as the Annual Phosphorus Loss Estimator Tool (APLE), with watershed-scale models, such as the Soil and Water Assessment Tool (SWAT), and how to address knowledge gaps evident across all models (e.g. specific transport phenomena not modeled). These models are often applied to validate P indices and estimate P loads into impaired waterbodies, for example. They vary not only in spatial and temporal scales, but in data requirements, sophistication, and ease-of-use. In the time since the original group formed, it has extended its purview to study how field- and watershed-scale models can inform regional models of phosphorus flows as well. For example, transport models may inform assumptions about P losses from manure application that are made in regional, substance-flow models.

All good transport models are beholden to the same laws of physics and chemistry. While they should concur with each other and with edge-of-field data when analyzing identical scenarios, especially in general direction of change, there remains a need for cross-validation studies to demonstrate model agreement. We also need to develop frameworks for integrating these models across scales. For instance, APLE’s extrapolation of total P losses from agricultural fields within a watershed should be similar in magnitude to the watershed-scale predictions of SWAT, and both models should jibe with edge-of-field data on total P losses. Where they don’t, we can identify further research needs for model improvements and integration. Furthermore, the models would ideally confirm and help provide a sound scientific underpinning to decision support tools, such as phosphorus indices. The latter can be accomplished, for example, by leveraging model simulations to estimate more accurate weights when calculating scores in a P index.

The first day of the meeting provided time for group members to update one another on recent progress on related research, and the second day developed work items to be carried forward. One of the tasks accomplished was to develop a research agenda for a postdoc who will be working in Dr. Carl Bolster’s lab at the USDA-ARS research station in Bowling Green, Kentucky, on key research themes for the group. These include such themes as how we account for legacy versus incidental P losses within models, how P hotspots might be identified using hydrologic models, and how well different models agree in these identifications. We also identified a number of areas ripe for inquiry, including: How do we better incorporate plant growth models? How do we adapt models to be more useful in P deficient systems (e.g. sub Saharan Africa)? How does fertilizer formulation affect transport? What should agronomists be measuring to improve modeling?

On day two, we outlined a group paper on best practices in phosphorus fate and transport modeling in agricultural settings. There is considerable room for user error in applying models to scenarios, and we aim through the paper to provide guidance on best practices for model use: What models are best used when? How well do specific scenarios pair with models? What questions can be asked and how long will it take to get an answer? We also discussed funding and outreach opportunities for the group.

The group was joined by 4 representatives from the Moroccan phosphate mining company OCP (foundational supporter of the Alliance) and the Moroccan l’Université Mohammed VI Polytechnique (UM6P). They were particularly interested in how such models might apply to the African context.

Collectively, this Phosphorus Transport Modeling Group set its sights on the ambitious goal of establishing the group as the “go-to” group for phosphorus fate and transport modeling questions. The Sustainable Phosphorus Alliance has built a steering committee, a web page, and other infrastructure to facilitate the group’s collaboration. Readers can look forward to future reports, including a presentation from Dr. Carl Bolster at our Phosphorus Forum 2020 event in Washington DC on April 30.

Participation in the working group is a benefit of Alliance membership and by invitation of the steering committee. Please contact us for further information.

A Tool for Trapping Dissolved Phosphorus

By Dr. Chad Penn

USDA-ARS, National Soil Erosion Research Laboratory

The P removal structure is a large, landscape scale filter for dissolved phosphorus (DP), intended to intercept and trap P from “hot spots” (i.e. legacy P) before reaching a surface water body. The P removal structure embodies four basic principles:

  1. Contains solid media with high affinity for P, commonly known as a “P sorption material”, or PSM.
  2. PSM is contained and placed in a hydrologically active area with high dissolved P concentrations.
  3. High DP water is able to flow through the contained PSM at a sufficient rate and contact time. Structures must be designed to handle peak flow rates since 90% of annual P losses are generally transported in less than 5% of the flow events, which are the largest flow events.
  4. The PSM is able to be removed and replaced after it is no longer effective.

Due to small amounts of PSM, poor contact between PSM and flowing water, and limited contact time, small in-line pipe filters and “socks” filled with filter media are not effective for removing appreciable amounts of P, nor do they remain effective for any significant amount of time. If a site contains appreciable P loads worth treating, then it will require several tons of filter media.

Phosphorus Sorption Materials (PSMs)

Many PSMs are by-products from different industries, and therefore can be obtained for low cost. Some PSMs are manufactured. However, all PSMs must first be screened for safety before use in a P removal structure. Some examples are shown below.

Types of P Removal Structures

P removal structures can appear in many different forms. They can be located on the surface or subsurface, in ditches, tile drains, drainage swales, drop inlets, blind/surface inlets, etc. Any unit that embodies the four basic principles is essentially a P removal structure. Several examples of P removal structures are shown.

Choosing an Ideal Location

In order to qualify as a potential site for construction of a P removal structure, a site must possess:

  1. Flow convergence to a point where water can be directed into a structure, or the ability to manipulate the landscape
  2. At least 0.2 ppm dissolved P (DP) in water
  3. Hydraulic head required to “push” water through structure: function of elevation change or drainage ditch depth
  4. Sufficient space to accommodate PSM

P removal structures are not a “silver bullet”, as they are intended only for sites that are legacy P sources, that is, excessive soil P concentrations that will remain elevated for decades, releasing dissolved P into drainage water even after ceasing P applications. This best management practice is not intended for trapping incidental losses of P from recently applied manure or fertilizer, as there are much less expensive BMPs for that type of P source, such as incorporation and proper timing of application.

Designing a P Removal Structure

Several inputs and target goals are required for designing a site-specific structure. The P-Trap software, which will soon become publicly available through the USDA-ARS, can be used to quickly design a structure with any effective and available PSM.

Example P Removal Structures

The confined bed structure shown above contained 40 tons of treated steel slag and intercepted runoff from a poultry farm with DP ranging from 2-15 ppm. This structure was able to remove 7.5 lbs DP in 2.5 yrs and handle ~1000 GPM flow.

The tile drain P filter shown above during construction, utilized a conventional septic tank. This structure contains 2.5 tons of a manufactured PSM (Fe-coated alumina) that can be regenerated after becoming saturated with P. This unit was designed to remove 40% of the 10 year cumulative DP load, and handle 300 GPM. After 10 years, the PSM will be regenerated in-situ.

Cost and Justification

The only other conservation practice that can truly remove P is soil P drawdown via plant uptake and harvest. Although necessary for solving the long term problem of legacy P, it requires many years (decades) for plant draw-down to reduce DP concentrations in drainage water. During that long draw-down period while dissolved P losses are still elevated, P removal structures can be used to trap P in drainage water. Cost of structures will vary dramatically with site and PSM utilized. Total costs are similar to waste water treatment: $50-500 dollars per pound of P removed.

Current and Future Efforts

Current research is focused on regeneration of PSMs and investigation of new by-products for reducing costs. The ability to regenerate PSMs in-situ, even once, will nearly cut the cost of P removal in half. The USDA-ARS National Soil Erosion Research Laboratory is also working closely with the NRCS, American Society of Agricultural and Biological Engineering, and American Society of Agronomy, in producing a series of training videos and certification program for design and construction of P removal structures. The P-Trap software will also aid in increasing the adoption of this new BMP. Many states include the P removal structure in their cost-share program, under the 782 Standard.

