Testing a waterless mechanical toilet flush - experiences from the laboratory and the field

In 2011, the Bill and Melinda Gates Foundation initiated the Reinvent The Toilet Challenge (RTTC), to find sustainable sanitation solutions for the 2.5 billion people worldwide who don’t have access to safe, affordable sanitation. In response to the RTTC, Cranfield University is developing the Nano Membrane Toilet (NMT), a novel technology which treats both liquid and solid fractions using a mechanical waterless flush, a settling tank for solid-liquid separation, membrane bundles and a dryer-combustor combination. (For more information visit www.nanomembranetoilet.org) A prototype of the toilet’s frontend – i.e. the user interface including the seat and the mechanical flush, which comprises a rotating bowl and a swipe to clean the bowl as it rotates downward to empty it’s contents into the settling tank – was tested in field trials at a research institution and peri-urban households in South Africa. Testing included physical tests as well as user surveys and –interviews. This poster focuses on the physical tests, the findings of which were later confirmed in controlled laboratory experiments using synthetic faeces, -urine, and -menstrual fluid.