Waste Wash- Retrofit Mechanism for Toilet Greywater Harvesting

Abstract

Water crisis has been declared as the fifth global risk in terms of impact on society. In India, on an average, households consume 400 gallons of water every day and 24% of this consumption is due to toilets. This toilet use of water is tagged as the largest source of wastage of water in households. Currently, there are smart toilets and vacuum toilets to resolve the problem. Smart toilets, currently at best offer a touch-free option or give a manual dual option for the amount of water one chooses to flush. However, they use fresh clean water while flushing and are high-cost. Even if they include the siphonic flush system, this gravity flush system needs to be flushed multiple times to reduce the stickiness around the commode, defeating the purpose. Vacuum toilets need a vacuum station to dispose of the excretion being inefficient as well as high cost.  A normal person passes stool once a day and passes urine 6-7 times in a day. Urine comprises 95% water and 5% other wastes - urea, ammonia, inorganic salts. Inspired by this data, through filter chambers and electronics, an automatic or manual, portable device can be created that reduces water consumption.  Through the use of sensors, the intensity and amount of waste can be calculated, and whereby solid waste can be differentiated from the urine waste; and further the water output can be controlled to be multivariable and dependent on the nature of waste, and the urine wastewater can be simultaneously filtered by a three-stage filter. The recycled filtered urine wastewater can be used as greywater to help dispose of the majority of the excretion from the commode. Minimal clean water, through the already existing valve, can help give a rinse to the commode to maintain hygiene. Due to its portability and flexibility (manual or automatic) features, this solution can easily be implemented.