Environmental Fact Sheets

The rotating press marketed by Fournier Industries dewaters municipal and industrial sludges.

The sludge is fed into the rectangular section channel around the outside of the wheel. The sidewalls of the channel rotate and are made up of filtering elements which let liquid through and retain the solids. As it moves, the wheel compresses and transports the sludge. This, together with the low sludge feed pressure and the resistance brought to bear at the outlet, yields a cake with a high solids concentration. The cake from municipal waste water treatment plants may be used as part of a benefical reuse program or it can be sent to a sanitary landfill.

The rotary press can obtain a 45% solids concentration with some types of municipal sludge and up to 70% with certain industrial sludges. It can treat between 300 and 50,000 litres of sludge per hour, depending on the equipment selected and the characteristics of the sludge.

The press is easy to operate and maintain because of its robust construction and limited number of mechanical parts. It is entirely enclosed, runs quietly, takes up little space and consumes little energy.

A pilot unit or mobile unit is available for preproduction tests when the nature of the sludge so requires, or when the sludge's dewatering parameters are unknown.

The product is a cake with a high solids concentration along with a filtrate containing few solids which is then treated or reused in the process itself. Because the equipment is fully enclosed, there are no odours or other emissions.

There are currently six models of varying size and capacity. Selection depends on the type of sludge and the quantities requiring treatment. The presses vary in weight from 170 to 10,000 kg.

Operation requires little human intervention and about 10 kWh of power per tonne dry weight treated. Workers require no special protective clothing.