PSA - Methane Mitigation at Closed Biosolids Landfill at Organic Resources Facility - Weaver Consulting Group North Central, LLC

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Weaver Consultants / Group December 11, 2019 Ms. Andrea Alexander Manager of Environmental Compliance City of South Bend 3113 Riverside Drive South Bend, IN 46628 RE: Proposal for Technical Assistance Methane Mitigation Plan Biosolids Landfill -Organic Resources Center City of South Bend, Indiana Dear Ms. Alexander. At your request, Weaver Consultants Group (WCG) has prepared this scope of work and cost estimate for professional services pertaining to elevated methane readings at gas monitoring probes associated with the closed Biosolids Lagoon #4. WCG will assist in determining a strategy for potential remedial measures to address the elevated methane readings and assist to determine its extent. The paragraphs below outline the proposed scope and costs to perform this work. Project Scope Monitoring of the gas monitoring probe network associated with Biosolids Lagoon #4 has indicated elevated levels of methane gas has been detected in some monitoring probes, generally located on the eastern border of the property. To assist the city staff in determining the most cost effective and logical course of action to mitigate future methane migration, WCG proposes to review and update the existing conceptual methane mitigation plan prepared in 2017 to address the primary area of concern along the eastern border of Biosolids Lagoon #4. To update the methane mitigation plan, WCG will review available historic monitoring probe data and engineering/geologic information to determine potential gas migration pathways and mechanisms along the eastern border of the site, building upon previously constructed remedial measures. The condition of vents and other in -place engineering controls will be assessed based on available as -built information, monitoring data, and a site inspection. The mitigation plan will include an executive summary of historical data. The plan will also summarize mitigation actions taken to date, and suggest future mitigation actions to be considered. 7121 Grape Road • Granger, Indiana 46530 • 574.271.3447 • wcgrp.com • Offices Nationwide