This literature study focuses on the feasibility of using constructed wetlands (CW) for denitrification of leachate at a local leachate treatment facility, in cold climate. Constructed wetlands have the advantage of requiring less maintenance and control compared with more sophisticated systems. They are also cheaper to run. Finely they are part of the natural nutrient cycle. The environmental factors identified as limiting factors for the constructed wetlands considered in this literature study, e.g. the leachate salinity and the climatic conditions, governed the design of the wetland and the choice of the vegetation. Denitrification is done by heterotrophic microorganisms living in the soil, in anaerobic conditions. They use decaying organic material as carbon source. The role of the plants in the constructed wetlands is to provide substrate to the microorganisms as well as the root system increases the surface available to bacterial colonisation. The cold and long winter sets high requirements on the constructed wetlands. It shortens the period when the bacteria are most efficient i.e. when the water is warm. It will lead to a short period of high activity and the load will have to be reduced during winter and eventually stopped. Subsurface flow systems filled with gravel appeared to be the best alternative. Baffles should be installed to force the water transport around the in constructed wetlands. To reduce the risks for short cuts of the water flow the inlet and outlet of the systems were placed at the bottom to avoid risks for freezing. A design with edges is also recommended to increase snow accumulation on the top of the constructed wetland. Local species were selected for their tolerance to salt and high nutrient content in the water.