Sustainable water usage systems: models for the sustainable utilization of domestic water in urban areas

Present water usage of our society cannot be considered sustainable; too much water of high quality is taken from the eco-systems and to much polluted water is discharged. Part of this problem is due to domestic water usage. In the past decade a number of technical measures on appliance level have been developed to reduce domestic water consumption and the efficiency of chemicals used has been increased to enable lower dosages. But further reductions are needed. Reuse and/or recycling water within the domestic system could, in theory, lead to further reductions. Models for integration and cascading of domestic water flows that have been developed are discussed. It is shown that water usage systems with various levels of integration and cascading can lead to significant reductions in domestic water consumption and thus lower the environmental impact of domestic water usage.