Microwave disinfection as a treatment for blackwater from dewatered sludge

Background: Fast and efficient on-site treatment of blackwater, rejected from the dewatering process, can decrease the costs associated with disposal of fecal sludge removed from pit latrines by reducing the volume of sludge transported to the disposal site.
Methods: In this study, we examine the potential use of low cost consumer microwave units for disinfecting pathogen-rich blackwater. Domestic bench top microwave units were modified to allow flow through and re-circulation of blackwater. Energy, throughput, and disinfection characteristics related to microwaves are studied and compared to conventional thermal heating. A custom flow through stack of 5 microwaves was designed and used to examine the feasibility of single pass, high throughput application.
Results and Conclusions: The results show microwave energy does not play a role in the disinfection of blackwater. The benefits of a microwave disinfection system are shown to be high energy efficiency, compact size, and cost efficiency.