Final Report: Economic recovery and reuse of nutrients from wastewater

EPA Contract Number: EPD17009
Title: Economic recovery and reuse of nutrients from wastewater
Investigators: Kadossov, Evgueni
Small Business: XploSafe, LLC
EPA Contact: Manager, SBIR Program
Phase: I
Project Period: November 1, 2016 through April 30, 2017
Project Amount: $100,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2016) RFA Text |  Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Water

Description:

Nutrient pollution caused by excess nitrogen and phosphorus in the water is a costly and challenging environmental problem. It has a widespread potential for negative health and ecological effects. The proposed solution to this problem is the capture of ammonium, urea, nitrate and phosphate on low-cost biodegradable sorbent pellets. Upon saturation with these nutrients, the developed sorbent pellets can be effectively employed directly as slow-release fertilizer, thus adding both minerals and key nutrients to the soil. The XploSafe sorbent-fertilizer technology can potentially prevent eutrophication of natural waters and lower dependence on manufactured fertilizer through recycling. The replacement of high-energy oxidation processes with a low-energy and cost sorption process should lead to economic and environmental benefits. It can also have similar energy and economic and energy advantages over other wastewater-to-fertilizer technologies such as magnesium ammonium phosphate (struvite) precipitation or production of heat-dried microbial matter. Wastewater treatment plants can also generate added revenue streams from the sale/use of the spent sorbent as a slow release fertilizer.

The overarching goal of the proposed research was to determine the technical feasibility and assess the commercialization potential of the use of low-cost novel sorbents that can passively adsorb ammonia, nitrate, urea, and phosphate from wastewater and be used subsequently as a slow-release fertilizer.

Summary of Findings:

In this Phase I Small Business Innovation Research (SBIR) project, XploSafe successfully conducted the preparation and modification of the proposed nanocomposites; characterized their nutrient absorption capacity; and enumerated the performance of the "nutrient-enriched" nanocomposites as time-release fertilizers. The surfaces of the respective base metal oxide sorbents were functionalized to investigate any potential improvements in the uptake capacity and rates of adsorption for the target nutrients. Thirty-three distinct metal oxide and mixed-metal oxide loaded nanocomposite sorbents were synthesized and tested during the Phase I research efforts.

Target nutrient uptake studies were performed using both adsorption columns in fixed-bed experiments and by adding a small mass of sorbent media to rotating stock solution vials. XploSafe built an industry standard wastewater treatment column utilizing different amounts of sorbent for the treatment of flow-regulated wastewater streams. Next, bed depth service time model (BDST) was used to quantify and analyze sorbent uptake capacities in the treatment of primary and secondary wastewaters. In particular, the XploSafe sorbents demonstrated complete removal of phosphates from primary and secondary wastewater. A preliminary wastewater treatment capacity for XploSafe’s magnesium based nanocomposite sorbent was also quantified at 10 L/g sorbent. Based on the obtained results, an initial QA/QC procedure for forthcoming large scale manufacturing of the sorbent/fertilizer batches was proposed.

In parallel to XploSafe’s wastewater treatment studies, Dr. Jeanmarie Verchot at Oklahoma State University (OSU) independently conducted an eight-week plant growth study to test the feasibility of using the developed material as a plant fertilizer. This plant growth study investigated the viability of using XploSafe’s magnesium-based nanocomposite sorbent as an effective slow-release fertilizer after its saturation with adsorbed target nutrients. It examined the development and maturation of “Miss Oklahoma” canna lily rhizomes. Progress of the canna growth was quantified by comparing visible growth factors such as the number of shoots growing from the rhizome, number of leaves formed, and the vibrancy of the green chlorophyll in the leaves. Success was measured by larger, leafier, and greener plants. A control group characterized by the absence of exposure to fertilizer treatment was used as a baseline for comparison. The results obtained from the plant study confirmed the effectiveness of XploSafe’s slow release fertilizer as compared to commercial organic nitrogen based and a synthetic slow-release fertilizer. It was also determined that XploSafe fertilizer could be effectively blended with commercial off-the shelf fertilizers to achieve sustainable plant growth. Based on the obtained results, it was inferred that the use of XploSafe fertilizer resulted in the most consistent flowering, suggesting that a larger number of plants reached full maturity after treatment with XploSafe fertilizer than after treatment with the commercial synthetic fertilizers. Although the organic nitrogen based fertilizer also produced plants with consistent flowering, the XploSafe-treated cannas exhibited the most intense flowering and produced higher quality, leafier, and more vibrant plants.

