Demonstrating process robustness of potable reuse trains during challenge testing with elevated levels of acetone, formaldehyde, NDMA, and 1,4-dioxane

Robustness of a demonstration potable reuse facility was evaluated through a series of system-wide chemical challenge tests spiking neutral low-molecular weight compounds (acetone, formaldehyde, N-nitrosodimethylamine (NDMA), and 1,4-dioxane) which are known to be challenging for removal through advanced treatment. Two advanced treatment train arrangements were compared: O3/BAC-MF/UF-RO-AOP and RO-AOP. Ozone and biological activated carbon (O3/BAC) offered significant attenuation of the smallest and most biologically degradable compounds tested: acetone and formaldehyde. These two compounds had limited reduction across the reverse osmosis (RO) membrane barrier and the different advanced oxidation process (AOP) setups used. 1,4-Dioxane was partially reduced across the oxidation barriers: 62% across ozonation and up to 95% across AOP depending on oxidant used and oxidant dose. Both a hydrogen peroxide (H2O2) based AOP (UV/H2O2) and a sodium hypochlorite (as HOCl) based AOP (UV/HOCl) demonstrated sufficient oxidation, providing no less than 0.5-log (68%) 1,4-dioxane attenuation required by regulators in the USA. NDMA was reduced across both UV/H2O2 and UV/HOCl from 157 to 267 ng/L to below the 10 ng/L established notification level for drinking water in California. Overall, addition of O3/BAC enhanced cumulative removal of all the spiked trace organic chemicals, providing greater protection against the spiked contaminants than RO-AOP alone. In addition, online total organic carbon (TOC) monitoring successfully captured the presence of the spiked chemicals. doi: 10.2166/aqua.2019.134 s://iwaponline.com/aqua/article-pdf/68/5/313/579400/jws0680313.pdf Rodrigo A. Tackaert (corresponding author) Aleksey N. Pisarenko Elise C. Chen Aviv Kolakovsky R. Shane Trussell Trussell Technologies, 380 Stevens Avenue, Suite 212, Solana Beach, CA 92075, USA E-mail: rodrigot@trusselltech.com Brian M. Pecson Trussell Technologies, 1939 Harrison Street, Suite 600, Oakland, CA 94612, USA Jörg E. Drewes Chair of Urban Water Systems Engineering, Technical University of Munich, Garching, Germany R. Rhodes Trussell Trussell Technologies, 232 North Lake Avenue, Suite 300, Pasadena, CA 91101, USA