A Sewerless Thermal Sanitation Unit for a Household: Computed Pathogen Lethality, Energy per Use, and Safe-Handling Intervals for a 2-Litre Batch Design

SIMULATED, NOT MEASURED. A design and computation for a sewerless household batch unit that heat-treats 2.0 kg of faecal material before handling. Using first-order thermal inactivation with stated D- and z-values, Ascaris suum eggs are the limiting organism: at 65 degrees C the 6-log time is 20.24 min and the specified 25 min hold gives a computed 7.41-log reduction, using 0.1188 kWh per cycle (0.0238 USD at 0.20 USD/kWh). Parts cost 118.00 USD, or 303.50 USD with a solar supply yielding 0.600 kWh per day. Safe-handling intervals are 11.06 h sealed or 1.11 h vented to 40 degrees C. No unit has been built and nothing has been tested in hardware; all pathogen figures are computed lethality under the stated assumptions. The computation script and its full output are deposited with the paper.