Since 1988, B&N has provided groundwater monitoring, engineering consultation and hydrogeologic investigations for the Pike Sanitation Landfill, an active municipal solid waste disposal facility near Waverly, Ohio.
Landfill Expansion
In 1996, Pike Sanitation received OEPA approval to increase the 23-acre landfill site to 137 acres. B&N provided engineering consultation, slope stability evaluations and a hydrogeologic investigation to determine the feasibility of dewatering the uppermost aquifer under the landfill during construction.
In addition, Pike Sanitation needed to know the depth of bedrock in the expansion area so they could plan for geologic constraints, and avoid cost overruns and construction delays due to unexpected encounters with bedrock. B&N accomplished this by importing survey data from monitoring wells and soil borings into GIS to create a 3-D model of the site. Volumes of clay units were calculated to obtain an estimate of how much on-site soil would be available for the landfill construction and closure. Volume calculation reports also were generated based on the horizontal and depth extents.
Alternate Source Demonstration
While B&N was implementing a groundwater detection monitoring program at the landfill, statistically significant concentrations of chloride were detected in one of the monitoring wells. B&N conducted an alternate source demonstration to identify the source of the chloride.
The monitoring well is located next to a sedimentation pond that is hydraulically connected to the saturated zone and adjacent to one of the facility’s haul roads. B&N sampled and analyzed surface water from the pond. The results concluded that the pond was not the cause of the chloride increase. A second monitoring well also was sampled and analyzed. It, too, was ruled out as the cause.
Next, the team looked at activities on the adjacent haul road. With the construction of the new waste disposal cell, traffic had increased. It was suspected that road salt runoff from the waste disposal vehicles during the winter months could have altered the groundwater geochemistry. Through citation of published documentation on the effects of road salt on water quality, evaluation of trends in concentration of various parameters, and the presentation of rate of transport calculations of contaminants through the saturated zone, B&N demonstrated that the increase in chloride concentrations was due to a source other than the landfill.