Abstract: A molded-block arrangement is disclosed for a ground covering for the production of humus by means of composting for producing soil from sewage sludge for the purification of waste-water and waste-gas, and the like. Molded blocks are provided with groove-and-tongue-type longitudinal sides. A longitudinally and transversely extending channel system is formed in the blocks by recesses extending on the longitudinal sides and sloped areas arranged transversely to said recesses, below their surface, grooves leading into the channels and extending at the top side of the blocks are also connected with the space below the products stored on the ground covering. The new molded-block arrangment permits an excellent drainage and/or aerating and is therefore also suitable for the production of soil from sewage sludge in reed basins for floors of optimal stables and for the separation of coarse substances.