For more information, please contact Dr. Chad Penn at the USDA-ARS (

Additional Sources:

Penn, C.J., and J.M. Bowen. 2017. Design and construction of P removal structures for improving water quality. Springer Publishing. ISBN 978-3-319-58657-1

Penn, Chagas, Klimeski, and Lyngsie. A Review of Phosphorus Removal Structures: How to Assess and Compare Their Performance. Water (20734441), August 2017. DOI 10.3390/w9080583

Opinions expressed here do not necessarily reflect those of the Sustainable Phosphorus Alliance.


OCP: Feeding the Soil to Feed the Planet

By Krista Maruca of OCP North America

Krista Maruca

OCP Group is a global player with a leadership position across the phosphate value chain in extracting, marketing and selling phosphate and its derivatives. As the top global producer of phosphate in all its forms – rock, acid, and phosphate-based fertilizer – OCP has a strong international presence on all five continents. Recognizing the significant role OCP plays at the top of the value chain as a supplier of the world’s phosphate needs, the company joined the Sustainable Phosphorus Alliance as a foundational supporter and board member at its launch in 2016.

OCP’s Approach to Phosphorus Sustainability

OCP’s unique position requires continually striving to innovate in order to improve environmental sustainability and phosphorus efficiency. As part of that mission, OCP has set ambitious goals with the launch of its Circular Economy program in 2018, which is oriented around four pillars: natural resource preservation, sustainable production, smart consumption, and creation of value through transformation and recycling. This circular approach aims to better integrate its industrial ecosystem with the natural environment and communities in which it operates. In its industrial operations, OCP has publicly committed to goals to transition to 100% green power through solar, wind, and co-generation; zero consumption of public water resources through desalination and purification of wastewater; a reduction in emissions and waste by-products through the use of newly available technology; and to maximize the value of low-content phosphate and other recoverable minerals. Those goals are well on their way to being met through significant investments in new technology to more efficiently source phosphorus.

In the US, OCP’s North American subsidiary has set in motion plans to further the mission of sustainable phosphorus on a local level. On-farm nutrient management has come under the national spotlight in recent years due to highly visible algal blooms that disrupt local business, tourism, and recreation. In some years, when adverse weather conditions lead to a particularly nasty bloom, the issue has risen to crisis levels. The science of phosphorus runoff is complex, with fertilizers’ application rate, timing, source, and placement all playing a role in phosphorus losses to the environment. Moreover, fields with various soil types and management histories have divergent needs, meaning there is no one-size-fits-all solution to reduce runoff. 4R Nutrient Stewardship — working with farmers to ensure applications are at the right place, right time, right rate, and right source — is one approach to close the loop on phosphorus losses. Responsible nutrient stewardship can minimize impact on the environment and rural communities and has positive impacts for the farmers we serve by advancing soil health and productivity. OCP North America is a partner in the 4R effort to promote sustainable on-farm management of phosphorus in the US and Canada.

Platform for Scientific Research and Collaboration

Joining the Sustainable Phosphorus Alliance is not only in line with OCP’s own corporate mission but also fills an important need for the sector more broadly. As farming communities and local policy-makers grapple with ways to reduce nutrient loading into waterways and limit waste, there is a greater need for collaborative research that will provide a scientific basis of understanding of the complex issues of soil health, water quality, and phosphorus management. The Alliance’s ability to bring together technical experts from industry and academia is the first step to advancing shared knowledge of phosphorus dynamics and ensuring evidence-based decision-making.

OCP is proud to contribute to this effort, including by making it a focus of faculty and students at the University Mohammed VI Polytechnique (UM6P). Inaugurated in January 2017 and housed in Ben Guerir, Morocco, several UM6P programs and joint research projects tackle challenges linked to phosphorus sustainability. At the School of Agriculture, Fertilizers, and Environmental Sciences, students learn about environmental conditions in African agriculture for preserving water, soil quality, and natural resources. Programs in industrial operations build upon mining and fertilizer manufacturing technology, including through a new experimental mine that provides a full-scale living lab for developing new innovations in phosphate mining. Exchanges with the scientific community in the Alliance network offer the opportunity for UM6P researchers to contribute to the growing body of global knowledge on phosphorus sustainability.

Making a real impact on phosphorus use efficiency will require collaboration across all players in the value chain; the Alliance creates that space by providing a platform for cooperation and new partnerships. OCP is looking forward to continuing its leadership in the Alliance and building relationships with other new members in the coming years.

Opinions expressed here do not necessarily reflect those of the Sustainable Phosphorus Alliance.

About OCP North America

The OCP Group is the world’s largest exporter of phosphate rock and phosphoric acid, as well as one of the world’s largest producers of fertilizer. The company is integrated across the entire phosphate value chain, extracting, marketing and selling phosphate and its derivatives, phosphoric acid, and fertilizers. Headquartered in Morocco, the OCP Group is the largest corporate employer in the country. OCP’s North American subsidiary was launched as OCP Research LLC in 2016 and transitioned to OCP North America in February 2019 to manage its engagements across the U.S. and Canada.


The Phosphorus Sustainability Challenge

By Matt Scholz of the Sustainable Phosphorus Alliance

Matt Scholz

Phosphorus is both a vital nutrient upon which global agriculture depends and a devastating pollutant of our planet’s freshwater resources. The Sustainable Phosphorus Alliance is committed to managing this finite resource sustainably, and we’re inspiring collective action towards better phosphorus management through the launch this April of our Phosphorus Sustainability Challenge.

Worldwide, many organizations work hard to manage our phosphorus resources sustainably. The Phosphorus Sustainability Challenge will be a place where they can gather to publicly commit to reducing their phosphorus footprint and to see how their individual efforts contribute to greater goals. These goals include using phosphorus more efficiently in crops and animal feed, diverting and removing phosphorus from our waters, and recovering and recycling phosphorus wastes—including food
wastes—back into the food system.

How will the Challenge work? Organizations will publically commit to reduce their collective phosphorus footprint. In return, they will receive public recognition for their leadership, see how their own efforts contribute to larger scale impacts, and network with like-minded organizations through sector-specific action networks. Commitments must be SMART: Specific in what they set out to achieve, Measurable on an annual basis, Ambitious in their targets, Relevant to Challenge goals, and Time-bound. Applicants will need to make new commitments or state existing commitments that have yet to be achieved or publicized, and all committments will have to go beyond what is required for regulatory compliance.

Who can participate? Any government at any jurisdictional level and any public or private institution or company of any size. The platform is being designed to allow everyone from transnational corporations to small, local groups to make meaningful contributions. We need all hands on deck.

How is it funded? The Challenge development is currently funded by the Sustainable Phosphorus Alliance but we seek foundational support. Please contact us if your organization would like to support our effort to keep our waters blue and our fields green.

How will achievement be verified? Participants who obtain third-party or second-party verification for their progress will be recognized as such on the platform upon submitting proof of verification. Otherwise, there is no verification required but commitments will be in the public record. Any verified misrepresentation of prior achievement will bar applicants from further participation in the Challenge.

The Challenge will be launched at our Phosphorus Forum on April 5, 2019. Please contact us for more details.

Notes from the Alliance’s 2018 Phosphorus Modeling Workshop

By Dr. Grey Evenson, Ohio State University

Grey Evenson

The Phosphorus Field-to-Watershed (P-F2W) Modeling Workshop brought 16 researchers and policy experts to Columbus, Ohio, on August 23rd and 24th. The group discussed soil test phosphorus measurements and their relationship to fertilizer application recommendations, status and trends of edge-of-field and in-stream water quality observations for the Maumee River basin (a tributary of Lake Erie and a major contributor of P loadings to the lake), and existing models to simulate soil phosphorus and their application in the Maumee basin.

