Feasibility of recycling grey-water in multi-storey buildings in Melbourne

The Australian government has been promoting water conservation and recycling through active campaigns and through offering incentives/grants for water saving ideas/innovations. One of several water conserving techniques is on-site grey-water recycling for non-drinking purposes. However, there is a general reluctance to adopt on-site grey-water recycling measures. One of the reasons behind this reluctance is lack of awareness of the shortness of payback period for initial investment through potable water savings. In this study, the feasibility of grey-water recycling in multi-storey buildings in Melbourne was analysed and discussed. The study confirmed the significant potential for reducing the water demand and the benefits that the Melbourne population and water authorities can gain through adopting simple water conservation practices and greywater recycling in multi-story buildings. In such buildings, the available grey-water can significantly exceed the demand, which suggests that grey-water collection from some floors would be enough to meet the demand of all the floors in a building. The discussion was extended to proposing unique greywater recycling schemes for Melbourne, involving partial grey-water recycling from the higher floors of multi-storey buildings, and locating greywater treatment systems on the roofs of buildings. Finally, the effect of the number of floors on cost recovery periods was investigated, and the effect of using water conserving devices in combination with greywater recycling on cost recovery periods was assessed.