Verfahren zur thermischen Behandlung und stofflichen Verwertung von Klärschlamm

摘要

In a process to dispose of sewage or industrial sludge containing no more than 85% water, sludge is especially combined with a hydraulic binding agent and further solids. The resulting substance is pressed into bodies which are allowed to dry and harden prior to surrender to a shaft melting oven with a regulated force-feed of oxygen or air. In the oven the pressed bodies are arranged in a vertical series of differentially-heat charges which are progressively dried and reduced to combustible gas, molten metal and a liquid which subsequently cools to cinders. Following the initial admixture of binding agent to the sludge, the resulting exothermic reaction progressively reduces the water content to below 20%. The final moisture content is determined by the binding agent formula and the drying time. The oven process is regulated at different levels by the controlled admission of oxygen or air and further solids/liquids/gases. The oven temperature regulated by the liberation of energy which is reintroduced as required to further dry the bodies progressively descending through the shaft, facilitating the introduction of further charges with a residual moisture content above 20%. The pressed mixture of sludge and binding agent contains up to 5% cement, 5% chalk and 6% further additives. The pressed forms are allowed to dry at ambient temperature. The mixture of sludge to binding agent is freely variable. Cinder characteristics are regulated by the controlled admixture of dust or granular additives outside the oven.