WATER SAVING THROUGH DESIGN IMPROVEMENT IN TOILET CISTERN

Abstract

The water closet (WC), in conjunction with the water based sanitation systems, has been proven to provide communities with high levels of public health and convenience over the past 150 years. Whilst providing these benefits, WC consumes substantial volume of fresh water. Internationally, government and water authorities, together with industry, have been successful in developing WC systems that have led to substantial reductions in water consumption. Unfortunately, this system is currently not adopted in Pakistan. Institute of Environmental Science and Engineering, NUST, in collaboration with Ministry of Environment in greatest national concern conducted this study cum research to design the dual flush system in Pakistan. The study included (a) Survey of existing water use in toilets. (b) Designing and testing of a prototype dual flush cistern and (c) Water conservation analysis based on the designed cistern. Rawalpindi city (domestic consumers only) was selected as the case study. Number of residents, type of toilet systems, and existing capacity of cisterns, total water consumption in house and percent water used for flushing were considered major parameters for study. Initially a dual flush cistern with 6/3 liters flush volume was designed. Trials conducted on this system did not achieve desired results. Therefore re-modeling with 9/3 liters flush volume was carried out. Trial results of this prototype showed that water conservation up to 62 percent flushing and up to 10 percent in overall water consumption in a house can be achieved. Public awareness and installation of this system in Pakistan can be used as an important tool for combating water crisis.