We report on development of a novel type of sensor for in-line analysis of nitrogen-based molecules, such as nitrate, nitrite and ammonia, in municipal wastewater. The sensor utilizes pre-concentration of analytes with ion-selective materials and subsequent optical detection in the mid-infrared spectral range. Advantages of this sensor include in-line autonomous measurements, self-calibration mechanisms and high selectivity to different nitrogen species. The sensor targets implementation at wastewater treatment plants (WWTPs) to enable control and optimization of the aeration process, thereby reducing energy consumption and cost. We will discuss challenges encountered during the transition of the technology from the lab bench to WWTPs, including operational efficiency of the optical sources, such as quantum cascade lasers (QCLs) vs. thermal sources. Extension of the sensor capabilities for sensing of additional contaminants and for bioreactor systems control will be discussed.
Infrared technology can provide a wealth of information related to biological and chemical hazards in the environment. However, this technology mostly exists in the form of bulky instrumentation on optical benches in academic laboratories. We discuss the transition of IR sensing to various points-of-need applications, including food and water safety, bioreactor process control and chemical analysis of drinking water. In particular, in remote locations the access to clean drinking water is critical to soldiers’ health. Mid-infrared spectroscopy is a powerful tool for identification and quantification of a wide range of common organic and inorganic compounds. In this contribution we present data demonstrating proof-of-concept of a quantum cascade laser (QCL)-based infrared sensor for evaluation of toxic industrial chemicals (TICs) and toxic industrial materials (TIMs) and discuss the path for development of miniaturized, point-of-need IR photonic integrated circuits (IR-PIC).
There is a growing demand for hand-held and/or field-grade sensors for biochemical analysis of fluids. These systems have applications in monitoring of nitrogen-based compounds (such as nitrate and ammonia) in the wastewater treatment industry; bacterial detection in drinking water; analysis of biofluids, such as urine or blood; and in many other areas. Mid-infrared (midIR) spectroscopy is a powerful tool for identification and quantification of a wide range of common organic and inorganic compounds. Although IR radiation is strongly absorbed in water, this technology can be adapted for analysis of fluids by utilizing the principles of attenuated total reflection (ATR). In this contribution we highlight the application of IR spectroscopy in wastewater analysis as well as for metabolomic analysis in bioreactors. We discuss the requirements for IR signal stability that are necessary for biochemical analysis of fluids and provide examples of challenges encountered during transition from FTIR to a QCL-based platform. Overall, our stepwise efforts target eventual integration of a QCL light source, waveguide sensor, and IR detector onto a single photonic integrated circuit (PIC) for applications in the defense sector as well as for a broad consumer market.
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