CATEGORY OF SERVICE, LOCATION:

Class I Hazardous Landfill Clean-Closure, Stockton, California

TYPE OF CLIENT:

Commercial/Industrial Property Owner

BACKGROUND:

 Class I Hazardous Landfill Clean-Closure, Stockton, California

Class I Hazardous Landfill Clean-Closure, Stockton, California

An unlined surface impoundment was used as a wastewater pond circa 1970 until about 1988. It received a variety of solvents, petroleum wastes, acids, and other industrial chemicals throughout the duration of its operation. The surface impoundment was located in a sensitive area, directly adjacent to a slough, a designated wetland under the United States Fish & Wildlife Service National Wetlands Inventory.

In 1989, the Central Valley Regional Water Quality Control Board (CVRWQCB), ordered the property owner to remove all hazardous wastes from the surface impoundment. The property owner excavated approximately 2,000 cubic yards of waste from the unlined surface impoundment and disposed of it at a Class I Landfill. Confirmation soil samples collected from the subsurface after the removal of waste indicated that hazardous levels of lead remained in soils.

Because soil was left in place with hazardous concentrations of lead, the property owner implemented a closure in 1995 pursuant to Waste Discharge Requirements (WDR). Closure conditions included: 1) a 2-foot thick, low-permeability clay cap over the residual lead‑impacted soil; 2) groundwater and surface water monitoring and reporting, 3) annual inspections, and 4) annual WDR fees.

In 2007, the property owner attempted to clean-close the landfill by excavating and disposing of the residual lead‑impacted soils and the clay cap. The impacted area was significantly larger than expected, and the impacted soil was not entirely removed. Following excavation and stockpiling of approximately 2,000 tons of soil in 2010, the project was suspended due to limited funding.

In 2015, the property owner contracted Trinity to develop a strategy to reimplement the landfill clean-closure plan and to rescind the WDR. 

Trinity implemented disposal of approximately 2,040 tons of non-Resource Conservation Recovery Act (RCRA) and RCRA hazardous waste (lead contaminated soil) at an offsite Class I Landfill in 2016.

Trinity conducted a waste delineation investigation at the Site in 2016 and it was determined that elevated lead concentrations still remained in soils but groundwater had not been impacted.

Trinity concluded that the remaining lead-impacted soils do not threaten water quality and met the performance standard for clean closure of a landfill; and recommended terminating the groundwater and surface water monitoring program associated with WDR, properly destroying the existing groundwater monitoring wells, and rescinding the WDR.

The CVRWQCB agreed with Trinity’s conclusions and recommendations, and the WDR was rescinded in 2017.

CLIENT GOALS FOR PROJECT:

The property owner sought to clean-close the Class I Landfill and rescind the WDR, to terminate the WDR fees and market the property for sale.

PROJECT APPROACH:

  • Coordinated stakeholder meetings with the CVRWQCB regulators and the client to develop a plan to achieve landfill clean-closure.
  • Trinity developed a stockpile sampling approach that limited the number of profiling samples typically required for landfill disposal, saving on cost.
  • Based on the profiling results, Trinity segregated the stockpiles into three different waste streams, non-RCRA, RCRA and RCRA with lead stabilization and managed the transport and disposal of each waste stream under manifest.
  • Trinity conducted a comprehensive waste delineation investigation where over 2,000 soil samples were collected at 6-inch intervals to sufficiently delineate lead impacts at the Site. Grab-groundwater samples were collected from the base of the surface impoundment to evaluate groundwater conditions directly under the Class I Landfill.
  • The 6-inch sampling resolution was selected to limit the quantity of soil that may have required excavation.
  • Trinity developed a site-specific data assessment methodology approach by using the CVRWQCB’s Designated Level Methodology for Waste Classification and Cleanup Level Determination (Designated Level Methodology), the Synthetic Precipitation Leaching Procedure (SPLP), and soil pH results to determine if lead concentrations in soil could leach to groundwater at concentrations capable of impacting groundwater above the Maximum Contaminant Level (MCL).
  • Trinity calculated background lead concentrations for onsite soils that were assumed to have not been influenced by historical site releases related to the Closed Class I Landfill. Trinity used guidance from the Determination of Background Concentrations of Inorganics in Soils and Sediments at Hazardous Waste Sites and calculated two onsite background lead concentrations for the Site, a native soil background lead concentration and a Site-specific anthropogenic lead background concentration. The anthropogenic background recognizes that lead in surficial soils is widespread due to the historical use of leaded gasoline and associated emissions and long-term industrial use at nearby sites.

RESULTS, RESOLUTION, NEXT STEPS:

  • The client’s goals have been met.
  • The WDR is rescinded. 
  • The property has been sold.
 

 

CATEGORY OF SERVICE, LOCATION:

Former Circuit Board Manufacturing Facility, Milpitas, California

TYPE OF CLIENT:

Industrial Manufacturer

BACKGROUND:

Client is in the process of closing a former circuit board manufacturing facility. Client received approval from Milpitas Fire Department (MFD) (http://www.ci.milpitas.ca.gov/milpitas/departments/fire/) for a Closure Plan for the facility which included demolition and disposal of the facility’s concrete slab.  In accordance with the Closure Plan, Trinity was contracted to assess the facility’s concrete slab and soils underlying the slab for impacts related to past industrial uses, and to determine the waste classification of the concrete slab for disposal. 

 Former circuit board manufacturing facility, milpitas

Former circuit board manufacturing facility, milpitas

CLIENT GOALS FOR PROJECT:

  • Assess soils underlying facility’s concrete slab for potential impacts related to past industrial uses
  • Classify the concrete slab for appropriate disposal in accordance with the MFD approved Closure Plan.
  • Achieve facility closure.

