Cost Comparison of Soil Vapor Extraction and Subslab Depressurization for Vapor Intrusion Mitigation
Citation:
Lutes, C., L. Stewart, R. Truesdale, J. De Loeora, J. Zimmerman, AND B. Schumacher. Cost Comparison of Soil Vapor Extraction and Subslab Depressurization for Vapor Intrusion Mitigation. GROUNDWATER MONITORING AND REMEDIATION. National Ground Water Association, Westerville, OH, 42(4):43-53, (2022). https://doi.org/10.1111/gwmr.12510
Impact/Purpose:
This article is the first to compare soil vapor extraction (SVE) and subslab depressurization (SSD) costs vapor intrusion (VI) mitigation. This study compares capital, operation, and treatment costs of SVE and SSD systems based on data collected during a multi-year demonstration project conducted at eight buildings in an urban setting. The capital cost of the SVE system was substantially less than the total capital cost of the SSD systems for the base case. The SVE operating costs are higher, especially in the early years of operation when the SVE is being operated for mass removal and treatment, with substantial energy and waste disposal costs. As a result, the cumulative SVE system cost rises above that of the SSD systems in the sixth year of operation. A significant portion of the operations and maintenance cost advantage of the SSD systems comes from the assumption that off-gas treatment would not be required for SSD systems. Alternative cases are analyzed that show SVE costs are likely to be lower in cases where a numerous small buildings requiring independent SSD systems overlie the SVE zone of influence. Conversely, SSD systems are less costly for cases with few small buildings overlying the SVE zone of influence. The additional benefits of SVE in providing both building mitigation and mass removal are recognized. In a situation where an existing SVE can be repurposed for VI protection from residual volatile organic carbon (VOC) mass or replaced by a small system, the SVE cumulative costs over 30 years can remain lower than the cost of installing and operating SSD systems in multiple buildings. The results of this research would be of interest to EPA program and regional partners, local communities and the general public.
Description:
Soil vapor extraction (SVE) can be applied for remediation, and also as an alternative to sub-slab depressurization (SSD) for vapor intrusion (VI) mitigation. This study compares capital, operation, and treatment costs of SVE and SSD systems using data collected during a multi-year demonstration project conducted at eight buildings in an urban setting. The capital cost of the SVE system is substantially less than the estimated total capital cost of individual SSD systems. The SVE operating costs are higher, especially in the early operating years when it is being operated for mass removal and treatment. As a result, the cumulative SVE system cost rises above that of the SSD systems in the sixth year of operation. A significant portion of the operations and maintenance cost advantage of the SSD systems comes from the assumption that off-gas treatment is not required. Alternative cases show SVE costs are likely to be lower in scenarios where numerous small buildings requiring independent SSD systems overlie the SVE zone of influence. Conversely, SSD systems are less costly for cases with few small buildings overlying the SVE zone of influence. An additional benefit of SVE is continued mass removal. In a situation where an existing SVE can be repurposed for VI protection from residual volatile organic carbon (VOC) mass, the SVE cumulative costs over 30 years can remain lower than the cost of installing and operating SSD systems in multiple buildings.
URLs/Downloads:
DOI: Cost Comparison of Soil Vapor Extraction and Subslab Depressurization for Vapor Intrusion Mitigation