New Screw Press Sludge Dewatering Equipment

Reduction of Sludge Moisture Content with a Minimum of Operator Maintenance

Abstract

Diversity of sludge type due to the development of higher levels of waste water treatment, increased quantities of difficultly dewatered sludge, higher unit costs of industrial waste treatment and so forth call for sludge dewatering devices which can reduce the volume of dewatered sludge cake and require a minimum of operator attention and maintenance. Organo's new Screw Press Sludge Dewatering Equipment CPHS has been developed to meet with such requirements. This sludge dewatering equipment is the culmination of many years of Organo's experience not only in manufacturing various types of sludge dewatering equipment but also in the coagulation technology using polyelectrolyte coagulants. This patented equipment has three features. Firstly, sludge under pressure is automatically introduced to a screw press. More specifically, coagulated sludge is pushed into the screw press on the strength of the delivery pressure of a sludge feed pump. Secondly, this sludge dewatering equipment is provided with an automatic high pressure cleaning system which consists of a cleaning header fitted out with spray nozzles. This cleaning header moves back and forth to clean punching metal (filter medium) with water under high pressure. Thirdly, the screw press is characterized by a unique cake scraper which is designed to squeeze the dewatering cake by means of a keep plate located at the outlet of the screw press. This keep plate is forcibly opened and closed via a hydraulic cylinder. These features lead to such advantages as shorter lengths ofscrew press, (L/D=3 5), little splashing of odors and/or sludge from the coagulation tank, etc., no lagging of the punching metal (to present higher moisture content of cake anddrop in broghout (?) capacity of the screw press), less cleaning requirements, lower moisture content of cake squeezed under high pressure, no overloading on the screw.press, and better control of dewatering. In preparing coagulated sludge to be fed to the screw press, it is very important to form large aggregates or flocs which are stable and so not disintegrate. Cationic and anionic polyelectrolytes and inorganic coagulates or combinations thereof are used depending upon sludge characteristics. The Screw Press Sludge Dewatering Equipment CPHS has found wide use in food processing, chemical, machine and metal industries. We believe this equipment will also come into its own in the treatment of sludge generated from wastewater treatment in the pulp and paper industry.