An open source ultrasonic flowmeter for monitoring the input/output flow rates of wastewater treatment plants

Sensors play an important role in both the continuous monitoring and intermittent analyses, which are essential for the study of wastewater treatment plant management and conducting related research. Given the significant environmental impact of the issues involved, accurate measurement of the volume of water flowing into and out of treatment plants is a key parameter for plant management, ecotoxicological studies and academic research programs. Traditionally, flow measurements have been based on calibrated weirs or venturi flumes, using water level measurements for conversion into flow, according to established relationships. In this article, the authors propose an innovative approach to explore the feasibility of developing an open-source, reparable and cost-effective data logger for flow monitoring using ultrasonic technology. By leveraging Arduino modules and a complementary Grove shield, the proposed data logger offers seamless integration and affordability. In particular, it features an on-board web server to facilitate data collection and device testing, offering accessibility through Wi-Fi connectivity with smartphones or computers. The authors demonstrate the effectiveness of their flowmeter by comparing its performance with that of a commercial reference flowmeter, yielding a maximum permissible measurement error of 0.6 mm on the water level measurement. Furthermore, they demonstrate the durability and reliability of the developed data logger through extensive field-testing over a 9-month period.