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Experience using the winning sensor from the nutrient sensor challenge: using the WIZ for surface water
Citation:
Lindquist, Alan, T. Faber, B. Patel, L. Boczek, J. Hoelle, K. Daniels, AND G. Norris. Experience using the winning sensor from the nutrient sensor challenge: using the WIZ for surface water. 11th National Monitoring Conference, Denver, CO, March 25 - 29, 2019.
Impact/Purpose:
EPA co-sponsored a competition for low cost nutrient sensors. This abstract describes the experiences in deployment of two of these probes, which have been deployed in different environments. The presentation will be made at the National Water Monitoring Conference. This is a conference of individuals who conduct and research water monitoring, and this abstract and presentation is designed to inform the audience of individuals active in monitoring surface water quality, about the operational details and performance of the sensor that won the nutrient sensor competition.
Description:
EPA, in accordance with current government policy to use competitive challenges to promote the production of useful technologies, sponsored a competition to develop a low-cost nutrient sensor, to detect and quantify the presence of nutrients in water. The competitive process tested the sensors in multiple field locations, and assessed several aspects of the sensors and their performance. This competition led to the development and testing of several sensors, including the winning sensor, called the WIZ. The WIZ sensor uses a wet chemistry approach to conduct assays for ammonia, nitrate, nitrite, and phosphate. EPA purchased two of these sensors for preliminary deployments at different locations. As with any new technology, there were difficulties in establishing this technology within EPA systems and practices. Being a wet chemistry sensor, the chemical reagents need to be prepared on a recurring schedule, every three to four weeks. The WIZ sensor is calibrated in the field and collects measurements every hour Field calibration is complicated by the short shelf life of nitrite standards under field conditions, and by the conditions of calibration. Operation of the WIZ required training by the service representative. The training and operation is fairly time consuming and complicated, requiring considerable time. Although the WIZ is designed for submersible deployments we are using it in an enclosed building. Reagent preparation required several hours of personnel time each month, and field maintenance and calibration requires approximately one working day. When operational, the sensor appears to be sensitive, and specific, although testing in a wider range of environments is further warranted. The technology may have promise in environments where more real-time information is required, or in locations where there are rapid changes in nutrient concentrations, which may be missed by periodic monitoring. There are multiple potential applications of the WIZ sensor, but the logistical details must be accommodated in any implementation plan.