Chad Penn (USDA-ARS) discussed how soil test phosphorus measurements are used to guide fertilizer application rates. Dr. Penn suggested that these recommendations provide good “ball-park” application recommendations but that they may be better tailored to the soil texture, the crop being grown, and other site conditions. He suggested that these improvements should improve agricultural efficiency while decreasing P loss from fields.

Laura Johnson (Heidelberg University) and Kevin King (USDA-ARS) presented their efforts to assess phosphorus loadings to Lake Erie using in-stream and edge-of-field monitoring networks, respectively. In summarizing long-term, in-stream observational data, Dr. Johnson showed that current, flow-weighted, mean dissolved P concentrations are consistent with historical trends – implying that recent efforts to decrease loadings to the Lake have not been successful, at least to this point in time. Dr. Johnson also suggested that the continuing problem may be partly attributed to increased soil P stratification (i.e. higher P concentrations at the top with lower concentration at greater depths) as a consequence of reduced tillage. Dr. King then described his network of edge-of-field sites that measure P loss from fields in surface and tile flow and noted that most of the monitored fields do not show excessive quantities of P export. Dr. King additionally discussed the impact of various best management practices as applied to these sites, reviewing the relative success of each.

Peter Vadas (USDA-ARS) and Margaret Kalcic (Ohio State University) discussed their work to simulate soil phosphorus dynamics using empirical and process-based models. Dr. Vadas reviewed the evolution of models that simulate soil phosphorus dynamics in agricultural systems – beginning with the EPIC model, then moving to the APEX, SWAT and APLE models. He described the individual “pools” of phosphorus (i.e., labile, active and stabile mineral phosphorus, and organic phosphorus) and emphasized that the labile mineral pool can be initialized using common soil test phosphorus measurements. He then outlined previous work to validate SWAT’s phosphorus routines and introduced his continuing work with the APLE model. Dr. Kalcic provided an overview of the SWAT model and recent applications of that model in the Maumee watershed. She then introduced a new iteration of the model – wherein the most basic spatial unit of simulation approximates the size of agricultural fields – and her ongoing efforts to validate SWAT’s simulation of soil phosphorus dynamics, including phosphorus export through surface and tile flow. She also discussed several challenges in simulating phosphorus in the Maumee – namely problems with calibration when initializing labile P at higher values and with the insensitivity of modeled crop growth to soil phosphorus levels.

Finally, Tom Zimnicki provided a summary of a workshop hosted by the Cooperative Institute for Great Lakes Research at the University of Michigan, Ann Arbor, in July 2018. The workshop hosted a number of researchers and sought to improve hydrologic model representation of soil health as impacted by agricultural best management practices.

Following presentations, the group plotted a path forward. Three specific areas of investigation were identified for additional discussion: identifying whether legacy or incidental losses were the primary sources of P loadings to Lake Erie; coupling fertilizer production, particularly from recycled organics, and watershed hydrologic models; and identifying “hotspots” (i.e. locations of elevated P export) using hydrologic models. The meeting was concluded by discussing plans to collaborate in investigation of these specific topics.

The workshop was organised by the Sustainable Phosphorus Alliance. The workshop agenda and presentation slidedecks are available for download in PDF format in the sidebar to the event listing on this page. In addition, you can view video of these talks on our YouTube channel.

Grey Evenson is a postdoctoral fellow in the Department of Food, Agricultural and Biological Engineering at Ohio State University. Grey is a watershed scientist with an interest in applying models to improve environmental outcomes. Opinions expressed here do not necessarily reflect those of the Sustainable Phosphorus Alliance.

Europe Continues to Move Nutrient Policies Forward

By Chris Thornton, European Sustainable Phosphorus Platform

Chris Thornton

The 3rd European Sustainable Phosphorus Conference (ESPC3) brought together 300 companies, policy makers and experts in Helsinki, June 2018. New EU policies announced include the obligation for farmers to implement nutrient budgets, the new EU Fertilisers Regulation and the draft Water Reuse Regulation. The ambitious new Fertilisers Regulation, currently under finalisation and part of the EU Circular Economy package, will fix quality and safety criteria for placing on the market recycled nutrient products including composts, digestates, organic fertilisers and soil improvers, recovered phosphate salts, biochars and ash-based products. The Water Use Regulation will fix quality and safety criteria for use of treated sewage discharge water for agricultural irrigation / fertigation.

Companies presented success stories showing that nutrient recycling is already operational through different routes including animal by-product incineration ashes, sewage biosolids, struvite, spent fire extinguisher chemical recycling, forestry and bio-energy by-products, gypsum and nitrogen recovery from digestate. Discussions confirmed the need for data, risk assessment science and dialogue around acceptance of recycled nutrient materials, both organic materials and technical recovered nutrients. The positive marketing message of nutrient and organic carbon recycling needs to be developed, alongside labelling and product traceability, in order to support acceptance of nutrient recycling in food and beverage industry and supermarket purchasing and sustainability criteria.

Despite considerable investments already made in waste water treatment, phosphorus continues to be one of the biggest challenges to water quality across Europe. Tighter sewage works phosphorus discharge consents are expected. New technologies combining phosphorus removal with recovery for recycling are being proposed. Approaches to remove nutrients from water bodies and sediments will be needed to restore eutrophication impacted waters, such as the Baltic Sea, with development of both restoration technologies and biological systems (such as harvesting of zooplankton consuming fish). Again, success will depend on product commercialisation, such as developing new recipes for such often not consumed fish.

The conference was organised by BSAG (Baltic Sea Action Group) and ESPP (European Sustainable Phosphorus Platform). Full conference summary in the ESPP SCOPE Newsletter n°127 ( and short article at

Opinions expressed here do not necessarily reflect those of the Sustainable Phosphorus Alliance.

Biosolids and Manure Task Force

Manure Task Force

Participation in a task force is one of the opportunities for our partners to contribute to the Sustainable Phosphorus Alliance. One example is our Biosolids and Manure Task Force, which undertook a comparative analysis of the federal and state regulations governing the application of biosolids and manure in the US and hopes to encompass Canada as well. That work has been embedded in an online tool, called GIS-P (rhymes with crispy), that presents the regulatory data alongside other contextualizing data in a geographically browsable format.

Member organizations of the Sustainable Phosphorus Alliance and other invitees from industry and government are contributing to the task force by providing oversight and feedback. Thank you to our Oversight Board members representing Kieser & Associates, Lystek International, Metropolitan Water Reclamation District of Greater Chicago, Mid-Atlantic Biosolids, National Association of Clean Water Agencies, National Milk Producers Federation, NEFCO, North East Biosolids & Residuals Association, Smithfield Foods, Synagro, US EPA, and Veolia.

The task force objectives are:

  • To compile and compare all state and federal regulations related to biosolids and manure land applications
  • To identify local variations in regulatory interpretations
  • To produce an online tool that facilitates study of the data, now available here

If you would like to support the work of the Sustainable Phosphorus Alliance, please contact us about joining as a member.

Alliance Launches Biosolids and Manure Project

By Matt Scholz of the Sustainable Phosphorus Alliance

Matt Scholz

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 or donate now.

Understanding Composition: One Key to Recycling Manure

By Rebecca Muenich of the Sustainable Phosphorus Alliance

Precision agriculture, the practice of employing monitoring systems, software, and equipment to modify farming inputs in a productive and efficient manner, is applied everywhere in modern agricultural systems, except when it comes to a majority of manure applications. Compared to inorganic fertilizer sources that have clearly documented, consistent compositions, manure and its associated nutrient values are not well appreciated and are even treated as waste by many farms in the US. This is especially true for large farms with a lot of liquid manure, including dairy and swine operations.

