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A Holistic Approach to Improving National Water Quality
USDA/NRCS, United States of America;
Human survival depends on the availability of fresh water. The total amount of water on planet Earth has not changed but the quality has reduced considerably because of its extensive and improper use. The global supply of fresh water per capita is expected to further drop because rising world population and the greater demand for food, fiber and fuel. Sources of water pollution, caused by interruptions to natural water cycle (both natural and human), are broadly classified into point-sources (discharges from sewage and other industrial plants) and non-point sources (primarily agriculture). In the United State, major regulatory emphasis has been in controlling discharges from point sources that has lead to improvement in US waters. However, there are still several waterbodies that are polluted and need continuous attention to maintain and improve their water quality. It is well documented that agriculture is the largest user and the biggest polluter of water. There is urgent need to explore an integrated approach where both point and non-point sources are bridged together for improving national water quality. This presentation introduces a framework of three-legged stool (legislation, policy, and tools & techniques) for improving national water quality. It presents a thematic model that integrates water pollution contributing factors and how US regulations such as the US-EPA Clean Water Act and related to TMDL (Total Maximum Daily Load) have been helping in controlling the pollutions. The innovative approach of the water quality trading that serves as a bridge between point and non-point sources will be elaborated along with some of tools such as NTT (Nutrient Tracking Tool) and WQIag (Water Quality Index for Agricultural Runoff) being developed by NRCS to facilitate the new approach for improving the national water quality.
Phosphorus Recovery and Upcycling in the Utility of the Future
Menachem Tabanpour, Gerhard Forstner
Centrisys-CNP, United States of America;
Sludge streams in water resources recovery facilities present promising opportunities of nutrient recovery. Brushite and struvite crystallization are two feasible methods of phosphorus recovery. This longitudinal study was completed between April and November of 2018 in conjunction with a Water Research Foundation (WRF) project to independently evaluate the CalPrex™ brushite phosphorus recovery technology. While operating at the Madison, WI Nine Springs facility, the CalPrex process took 10 gallons per minute of acid digest sludge with a high soluble phosphorus content and recovered brushite, a calcium phosphate mineral that is also a valuable agricultural fertilizer. The pilot was built with scalability in mind and the process was systematically optimized to create stable recovery rates during the each run period. Results from mass balance samplings indicate a 42% total phosphorus recovery rate. The implications of this study are that a calcium based phosphorus recovery solution is a viable method of recovering phosphorus and that having additional soluble phosphorus in the system can result in higher recovery rates. This will support utilities in their goals to lower operation and maintenance costs related to high phosphorus loading while recovering a valuable phosphorus fertilizer.