Indicators for technological, environmental and economic sustainability of ozone contactors

Various studies have attempted to improve disinfection efficiency as a way to improve the sustainability of ozone disinfection which is a critical unit process for water treatment. Baffling factor, CT10, and log inactivation are commonly used indicators for quantifying disinfection credits. However the applicability of these indicators and the relationship between these indicators have not been investigated in depth. This study simulated flow, tracer transport, and chemical species transport in a full-scale ozone contactor operated by the City of Tampa Water Department and six other modified designs using computational fluid dynamics (CFD). Through analysis of the simulation results, we found that baffling factor and CT10 are not optimal indicators of disinfection performance. We also found that the relationship between effluent CT obtained from CT transport simulation and baffling factor depends on the location of ozone release. In addition, we analyzed the environmental and economic impacts of ozone contactor designs and upgrades and developed a composite indicator to quantify the sustainability in technological, environmental and economic dimensions. (C) 2016 Elsevier Ltd. All rights reserved.