ASCE has honored the writing team of Mongkolaya Rungvetvuthivitaya, Aff.M.ASCE; Rengao Song; Mark Campbell, A.M.ASCE; Eric Zhu; Tian C. Zhang, Ph.D., P.E., D.WRE, F.ASCE; and Chittaranjan Ray, Ph.D., P.E., D.WRE, F.ASCE, with the 2020 Samuel Arnold Greeley Award for the paper “Decay Kinetics of Chlorite Under Simulated Distribution System Conditions,” in the April 2019 issue of Journal of Environmental Engineering.
In the selected work, the researchers investigated parameters such as dissolved organic carbon, chloramine, pH, and temperature that might influence the decay of chlorite in synthetic and finished chloraminated water from Louisville Water Company. Their results showed that in the absence of chloramines, chlorite is stable under typical distribution system conditions (buffered water at pH of 7–9; temperature between 15°C and 35°C; and in the presence of natural organic matter, ammonia, nitrite and nitrate). However, under these same conditions chlorite decays if chloramines are also present; chlorite and chloramines both degrade in the presence of the other, reducing the effective disinfectant residual in the system. An empirical model was developed to show the dependence of chlorite decay on chloramine concentrations and other environmental conditions.
This study is especially useful in that utilities can use the model as a guide for the chlorite feed concentration and estimation of the chlorite decay in the distribution system.
The Samuel Arnold Greeley Award is presented for papers on the design, construction, operation or financing of water supply pollution control, storm drainage or refuse disposal projects.