A Low-Cost Real Time Bio-Electrochemical Nitrate Sensor for Surface Water Monitoring

"Nitrate (NO3) in surface water runoff from agriculture activities is a serious environmental problem. Nitrate levels in United States waterways have increased dramatically in the past half-century, two0fold in the Mississippi River since 1965 and as much as ten-fold in the northeast since 1990. This widespread nitrate contamination has led to significant environmental consequences. In particular, contamination that travels through the Mississippi River Basin and into the Gulf of Mexico has had suffered devastating effects on ecosystems, creating large anoxic dead zones, putting a strain on fisheries and bringing this problem into the public spotlight. As regulations tighten around the environmental release of nitrate to prevent such catastrophes, the need for accurate and affordable distributed nitrate sensing will increase substantially. In addition to the environmental impact to our watersheds from nitrate pollution, maintaining optimized level of nitrate is a critical economic problem for precision agriculture. In this context, nitrate monitoring in runoff from cropland can help to maximize crop yields while minimizing expensive fertilizer inputs. As the focus on nitrate pollution increases, nitrate monitoring in surface water from inherently spread-out agricultural sources will require remote sensing in multiple locations for targeted identification and remediation of the problem. Unfortunately, existing sensors for nitration are either too expensive or lack the sensitivity required for extensive remote monitoring. IntAct Lab has invented a revolutionary low-cost real-time ampreometric sensor technology based on the concept of a microbial fuel cell (MFC). The proposed design detects level of substances action as terminal electron acceptors for the microbial species involved in the extra-cellular electron transfer of an MFC. As a result, our sensor will directly translate the concentration of both oxygen and nitrate into differential electrical signal for extended real-time monitoring of run-off streams. This design takes advantage of the extremely high specificity of biological processes, and because of the MFC framework, this sensor requires no additional power source and utilizes and inherently inexpensive design. We envisage that our low-cost real-time nitrate sensor will be of significant interest to users in the agricultural (individual agriculturalists, agricultural consultants), watershed management (regulations and watershed management associations) and research fields. This Phase I project will prove feasibility of the sensor concept and establish critical parameters for the design of the first-generation sensors. "