Advancements in Organics Monitoring Lead to Improved Jar Testing Optimization

Oral Presentation

Prepared by A. Scott, D. Biller, S. Sytsma
GE Analytical Instruments, 6060 Spine Road, Boulder, CO, 80301, United States

Contact Information:; 720-390-9714


Jar testing is used extensively in the drinking water purification industry to simulate the performance of various chemical coagulants and process conditions without altering the full-scale treatment process. This testing has become even more critical in recent years due to the regulatory requirements of the US EPA’s Stage 2 Disinfection By-Product Rule. For many plants, the rule requires optimization of the treatment process to increase the removal of total organic carbon (TOC), which is a precursor in the production of undesirable and highly regulated disinfection by-products (trihalomethanes and haloacetic acids). TOC removal can often be improved by selecting the optimum dose and type of aluminum or ferric-based coagulant. Other treatment parameters including the addition of permanganate, powdered activated carbon, or pH adjustment can also be easily modeled in jar testing. Traditionally, turbidity and often UV absorbance have been used as a primary indicator of good floc formation and a measure of optical clarity in jar tests. More recent laboratory and field testing has shown that TOC may be a far better indicator of a fully optimized treatment process for many waters. This is particularly true if TOC measurements can be made immediately as various process changes are made to a jar testing plan. In addition, a Size Exclusion Chromatography TOC instrument can be used to evaluate organic size distributions before and after jar testing. Real-world advantages of fully optimized jar tests may include reduced chemical usage or cost, improved removal of organics, and a reduction in regulated disinfection by-products. This study includes jar testing results with turbidity, UV absorbance, and TOC data for water samples from multiple locations across the United States.