In a typical wastewater treatment plant (WWTP), the anaerobic digestion process generates a sidestream with high level of ammonia (NH3-N) and ortho-phosphate (ortho-P), which contributes to as much as 20-40 percent of total nutrient loading to the main plant stream. Traditionally, the sidestream is returned to the main stream and treated in biological nutrient removal processes, at significant cost in terms of capital investment and M&O cost. With increasingly more stringent nutrient limits imposed on municipalities, the practice of returning this recycled stream to main stream for treatment becomes less desirable. A trend has emerged in the industry to treat the sidestream separately from main stream, with a potential market valued at $490 million annually. Among the many nutrient management solutions available for sidestream treatment, nutrient recovery is a viable option. Ammonia recovery technologies existing on the market recover ammonia in the form of free ammonia or ammonium sulfate solution as fertilizer, but the overall process economics are poor due to high cost of recovery and low value of recovered products. As a result, adoption of ammonia recovery technologies for sidestream treatment is very limited in the wastewater industry. In comparison, phosphorus recovery as Struvite has gained more traction in the industry because recovered products can be marked as premium slow release fertilizer. However, only about 20 percent of ammonia in sidestream is recovered by Struvite formation, with the remaining 80 percent still returned to main stream for further treatment. This Small Business Innovation Research Phase I project proposes to develop a new process to recover nutrients from sidestreams. The process is based on a newly discovered chemistry in which ammonia reacts with a commercially available additive to form a short chain polymer (or oligomer). The reaction is not only selective but also fast, reaching completion in minutes. And more importantly, the reaction is carried out in neutral or mild alkaline pH, a condition that is compatible with the Struvite recovery process. Preliminary studies using sidestream obtained from WWTPs have demonstrated the following: The process can be combined with the struvite recovery process in a single reactor to recover both NH3-N and Ortho-P The process can consistently and reliably achieve 70% reduction for NH3-N and 80% for Ortho-P reduction The recovered product is a composite of struvite and oligomer, with analyzed nitrogen and phosphorus values comparable to commercially available N-P fertilizer The objective of this SBIR project is to further expand LJJW AquasolutionÂ’s work to validate the new nutrient recovery process by: Demonstrating the broad applicability of the process to consistently achieve 70 percent NH3-N reduction and 80 percent ortho-P reduction in sidestream samples obtained from different WWTPs Recovering sufficient quantities of products to perform guaranteed nutrient analysis following fertilizer registration protocols Characterizing the slow release properties of recovered products by performing accelerated nutrient analysis and nitrogen release study If successfully demonstrated, this new nutrient recovery process offers the advantage of recovering ammonia and phosphorus in one single reactor, with the potential to significantly reduce capital investment on nutrient treatment in sidestream. In addition, the recovered product may be potentially marketed as a high value-added slow release fertilizer, which further reduces M&O cost associated with nutrient treatment. Currently, there is no other known technology on the market that can recover ammonia and phosphorus simultaneously in one process, and therefore our technology is anticipated to outperform competitions. Some of the end users contacted by LJJW Aquasolution have expressed strong interests in this technology.
