Parameter correlation in wastewater dispersal area groundwater monitoring wells serving Corolla Light #1 Wastewater Treatment Facility in Currituck County, North Carolina

Abstract

ABSTRACT More than half of North Carolina’s population utilizes groundwater as a drinking water source. Efforts to protect water sources include groundwater monitoring around some of the larger wastewater systems. Samples collected from system monitoring wells are analyzed for selected contaminants, typically outlined in wastewater systems’ operation permits. Detection of targeted parameters can result in early intervention of contamination identified through parameter correlation. This investigation focused on wells located around the Corolla Light #1 WWTF in the Corolla, NC. The WWTF has seven system monitoring wells for which sample analyses results were assessed for discernable correlations between parameters. The On-Site Water Protection (OSWP) system is monitored by wells MW-4, MW-5, and MW-6. The Division of Water Resources (DWR) system is monitored by wells MW-1, MW-2, MW-3, and MW-7. The OSWP system utilizes subsurface dispersal and the DWR system utilizes surface dispersal. Monitoring conducted around the areas is reported to OSWP and DWR. Results for samples collected November 2006–2016 were compiled and results for pH, TDS, Cl-, and NO3- examined. Evaluation by regression analyses appeared to indicate no correlation between concentrations of NO3- and the other three parameters. There did appear to be a significant relationship between TDS and Cl- in five of seven wells sampled. Only two wells (MW-1 and MW-7) appeared to have a relationship between pH and both TDS and Cl-.