The countries of Western Europe for leachate treatment employ the combination of biological, chemical and physical methods as well as the membrane method of reverse osmosis, which is the physical process of the separation of soluble substances. The main advantage of the reverse osmosis method, when employed to neutralize landfill leachates, is its capability of the separation and concentration of leachate components on a molecular or ion levels without the phase transition. This process generates practically pure water, which is fit for channelling into surface waters, and a concentrated solution, which is often carried back to landfill sites. This pure stream of water makes up 70-80% of untreated leachates. The reverse osmosis method is ecologically compact and economically efficient. There are hundreds of sewage treatment plants in the EU which employ this technology. The number of users is still increasing.
