Under what condition does a water system using conventional filtration not need to use enhanced coagulation?

The condition under which a water system using conventional filtration does not need to employ enhanced coagulation is when the treated water total organic carbon (TOC) level is less than 2.0 mg/L. Enhanced coagulation is generally applied when TOC levels are high, as it aims to improve the removal of organic compounds that can lead to the formation of harmful disinfection byproducts when chlorine is used for disinfection.

When TOC levels are sufficiently low (below 2.0 mg/L), it indicates that there isn't a significant amount of organic material present that could contribute to byproduct formation. Therefore, conventional filtration processes are typically adequate in these scenarios to meet safety and quality standards without the need for additional measures like enhanced coagulation.

In contrast, if TOC levels are higher or other water quality parameters are concerning, enhanced coagulation may be necessary to ensure compliance with regulations and the safety of the water supply. This makes understanding TOC levels crucial for municipalities and water treatment operators in managing water quality effectively.