A waterless toilet designed by British student designer Archie Read that uses sand as a flushing mechanism could provide a sustainable solution to the sanitation crisis in low income countries around the world.
Inspired by his placement year stint at LooWatt, a sustainable sanitation company focussed on providing permanent waterless sanitation for urban Madagascar, Read decided to use his exposure to develop a solution targeting the crisis. After conducting research into the state of sanitation globally, he identified Sub Saharan Africa, which has the highest percentage of population with unfit sanitation, as his target region.
His design brief was to design and prototype a dignified waterless toilet solution for low-income countries, with the capacity to deal with excreta from a household of 7 adults for 2 days or 3kg of solid waste and 30 litres of liquid waste. The toilet should also offer adaptability in its storage/disposal method, have a maximum footprint of 1m x 0.6m and not cost more than $72 per unit. The proposed toilet should also be able to safely receive excreta from users, separate urine and faeces, use no water or chemicals, have mechanical functions, safely store waste, and allow easy retrieval/ transportation of waste.
After considerable research into flushing options, he opted for the sand flushing idea as sand creates a semi-seal to prevent contamination, positive waste streams of urine and faeces remain uncontaminated, the low complexity flush will be easy to maintain, and the flush mechanism takes up minimal space.
The main components of ‘Sandi’, Read’s sand flushing toilet are a bowl where the waste will be received, a conveyor that allows the solid waste to progress to the containment and creates a separation from the waste, a drive mechanism for the user to initiate the flush and drive the conveyor, a hopper for storage of the waste and flush material, and which also allows the material to feed onto the belt, and a toilet body, which serves as the outer shell to contain all of the components.
Listing out Sandi’s USPs, Read said the dry flush toilet requires no building or digging work and has minimal set-up. The toilet is simply pinned to the floor with flush material and is ready to be used. Since the waste is separated into solids and liquids, and uncontaminated by chemicals, it doesn’t need to be treated, making reuse of waste safe, easy and economical, and the toilet has extremely low operational costs.
The waste is completely sealed away from users, making it very safe for in-home use. With its capacity, a 7-member household needs to only empty the waste container once every 10 days.
Read conducted extensive tests using the prototype to evaluate its performance, with all tests returning successful results.
Images: Archie Read
