Concept of Viscous Heating to Reinvent the Toilet

Abstract

Highly viscous substances, such as feces, produce significant heat when layer deformation occurs. We describe the use of viscous heating to destroy disease-causing microorganisms and whipworms in feces using a small amount of power. The laboratory-scale unit has a rotating central core with a space between a fixed shell wall. Viscous heating of feces proved effective for disinfection. Data were obtained over a range of operating conditions with simulant materials. In addition, baboon feces were tested for parasite destruction. For simulants, the temperature observed with the smallest spacing approached 200�C. Baboon feces showed 99% destruction of Trichuris trichiura as a result of shear stress only because temperature was limited as a result of hair in samples. Vegetable dye passed through the reactor demonstrated plug flow. Alternative geometries, such as two rotating parallel disks, a solid sphere inside another hollow sphere could be considered for high-volume sludge processing. Design variations include spreading the output mass into a thin layer for efficient water evaporation and recovery. Since the process can sterilize fecal mass, other treatment technologies should consider integrating viscous heating into their process streams.