Solutions

Solutions

Many organizations are already developing solutions for P recycling and efficiency.
Please see examples below of North American cases of P sustainability innovation.

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Six microbial fuel cells stacked in one reactor block photo credit Bruce Rittmann.

"At-the-Source" Efficient Wastewater Treatment Recovers Energy and Sets the Stage for P Recovery - ASU Engineering partners with Arbsource

Dr. Bruce Rittmann, Regents’ Professor in the Ira A. Fulton Schools of Engineering, at Arizona State University with Dr. Cesar Torres and colleagues in the Swette Center for Environmental Biotechnology are developing new technologies that enable P and energy recovery from organic wastes. The technology is based on microbial electrochemical cells. Once this technology is ready, they have a ready partner in Arbsource. Currently Arbsource's patent-pending Arbcell® is a microbial fuel cell optimized to degrade the Chemical Oxygen Demand (COD) in wastewater. The Arbcell product design, developed in partnership with Dow Chemical and Arizona State University, uses non-genetically modified Anode Respiring Bacteria (ARB) inside fuel-cell inspired bioreactors called microbial fuel cells. The ARB consume wastewater pollutants Arbsource’s customers would otherwise pay to send down into the sewer. The competing technology is anaerobic digestion, which has a long history, but can be applied economically only on very large installations because it needs bulky, expensive methane purification and combustion equipment to generate electricity. Arbcell overcomes the drawbacks of anaerobic digestion by generating higher value energy outputs and doing it in a much smaller footprint that reduces costs. Biodegradation of the organic matter in the Arbcell releases inorganic phosphate that can be readily recovered in separations technologies being developed by Dr. Paul Westerhoff, Associate Dean of Research of the Ira A. Fulton Schools of Engineering, at Arizona State University and colleagues in ASU’s School of Sustainable Engineering and the Built Environment. These new methods rely on selective separation of phosphate into concentrated outputs that can be used as feedstock for fertilizer that has the same utility as today’s fertilizer from mined, non-renewable sources. When combined with the Arbcell technology, organic wastes become the resources for renewable energy and P.

Photo credits to Roberto Gaxiola

P Efficient Plants

Critical to agricultural P-use efficiency is improved uptake of P in crops. Associate Professor Roberto Gaxiola in the School of Life Sciences, Arizona State University, has developed this trait in lettuce and tomatoes and is working together with Professor Charles Sanchez at the University of Arizona to develop the trait in other crops, including corn, rice, cotton, carrots, and others. Specifically, Gaxiola’s group has unraveled a fundamental physiological mechanism by which plants regulate root activity and nutrient uptake. Through a series of laboratory experiments, the team has found a protein within plant membranes, a proton-pyrophosphatase (H+-PPase), that has been implicated in regulating sugar transport from leaves to roots. Artificial enhancement of this H+-PPase greatly increases plant nutrient uptake by increasing root production and activity, thus allowing plants to better exploit soil resources. These plants will produce higher yields in nutrient poor soils such as those found in many developing countries that have limited access to expensive fertilizers.

Recovering nutrients from wastewater to create slow-release, environmentally friendly fertilizer - Ostara Nutrient Recovery Technologies

Instead of viewing treated liquid streams as waste, the company Ostara sees a renewable resource that can generate costs savings and revenues for waste water treatment plants while helping them meet increasingly stringent environmental regulations. Many waste water treatment plants concentrate large quantities of nitrogen and phosphorus in their sludge de-watering streams. Ostara’s Pearl® Process resolves many waste water treatment plant issues and provides a comprehensive approach to nutrient management. The technology is based on controlled chemical precipitation in a fluidized bed reactor that recovers struvite in the form of highly pure crystalline pellets or “prills.” In a municipal waste water treatment plant, up to 90 percent of the phosphorus and 40 percent of the ammonia load is removed from sludge de-watering liquid using this process and the resulting product is marketed as a commercial fertilizer called Crystal Green®, a slow-release form of phosphorus, with nitrogen and magnesium and what makes it unique is the way it releases. Unlike conventional fertilizers, which release in response to water – rain or irrigation – Crystal Green is highly insoluble in water. Instead, it releases nutrients in response to certain acids exuded by growing root systems. Once the growing cycle has stopped, Crystal Green stops releasing, resulting in significantly reduced leaching and runoff that you find with conventional phosphorus fertilizers. Ostara markets the product to growers in the agriculture, turf and ornamental sectors.


Please visit the European Sustainable Phosphorus Platform P-Solutions page for more innovations in Europe:

http://www.phosphorusplatform.org/p-solutions.html