Contamination event detection using multiple types of conventional water quality sensors in source water

Abstract

Early warning systems are often used to detect deliberate and accidental contamination events in a water system. Conventional methods normally detect a contamination event by comparing the predicted and observed water quality values from one sensor. This paper proposes a new method for event detection by exploring the correlative relationships between multiple types of conventional water quality sensors. The performance of the proposed method was evaluated using data from contaminant injection experiments in a laboratory. Results from these experiments demonstrated the correlative responses of multiple types of sensors. It was observed that the proposed method could detect a contamination event 9 minutes after the introduction of lead nitrate solution with a concentration of 0.01 mg L(-1). The proposed method employs three parameters. Their impact on the detection performance was also analyzed. The initial analysis showed that the correlative response is contaminant-specific, which implies that it can be utilized not only for contamination detection, but also for contaminant identification.

Performance Evaluation for a Contamination Detection Method Using Multiple Water Quality Sensors in an Early Warning System

“…The method detects contamination by exploring the correlative relationship between responses from multiple water quality sensors [21]. This relationship is evaluated using the correlation coefficient r, which is calculated by: …”

“…Liu et al [21] showed that this method was able to detect a contaminant event in a short time period and that the parameters had a significant impact on the detection performance. Likewise, in our study, an event can be detected if three parameters are given optimal values.…”

“…Liu et al [21] proposed a method for real-time contamination detection using multiple conventional water quality sensors for source water. Eight sensors were used in the case study.…”

A real time method of contaminant classification using conventional water quality sensors

“…Three groups of the most common six pollutants were selected: herbicides (atrazine, glyphosate), heavy metals (cadmium nitrate, nickel nitrate) and inorganic salts (sodium fluoride, sodium nitrate). For more information about the CIE platform and the injection experiment, the readers could refer to Liu et al (2014Liu et al ( , 2015.…”

“…A new group of contaminant injection experiments were conducted to produce data for contaminant classification. The raw data after the first detection alarm were taken for contaminant classification, which were truncated according to the results from the detection module (Liu et al, 2014). They were treated following the same procedure above to obtain sample feature vectors.…”