Water Conservation Optimisation For Building Drainage Systems

An assessment of the impact of water conserving fixtures and fittings in typical housing development subject to aggressive water conservation measures is conducted. A range of 25 different house styles were simulated with a diversity (random usage) profile based on appliance type and site investigation. The simulation was conducted by DRAINET, a simulation engine based on the Method of Characteristics and a finite difference scheme validated through field studies. Simulation results show that water conservation down to 80% of non-conserved levels did not significantly reduce the solid transport capability of the associated waste water collection system. At 60% of non-conserved levels, there was a marked reduction in the solid transport capability of the waste water collection system. The use of a small (14 litre) intermittent discharge tank (tipping tank) is suggested as a means of extending safe water conservation practices. The tipping tank option would be the best value and fastest technology to implement as a retro-fit option or as a feature in new-builds. Using only approximately 10% of the water conserved, this measure is effective in maintaining solid transport down to 60% of non-conserved levels, which is significantly lower than current water conservation initiatives are achieving.