title: Viscous heating effect on deactivation of helminth eggs in ventilated improved pit sludge.
abstract: Viscous heating by extrusion of faecal material obtained from ventilated improved pit (VIP) latrines can be used to deactivate soil-transmitted helminth (STH) eggs by increasing the temperature of faecal sludge uniformly. Viscous heating can deactivate STH eggs present in sludge to make the material safer to transport, dispose of, or use in agricultural applications or as an energy source. The mechanical energy required to generate the shear rate can originate from any source. No other heat source or additive is required. Here we determined a baseline for the deactivation of STH eggs using viscous heating. To characterize equipment performance, three parameters were investigated: (1) minimum temperature required for deactivation; (2) local maximum temperatures for various flow rates and moisture contents (MCs); and (3) thermal efficiency. Excess water is undesirable since low viscosities require extended residence time and increased energy input. The minimum temperature to achieve greater than 90% helminth egg deactivation is 70 °C. For the laboratory-scale equipment tested, the maximum allowable mass flow rate for VIP sludge with 77% MC was found to be 3.6 g/s.
authors.affiliation: School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078, USA.
authors.forename: D
authors.initials: D
authors.lastname: Belcher
authors.affiliation: Computing and Engineering, University of Missouri, Kansas City, MO 64110, USA E-mail: garyfoutch@outlook.com.
authors.forename: G L
authors.initials: GL
authors.lastname: Foutch
authors.affiliation: Materials Science and Engineering, Oklahoma State University, Tulsa, OK 74106, USA.
authors.forename: J
authors.initials: J
authors.lastname: Smay
authors.affiliation: School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Westville 3630, South Africa.
authors.forename: C
authors.initials: C
authors.lastname: Archer
authors.affiliation: Pollution Research Group, University of KwaZulu-Natal, Howard College Campus, Durban 4001, South Africa.
authors.forename: C A
authors.initials: CA
authors.lastname: Buckley
mesh_terms: D000818:Animals; D004867:Equipment Design; D005243:Feces / Q000469:parasitology; D006361:Heating; D006376:Helminths / Q000254:growth & development; D006358:Hot Temperature; D010063:Ovum / Q000254:growth & development; D012722:Sewage / Q000737:chemistry / Q000469:parasitology*; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*; D014873:Water Pollutants / Q000302:isolation & purification*
chemical_list: D012722:Sewage; D014873:Water Pollutants