Performance Monitoring of Remediation Technologies for Soil and Groundwater Contamination: Review

Abstract

Performance monitoring of applied remediation technologies is an important part of site remediation. It involves periodic measurement of site parameters to evaluate whether the remediation technologies perform as expected or to determine the termination date of remediation projects. Performance monitoring can be a difficult undertaking if there are no well-defined and measurable remediation objectives, such as a reduction in mass discharge rate from a contaminant source. Besides, the selection of the site parameters to be monitored is highly dependent on the remediation objectives established and the remediation technologies applied. For instance, contaminant concentration in soil, soil vapor, and groundwater within a contaminant zone should be monitored if reduction of the mass or volume of a contaminant zone is the prime remediation objective, while contaminant concentration in groundwater just outside a contaminant zone should be the main monitoring parameter if the objective is to mitigate the contaminant migration. Furthermore, subsurface temperature is a unique monitoring parameter for in situ thermal remediation to ensure the proper operation of the technology, whereas groundwater oxidant concentration is the monitoring parameter only for in situ chemical oxidation technologies. This paper mainly covers the general criteria for establishing the site-specific remediation objectives and the key monitoring parameters for various remediation technologies, which help avoid waste of efforts to collect unnecessary site parameters during the performance monitoring.