Abstract: An improved rigid filter plate for use in sludge dewatering or oil and water separation is characterized by a lower layer of relatively large material and an upper layer of relatively smaller material bonded thereto, with grains of sand interspersed within the upper layer and bonded to the material making up the upper layer. The device yields high efficacy in sludge dewatering and oil and water separation, while requiring a low level of cleaning and maintenance, yet is resistant to damage from mechanical cleaning when cleaning is necessary. An efficient and economical method of producing the device is also disclosed herein.