PROJECT APPROACH:

  •  Trinity collected 45 concrete core samples throughout the facility and advanced and sampled 20 soil borings to 5 feet below ground surface beneath selected concrete core sample locations. Trinity Drilling, Inc. advanced the soil borings using an LT-54 limited-access direct-push drill rig. All sampling work was performed under MFD inspector oversight and samples were submitted to a State-Certified analytical laboratory.
  • Trinity evaluated initial concrete sample analytical results and coordinated additional laboratory analyses as required to complete the concrete waste classification.

RESULTS, RESOLUTION, NEXT STEPS:

  • Soil sampling results indicated that soils underlying the facility’s concrete slab have not been impacted by the historic site use.
  • Based on concrete sampling results Trinity classified the facility’s concrete slab based on California Title 22 (http://www.dtsc.ca.gov/LawsRegsPolicies/Title22/) disposal regulations as either Federal RCRA-hazardous waste, Non-RCRA California‑hazardous waste, or non-hazardous waste. Trinity provided a map of waste classifications of the facility’s concrete slab for use by client subcontractors.
  • Client’s subcontractors used the determined waste classifications to properly remove and dispose of the facility’s concrete slab in compliance with Federal and State regulations.
  • Trinity prepared and submitted letter reports to the MFD documenting soil assessment concluding that soils have not been impacted by the site former industrial use. Further soils assessment was not required by MFD.
  • After removal and disposal of the concrete slab was completed, Trinity submitted a letter report to MFD documenting the concrete slab assessment, classification, removal, and disposal. Trinity anticipates MFD will certify facility closure based on this work.

 

 

 

CATEGORY OF SERVICE, LOCATION:

Remedial Excavation and Facilities Demolition Management and Site Closure, Santa Cruz, California

TYPE OF CLIENT:

Municipality

BACKGROUND:

City of Santa Cruz shooting range was shown to be impacted with hazardous levels of lead in soils.  A Remedial Action Workplan called for excavation of 4,200 tons of lead-impacted soils, and disposal at Class I and II landfill facilities.  In addition to performing the remedial excavation work, the City wanted to demolish and remove all shooting range structures and convert the land back into City Park natural open space. Trinity was contracted to review and help prepare the City’s excavation bid documents, recommend a contractor, and manage and oversee all aspects of the remediation contractor’s operations, on the City’s behalf.

CLIENT GOALS FOR PROJECT:

Provide supervision of remediation contractor, to validate costs incurred and seek cost-savings where possible, and to ensure compliance with State and Federal rules and regulations, the approved Remedial Action Plan, and Health and Safety Plan.

PROJECT APPROACH:

  • Trinity managed all aspects of the demolition and remedation project for the City including regulatory liaison, risk management, public interface and notifications, contractor coordination, scheduling and planning, field operations oversight and management; provided contract, unit price and change order oversight and management; and reviewed draft and final reports.
  • As a cost saving measure, Trinity recommended pre-profiling soils before beginning excavation activities.  A pre-profiling plan was developed by Trinity and the contractor and implemented before excavation work progressed.

RESULTS, RESOLUTION, NEXT STEPS:

  • Pre-profiling data significantly reduced the volume of soils expected for excavation and disposal from 4,200 tons to 2,631 tons.  Of this volume, 1,763 tons were disposed as non-RCRA hazardous waste at a Class II rather than Class I landfill.
  • Pre-profiling significantly reduced the cost of the project which allowed the City to add removal of the upper three feet of soil over the entire foot print of the gun range and perform additional grading, seeding and winterization work.
  • The project was completed 28% under budget including extras.
  • Regulatory site closure was received within six months after completion of field work.
 

 

CATEGORY OF SERVICE, LOCATION:

Former aluminum extrusion and anodizing facility, Watsonville, California.

TYPE OF CLIENT:

Commercial Property Developer

BACKGROUND:

The former property owners operated an aluminum extrusion and anodizing facility for approximately 40 years until the facility closed in 2007. During the facility closure, 37 separate areas of potential environmental concerns (APECs) were identified and required evaluation with select APECs requiring remediation for chemicals of concern in soil. The work was overseen by the lead agencies, the Central Coast Regional Water Quality Control Board (CCRWQCB) and the Santa Cruz County Environmental Health Service (SCCEHS). The property was sold before case closure was issued with several APECs requiring further assessment at the site, specifically, elevated soil pH in three areas.

CLIENT GOALS FOR PROJECT:

The property owner intends to develop the site for commercial use. Trinity was contracted by the property owner to address the remaining APECs.

PROJECT APPROACH:

  • Trinity submitted a work plan with a contingent remedial excavation plan to the SCCEHS. The contingent excavation plan was proposed to expedite the case closure process in the event pH impacted soils required remediation.
  • Trinity investigated three areas where historical elevated pH values were at or above the recommended level for the site of 11.5, determined by a certified industrial hygienist.
  • Trinity developed a remedial excavation plan to separate reusable soils from soils with elevated pH above 11.5.

RESULTS, RESOLUTIONS, NEXT STEPS:

  • Trinity developed a pH field soil sampling plan to minimize project cost and time. Trinity’s field staff collected the soil samples and measured soil pH in the field via Environmental Protection Agencies (EPA) Method 9045D. Some of the samples were sent to a certified laboratory to verify field soil pH results.
  • Soils with a pH at or above 11.5 were sufficiently delineated and remediated at the site via investigation soil borings, field and laboratory soil pH measurements, remedial excavations, and offsite disposal. A total of 418 tons of pH-impacted soils were excavated and disposed of under non-hazardous waste manifests to offsite landfill.
  • Trinity submitted a pH Soil Investigation Report to the SCCEHS and recommended no further action and that the Site case be closed by SCCEHS and CCRWQCB.