Research has shown the potential value of these recycled fertilizer products (Schröder 2004; Choudhary et al. 1996), so it is perhaps surprising that, in many places in the US, manure is treated as waste product and contaminant source rather than a nutritional opportunity. Understanding manure composition is key to addressing this problem. This is because variable composition has been identified as a barrier to farmers’ distribution or sales of their manure to other farms, especially non-livestock farms (Battel and Krueger 2005).

There are many references available to help calculate the nutrient content of manures, including the American Society for Agricultural and Biological Engineer’s “Manure Production and Characteristics” Technical standard ASAE D384.2, generalized table values available in many online extension publications (University of Maryland Extension; Ohio State Extension), and in permit information for regulated facilities. However, the micro- and macronutrient content of recycled fertilizers can vary dramatically by source and even over time. For manure specifically, it is well known that factors such as the feed an animal eats, the age, size, and species of animal, and the method of manure storage can all affect the nutrient content. Composition may also be affected by such practices as the addition of compost or water from other parts of the farm. In addition, the variation in methods for calculating nutrient content alone creates discrepancies.

In my work to understand manure application practices in the Lake Erie basin with colleagues at Ohio State University and the University of Michigan, we compared lab-measured nitrogen and phosphorus contents of manure to estimated “book values” for large, regulated animal operations where data were available. This comparison supported what others have found: that using book values alone may not be enough to understand the nutrient composition of excreted and/or stored manure. This variability can have important implications for farm economics as well as environmental management. Putting on too little or too much nutrients can put a farm at risk. Therefore, lab testing of manure nutrient content should be a preferred source for composition information.

We demonstrated on a small scale with very detailed data that there is a great potential to redistribute (i.e. recycle) manure by applying it to lands that have lower soil nutrient contents. It is often the case that cropland currently receiving manure applications is not in need of more, as a history of consistent manure applications can lead to a buildup of nutrients in the soil (Sharpley et al. 2013). Yet redistributing and applying manure at appropriate rates will require improvements in measuring and conveying the nutrient content of manure products to potential end users.

More frequent, replicated samples and more nuanced reporting are called for. In terms of reporting, manure composition tests may not break down the phosphorus in the sample into organic and inorganic forms, though they may indicate how much is available in the first year. Giving farmers a better idea of the total amount of phosphorus and its speciation (to assess bioavailability) can improve nutrient management. More testing is needed too. While testing manure compositions is required for large, regulated operations on typically an annual basis, it is not a widespread technique used in manure management, at least in the Lake Erie Basin states. On small farms with fewer resources, manure composition testing (~$30/sample) may not seem economically beneficial at first glance. However, if manure nutrients can contribute to crop nutrient needs, overall fertilizer additions may be decreased, saving money while decreasing the risk of nutrient pollution.

Improved and more frequent testing and communication of manure compositions is key in achieving the “Right rate” in 4R Nutrient Stewardship.

[Open source] Battel RD, Krueger DE. 2005. Barriers to change: Farmers’ willingness to adopt sustainable manure management practices. Journal of Extension, 43(4).

Choudhary M, Bailey LD, Grant CA. 1996. Review of the use of swine manure in crop production: Effects on yield and composition and on soil and water quality. Waste Management and Research, 14(6).

Schröder J. 2004. Revisiting the agronomic benefits of manure: a correct assessment and exploitation of its fertilizer value pares the environment. Bioresource Technology, 96(2): 253-261.

[Open source] Sharpley AS, Jarvie HP, Buda A, May L, Spears B, Kleinman P. 2013. Phosphorus legacy: Overcoming the effects of past management practices to mitigate future water quality impairment. Journal of Environmental Quality, 42(5): 1308-1326.

University of Maryland Extension. Manure Summary Report. Available at:

Ohio State Extension. Ohio Livestock Manure Management Guide. Bulletin 604. Available at:

Unconventionally Mining Phosphorus from Wastewater

By Michael Schmid of Renewable Nutrients

Conventional wastewater treatment facilities have evolved to become extremely proficient in the practice of sequestering nutrients, particularly phosphorus and nitrogen, present within their incoming municipal and industrial waste streams. Many facilities, and perhaps the case could be made to suggest “most” of the 16,000+ treatment plants in the United States, employ a form of chemical precipitation that serves to bind dissolved phosphorus to a metal salt or rare earth elements (e.g. – ferric chloride, alum or cerium chloride). This precipitations segregates the phosphorus such that it travels with the solids portion of the treatment process and thereby delivers to receiving waters a final liquid effluent that is low in phosphorus (or at least within a mandated tolerance for the nutrient).

The common practice of dosing an incoming waste stream with metal salts does have its disadvantages, however. In many cases, it can be rather costly just from a chemical consumption perspective, which is driven by the amount of daily incoming total phosphorus that needs to be isolated and removed from the liquid stream. The addition of metal salts also adds to the facility’s overall sludge content, creating more solids material that must be treated, digested, dewatered and ultimately disposed, and compounding the operational cost drivers that have to be controlled and managed. Finally, from an environmental standpoint, it simply cannot be beneficial long-term to landfill or even land apply biosolids that are artificially saturated with metals (and phosphorus), so beyond the daily cost of operations, there may very well prove to be a heavy cost to the environment.

Fortunately, many treatment facilities have recognized the operational and environmental costs associated with dosing metal salts and are employing alternatives. One emerging technology for managing incoming phosphorus, which has gained wide acceptance especially by progressive treatment plant operators, is bio-P. Here, phosphorus is captured and removed from the incoming liquid stream biologically by phosphorus accumulating organisms (PAOs). While bio-P can be very efficient at removing phosphorus and isolating it to the solids stream, the PAOs tend to release the nutrient from within their cell walls during and after anaerobic digestion. Unfortunately, this released phosphorus typically follows the liquid portion of the solid stream through dewatering, producing a high-P liquid side stream that is nearly always routed back to the plant’s head works, and must ultimately be re-treated again and again by the bio-P process. This side stream is commonly referred to as a “recycle stream,” and in many cases can exhibit phosphorus levels as high as or even exceeding 500ppm. Recycling this phosphorus-laden stream serves to limit the capacity and effectiveness of any bio-P process, yet it also yields a single, concentrated point or “reserve” from which phosphorus can be mined, recovered, and even re-used beneficially.

While academics and scientists have studied, debated, and preached about nutrient (and specifically phosphorus) recovery from waste streams for many years, putting the concept to practice is a relatively recent phenomenon. There are several new technologies on the market today that can assist a treatment facility in removing and recovering phosphorus from its waste streams, but one emerging technology that has proved particularly effective at recovering phosphorus from side streams or recycle flows is Quick Wash® – a concept originally developed by the USDA and commercialized by Renewable Nutrients.



Quick Wash is versatile enough that it can recover phosphorus from both liquid and solid streams, but given a bio-P operation (also sometimes referred to as Enhanced Biological Phosphorus Removal – EBPR), one area in particular where it can be effectively deployed is downstream of dewatering to treat the liquid side stream (or recycle stream). In the illustration above, the Quick Wash system receives the recycle flow and extracts nearly all of the phosphorus that is not already in solution. The system then precipitates out the phosphorus by introducing lime and forming calcium phosphate. The calcium phosphate is filtered using a liquid/solid separation apparatus and can be used beneficially as a phosphate fertilizer, an animal feed additive, or as a supply of raw material where calcium and phosphorus are required. The final liquid effluent from the Quick Wash system is routed back to the facility head works as a clean, very low-P or even no-P stream. So Quick Wash not only recovers phosphorus and produces a valuable byproduct, but it eliminates the recycle flow of phosphorus and yields greater capacity and efficiency in a bio-P operation. This increased capacity gives a facility the flexibility to increase its incoming waste stream flow without the addition of major infrastructure upgrades.

