Determination of the Stability of a Potable Water Production Line Using Lean Six Sigma Method: A Case Study of XYZ Water Factory

Abstract

The research, being a case study, aims to determine the stability of the potable water production line of XYZ water factory, for possible improvement, using tools from the lean six sigma (LSS) methodology. This research was carried out on the mean weekly laboratory results of physicochemical water parameters (pH, conductivity, turbidity, alkalinity, chloride, total dissolved solids (TDS), magnesium, nitrates, sulphate, hardness, calcium, lead, copper, iron, and zinc) for regulatory purpose. The data obtained were analysed using control charts from the minitab 2021 ® statistical software package. The values of the parameters (except iron) in the control charts were beyond the conventional limits at various points in time throughout the period. The research results showed that the water production process is not stable, indicative of assignable causes of variability in the production line for all the parameters. Therefore, there is need to carry out investigations to know the causes and take action to correct them. This could be achieved by deploying the appropriate tools in the lean six sigma (DMAIC) methodology.