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amec— <br /> TECHNICAL <br /> ATTACHMENT B.2 <br /> Bioaugmentation Feasibility Assessment <br /> Nestle USA, Inc.- Ripon, CA <br /> 1.0 INTRODUCTION <br /> On behalf of Nestle USA Inc., AMEC has assessed the feasibility of implementing <br /> bioaugmentation for in situ treatment of groundwater in the vicinity of City of Ripon Wastewater <br /> Treatment Plant (WWTP) affected by chlorinated volatile organic compounds (VOCs) that may <br /> have been historically discharged to the WWTP. The feasibility of groundwater remediation by <br /> bioaugmentation is evaluated in this document in terms of its potential effectiveness, <br /> implementability, and cost. Section 2.0 provides an overview of the bioaugmentation <br /> technology, including key design considerations for effective implementation; the potential <br /> effectiveness, implementability and cost is evaluated in Section 3.0. Section 4.0 summarizes <br /> conclusions from the feasibility analysis and Section 5.0 includes a list of references. <br /> 2.0 TECHNOLOGY DESCRIPTION <br /> There are two general approaches for promoting the microbiologically-mediated in situ <br /> destruction of VOCs: <br /> 1. Biostimulation, which involves adding nutrients and other substances to promote the <br /> growth of indigenous microbial populations that degrade target VOCs; and <br /> 2. Bioaugmentation, which involves the direct injection of laboratory-grown microbial <br /> enrichment cultures or isolated microbial strains that are known to have the ability to <br /> degrade target VOCs. Bioaugmentation is usually implemented in addition to <br /> biostimulation. <br /> The reported advantages of bioaugmentation include shorter acclimation periods (i.e. <br /> decreased lag time before remediation begins), faster degradation rates, and in some cases, <br /> lower concentrations of undesirable byproducts or intermediates such as vinyl chloride <br /> (Alvarez and Illman, 2006). Bioaugmentation of aquifers is a challenging task, and critical <br /> issues include the ability to distribute injected microbes throughout the treatment zone, the <br /> survival of added strains, and the availability of sufficient nutrients and contaminants needed <br /> to support the foreign microbes in their new setting (Alvarez and Illman, 2006). <br /> Key considerations with respect to the potential effectiveness, implementability, and cost of <br /> bioaugmentation are: <br /> • Treatment processes, <br /> • Potential side effects of treatment on groundwater chemistry, <br /> AMEC Geomatrix, Inc. <br /> \\oad-fs1\doc_safe\9000s\9837.006\4000 REGULATORYTFS Assessment_Apx B_01 2711\Attachment B.2\Attach B-2.doc 132-1 <br />