Mapping the Path to Site Closure at the Fresno Sanitary Landfill Superfund Site
Presented on Monday, March 16, 2015
Bill Fernandez, PE1, John P. Nyznyk, PE, BCEE, LEEDAP2 and George Slater3, (1)CDM Smith, Walnut Creek, CA, (2)Environmental Remediation, CDM Smith, Walnut Creek, CA, (3)City of Fresno, Fresno, CA
The Fresno Sanitary Landfill (FSL) was operated by the City of Fresno (City) as a Class III municipal landfill, receiving municipal solid waste from approximately 1935 to 1987. Following detections of volatile organic compounds (VOCs) in groundwater in the vicinity of the landfill and evidence of migrating landfill gas, the FSL was placed on the National Priorities List (NPL). Remediation activities at the FSL included construction of landfill closure elements, including final landfill cover, landfill gas control, and stormwater management systems, and a pump-and-treat system to address VOC impacts to groundwater.
The USEPA approved a unique approach for the groundwater remediation at the FSL: a phased approach for implementation of remedial actions to address the VOC groundwater contamination, with each phase having specific remedial goals. Phased implementation allowed periodic adjustment of remediation system components to accommodate changing conditions, including increased regional groundwater use, declining groundwater levels, and expanding plume conditions. This phased approach has resulted in significant cost savings to the City.
The overall goal has been to make consistent progress toward delisting of the FSL from the NPL. Delisting will require demonstrating hydraulic control, plume stability, and compliance with defined groundwater cleanup levels. After each phase of remedial action, a detailed performance evaluation is performed to determine the need for further adjustments in the system.
The remediation system performance evaluations make use of a number of tools including three-dimensional numerical modeling to estimate extraction well capture zones, migration of contaminants under various pumping scenarios, and VOC mass removal. The impact of the seasonal operation of numerous agricultural wells in the area on the local flow field is also assessed with the groundwater model. The model is also being used to predict future travel of contaminants to ensure that the contaminant plume is contained and that cleanup levels can be met.
Bill Fernandez, PE
CDM Smith, Walnut Creek, CA
Bill Fernandez is a water resources engineer with more than 14 years of groundwater flow and transport modeling experience ranging from large, regional-scale to site-scale groundwater flow and transport. He has extensive experience performing hydrogeological investigations, feasibility studies, remedial designs, remedial actions, and other environmental activities associated with groundwater flow and transport.
John P. Nyznyk, PE, BCEE, LEEDAP
Environmental Remediation, CDM Smith, Walnut Creek, CA
John Nyznyk has more than 26 years of experience in environmental engineering with a focus in site investigation and environmental remediation. He currently serves as the manager of the Environmental Remediation Division for CDM Smith in Northern California. His project work encompasses a broad range of engineering disciplines, including solid waste and hazardous waste management; planning, permitting, and design associated with remediation systems; hazardous waste site assessments; and environmental management program compliance.
George Slater
City of Fresno, Fresno, CA
George Slater is a Landfill Closure Consultant at the City of Fresno, where he oversees the successful operation of the remediation system at the Fresno Sanitary Landfill.