Progressive wastewater treatment facilities that operate bio-P combined with anaerobic digestion are producing an untapped, yet readily available phosphorus reserve in the form of phosphorus-rich recycle streams. Recycling released phosphorus from the solid stream back into the liquid stream only serves to add to a facility’s daily phosphorus load and create a scenario in which its bio-P operation is unable to operate at its intended capacity. The phosphorus-rich recycle streams of such facilities present an opportunity for technologies not only to extract and recover phosphorus and re-purpose it for beneficial re-use, but also to eliminate the constant recycling and re-treating of phosphorus within a treatment plant. Given a finite or limited worldwide phosphate rock supply, and the need for phosphorus as a life-sustaining nutrient important to preserving global food security, it only makes sense to “tap” the phosphorus reserve created in treatment plant recycle streams. Thanks to technologies, such as Quick Wash, phosphorus recovery may soon be standard operating procedure and wastewater treatment plants may very well be able to truly own and live-out the moniker “Water Resource Recovery Facility.”


Opinions expressed here do not necessarily reflect those of the Sustainable Phosphorus Alliance.

About Renewable Nutrients

Renewable Nutrients is a private, North Carolina-based company that turns waste into sustainable and profitable resources. Through its patented Quick Wash® system, Renewable Nutrients enables waste treatment facilities and animal feeding operations to extract and recover phosphorus from biosolids and manure. The remaining biosolids or manure, which contain crop-friendly ratios of nitrogen-to-phosphorus, can be land-applied, thus minimizing the amount of waste trucked to disposal sites, and reducing or even eliminating the incidence of nutrient pollution from soil runoff. In addition, municipalities and farms can sell the recovered phosphorus on the open market, and engage in the trading or marketing of nutrient credits.


Phosphorus Extraction from Wastes: The Key to Phosphorus Problems?

By Nick Reckinger of FEECO International, Inc.

As one of the key nutrients in growth, phosphorus is critical to maintaining food security and life on Earth. This has scientists worried over the dwindling mineralogical reserves from which we mine this valuable nutrient source. Interestingly, the world faces a problem of too much phosphorus in other areas; excess phosphorus from nutrient runoff is contaminating waterways and causing toxic algal blooms and dead zones throughout the world.

As the world looks to feed a growing population, demand for this life-giving nutrient is not likely to waver. This has many looking at the opportunity to use this resource in a more sustainable way. Processing of organic wastes can help alleviate pressure on finite resources while diverting phosphorus from waste as runoff back into the soil where it belongs.

The Case for Recycling Phosphorus

Organic wastes are a renewable resource, so it’s easy to see why the potential to derive even a small portion of our phosphorus requirements from this growing category of wastes is so attractive. One recent study looked at three primary phosphorus waste streams (human food waste, human excreta, and animal manure) and concluded that it would take only 37% of the phosphorus available in these existing waste streams to support the yearly U.S. corn crop’s phosphorus requirements.

Recycling phosphorus from organic wastes would not only provide the world with a much needed renewable source of phosphorus, but it would also help to mitigate the environmental problems that result from phosphorus runoff. Dead zones, or hypoxic areas that kill off fish and other organisms in waterways as a result of insufficient oxygen, have largely been blamed on nutrient runoff, with agriculture being a major contributing source.

Although restoration is an option, it is costly, making the prevention of dead zones much more feasible. And while there are many contributing factors to runoff (proximity to waterways, soil type, distance to bedrock, etc.), minimizing the potential for runoff to occur through proper fertilizing techniques and nutrient management best practices will likely be a primary endeavor in protecting waterways.

Two materials in particular have seen a surge of interest for their nutrient recovery and reuse potential: biosolids and manure.


Biosolids, also commonly called wastewater treatment sludge, are the materials left over from the wastewater treatment process. While various methods exist for the disposal of biosolids, disposal methods such as landfilling or incineration usually disregard the valuable nutrient content that biosolids hold. Additionally, disposal is increasingly being seen as unsustainable from a long-term perspective. And with increasing regulation around land application, municipalities are in need of a workable solution.


Similarly, regulation around the land application of manure has also been increasing, putting a growing strain on farms dealing with the massive amounts of manure produced by the agricultural norm of large-scale farming operations. Farms are also limited in the distance they can haul their manure to land apply it, due to its high moisture content, which makes transportation a costly expense.

Simultaneously, farms are purchasing chemical fertilizers to provide much of their nutrient needs, while the value of the manure they land apply is not often fully realized due to runoff, resulting in an inefficient imbalance of nutrient resources for crop production.

Granulation: Key to Recycling Phosphorus?

Phosphorus recovery from organic wastes is still in its infancy as an industry, with much research under way, and still more to be done. As a fertilizer industry veteran, we have been among those on the forefront of this issue, having developed process solutions and systems around nutrient recovery from organic wastes for decades. We use our expertise in granulation to transform difficult to handle, moisture-laden materials into a dry, premium-grade granular product that exceeds the EPA’s 503 regulations for a Class A Biosolid. This, in combination with significantly reduced odor, eases many of the issues surrounding land application.

In addition to these benefits and reduced transportation costs, there is ample opportunity for customized formulations and nutrient blends through granulation. As such, granulation can serve as a means to producing a marketable product that can supplement the purchase of additional nutrients for both municipalities and large-scale farms, all while reducing waste management costs.

Reduced Runoff through Granulation

While granulation offers many benefits to the farmer and/or municipality, the granulation of organic wastes into fertilizer or soil amendment products ultimately aids in the runoff prevention effort; because granulation produces a dry product, there is less potential for runoff to occur. Unlike the moisture-rich raw materials, a dry product does not add moisture to the soil, which can increase the likelihood of runoff occurring.

Furthermore, a granular product makes following a nutrient management program much easier and more efficient. The N:P ratio is often imbalanced as a result of fertilizing to meet nitrogen demands and inadvertently over-applying phosphorus. Granular products allow the N:P ratio to be carefully controlled to suit the nutrient profile of the land where it will be applied, significantly reducing the opportunity for runoff to occur. Granules also allow for easier and more accurate dispensing; soil receives only what it needs, further reducing the chance for excess phosphorus to leach from the soil.

An Overview of the Granulation Process

The granulation process is different from one source material to the next, with necessary pre-conditioning methods also differing. However, in general, granulation works by taking the nutrient-rich cake left over from the digestion process (or the wastewater treatment sludge remaining after the water treatment process), and mixing it in a pug mill.

Additives and/or nutrients can be included here to customize the formulation. The pug mill thoroughly mixes the feed materials (along with process recycle) to form agglomerates. These granules are then dried in a rotary dryer, where the tumbling action further rounds them. A cooling step reduces the temperature of the product, yielding a product that will hold up to handling and storage, but still deliver nutrients in a timely manner upon application.

As each source material differs in how it will respond to granulation, pilot testing is required to work out process variables and scale up the process to full-scale production.

FEECO Vice President and General Manager, Lee Hoffmann, who is also a member of the Brown County Phosphorus Committee, had this to say on the matter: “The importance of utilizing our organic wastes to their fullest potential is becoming increasingly critical as the world hosts a growing population. Add to that that some of our resources are essentially being wasted as runoff, and it’s easy to see why this approach makes sense. As a fertilizer industry veteran and an expert in the transformation of wastes into value-added products, we are well positioned to provide solutions to this market.”


