A process and a plant for treatment of landfill leachates.

Technical field
The present invention relates to a process and a plant for the treatment of leachates from landfills and for treatment of waste waters and polluted liquids in general. Background Art Sanitary landfills and waste dumps daily produce a quantity of liquid known as leachates, that sits at the bottom of dump. This liquid is highly contaminated by organic and inorganic pollutants, particularly heavy metals, ammonia and azo- compounds. The quantity of leachates produced by an average waste dump in a day is around 500250 mc. This liquid has to then be treated so that it can be disposed without polluting the water bed. Some known methods for the treatment of leachates involve transporting the liquid itself from the waste dump to special plants where it is treated, for example, by inverse osmosis or by biological process after a chemical-physical treatment. As one can expect, these methods are extremely costly. There are other known methods for treating the leachates such as thermal oxidation, after evaporation or distillation of at least part of the water. In general the process of thermal oxidation is undertaken on the site of the waste dump, in a dedicated plant that uses part of the biogas produced by the waste dump itself. This method is less expensive than the ones mentioned above, it does, however, present some drawbacks, for example it is necessary to clean the exhaust gases of the plant from the heavy metals and the other pollutants present in them. Furthermore this is a “destructive” method, and as such it is energetically expensive. Disclosure of invention The aim of the present invention is to solve the above problems, by providing a process and a plant that will allow the treatment of the leachates produced by a waste dump, on site, economically, with the lowest possible demand of energy and recovering, at the same time, water and raw materials. This aim is reached by means of the present invention, that provides a process for the treatment of waste dumps leachates and other similar liquids, characterised according to claim 1.