ABSTRACT
The scope of this study was to investigate the impact of drinking water sources on the refractory DOC (dissolved organic carbon) in treated effluents used for groundwater recharge. Because the City of Mesa uses different surface waters and local groundwater for its water supply, drinking water DOC varies from approximately 1.3 to 3.2 mg/L. The variations of this DOC of natural origin significantly influences DOC concentrations of the treated wastewater. Drinking water DOC represents probably a 30 to 50 percent of the refractory DOC in the Mesa effluent. Refractory DOC was determined with an adapted soil-column system which simulates the degradation of DOC in aquifers. The impact of drinking water quality on treated wastewater was also confirmed by high correlations of chloride and sulfate concentration. This correlation allowed an estimation of the increase of salt concentrations from the use of water.
