Installation of Groundwater Treatment at a Municipal Well Field, 1996 Environmental Conference Proceedings

A former mill site is situated 0.8 kilometer (0.5 mile) from five wells that supply drinking water to a small Oregon municipality. The mill owners have agreed to protect the city’s wells from possible groundwater contamination due to mill operations. Levels of pentachlorophenol (PCP), tetrachlorophenol, and dichlorophenoxyacetic acid (2,4-D) below federal drinking water maximum contaminant levels were detected in a sampling from one of the wells. A groundwater remediation system using granular activated carbon (GAC) has been installed at the site, ready to be activated should water quality warrant it. GAC treatment was selected because of carbon’s high adsorption affinity for PCP. The GAC vessels were installed without the carbon. If conditions require activating the treatment units, the city will be responsible for placing activated carbon in the vessels and operating them. A design/build approach was taken, resulting in considerable savings to the mill. The treatment system incorporates existing well field configurations, and allows for eventually housing the wellheads and treatment equipment. Typical process and instrumentation diagrams, a limited construction drawing, a piping specification package, and an operations manual were prepared. The treatment systems were then handed over to the city.