In a 2 lab study, Lindie Aragon of Westminster WWTF, Evelyn Rhodes of Northglenn WWTF, and John Stillian of Timberline Instruments, Boulder, collaborated in an innovative method combining persulfate digestion and the Timberline TL-2800 to analyze for total nitrogen in wastewater. Paper published in the Rocky Mountain Water, a joint publication of the American Water Works Association and Rocky Mountain Water Environment Association, January 2019 issue, page 28.