Project Name : Water sensitive urban design to mitigate water shortage
Theme Name : Natural Resource & their Conservation
Project Objective: Our project is to redesign the water closet/flush to reduce the consumption of water, currently at 6 to 12 litres per flush to just 3 litres per flush. We make this possible with a simple mechanism added to the conventional closet that will create a partial vacuum when the user pushes down the flush
lever (a foot operated lever/pedal may be needed to use this). This vacuum will partially suck the excreta out any thereby reducing the dependence on the
flushing action to remove the excreta.
Working Investigation/Findings:
Summary: From our experiment, We found that in order to create a 50% drop in the overall water used in the toilet per flush, the amount of water needed to force out the excrement and the amount of water required to replace the water in the extended U–tube both had to be taken into account, and we found that the volume of water required for the full scale model of the extended U–tube was 1600 cubic centimeters or rather 1.5 litres, which would allow for the flushing out of 1.4 litres with the excrement if a 50% drop is intended, bringing down the overall consumption from 6 litres to a mere 3 litres.
Observations: The experiment we conducted were immensely insightful and helped us understand the various complexities in an otherwise simple-seeming design. Although the design may seem rather straight forward, we found there to be a lot of variables involved in the actual practical working of such a design:
Diameter of the flush outlet: Timing the release of the right quantity of water with the suction action of the piston. We found through our experiments that the outlet of the water from the flush tank into the bowl played a crucial role in the flushing of the matter. If the hole was too big, all the water would be released too quickly and would not be timed with the suction action of the piston, therefore proving to be rather inefficient in terms of flushing larger loads. But if the hole were to be too small, the overall volume of the water entering the bowl at the crucial moment of the descending of the piston would not be enough, again proving to be inefficient in terms of flushing loads
Style of water flowing into the bowl: The conventional spiral style of water flowing into the bowl proved to be the best, because it cleaned the walls of the toilet along with serving the purpose of providing a ‘pushing’ force. Various other types were tried, like directly letting the water down; none of them were as effective at both tasks as the above.
Consistency of the excrement: it’s commonly accepted thing that excrement comes in various different densities and consistencies, from the ‘bristol stool chart’ we were able to test the prototype with various close substitutes for the excrement. Some of which floated, some suspended and some sunk, this made the whole ordeal rather hard to flush down with the same efficiency, but eventually this problem was overcome by widening the piston chamber and adding some more water to the flush system. (still under 3 litres)
Quantity of the excrement: We also tested our prototype with various quantities of excrement substitutes and even matched it to the standard of that of conventional toilet manufacturers. Although, this aspect of it may need a little more development.
Conclusion: In conclusion, the Eco-Toilet can drop the water consumption of a toilet by roughly 50% and still prove to be just as efficient.
With a little more research and development, the “Eco-Toilet” design can be modified in such a way that it doesn’t use water at all with the help of bio-fertilizers. The various manufacturers of water closets can incorporate this design and phase out the old design to eventually completely get rid of all the old wasteful designs. In a span of 20 years, close to 60-70% of the world’s toilets can be of this design and eventually one day, practically all toilets will be “Eco-Toilet”.
This will reduce the load on water on our sewage systems & water recycling plants in each city and conserve water. It will also reduce the amount of polluted water entering our water ways & seas from city drains.
Name of the School: Bala Vidya Mandir Sr. Sec. School, Chennai, T.N.
