ANDRITZ rotating drum screens – Girapac and Girasieve – are enclosed, compact, and stand-alone units, for pre-treatment of industrial and municipal wastewater.

These rotating drum screen provides high solid/liquid separation, as well as sieving, desanding, degreasing, and additionally, the Girapac allows compacting and bagging of waste in one unit.

Operating Principle

The effluent feeds a distribution tank before passing over the upper part of the filter drum. Then, it passes through the filter screen, and waste particles larger than the mesh are deposited on the drum and carried away towards the discharge zone. The particles removed when coming into contact with the scraper drop into the screw compactor. The water falls through the lower part of the drum, ensuring self-cleaning of the filter screen by eliminating the remaining impurities. An internal washing ramp is used to complete the cleaning of the drum.

In the Girapac system, the waste is conveyed by a shaftless screw towards a compacting zone and then drops into a plastic bagging unit. Filtrates generated in the compacting zone are guided to the drum filtrate tank.

Girapac – Rotating drum screen with screw compactor

The average lifetime of an Andrtiz filter press is over 30 years.

With Andritz filter presses, the highest dry substance (DS) content can be achieved without additional heat consumption, and even smaller particle sizes can be retained in the filter press. Andritz will provide the right filter plates, cloths, or other components to achieve the exact degree of dewatering required.

Filter element technologies:

Chamber Filter Presses

Less peripheral equipment, resulting in lower investment and OPEX costs: Chamber filter presses are reliable and robust in many different applications. The plate pack consists of uniform chamber plates with a recess of 15- 50 mm to receive the filter cake. The standard material for chamber plates is polypropylene.

Possible operating pressures: 6 bar, 15 bar, and 30 bar.

Membrane Filter Presses

Higher DS content obtained with membrane filter presses: Membrane filter plates are designed in the same way as the chamber plates. A flexible membrane is secured to the support body. The membrane is
impermeable and compresses the cake within the chamber after the filtration process has been completed. Liquid or gas can be used as the membrane inflation medium.

Inflation pressures up to 30 bar are possible, and in special cases even higher.

Plate & Frame Filter Presses – Sheet Filters

Quick filter cloth change for process filtraton: The chambers in this type of filter press are formed by combining polypropylene filter plates and frames. This creates chambers of 5-40 mm, depending on frame thickness. Plate and frame type filter presses are suitable for pre-coating filtration, which is used in the beverage industry for clear filtration.

Operating pressures up to 6 bar.

The pump is driven by a direct-mounted light alloy maintenance-free motor with IP55 protection. The part of the diaphragm in contact with the pumped liquid is in chemically inert PTFE, and pumpheads are available in several material combinations.

The capacity of the pump is set by adjusting a micrometre graduated dial that can be locked in position.