| Alfa Laval |
The Aldrum drum thickener (photo) provides very gentle sludge handling and recovery. The unit is a range of mechanical sludge thickeners and works on the principle of conveying polyelectrolyte-treated sludge through a slowly rotating drum filter. The sludge remains in the drum, while the water phase passes through the filter cloth. Sludge concentration can be regulated by adjusting the feedrate, angle and speed of the drum. Aldrum drum thickeners are equipped with a drum cleaning system consisting of a spray bar for water. The drum is cleaned using potable water, final effluent or treated filtrate, which reduces overall water consumption. The unit is available in four sizes and all are offered as separate components or as complete sludge thickening modules. This company also offers the Spiral Heat Exchanger for heating and cooling of sludge. The Spiral Heat Exchanger is intended for sludge applications in which heat is interchanged between sludge flows. It consists of a spiral — wound from sheets of metal strips — that forms two concentric spiral flow passages. The channels are alternately welded on opposite ends to form a hot and cold channel. The hot channel is then closed while the sludge channel is accessible for cleaning. The design is engineered to lower the required surface area through more efficient heat transfer and reduce fouling and plugging. — Alfa Laval, Lund, Sweden