Construction of control charts to help in the stability and reliability of results in an accredited water quality control laboratory

In this 2022 article published in the journal Sustainability, da Silva et al. of the Polytechnic Institute of Beja demonstrate the usefulness of control charting in the realm of maintaining water quality. Using a test case of wastewater from a treatment plant associated with a slaughterhouse, the authors describe their materials and methods, which progressed from wastewater sample to analysis and databasing of the results, followed by analysis quantification and control charting. In this article, they show 10 control charts associated with five test variables, demonstrating the usefulness of the control charts in identifying at least one significant set of out-of-specification results, likely associated with a treatment failure at the facility. They conclude that the results demonstrate “how rapid detection of variations in small scales on control charts allows the lab to better act upon identifying potential causes of variability,” and they “show it is possible to state that all points are under statistical control, and thus by extension these types of control charts can have routine value in the laboratory.”

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