SCREENING

In the pre-treatment stage of raw wastewater (usually the first stage), the incoming raw wastewater is screened. In the screening stage, solids are separated from the wastewater and collected for further treatment. Our product range includes several different alternatives for this task: screens with different capacities, intended for various types of raw wastewater, with different separating degrees.

All our screens are of closed construction, virtually odour-free, easy to maintain and energy-saving. The main construction materials are stainless steel and other stainless materials, such as technical plastics, allowing us to ensure a long and problem-free life for the equipment.

Coarse screening, Bar screen

A bar screen is intended for coarse screening, which means that it separates solid material 20-50 mm in size from the water. The screen is mainly used for the screening of incoming water in drinking water plants, for example, when the raw water taken into the plant is surface water. It is also used in larger wastewater plants as the initial screening before the fine screening.

Structurally, this equipment is such that the water flows through a vertical screen. The solid matter caught in the screen is removed by a rake mechanism moving along a roller chain. Under all conditions, the drive mechanism moves above the surface of the water.

Fine screening, Hydraulic step screen

A hydraulic step screen is intended for fine screening, which means that this device typically separates solids 3-5 mm in size from wastewater. The screen is used after coarse screening and, in small water plants, only for the screening of incoming water. The screen is also used for highly-efficient screening of septic tanks.

The equipment uses hydraulic force that is powerful enough for even the largest screening unit. Thanks to the hydraulic unit, the parts of the electric motor that are sensitive to corrosion can be located outside the wastewater channel.

The step screen's high screening ability, as well as the fine separation degree, is based on the screen mat's sieving effect. The screen mat is not removed in one go, but is used as the screening surface for as long as possible. The screened material is raised one step at a time to the top of the bars and then discharged for further treatment.

Fine screening, Drum screen

A drum screen is intended primarily for fine screening, most commonly used in industry, in particular the food and fur industries. The drum screen removes all particles larger than the holes in the drum screen surface from the wastewater. Thanks to its operating principles, the drum screen also removes long fibres, sand and grease, although these, in terms of their particle size, would fit through the holes in the screen.

If the wastewater does not contain large amounts of sand, the drum screen also screens sand! The secret of the drum screen's excellent separating ability lies in the pressure on the screen surface and on the fact that the waste always tends to continue in the same direction and rotate in an ever-growing roll of waste.

The drum screen is of closed and compact construction, which makes it considerably easier to place the equipment and avoid the annoyance of odour and splashing. The drum screen is an energy-efficient screening solution and, because of its simple construction, is extremely easy to maintain and clean. The screening surface is cleaned with a water jet and a rotating brush.