COLUMBIA, S.C. — Crews from South Carolina’s Department of Health and Environmental Control (DHEC) say they have removed 20,000 tons of coal tar from along the Congaree River as part of Phase 1 of the Congaree River Clean Up Project.
A section of the river on the Columbia side, just below the Gervais Street Bridge, had a cofferdam installed and its water drained in May so that workers could remove the coal tar.
After the coal tar was excavated, DHEC says workers used high pressure water cannons to remove remaining coal tar and sediment until they reached the granite river bottom. The water used during the pressure washing was maintained within the cofferdam and pumped to a water treatment system for processing before going into the City of Columbia sewer system.
Workers also placed rocks along the river to reduce erosion.
Over the next few weeks, the Phase 1 cofferdam will be dismantled and the river will begin to flow freely again. Portions of the Phase 1 installation will be reused in a similar draining and cleaning process at another section down stream.
Phase 2 of the project is much smaller — about one-fifth the size of the first cofferdam. Depending on the weather, the Phase 2 process of coal tar removal should be completed in about 2-4 weeks.
The removed coal tar and sediments are being taken to a landfill in Richland County where Dominion Energy has set up a special area for the material to be examined by a team of archeologists. The archeologists will sift through the material in an attempt to locate any artifacts that might not have been detected during the Unexploded Ordinance team’s clearing of the Congaree before cleanup began. To date, several small Civil War artifacts have been identified.