A filtration tower with a vibrating screen provides pre-filtration for the cloth filter underneath. As a result, the use of cloth can be reduced considerably in certain business situations. Especially in the cultivation of potted plants there is a lot of coarse dirt in the drain water, causing the filter cloth to become dirty quickly. "If the cloth is used up quickly, it is not cost-efficient," says Richard Feijsman of Aqua D & S. Vegetable companies use about one roll of filter cloth of 20 microns per month; in pot plant companies that is a roll per day. A vibrating screen, which removes the coarse dirt, saves cloth.
The filtration tower consists of a vibrating filter with underneath it a collection bin of double-walled durable polypropylene and then the cloth filter with another collection bin below. In the vibrating screen, which is mounted on four springs, there is a stainless steel plate with holes. Depending on the mesh selection, it filters at 75, 100 or 150 microns. The vibrating screen has a capacity of approximately 28 m3 per hour.
Drain water is transferred to the vibrating plate via a shower head. When the pump is started, the vibrating screen is automatically activated. With air of 6 bar pressure, the vibration motor moves the vibration plate. The vibration causes the dirt, such as organic matter, sand, little stones, pieces of leaves and root, to be removed over the mesh through the funnel. Feijsman: "It does not matter how dirty the water is, after the vibrating screen the rough dirt is removed. The vibrating screen also removes the waste of algae."
From the vibrating filter the water passes to the collection bin. From this bin the amount of water for the water supply to the cloth filter can be regulated. Here the water is filtered depending on the choice of cloth, namely 50, 20, 5 or 1 micron. Then the filtered water enters the lower bin. Here a pump moves the water directly to the disinfection equipment.
Also rinse water from other filters can pass over the filtration tower, so that no water at all has to be discharged. Draining and rinsing water can therefore be fully reused.
Source: Glastuinbouw Waterproof