This volume presents 13 contributions about the potential, and use of, natural wetland ecosystems for wastewater treatment in cold climate areas. In this instance the term - natural wetlands - includes slightly man-influenced/changed wetland ecosystems, and free water surface treatment wetlands which normally have less constructive elements than subsurface flow treatment wetlands. This work will be valuable to researchers, planners, engineers and decision makers in the fields of applied ecology, ecotechnology, wastewater management, and environmental impact assessment.