Method for reclaiming soil, sediment and sludge dredged from watercourses contaminated by heavy metals and by dangerous and toxic organic compounds

A method for reclaiming soil, sediment and sludge dredged from watercourses contaminated by heavy metals and by dangerous and toxic organic compounds characterised in that the soil, sediment or sludge with a water content variable from 5% by weight to 60% by weight is subjected to the following steps: - mixing and homogenizing at a temperature not exceeding 140°C for a time not exceeding two hours with cement binders in a quantity variable from 5% to 50% by weight of the soil, sediment or sludge, to obtain a flowable granular powder with an average diameter between 0,1 mm and 4 mm which is compacted mechanically into briquettes or pellets with a maximum volume of 500 cm 3 , - a first curing step for cement setting and dehydration of the briquettes for a maximum time of nine days to attain a residual moisture content less than 15%, - a second curing step for a maximum time of twentyeight days.