Geosearch Remediates Coal Gasification Site

By Joanne Ray | September 28, 2010

Tony Zina from Geosearch electro-fuses the 24-inch HDPE pipe.

Geosearch Drilling and Construction, Inc. of Fitchburg, MA, had its work cut out for them recently when the 19-year-old company took on the remediation of this 7.5-acre site in Taunton, Mass.

From 1910 to 1956 the site was once the location of a coal-gasification plant. In 1965 the buildings were demolished, and by 2001 the site was capped and fenced to limit access.

During the capping, a drainage system was installed using 15-inch and 24-inch concrete drain lines. The site wound up listed as Remediation Operations Status (ROS) in accordance with the Massachusetts Contingency Plan (MCP).

During an evaluation of the site, engineers found that leaking occurred from the drain line joints and catch basins, resulting in a sheen of oily material on the nearby Taunton river.

The evaluation recommended the removal and replacement of the existing 550 feet of 24-inch and 200-feet of 15-inch concrete drain lines and corresponding catch basins. The new drain lines would be constructed of 16-inch and 24-inch High Density Polyethylene (HDPE) with electro-fused joints and welded to new 36-inch HDPE catch basins to create a sealed drainage system.

Tony Zina runs the fuse machine while clamping the HDPE pipe together

Prior to the start of trenching, all water and sediment in the catch basins and drain lines were vacuum excavated, and the material was stored in 20,000-gallon frac tanks on the site. Erosion control material consisting of hay bales, silt fences, siltation bags, and filter booms was installed to prevent any material from migrating off-site.

The 15-inch and 24-inch concrete drain pipe was exposed and removed from the trench. New 16-inch and 24-inch HDPE pipes were fused at the ground surface and lowered into the trench using a Volvo 110 excavator and slings to minimize entrance of personnel into the excavation.

Upon installation, the drain lines were pressure tested for leakage. The concrete catch basins were removed, and new 36-inch HDPE basins were constructed and the lines fused to the sides. The covers of the new basin were constructed to prevent surface water infiltration.

The piping was backfilled and graded and the area was seeded and mulched.