Abstract: An apparatus is presented for economically making crystallized glass products from waste ash produced from the sewage sludge dewatered by organic matters, which is usually regarded to be difficult to process. The melting is performed in two furnaces: the primary melting furnace and the secondary melting furnace. The primary furnace melts waste ash and the primary melt is charged into the secondary melting furnace. The glassy material produced in the secondary melting furnace is charged into a crystallization furnace to convert the glassy material to a crystallized glass product. This basic configuration of the apparatus allows the production of either irregular shaped crystallized products, such as crushed stone like products, or crystallized manufactured products, such as tiles and blocks, depending on the combination of processing equipment and their operating conditions.