EVALUATING CRITERIA FOR ENHANCED COAGULATION COMPLIANCE

Jar tests were performed on 31 natural waters from a variety of source s across the United States. These tests indicate that the majority of utilities supplying samples will have difficulty meeting the Step 1 to tal organic carbon (TOC) removal requirements in the Disinfectants/Dis infection By-products Rule. Utilities may need the proposed point of d iminishing returns alternative performance criterion to achieve compli ance with the enhanced coagulation requirement. Water sources with hig h TOC and low alkalinity were most likely to meet the proposed Step 1 TOC requirements. Those with low TOC were most likely to need the alte rnative performance criterion.