A multi low-cost sensors analysis for remote and real-time water quality monitoring system

Abstract

Low-cost sensors integrated with the Internet of Things can enable real-time envi-ronmental monitoring networks and provide valuable water quality informationto the public. However, the accuracy and precision of the values measured bythe sensors are critical for widespread adoption. In this study, 19 different low-cost sensors, commonly found in the literature, from four different manufacturersare tested for measuring five water quality parameters: pH, dissolved oxygen,oxidation-reduction potential, turbidity, and temperature. The low-cost sensorsare evaluated for each parameter by calculating the error and precision com-pared to a typical multiparameter probe assumed as a reference. The comparisonwas performed in a controlled environment with simultaneous measurements ofreal water samples. The relative error ranged from -0.33 to 33.77% and most of them were ≤ 5%. The pH and temperature were the ones with the most accurate results. In conclusion, low-cost sensors are a complementary alternative toquickly detect changes in water quality parameters. Further studies are necessaryto establish a guideline for the operation and maintenance of low-cost sensors.