Development of a Sensing Platform for Nuisance Sewer Gas Monitoring: Hydrogen Sulfide Detection in Aqueous Versus Gaseous Samples

Nuisance gases such as hydrogen sulfide (H
₂
S) are the main cause of unpleasant odors and corrosion in sewer pipes. Although there are treatment methods available, they are expensive and have negative side effects. Hotspot monitoring identifies specific locations within the sewer system for targeted treatment and thereby minimizes the use of chemicals and their negative impacts. Here, we present a new sensor and supporting platform for nuisance sewer gas detection and monitoring. The sensor is fabricated using a highly selective microfluidic gas channel coupled with a sensitive metal–oxide semiconductor (MOS) sensor. The supporting platform consists of a custom-built syringe pump, automated sample delivery, and vaporization chamber. To demonstrate the sensor’s sensitivity to H
₂
S (an important component in sewer gas mixtures), different concentrations of H
₂
S in a liquid phase are identified using special feature extraction methods and calibrated using gas chromatography. In addition, another setup for monitoring and detection of gaseous H
₂
S samples is developed and compared against the results of the aqueous samples. This comparison shows that although the features of the gaseous and aqueous samples share some similarities, the humidity in the latter dampens the response of the sensor. Finally, the capability and potential of the proposed sensing platform is further demonstrated by distinguishing H
₂
S from other gases present in the sewer (e.g., methane).