Abstract:
The provision of safely managed sanitation in densely populated urban
settlements of cities in low- and middle-income countries poses complex
challenges. To address these challenges, Cranfield University is developing the
Nano Membrane Toilet, a novel standalone household-level sanitation
technology that operates off the grid and safely treats human waste while having
an aspirational design. Developing such a complex novel product requires testing
a multitude of prototypes in numerous ways. Since designing, building and testing
the prototypes is often done by separate teams of various disciplines, the entire
testing process requires a considerable amount of planning and communication.
This thesis not only reports on field trials and laboratory testing of two prototypes
of the Nano Membrane Toilet, but also investigates the under-explored field of
planning and communicating prototype tests for complex product development
processes. In a first trial, a prototype mechanical toilet flush is assessed in user
tests and lab tests. It is shown to be liked by users of Urine Diversion Dehydration
Toilets, and it appears to perform best when lubricated and with a silicone rubber
with oil-bleed-effect for its swipe. A second round of tests explores settling and
displacement as means of solid-liquid separation in the Toilets collection tank.
Toilet paper is shown to inhibit settling of faeces, while a conical tank geometry
promotes it. From a literature review and subsequent interviews with experts in
prototype testing, a visual tool for planning and communication prototype tests
for the Nano Membrane Toilet is developed, validated and refined into a generally
applicable, modular version. This modular tool can be used to produce
customised visual testing strategies for a variety of product development
processes, to facilitate planning and communicating testing activities across
interdisciplinary teams.
