Phosphorus Removal and Recovery through Newly Developed Adsorption TechnologyEPA Contract Number: EPD15032
Title: Phosphorus Removal and Recovery through Newly Developed Adsorption Technology
Investigators: Varshovi, Amir A
Small Business: GreenTechnologies, LLC
EPA Contact: Manager, SBIR Program
Project Period: September 1, 2015 through February 29, 2016
Project Amount: $98,389
RFA: Small Business Innovation Research (SBIR) - Phase I (2015) RFA Text | Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Water
Much attention has been focused of late on phosphorus pollution and algae blooms. However, the problems of phosphorus mining and consumption are much more complex and can be categorized into two distinct areas of concern: (1) phosphorus’ critical role in food production and the dwindling supply of phosphate rock reserves; and (2) the mining and use of phosphate and the environmental impact of phosphate runoff and leaching. The environmental problem that this SBIR program addresses is the need for the development of technologies for sustainable phosphorus removal, recovery and conversion into reusable phosphorus products.
Enhanced biological phosphorus removal (EBPR) and chemical precipitation are the two most widely employed phosphorous removal methods. However, these technologies struggle in reducing phosphorous concentrations below algal growth limits and generally require infrastructure that limits their use to large installations. In contrast, adsorption technology has the ability to effectively remove phosphorus from dilute waste streams to levels below algal growth limits. Furthermore, adsorption methods require less infrastructure than other methods so they can be used locally, at the point of generation, thereby affording alternative approaches for limiting phosphorous entry into the environment.
GreenTechnologies intends to develop prototype phosphate adsorption systems that will be able to treat wastewater or phosphate-rich runoff on scales of several hundred gallons/day to tens of thousands of gallons/day. The technology, which is the intellectual property of the University of Florida and which has been optioned by GreenTechnologies, has demonstrated the high affinity and selectivity for phosphate. The phosphate can be released by treatment with added base, regenerating the adsorbent and allowing for nutrient recovery, thereby reducing the capital and operating costs of phosphorus recovery, which has been cost prohibitive for application in a number of industries. The adsorption technology can be used in phosphate filters, batch reactors, or other phosphate sequestration tools.
Commercial applications for phosphate filters include municipal water and wastewater treatment for removal of phosphorus in waste streams, removal of phosphorus from animal waste streams to reduce runoff and leaching related to agricultural operations, filtration of golf course water hazards where eutrophication and phosphorus pollution often run rampant, and smaller niche markets such as the aquarium and pool industry to control algal build up. The recovered phosphorus will be commercialized and marketed as a fertilizer for resale in already established fertilizer markets for crop production. On a global scale, the monetary value of fully exploiting nutrient recovery opportunities is estimated to be $6 billion, with potential phosphorus recovery accounting for $4.2 billion (Algeo and O’Callaghan, 2012). Economic opportunity in conjunction with environmental concerns provides strong motivations for the development and refinement of reliable and effective phosphate filter technology. Potential investors and commercial partners include private equity firms focused on green technology, existing equipment manufacturers already established in the wastewater treatment industry and private/public partnerships (PPPs).
According to the EPA, phosphorus pollution from municipal wastewater discharges, runoff from agricultural operations, and other sources is on track to becoming one of the most expensive and arduous environmental challenges of the future (EPA 2011). Over the next 20 years, phosphorus recovery is projected to become a widespread and established practice throughout industrialized nations (Sartorius, Von Horn, and Tettenborn, 2012). Commercialization of the innovative adsorption technology would culminate in a scenario where phosphorus can be sequestered from the environment and recycled by incorporating the recovered material into environmentally friendly, slow release fertilizer products. Adsorption technology is capable of removing phosphorus from both dilute and concentrated waste streams resulting in effluent water that easily meets or exceeds quality requirements in a wide range of applications and treatment scales.
Markets for such technology include the industrial and municipal wastewater treatment industry, the agricultural industry, and the aquarium and pool industry and further markets such as filtration of golf course water hazards and privately owned lakes and ponds. The value of these markets totals in excess of $50 billion per year. Increasing regulatory pressures is one of the most influential catalysts behind the growing interest and demand for phosphate filtration devices. Cost savings from reduced maintenance and repair expenditures, a multi-million dollar expense each year, cost savings from the utilization of recycled material and goodwill stemming from investments in environmentally sustainable practices are additional motivations prompting the demand for adsorption technology.
Laboratory tests have shown the adsorbent to be highly effective, reducing phosphate concentrations from 5-10 mg/L to 0.005 mg/L in test batch reactions, and to be reusable. Major barriers to development currently include lack of data at larger scales and with non-synthetic wastewaters. A functional prototype capable of demonstrating operation at larger scales is needed as a stepping stone to commercialization of a product based on these adsorption principles. To this end, a fluidized bed reactor utilizing the new adsorbent will be developed as part of this project to test performance. This reactor will then be used to determine critical parameters for optimization, such as breakthrough capacity for phosphorus adsorption, hydraulic retention time, flow velocity and particle sizes for optimal phosphorus removal. A combination of synthetic and natural wastewaters will be used to determine performance under the possible conditions required for specific markets. Regeneration of the adsorbent must also be assessed prior to commercialization, and will be performed by dilute washing with sodium hydroxide. The amount of sodium hydroxide necessary to clean the resin surface will be determined and reported, as the chemical inputs are critical for a complete life cycle analysis and cost analysis of the process. The capacity of the filter after several subsequent regeneration cycles will be monitored to assess feasibility of the device for commercialization.
Recovery of the phosphorus from the regeneration solution will be explored using chemical precipitation as a means for conserving phosphorus resources.
Compared with the prevalent technologies available for removing phosphorus today, this new technology removes a significantly larger portion of phosphorus from incoming effluent. Even the most stringent water quality phosphorus limits can easily be met using this technology. Compared with EBCR and chemical precipitation methods, this adsorption process requires less infrastructure and a smaller footprint, making it a viable technology even for niche applications and smaller water treatment operations where traditional water treatment methods would be prohibitive. In contrast to currently available ion exchange technologies, the new adsorption technology is highly selective towards phosphate, significantly improving removal efficiency and allowing it to be used in a broader range of contaminated water types. It is also resistant to chemical attack, allowing for multiple regeneration cycles with reduced loss of capacity compared with other types of ion exchange resins. As an added benefit, phosphorus removed from the contaminated water can be recovered from the regeneration solution and used as a valuable fertilizer. Overall, the new adsorbent technology will provide a complement to entrenched technologies by providing phosphorous removal and recovery at locations and on scales that are not now effectively served. Furthermore, it could be used in series with current technologies to meet increasingly stringent effluent phosphorous levels.