In the Field
Alyeska's Ballast Water Treatment undergoing major renovations

Renovations are underway at the Ballast Water Treatment (BWT) Plant at the Valdez Marine Terminal, a $91-million effort to modify the facility for lower ballast flows. It’s one of Alyeska’s largest projects, second only to Strategic Reconfiguration.

Today, there’s less ballast to process, due to lower tanker traffic, and an increase in tankers that separate oil and water. But in older-model tankers, ballast still fills the same compartment that hauls oil, leaving water tainted. BWT cleans the water before returning it to Prince William Sound.

“Our goal is always to make the water the cleanest you possibly can,” said Mike Britt, a BWT Operator. “Because Prince William Sound is where we fish. That’s where we boat. That’s where we play.”

Ballast water enters a separation tank, where oil rises and is skimmed away. Next, water goes into open tanks in the Dissolved Air Flotation (DAF) building, where chemicals congeal the oil, and bubbles push it to the surface for skimming. Treated water then enters the Biological Treatment Tanks (BTTs), where microorganisms – “bugs” – eat remaining oil particles.

After renovations, vapors that currently vent from three ballast tanks will travel through piping to the Vapor Control System. There, vapors can generate power, or divert back to the tanks, or get burned off.

Deep, open-air tanks at the Dissolved Air Flotation building will be replaced by Infused Gas Floatation Units, which are smaller and contained, further reducing emissions. BWT employees are testing a smaller-model unit, learning its functions and capabilities. Nearby, crews are also testing new covered containers that will replace the BTTs and house the oil-eating bugs.

Crews have marked a major milestone in the project, with the successful installation of a 620-foot underground pipe that is a major component in connecting the BWT with the Vapor Control System.

It took plenty of manpower and machinery to maneuver the 24-inch-diameter High Density Polyethylene pipe through the 30-inch-diameter hole. To see a slide-show of that two-day effort, click here.