• High dewatering capability
• Self optimizing process operation
• Approved technology and robust design
• Continuous operation without supervision
• Minimal maintenance and labour cost
• Low disposal costs
• Reliable process and control system

The Bucher HP-Press is the best solution for dewatering of digested municipal and industrial sludge. The process was designed for the liquid-solid separation of biomasses. To serve the individual demands in throughput, two different press sizes are available. The solids content of the sludge can be between 2 – 10 % while the final dewatered sludge will be between 30 and 40 %.

The press has a slowly rotating body consisting of a cylinder and a piston with a hydraulic drive. Between the piston rod head and the bottom of the cylinder up to 280 flexible drain elements are connected and sealed to separate solid and liquid for removal from the press casing. Basically a drain element consists of a round flexible but solid core with channels on the surface and a covering filter cloth.

The squeezing process consists of a pulse like filling, squeezing and discharging of the filter cake and takes, depending on the specific features of the sludge, 70 – 120 min. The filling is performed by up to 30 single filling steps. Each pulse filling step consists of filling with sludge, loosening of the filter cake during withdrawal of the piston, and squeezing the fresh sludge when the piston moves forward. The controller repeats the process up to 30 times, till the desired level of dewatering has been achieved. Afterwards the filter cake is removed by automatic opening of the press cylinder.

An essential characteristic of this process is the loosening step performed during withdrawal of the piston after each filling and squeezing. During loosening of the filter cake new surface and capillary formation ensures a high dewatering performance. Simultaneously during the withdrawal of the piston a vacuum in the cylinder is created and the filtering cloth is cleaned by counter current flow of air. This precaution guarantees long periods of operation without cleaning.

The complete process is controlled by the targets of the operator and the automatically operating algorithms to achieve maximum filtration performance.