Electronic Wastewater Management Using Statistical Process Control

Abstract

This paper will present few results based on the implementation of statistical process control (SPC) in an effluent treatment plant. A fundamental tool of SPC i.e. Control Charts are plotted for several variable such as pH, BOD and suspended solids level versus time. From these control charts, the true capability of the operating process can be predicted and established. Furthermore, several trends found from the charts could serve as indicators for process stability and the extent of deterioration. From the results, it was found out that most of the monitored variables were under satistical process control since most of the charts showed that the random distribution over time was repeatable and predictable (normal distribution). Only in one of the charts i.e. the conrrol chart for the concentration of a contaminating material, shows that about 20% of the samples taken were outside the upper control limit (UCL). This phenomena was a result of the excessive dumping of the contaminating materials to the treatment plant on that particular days. In conclusion, the process could be improved by using SPC technique that lead to willing operating cost. The installation of an on-line SPC alarms is suggested so that early warning could he given for any disturbance to the treatment plant. KEYWORDS: Statistical proce control; electronic waste effluent treatment; control chart; pollution; process monitoring and control.