干旱区生态环境知识资源中心

A sustainable use of a resource is when the resource use can be continued by society in the long run because the use level and system resource are to be renewed by natural or human-aided processes. When we use natural resources at a speed and in a manner which does not diminish them, or use them to create a way of living that can last so that we are not threatened with catastrophe as they run out, that use can be said to be sustainable. This is the case of wetlands for wastewater treatment use as they collect and purify waters that can be used as a renewed resource for human activities, especially for agricultural irrigation in an area (Sicily) that suffers from a high risk of desertification. In the present paper we present a case study in Catania (Italy) consisting of an application of "emergy" analysis to a constructed wetland coupled to a traditional wastewater treatment plant as a part of a quarry rehabilitation plan. Emergy is an analysis tool to measure the work previously required to produce a product or service. Emergy analysis may provide a more complete accounting since it can evaluate both economic and environmental systems. Emergy analysis differs from economic analysis because instead of using the money value of goods, services and resources, a measure of quality is used.