PNNL

Abstract

A framework for characterizing and monitoring the Monitored Natural Attenuation (MNA) and Enhanced Passive Remediation (EPR) options was developed to facilitate the use of these naturally passive remedial options. The framework provides the technical basis for evaluating, applying and monitoring MNA/EPR over the lifetime of application. The mass balance concept is used as the scientific and technical framework for this characterization and monitoring approach. The approach is organized into four transitional phases: screening characterization, decision characterization, process monitoring and system verification. The framework overlays the CERCLA process with the intent to expand the description of characterizations and monitoring and not to replace nor increase the requirements of the Remediation Investigation/Feasibility Study (RI/FS). The use of natural processes to promote cleanup is, in many ways, unique from engineered solutions. And, this framework allows MNA to be evaluated holistically taking into consideration the requirements over the lifetime of the remedy.