2018-624-E Solid Waste - Draper Aden amendment 2

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Engineering Surveying Environmental Services Draper Aden Associates Section Seven Approach and Understanding 38 Our approach to the environmental monitoring and control programs at OCSWM landfills has been, and continues to be, based on historical knowledge of conditions at the facility, assessment of data derived from the groundwater monitoring program, and economic conditions. For example, the concentrations of certain regulated constituents in groundwater, in certain monitoring wells at the facility, exceed their respective “Groundwater Protection Standards.” As a result, NCDEQ required that the North landfill enter a Groundwater Corrective Action program. During the several years in which the facility has been in Corrective Action, our strategy for managing the program has been based on two key concepts: (1) the quality of groundwater underlying the landfill represents negligible risk to human health and (2) the economic recession of the last several years has placed severe constraints on the budgets of local governments. For these reasons, our strategy has been to expend only enough effort on Corrective Action to prevent NCDEQ from pressing the OCSWM to embark on a more aggressive program of groundwater remediation. Another example is our Alternate Source Demonstrations (ASDs) that we have prepared on behalf of OCSWM. Draper Aden Associates has prepared ASDs for arsenic, cobalt, lead, selenium, and vanadium, each of which was subsequently approved by NCDEQ. ASDs are one of the available regulatory mechanisms to address “suspect” groundwater exceedances over site-specific background levels or groundwater protection standards. As a results, our successful demonstrations that sources other than the landfill have caused the apparent exceedance have allowed OCSWM to avoid unnecessary escalation in the groundwater monitoring program as they pertain to arsenic, cobalt, lead, selenium, and vanadium. Below is a brief overview of our experience, as a firm, specifically working on OCSWM environmental management programs. Orange County Regional Landfill: North (Closed) Facility Corrective Action Program (background). In a letter from Mr. Gayle Wilson (OCSWM) to Mr. Ervin Lane (NCDEQ; dated May 28, 2009), OCSWM accepted the corrective measures remedies presented in the ACM report (prepared by Draper Aden Associates; submitted October, 2008). The selected remedies include: monitored natural attenuation (MNA), enhanced bioremediation, direct oxidation. In a letter from Mr. Ervin Lane to Mr. Mike Meagher (OCSWM; dated September 11, 2009), NCDEQ approved the Groundwater Corrective Action Permit Modification Application. OCSWM implemented the following measures at the facility: institutional controls, engineering controls. In order to accelerate the remediation schedule, Draper Aden Associates assisted OCSWM in advancing from monitored natural attenuation to the more active components of the primary (phase 1) remedy: direct oxidation, enhanced biodegradation. Groundwater Injection Program - Hydrogeochemical Assessment. On behalf of OCSWM, Draper Aden Associates prepared an application to renew a permit to inject potassium permanganate into the groundwater in selected areas of the North landfill. DocuSign Envelope ID: 09434BEC-1F7E-41E5-A9D1-4CA5D7ECE339DocuSign Envelope ID: 41BC5C93-0D4F-4535-B939-248B032E3585