Relationships between Odor and Commonly Measured Water Quality Characteristics in Surface Water Supplies

Abstract

Weekly threshold odor numbers (TONs) were determined for the waters of three impoundments and the finished water produced by treatment at each impoundment site during a 2-year period. The correlation between the TONs and each of 20 commonly measured biological, chemical, and physical parameters was examined. The correlation coefficients were generally low, except those for nitrate-nitrogen, sulfate, manganese, and chlorine demand. The magnitude of taste and odor in the three impoundments was found to be a seasonal function. High TONs generally occurred during the period from May through October, the period of anoxic conditions in bottom waters of impoundments. Regardless of the magnitude of TONs for the raw waters, the TONs for the three finished waters ranged from 3 to 10 about 95 percent of the time. The probable causes of the excessive TONs are discussed, and predictions of the occurrences and magnitude of odor are presented, based on stepwise multiple regression analyses.