Subsequently, Oklahoma State University’s Soil, Water, and Forage Analytical Laboratory (SWFAL) was used to characterize soil samples from the plant growth study and to analyze the plant-available nutrient contents. This was followed by macro-nutrient characterization of the developed first generation XploSafe sorbent fertilizer which was determined to be 9-11-0.5 (N-P-K).

The primary life cycle analysis for the XploSafe nanocomposite-based treatment process was also conducted. When used as a sorbent, the XploSafe technology does not produce any adverse effects on the environment, and no contamination of soil or air occurs during its use as a fertilizer (it also does not emit any harmful gases during manufacture, prolonged storage, transportation, or final use). XploSafe worked with a wastewater treatment plant operator as an industry partner to perform engineering assessments and to conduct a preliminary economic feasibility analysis to estimate the magnitude of savings and energy requirements for the application of the developed sorbent fertilizer technology.

Conclusions:

XploSafe has successfully confirmed the technical feasibility of using its proprietary low-cost biodegradable sorbents to passively adsorb target nutrient ions (ammonium, nitrate, urea, and phosphate) from wastewater. The treated sorbents were subsequently applied as a slow-release fertilizer to effectively grow rhizomes. The complete removal of target nutrients from primary and secondary wastewater streams represents a significant technology improvement over the current state of the art, nutrient precipitation technology that can remove only up to 90% and 20% of nitrates and phosphates, respectively. Further, the XploSafe slow-release sorbent fertilizer generated post wastewater treatment provides a vastly superior alternative to the currently utilized energy and cost intensive nutrient recovery and reuse solutions. The developed XploSafe technology represents an evolution towards improved utilization of wastewater, including remediation and restoration coupled with the improvement in soil quality that can enable sustainable and productive agriculture. It represents a sustainable solution that does not require additional energy and associated costs (labor, equipment etc.) for its application making it accessible to all types of users (including small and large wastewater processing facilities).

Publications:

Publications are being withheld until intellectual property protection is in place. XploSafe intends to disseminate technology performance data gathered during operational testing in Phase II; white papers and journal articles featuring technology use and associated economic and environmental benefits will be shared. Patents are under preparation and will be filed in the next three months. XploSafe does not anticipate the need to acquire/develop any supplementary intellectual property for successful implementation of the proposed technology.

Commercialization:

XploSafe aims to commercialize a highly economical and sustainable sorbent fertilizer technology for in-situ recovery of target nutrients (ammonia, nitrates and phosphates) from wastewater streams. A comprehensive commercialization assessment report for the technology was developed in conjunction with Foresight. The findings validated XploSafe’s sustainable technology advantage when compared to competitive solutions and substitutes. The report also confirmed the market niche and overall market size of $38 billion based upon detailed interviews with stakeholders including experts and end-users in the wastewater treatment industry. XploSafe has confirmed the requirements for establishing a partnership with a major licensing partner for technology commercialization. The identified commercialization partner has a proven record of licensing, scaling and successfully launching wastewater treatment solutions in the U.S. and across the globe. The preferred point of market entry was narrowed down to small wastewater treatment facilities in agricultural areas. This target user persona was further segmented to include users that treat agricultural wastes and are currently facing deficiencies in effectively removing phosphate to meet compliance requirements. The likely market driver was confirmed as regulatory compliance with an impact on overall costs and efficiencies in removal and potential reuse of the target nutrients (phosphate, nitrates, ammonium and urea). XploSafe established communication with sources of capital investment for transitioning the technology to commercial use. The focus of the commercialization plan will be to efficiently demonstrate the value proposition of XploSafe’s differentiated environmentally friendly technology that can facilitate regulatory compliance while reducing overall costs and enabling revenue enhancement for the customers and end users.

SBIR Phase II:

Economic recovery and reuse of nutrients from wastewater