The reuse of industrial wastes from a coal-fired power plant and a plasma electrolytic oxidation process was attempted to realize a zero discharge. The batch composition was adjusted by adding sodium hydroxide and sodium aluminate. A single-mode microwave oven equipped with reflux condenser was used for crystallization under atmospheric pressure. The synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, BET, thermogravimetric analysis, and cation-exchange capacity (CEC) measurement. Analytical results indicated that Na-A zeolite with a defined maximum crystallinity could be successfully synthesized by hydrothermal treatment of fly ash with wastewater. Due to the high CEC, the product can be applied for gas purification and soil remediation processes.