Multiple uses of wastewater: A methodology for cost-effective recycling

Other title: "Proceedings of the 3rd Australian Water Association Water Reuse and Recycling Conference (REUSE07)" While wastewater recycling is being promoted to serve varied objectives, little or no research has been done on its economics. Given the fact that wastewater can be used in various sectors: agriculture, households, industry and recreation, the questions that need to be answered are – to what extent should wastewater be recycled, in which sectors and at what cost? A Cost-Effectiveness Analysis of wastewater recycling across the sectors will be done to assess the relative desirability of recycling in one sector over the other depending upon the objectives of stakeholders and budget constraints. Then a choice modelling technique will be used to weight the different objectives and to determine appropriate sectoral use of recycled wastewater. The methodology is currently in development stage and the research will be conducted using the case study of Melbourne where, wastewater is currently being recycled from the Western Treatment Plant and has been mandated to increase to 20 % by year 2010 through increased recycling in sectors other than agriculture. The results of the research can be used to develop a decision support tool which will help to determine the amount of wastewater that should be allocated to each sector depending upon the objective one wants to achieve. A further step in the research depending upon the objective i.e if the objective is to complement the urban water sources, would be to compare the cost-effectiveness of wastewater recycling versus other options like buying water on the market from the agricultural sector, tapping ground water resources, storm water, new catchments and rainwater recycling.