The site is 400+ acres in Los Angeles that includes a former refinery process area, a former chemical manufacturing/current chemical storage facility, and a large active petroleum tank farm area. The site is bounded by residential, commercial, and industrial land uses. Within the facility there were several locations where tar had been previously deposited into pits and large open surface areas. The site owner's goal for this project was to prepare the site for future uses by removing the geotechnically unsound tar, often found mixed with asbestos-containing material.
Geosyntec's Scope of Services
Geosyntec provided construction management (CM) services beginning with overall project planning. We obtained construction and environmental permits, prepared construction bid documents, conducted the pre-bid job-walk, performed the construction bid evaluation, and performed perimeter air quality monitoring for the excavation of 60,000 tons of tar and tar-impacted soil at the site. Additionally, we provided South Coast Air Quality Management District (SCAQMD) Rule 1166 permit monitoring for the control of fugitive volatile organic compounds (VOC) during excavation of VOC-contaminated soil. Rule 1166 thresholds define handling and disposal requirements based upon concentrations of VOCs at the time of excavation. The excavated tar was shipped to appropriate landfills, largely as either Cal-Haz or RCRA hazardous waste because of the levels of lead in the excavated tar.
The control of high concentrations of VOCs and strong obnoxious odors presented challenges on this project. Due to the presence of VOCs, Geosyntec performed portions of the work using supplied air (Level B Personal Protective Equipment). We used water with surfactants and foam to control odors, emissions, and dust from impacted soils and tar. Geosyntec also directed the use of a combination of sealed roll-off bins and end-dump trucks for waste transportation to the designated landfills, depending upon the results of laboratory analysis of the waste.
Due to the distances from the site to the landfills, transportation logistics and coordination of transportation with excavation activities was of paramount importance. Permits limited the amount of material that could be stockpiled onsite. The distances to the landfills dictated that haul trucks could only accomplish one round trip per day to the landfills. Therefore, all haul trucks had to be loaded and depart the site no later than noon. A balance of resource utilization was achieved by focusing on loading over 100 end-dump trucks every day before noon, and concentrating afternoon efforts on excavation and stockpiling.