Industrial Wastewater Remediation System Construction and O&M

Client: Chevron (former MolyCorp facility)

The treatment system addressed groundwater, storm water and decontamination waters generated during clean-up of this site contaminated with low-level radiation.

NGE was contracted to perform the installation, construction, operation, and maintenance of a base contact water treatment plant for a low-level radiation remedial site in southwest Pennsylvania. Site-wide contact water was pumped to a five-tank 100,000-gallon holding area. The holding tanks were set up in series to allow solids to settle in an upfront EQ tank. Contact water then flowed from the storage tanks to a reaction/flocculation tank where the pH was adjusted. Then an oxidant/coagulant and polymer were added to promote solids precipitation and agglomeration. Treated water then flowed into an inclined plate clarifier for removal of solids by gravity settling. Clarified water then overflowed from the inclined plate separator into an effluent collection tank. Settled solids were removed from the bottom of the clarifier to a 1,000-gallon sludge holding tank. Clarified water was then pumped to a filtration unit for removal of fine suspended particles using a proprietary media (MnO₂) to promote removal of manganese. In addition, bag filters were provided as backup units during periods of maintenance of the media filter.

Following particle filtration, the water was processed through two carbon filters for removal of organics and two ion-exchange vessels to address specific constituents in the contact water. Finally, the pH of the water was adjusted to meet discharge standards. Process water then flowed either to the discharge point or to the “clean” water frac tank.

During this wastewater remediation project, routine field analytical tests (iron, manganese, aluminum, molybdenum, and turbidity) were run on the process water to maintain discharge compliance and to regulate chemical dosage. In June 2007, NGE constructed an additional leg to the system that would remove additional suspended particles. This additional system was incorporated into the existing system and also maintained by NGE.