Abstract: A process for treating contaminated sludges such as municipal sewage sludge, industrial waste sludge and riverbottom sludge with calcium oxide (CaO) and/or calcium carbide (CaC.sub.2) with reclaiming and recycling of calcium oxide (CaO) from the reaction materials. The process is also applicable for dechlorinating PCB contaminated sludges.

Abstract: Hazardous radioactive waste is compacted and cast into safely handled monolithic castings having a radiation barrier wall completely enclosing the radioactive waste by centrifugal casting processes in which the barrier wall may be either a pre-formed shell transported to the jobsite or it may be formed by biaxial centrifugal casting and curing of the barrier wall in a mold. When a pre-formed shell is used, means are provided for thickening the radiation barrier if necessary by biaxial casting of additional barrier material inside of the shell. Castable radioactive material is cast inside the barrier wall before removal of the casting mold from the finished cast monolith. The cast monolith is supported for rotation as the mold is removed therefrom so that additional impact resisting and radiation barrier material can also easily be applied to the exterior surface monolith if radiation leakage exceeds tolerance levels.

Abstract: Hazardous radioactive waste is compacted and cast into safely handled monolithic castings having a radiation barrier wall completely enclosing the radioactive waste by centrifugal casting processes in which the barrier wall may be either a pre-formed shell transported to the jobsite or it may be formed by biaxial centrifugal casting and curing of the barrier wall in a mold. When a pre-formed shell is used, means provided for thickening the radiation barrier if necessary by biaxial casting of additional barrier material inside of the shell. Castable radioactive material is cast inside the barrier wall before removal of the casting mold from the finished cast monolith. The cast monolith is supported for rotation as the mold is removed therefrom so that additional impact resisting and radiation barrier material can also easily be applied to the exterior surface monolith if radiation leakage exceeds tolerance levels.

Abstract: A casting containing toxic waste is made by centrifugally casting toxic waste in a pre-formed cage having heat conducting means therein. The casting is formed with suitable shielding materials selected as a function of the waste being cast. The finished casting may contain passageways through which heat is removed. These passageways are oriented such that when two or more castings are stacked in abutment, the passageways of adjacent castings interconnect. Also disclosed is a method and apparatus for forming castings of polygonal exterior cross section having a contaminant barrier wall of substantially uniform thickness so that the waste storage volume of the castings is maximized and so that the castings may be stacked and stored in honeycomb fashion in a respository to minimize dead storage space.