Blackwater Disinfection Using Potentiodynamic Methods and Surface-Modified Electrochemical Packed Bed Electrode Materials

Abstract

The present work investigates the use of an electrochemical packed bed reactor (EPBR) for improving the energy efficiency of disinfecting human-generated blackwater. Potentiostatic and potentiodynamic treatment methods are used to compare packed-bed electrodes of magnelli-phase titanium-oxide, granularized activated carbon (GAC), and surface modified forms of both. Our results highlight the differences in energy expenditure, oxidant generation, and EPBR operating conditions, as well as time needed for disinfection of blackwater as a function of packed bed electrode material and potentiometric treatment method. It is proposed that potentiodynamic treatment methods offer a more energy efficient and practical solution to treating blackwater than potentiostatic methods. Moreover, the benefits and drawbacks of using magneli-phase titanium oxide compared to common granularized carbon electrode materials are highlighted by correlating disinfection to energy expenditure and electrochemically generated oxidants. Reactive oxygen species, such as H2O2, and chlorine containing species, such as Cl2, are quantified and correlated to the reduction of bacterial concentration for each electrode material and treatment method. Lastly, the effects of flow-rate, particle size, and blackwater composition are correlated to the optimal conditions for blackwater disinfection.