Dissolved Oxygen Sensor System for Real-time, In-situ Subsurface Monitoring: Geospatial Mapping of DOE Field Sites

Environmental sensor networks capable of taking data quickly enough to capture minutescale fluctuations and durable enough to capture these data for entire seasons provide essential information for studying the seasonal and annual effects of microbial activity across complete ecosystems. Distributed sensors for subsurface dissolved oxygen (DO) concentration measurement are of particular interest because of the outsized role DO plays in catalyzing a diversity of environmentally important biogeochemical reactions. Commercially available DO sensors cannot provide the desired spatial and temporal density for resolving data over extended periods at the ecosystem level The overall goal of this proposed body of research is to develop a monitoring technology that provides insight into spatial and temporal variations in dissolved oxygen as a result of hydrological factors, such as seasonal infiltration events and excursions groundwater elevation. To accomplish this goal, a cost competitive DO sensor that can operate for months (or longer) in an uncontrolled, outdoor environment without the need for human intervention and/or recalibration will be developed. The sensor design will allow having multiple sensing sites within a single sensor probe. This will enable data acquisition from multiple probes to generate fourdimensional (space and time re solved) maps of oxygen concentration by the importing the timetagged data from the sensors into commercially available geographic information system (GIS) systems. Commercial Applications and Other Benefits: Recent USGS studies have shown that dissolved oxygen is a proxy for detecting a broad array of chemicals which would otherwise require an extensive suite of sensors to identify. Since the use of a single sensing modality device greatly reduces deployment costs, DO probes could be widely deployed, thereby providing realtime environmental assessment. The data gathered from an ecosystemwide network of DO probes will provide water system operators with the information they need to proactively respond to changes in the environment, thereby ensuring the publics access to safe drinking water.