Portland Business Journal: Portland's Superfund efforts show signs of life

Read this full report at: http://www.bizjournals.com/portland/blog/sbo/2015/04/portlands-superfund...

by Wendy Culverwell

• Portland Harbor is largely isolated from Combined Sewer Overflows or CSO, which result when rainfall overwhelms sewage systems and flows directly into rivers. There are hundreds of outfalls in Portland Harbor but most operate under stormwater permits.

Portland Harbor also enjoys an advantage that its sister Superfund site in Seattle, the Duwamish Waterway, lacks: Forest Park covers one half the area that drains into Portland Harbor, meaning much of the stormwater entering the stretch is uncontaminated.

"We are the only town in the country that can say, 'We have a Superfund site with CSOs that are controlled,'" she said.

• There's progress on the BP (Arco) seawall replacement project. The Linnton tank farm had a badly failing seawall that needed replacing. The site, used for petroleum products and storage, had groundwater issues as well as contamination in the river.

Since the project disturbed the river while doing the wall work, workers removed contaminated sediment from the river as well. The project involved constructing a solid wall around the project area in the river to ensure contaminants stayed out of the main channel.

The new, deeper seawall includes a pump system that collects contaminated groundwater and sends it to a treatment site.

The Gasco site near St. Johns on the southwest bank operated as a gas manufacturing plant starting in 1910, later adding by-products refining. The site, now about 44 acres in size, was contaminated by benzene, cyanide, heavy metals and other toxics.

To control the contaminants, an expansive pump system keeps ground water levels at the site below river levels to avoid leaching. Water that gets pumped is treated and discharged under a permit.