Phosphorus is an invaluable nutrient to life on Earth. Maximizing available resources, while taking the pressure off of finite phosphate reserves is essential for long-term, sustainable phosphorus management.

Considering that renewable phosphorus resources in the form of manure and biosolids are often going to waste and even contributing to environmental issues, the potential these organic wastes hold to meet sustainable phosphorus goals is an incredibly valuable opportunity.


Opinions expressed here do not necessarily reflect those of the Sustainable Phosphorus Alliance.


FEECO provides feasibility testing, process and product design, and custom processing equipment for organic waste materials, including biosolids and manure. From idea, to complete process solution and custom equipment, FEECO offers capabilities in transforming organic wastes into value-added, marketable products. FEECO is based out of Green Bay, WI. In addition to their custom process equipment and systems, they offer a unique testing facility where they can conduct both batch and continuous, pilot-scale tests to simulate commercial production conditions.

Reclaiming the Value of Urine for Agriculture

By Tatiana Schreiber of the Rich Earth Institute

Abe Noe-Hays is a co-founder of Rich Earth Institute. The institute promotes collecting and using human urine as a plant fertilizer. Here Abe applies pasteurized urine to a test bed of lettuce. Photo by Marcin Szczepanski/Senior Multimedia Producer, University of Michigan, College of Engineering
Photo by Marcin Szczepanski

What is the potential for reclaiming the phosphorus present in human urine for agricultural use? World-wide there are a number of projects exploring this question, but few in the United States.[1] A small-scale but exciting example is the Rich Earth Institute’s Urine Nutrient Reclamation Project (UNRP) in Brattleboro Vermont.  Since 2012, Rich Earth has been collecting urine from 150 – 200 households in the community, transporting and sanitizing it, and using it as fertilizer on test fields of hay and vegetables. Rich Earth currently invites participants to save urine at home and bring it to a central depot. The long-term goal, however, is to support the wide-spread use of simple toilets and storage systems that can divert urine from aging sewage, storm water and water treatment systems, many of which are underperforming in cases of extreme weather events and changes in water cycles due to climate change.  Urine accounts for roughly three-quarters of the nitrogen and roughly half of the phosphorus in municipal waste streams. Research Director Abe Noe-Hays estimates that one thousand gallons of urine contains the equivalent of 109 pounds of urea, 13 pounds of triple superphosphate, and 29 pounds of muriate of potash (KCl), as well as smaller amounts of calcium, magnesium, sulfur and micronutrients Therefore, substituting urine for chemical fertilizers can be an appealing prospect depending on the nutrient needs of specific crops and the nutrient status of soils.

Rich Earth’s field tests on hay over several years have shown equivalent yields between urine-fertilized and chemically-fertilized test plots, both significantly higher than unfertilized plots. Forage quality remained high, and one farmer has been able to achieve a solid second cutting of hay where previously yields were not sufficient to warrant a second cutting.  Farmers participating in the project have had good results applying the sanitized urine to hayfields without dilution; one of Rich Earth’s goals is to develop a concentrated product that can be applied directly to reduce labor requirements. While it is likely the nitrogen rather than the phosphorus from urine is what has been the most significant nutrient in these Vermont test fields (because the soils were not deficient in phosphorus at the start), these experiments are an important model for the potential of recycling human waste for fertilizer world-wide.

Among hay and vegetable farmers in New England that Rich Earth has surveyed, interest in the potential of a urine-derived fertilizer is high, although farmers are cautious.  Respondents wrote, for example, “I think it is a great way to start closing the nutrient cycle – counting humans as part of the whole environmental web,” and “Could be a silver bullet; cost effective, renewable, recycling,” and “It’s about time we started using this valuable nutrient in the field instead of allowing it to contaminate drinking water by flushing it down the toilet.” Research suggests that farmers who currently practice organic or ecological methods may be more open to using urine than conventional farmers, but they may also have more concerns about potential contaminants in the urine including their impact on the health of soil biota. Not surprisingly, many also express concerns about how their customers may respond to the use of urine-derived fertilizers on their crops.

Rich Earth’s research aims to respond to some of these concerns. The organization will assess farmer interest and technical needs with regard to using these fertilizers on animal feed and fiber crops, perennial crops (such as fruit trees), ornamentals and other non-edible and edible crops. Testing indicates that heavy metal levels are extremely low – on average a thousand times below accepted risk levels. And although fiber, biomass, and animal feed crops could utilize all urine-derived fertilizer for the foreseeable future, Rich Earth has conducted field studies with lettuce and carrots to examine the fate of pharmaceuticals as well as biological components (viruses and bacteria) when urine-derived fertilizers are used for growing edible crops. Final results from this research have not yet been published, but the data so far indicate that while trace levels of pharmaceuticals could be detected in both lettuce and carrot tissue, the levels were very low. As Noe-Hays puts it, “a person would have to eat a salad from the study plot every day for two thousand years to get a single dose of acetaminophen (Tylenol).” With regard to bacteria and viruses, this research is ongoing, but current standards specify that urine can be effectively sanitized by pasteurization or by storing it from one to six months before using. Rich Earth’s ongoing research will help to better understand what happens under different storage and treatment practices.

With regard to public perceptions, Rich Earth’s social research seeks to learn more about what people know and think about what happens to their waste currently, and discover the most useful communication strategies to help attitudes evolve. In surveys and interviews with people who have contributed urine to the UNRP over the last four years, one important message stands out: people can and do change their attitudes over time. Although sometimes reluctant and uncomfortable at first, participants have become more and more enthusiastic about saving their urine and seeing it reused for agriculture. Learning about the value of urine as a fertilizer has inspired much of this evolution. For example, one person said, “I am so impressed by this simple process that turns a waste product into something so useful, saves water and avoids chemical fertilizers in our soil. Amazing! I love the environmental education that happens when curious visitors ask about that weird jug in our bathroom. It has started some good conversations!”

Of course there are no “weird jugs” when simple urine-diverting toilets are employed. Rich Earth is working towards more wide-spread use of these systems for source-separation and nutrient reclamation from urine, including addressing regulatory issues. Until now, human waste has been seen by regulatory agencies as something to be “disposed of” so as to protect public health.  But Rich Earth sees urine is a resource. Rather than needing to be “disposed of,” it should be collected and made use of as a “value-added” product. The organization currently has a permit for a mobile-pasteurizing unit through the Vermont Agency of Natural Resources’ Watershed Management Division. This has allowed local regulators to become comfortable with the concept of recycling urine for fertilizer. Using this permit, Rich Earth has developed the tools and equipment needed for larger scale processing of urine.

Ongoing research, now funded with a four-year grant through the National Science Foundation, will allow the organization to learn more about what regulators need to know and how best to communicate with them so that regulations can be written that will protect human health and the environment by keeping urine out of the waste stream and returning it to the soil.  Step by step, community by community, it will then become possible to close the loop and recycle the abundant nutrients, such as phosphorus, that we so generously expel in liquid form every single day.

Opinions expressed here do not necessarily reflect those of the Sustainable Phosphorus Alliance.

Tatiana Schreiber is an independent scholar with a doctorate in Environmental Anthropology. She teaches in the areas of agroecology, environmental studies and writing at Keene State College in New Hampshire and is a research associate at Rich Earth Institute. She also operates Sowing Peace Farm in Vermont, selling organic seedlings of heirloom and unusual varieties of vegetables and medicinal plants. Contact her at 


Featured Member: Ostara


Vancouver-based Ostara helps protect valuable food and water resources by changing the way cities and industries around the world manage essential nutrients. It is a Founding Member of the Sustainable Phosphorus Alliance, and VP of Nutrient Recovery Solutions, Matt Kuzma, serves on our Board of Directors.

