AWWA WQTC71403

This powerpoint presentation begins by providing a brief overview of the City of Scottsdale, Arizona Water Campus, specifically focusing on the water reclamation plant (WRP) and the advanced water treatment facility (AWT). Compounds of potential concern (CPC) include: more than 40 CPCs monitored by the City; one compound identified as priority contaminant is N-Nitrosodimethylamine (NDMA), based on CDPH public notification level of 10 ng/L. Expansion of AWT includes: design of expansion to 20 mgd is currently underway; and, evaluate the occurrence of NDMA and implement NDMA mitigation strategies, including process optimization and additional treatment processes. Full scale sampling results are presented, along with WRP and AWT plant profiling and the impact of other water quality parameters. Bench scale test results are provided, along with chlorine to ammonia ratio, preformed chloramination, free chlorine contact time, and pH. A summary of full scale testing is presented, including free chlorine contact time tested = 5 -15 min prior to ammonia addition, and the formation of NDMA was substantially reduced (75%) without exceeding TTHM limits. Includes table, figures.