Monitoring volatile compounds in sewer systems is highly important due to the toxic and corrosive nature of various nuisance chemicals generated, such as hydrogen sulfide (H₂S). Hotspot monitoring facilitates identification of the location of the generated H₂S, and thereby targeted treatment can be applied, which eventually minimizes the use of chemicals and lowers the environmental effect within the sewer system. In this thesis, we present a portable detector that is designed to extract

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... e components from aqueous samples by vaporizing the sample and then exposing it to a microfluidic-based detector, fabricated by a selective microchannel embedded with a metal oxide semiconductor (MOS) sensor. The setup consists of an exposure and recovery chamber, heater, servo, and a peristaltic liquid pump. The entire device is controlled using a microcomputer that transmits sensor data and receives inputs from the user. A testing procedure is also established for the setup, which consists of 5 steps, including sample extraction, vaporization, exposure, recovery, and purging. Using a wide concentration ranges of H₂S and ammonia (NH₃) dissolved in water (i.e., two components which the MOS sensor has potential cross-selectivity), a database for classification and regression was developed: the device was capable of classifying between NH₃ and H₂S by a recall value of 100% and 96% in separate and also returned a recall value of 97% with H₂S classification and 96% with NH3 classification in mixture aqueous solutions. Regression precision for separate and mixture aqueous solutions was 84.6% and 88.77%, respectively. The developed setup was used in a field test (at Annacis Island (Delta, BC) wastewater treatment plant (AI-WWTP)) where various tasks such as sample extraction, evaporation, and data transmission were automatically performed. The results show that the device is capable of identifying and measuring the concentration of H₂S and NH₃ in raw influent with 83.48% precision. Overall, the results presented show the potenti [...]