Miniaturized water quality monitoring pH and conductivity sensors

The development of cost-effective, durable and sensitive on-line water quality monitoring sensors that can be installed across water distribution networks has attracted attention to increase the frequency of monitoring and hence reduce the risk of accidental or deliberate contaminations or improve routine control of water quality. This paper presents microsensors fabricated and implemented in a serpentine channel interface for the measurement of pH and conductivity, two important water quality parameters. The performance of these sensors was tested in both still (static) and flowing (dynamic) water. The serpentine channel interface, numerically optimized, provides a constant flow and a constant outlet pressure condition for dynamic experiments. Tests conducted for evaluating the effect of the exposure time on the sensor performance show no change in the sensor response even after one month. Finally, the pH and conductivity sensors were compared against the common commercial sensors used for evaluating water quality. The results show that the pH and conductivity sensors are as precise as the commercial sensors in both static and dynamic conditions. However, the cost of the sensors presented here is significantly lower than that of the commercial sensors.