Selected Proceedings of the International Conference on Future of Urban Wastewater Systems - Decentralization and Reuse; 18-20 May 2005, Xian, China. Shortage of available water resource is a common problem in many regions of the world. One important measure to solve the problem is to use treated wastewater for non-drinking purposes. Centralized wastewater treatment and reuse often needs large investment and sophisticated management and maintenance systems, which may be unaffordable in less developed countries, and even developed countries need to reduce the cost of wastewater reuse. In comparison, decentralized systems can offer low cost, easy operation and maintenance, and flexibility for wastewater treatment and reuse. Innovative technologies have recently been developed and... implemented for decentralized systems. However, many technical, operational, managerial, social and economic issues remain to be studied, which supplied the focal points of the 'Future Urban Wastewater Systems - Decentralization and Reuse' conference: innovation of conventional technologies and newly developed technologies for decentralization of urban wastewater collection, transport, treatment and reuse. The 30 papers in these proceedings, selected after full peer review, cover future trends in urban development, biological treatments, membrane applications, enhanced primary and advanced treatments, sustainability, and control and monitoring techniques.