How big is your company and where does it operate?

Ostara is about 30 people and operates across North America and Europe primarily.

What does your company do related to phosphorus sustainability?

Ostara covers two facets of sustainable phosphorus management. First, we recover phosphorus from industrial and municipal waste streams to reduce pollution from point sources. Secondarily, this recovered phosphate is upcycled into Crystal Green fertilizer, which is citrate-soluble (not water soluble and normal soil pH ranges), and thus reduces potential for nutrient pollution through runoff from fields or groundwater leaching.

What’s your business model?

Ostara is uniquely positioned as a recovery for reuse company, with business units delivering nutrient recovery technology and crop nutrition solutions. We are integrated into markets through contracts to both implement the nutrient recovery technology on applicable water streams and to take the recovered fertilizer product to market through any required processing, registration, licensing, marketing, distribution, and logistical support. It is only through this aggregated supply chain that market-competitive volumes and economies of scale can be achieved.

What are the biggest challenges you face?

Interesting question, as this effort to shift thinking from removal to recovery has been a challenge in the technology adoption rate from many market sectors that don’t view sustainable phosphorus management as a responsibility. While many water treatment facility owners/operators are required to remove phosphorus from their streams, they are not incentivized to invest in longer term solutions that complete the cycle of a circular phosphorus economy. Commonly, this type of practice as viewed as greater risk and/or cost, without accounting for the longer term benefits or impacts of such an investment. From the crop nutrition aspect, it takes time to build the awareness in the market (both retailers and growers) of the benefits of a non-water soluble fertilizer. There are agronomic, economic, and environmental benefits which are all vital to the value proposition and adoption speed for our product.

Where do you see the biggest opportunities for advancing phosphorus sustainability?

There is tremendous opportunity for both increased adoption in the established markets, but also broadening markets for geographies and industrial segments that are increasingly developing more advanced practices. While there is also great opportunity and demonstrated technical feasibility in the animal waste segment, this will require new business models with aggregation to reach economies of scale where implementation makes economic sense. That said, this recovery must be done in conjunction with reuse wherein our agriculture communities adapt and adopt new crop nutrition products like Crystal Green to reduce the non-point source pollution points in parallel with point source.

What’s been your biggest sustainability win?

We’ve established the largest installation base of phosphorus recovery sites, and are both producing and selling the largest volume of recovered phosphorous fertilizer in the market.

USDA and OCP North America Jointly Fund Phosphorus Research

OCP North America has provided matching funds to support a two-year postdoctoral research fellow in the lab of Dr. Carl Bolster, research hydrologist at the USDA-ARS’s Food Animal Environmental Systems Research Unit in Bowling Green, Kentucky. The postdoctoral researcher will work on topics directly related to the Sustainable Phosphorus Alliance’s Phosphorus Transport Modeling Group and in collaboration with researchers at the ARS Soil Drainage Research Unit and Ohio State University.

The unique collaboration leverages a combination of public and private sector funds to advance the study of phosphorus flows from agricultural fields in the Western Lake Erie Basin, a significant eutrophication hotspot. Research will focus on the development and testing of a model to determine the relative contributions of legacy and incidental phosphorus losses from agricultural fields.

OCP is a global leader in plant nutrition and a foundational supporter of the Sustainable Phosphorus Alliance, who facilitated the collaboration. “OCP North America is very pleased to provide support for this important work,” said Kerry McNamara, Chief Executive Officer of OCP North America and Alliance Board member, “which is fully aligned with our mission of helping North American farmers maximize their productivity while protecting the environment, including promoting sustainable nutrient management practices that protect water quality.”

Current models of phosphorus transport fail to address whether phosphorus found in waterways is from recent years or decades-old applications. That knowledge is essential in determining strategies for reducing phosphorus losses to the environment, which contribute to algae blooms in Lake Erie. The new research collaboration will be used to help to identify management practices best suited to reducing phosphorus losses from farmland in the Western Lake Erie Basin.

The Alliance’s Phosphorus Transport Modeling Group is establishing itself as the go-to resource for understanding the science of agricultural phosphorus transport modeling. For further information, please contact us.

AgSTAR’s New Anaerobic Digester Project Development Handbook

By Vanessa McKinney and Nick Elger of AgSTAR

For 26 years, the United States Environmental Protection Agency (US EPA) AgSTAR Program has been helping farmers and communities across the United States develop and implement anaerobic digestion (AD)/ biogas systems. These systems are critical to reduce methane emissions from manure management operations, while also providing other environmental and economic benefits. As a trusted partnership program, AgSTAR helps educate the public on best practices for designing, implementing and maintaining digester projects and brings together leading experts to discuss opportunities and challenges for advancing the biogas industry.

Anaerobic digestion systems are a useful technology for managing nutrients on livestock farms. When paired with nutrient recovery technologies, they can be effective at reducing nutrient runoff and improving soil health and local water quality.

AgSTAR’s newest resource, the soon-to-be-released Anaerobic Digester Project Development Handbook is a comprehensive compilation of the latest knowledge in the industry on best practices for AD/ biogas systems. The goal of the Handbook is to ensure long-term project success for AD biogas systems by providing background and a framework for AD project development.

The 3rd edition of the Handbook covers the basics of AD systems, including an overview of the biology and chemistry of the system, and addresses key questions to ask when developing and implementing an anaerobic digester project, including those related to complex business development aspects of projects. In addition, the Handbook includes information on AD/ biogas systems best management practices for nutrient management.

For whom is the handbook intended?

Although “Project Development” is in the title, this publication is not just for AD Project Developers. The Handbook has over 100 pages and 11 Chapters of content, with topics relevant to policy makers, financiers, and others interested in implementing AD/ biogas systems.

10 Keys to Digester Success

The 10 keys for digester success is a component of the Handbook that introduces the essentials for successful farm-based digester projects. This new resource was developed with feedback from experts in AD/ biogas system project development and offers helpful tips to consider for start-up, implementation, operation and continuous improvement of AD/biogas systems.

Action Desired Outcome
1. Plan for Success During the planning stage, identify and define clear project goals. To establish these, site-specific farm information should be collected, including ownership and managerial goals and projections, animal information (e.g., number, types, maturity, bedding type, etc.), type(s) of manure recovery, volume of manure, manure analytical information, past and current disposal practices, and operational costs, etc.)
2. Recruit and Secure an Experienced Team Work with an experienced team to initiate and implement the project. This will substantially increase the chance of project success. The complexity of these projects requires specialists.
3. Use a Sustainable Business Model Not only should the project be cost-effective, it must meet the project’s financial goals including revenue and profit generation and return on investment. The economic factors include well-defined project costs, expenses, revenue or income, and liabilities, among many others. Personal goals for the project’s liquidity and profitability potential define the financial factors. The business model could consider involving partners, utilizing third party investments, or implementing other traditional ‘cooperative’ models.
4. Secure Suitable Feedstock Supply Identify the quantity and quality of all suitable feedstocks and test feedstock initially for Total Solids (TS), volatile solids (VS) and Chemical Oxygen Demand (COD). Tests for biomethane potential (BMP) and Anaerobic Toxicity Assays (ATA) can be subsequently done. See AgSTAR Codigestion Guidelines for additional information.
5. Identify Appropriate Technology No single AD technology can be used for all situations or all feedstocks. Rather, the AD technology must be chosen to match the project conditions and feedstock characteristics. There are alternatives such as composting, and aerobic technologies, which are also effective at converting organics.
6. Analyze Options for Biogas and Digestate Use Consider market availability, capital and operating costs, and potential revenue to determine the most beneficial use for biogas. Determine the ability for digestate on-site use. Consider external markets for products such as bedding, compost, and fertilizer.
7. Develop Off-Take Agreements Establish off-take agreements for energy and digestate products, including the prices and detailed specifications for all delivered materials.
8. Evaluate Added Benefits Consider the added benefits of using AD, which may be difficult to quantify. These include climate, soil, water quality, sustainable food supply, community relations, and odor control.
9. Community Outreach Community outreach and education is critical to obtain buy-in and approval from the community, including, but not limited to, regulatory approval and community and neighborhood approval where the project is located.
10. Plan for Operation and Maintenance Good operation and maintenance practices are key for effective operation of AD/biogas systems. This includes continuous monitoring and management to ensure the biological processes and mechanical equipment are working properly. It is also important to consider whether current staff or a third party will be used to perform these functions.

