Development of a low-cost hydrogen sulfide gas sensor for wastewater monitoring applications

Abstract

Monitoring hydrogen sulfide(H2S) gas in pump stations is an essential aspect of corrosion and odor management in wastewater networks. Monitoring H2S gas concentration allows wastewater utility companies to identify potential problems in wastewater networks, such as blockage of pumps, corrosion buildup, and hazardous environments. However, wastewater utilities do not have H2S gas sensors in most pump stations because there are many pump stations to monitor. The sensors have unnecessary features and thus expensive.

This thesis develops a low-cost H2S gas sensor device for the wastewater network environment. This is accomplished by evaluating the feasibility of two electrochemical sensors technologies: the Winsen and SPEC sensor technologies. These technologies are tested in a pump station to determine their response time, accuracy and feasibility.

The results show that utilizing the Winsen sensor technology with the UART method to yield continuous readings is feasible. Conversely, the results show that the SPEC sensor yields negative concentration values and does not react to changes in environment. The proposed sensor device comprises the Winsen sensor technology, a microcontroller, a real-time clock and a 5-volt power supply, which accomplishes a low material cost of approximately 35 USD. The Winsen sensor technology conforms to the specification established by the client company. Nevertheless, further development could lead to a more refined test method and an accurate calculation of sensor accuracy.