This volume presents 17 contributions focusing on the potential, and use of, constructed wetlands for wastewater treatment in cold climate areas. The central issues examined are the long-term experiences of such wetlands, optimum design to improve purification efficiency, the intensity of the critical processes of organic matter mineralization and nutrient retention during winter, and constructed wetland use for multiple purposes. This tile will be valuable to researchers, planners, engineers and decision makers in the fields of applied ecology, ecotechnology, wastewater management, and environmental impact assessment.