A Connected Resource

In addition to details about AD/biogas system best practices, the Project Development Handbook contains links to dozens of additional resources from experienced professionals in the field to ensure that users have access to information beyond what is covered in the handbook.

EPA AgSTAR Program is eager to keep growing the number of successful AD/ biogas systems in the US. Be sure to check out the new soon-to-be-released Anaerobic Digester Project Development Handbook, as well as the AgSTAR website to learn more.


Opinions expressed here do not necessarily reflect those of the Sustainable Phosphorus Alliance.

About the authors

AgSTAR is a collaborative partnership program sponsored by EPA and USDA that promotes the use of biogas recovery systems to reduce methane emissions from livestock waste. Vanessa McKinney is the Program Manager for EPA’s AgSTAR Program, where she works with U.S. livestock, biogas and government stakeholders to advance the deployment of digesters and biogas systems. Nick Elger is the Program Manager for the EPA AgSTAR Program and serves as the Agriculture Lead with the Global Methane Initiative. In his role as Program Manager for AgSTAR, Nick works with the U.S. livestock industry, state and federal agencies, and biogas industry stakeholders to advance the deployment of digesters and biogas systems. While supporting the Global Methane Initiative, Nick helps advance anaerobic digestion of organic feedstocks globally for methane mitigation and energy production.

Featured Member: Biochar Now

BiocharNow logo

Incorporated in November 2011, Biochar Now is a pioneer in the biochar industry with strong engineering, manufacturing, sales and administrative personnel focused on making and selling quality biochar on a very large scale. They became members of the Sustainable Phosphorus Alliance in 2018.

How big is your company and where does it operate?

Our company currently has a biochar production operation in Berthoud Colorado. We currently have 23 employees. We have recently closed on expansion funding and we have agreements in place to set up several additional production sites around the US over the next year. One site will be located in the Southeast, another on the East Coast and one site will be located in California. This will reduce the shipping expenses of our customers that currently take delivery from our Colorado facility.

What does your company do related to phosphorus sustainability?

We produce a high-quality carbon from dead trees and waste wood. This carbon has a cation exchange property that effectively binds phosphorus and other nutrients. Our product has been used to treat scores of water bodies nationally and actually removes the nutrients from the water bodies when you remove the carbon filters laden with the nutrients.

What’s your business model?

We sell our product to lake treatment companies, dredgers and other contractors that utilize our product to meet their nutrient removal needs. They use our biochar product to filter nutrients from nutrient laden waters. If needed, we can also participate in the resale of the product after retrieval from the waters.

What are the biggest challenges you face?

We find it easy to get utilized on smaller projects, such as small lakes, golf course ponds, etc. But we actually find our cost effectiveness to be an issue on being included on the largest cleanup projects. Sadly, the projects with the largest budgets are highly visible and end up with perverse incentives to the contractors. The contractors know the money will keep flowing year after year on these projects, as long as the problem persists, because the public will demand “something” be done. If they solve the problem on those projects then they are afraid the funding will stop and it will take a long time for other large projects to clear the permitting hurdles for treatment.

Where do you see the biggest opportunities for advancing phosphorus sustainability?

We are able to remove phosphorus from the environment very cost effectively as we are able to reuse the nutrient laden biochar with our agricultural and landscape customers. This cascading use can allow the recapture of project funds and expand further the reach of the project. When the cost is greatly reduced, this opens more projects that can be launched with the limited funds available for clean up.

What’s been your biggest sustainability win?

Our manufactured biochar product is a carbon-negative product that qualifies for carbon credits. Thus, we are in essence sequestering carbon from entering the atmosphere and utilizing that carbon to clear our nutrient laden waters. We then put that nutrient laden carbon into the earth to increase plant growth and further bind and stop nutrient runoff from fields and landscaping when fertilizer is applied. It makes for a very virtuous sustainability circle.

Research Needed in Food Waste Co-digestion

By Dr. Michelle Young

Arizona State University, Swette Center for Environmental Biotechnology

Food waste is a problem in the United States. About 30 to 40% of the U.S. food supply, or roughly 40 million tons, ends up as pre- or post-consumer food waste (1). Of that, 76% of food waste and its nutrients is landfilled, which accounts for 15% of the material landfilled in the US (2). Food waste accounts for one-third of landfilling-related emissions, or 36.2 million metric tons of CO2 equivalents. Isn’t composting an option? While composting provides the added benefit of producing fertilizer and soil amendments, about 2.2 million metric tons of CO2 equivalents are emitted from the biodegradation of food waste (3).

What about making energy from food waste instead? This is one of the hottest topics in the food waste and municipal wastewater treatments sectors: co-digesting food waste in anaerobic digesters at your local wastewater treatment plant to produce natural gas as methane. Medium to large municipalities often have underutilized anaerobic digesters at their wastewater treatment plants as part of sewage treatment. These digesters provide a financial benefit to the treatment plant: Solids produced during wastewater treatment (i.e., bacteria) are broken down to soluble organic molecules, such as acetate, reducing the amount of solids sent to landfills. Acetate can be consumed by methanogenic bacteria to produce methane–essentially natural gas—for combustion in engines and turbines to produce electricity for plant operations.

During co-digestion, wastewater treatment plants supply food waste to the anaerobic digesters from streams as varied as industrial waste streams from food and beverage manufacturing, household food wastes, restaurant wastes, and grease from grease interceptors and traps. Because these organics are rich in energy and biodegradable, adding food waste to the digesters can double methane production. For example, East Bay Municipal Utility District in Oakland, CA, produces 30% more energy than needed to operate the plant and returns excess to the electrical grid. In total, it is estimated that municipal co-digestion produces 551 million kWh per year of electricity – enough energy to power about 50,000 homes.

One largely overlooked area in the food waste co-digestion literature is nutrient recovery from the solids and liquids produced during digestion. To some extent, phosphorus is discussed as a necessary nutrient for healthy microbial communities during anaerobic co-digestion. The few review papers that discuss phosphorus liken its recovery to that of traditional anaerobic digestion processes, where most of the phosphorus remains in the biosolids, making recovery difficult. Most traditional anaerobic digesters recover phosphate for agricultural purposes using struvite precipitation, biosolids application, or incineration of sludge ash. Each of these processes has its own obstacles to larger commercialization due to the energy required. Ultimately, how food waste digestion effects these processes is unknown and provides an excellent opportunity for future research.

(2) US EPA

Michelle Young is a post-doctoral researcher in the Biodesign Swette Center for Environmental Biotechnology. She received her Ph.D. in Environmental Engineering in 2018. Her research focuses on utilizing existing wastewater treatment resources for improved nutrient and energy recovery from wastewater and non-traditional waste streams.

Opinions expressed here do not necessarily reflect those of the Sustainable Phosphorus Alliance.