Project Description

This site had previously been capped after placement of oily waste in a marshy area. The subsurface oily waste continued to undergo anaerobic biological degradation, producing noxious hydrogen sulfide (H2S) gas that permeated the cap. The high- profile site, located in a residential area, had significant issues relating to community relations and public health. The H2S required that in-situ stabilization and excavation be performed in an extremely controlled manner. URS/ROS was awarded three Task Orders. The first task order included the design documents for the in-situ stabilization of the oily wastes. Under the second task order, ROS performed stabilization treatability studies and a field demonstration test. The third task order was issued to prepare work plans and to implement the remediation at the site with the selected stabilization technique (Lang Tool Deep Soil Mixer). The work involved stabilization, excavation and backfill of 55,000 yds of contaminated oily wastes and soil. This work was accomplished utilizing a Lang Deep Soil Mixer attached to a Komatsu PC 400 excavator. The waste was also found to be buried under two homes adjacent to the site. The two homes were demolished so that the waste could be treated.
In addition to stabilizing the waste, ROS installed and operated a wastewater treatment plant. This plant was used to pre-treat the groundwater and surface water that came in contact with the stabilized waste in the excavation prior to discharge to the local POTW. Following stabilization and removal activities, the site was capped with clay. ROS developed the site as a recreational park.