One of the biggest challenges for clean dredging in sensitive and often confined areas is the difficult access and limited floor plan where the operation can be set up. It requires comprehensive use of precise equipment, correct and balanced use of chemicals and the smallest footprint possible for the containment dewatering setup.

On our US Army project in Natick, MA for example, Inner Space Services, Inc. was contracted for the dredging , treatment, containment and dewatering in Pegan Cove on Lake Cochituate, where PCB concentrations exceeded the acceptable EPA levels. The objective was to remove the PCBs and cap the areas, to bring the average concentration down to acceptable levels.

ISSI stepped up to the challenge by introducing its Optimizer Realtime treatment system that can handle and treat up to 3000 gallons/minute of dredge slurry for treatment. Additionally, Inner Space Services, Inc. designed and built a highly effective two-part dewatering basin to contain the Geotextile tubes in while they captured the PCB laden sludge and dewatered it to optimum dryness for trucking and disposal.

“The project threw us a number of challenges. There was very little room to build a containment and dewatering area, and in adition to the high PCB content, there was a high iron content as well in the slurry mixture that needed to be precipitated out before the decant water could be returned to the lake."

Laurie Mason