Grit washing in grit trap: Complete Plant plus grit washing plant

Complete Plants are complete systems for the mechanical treatment of small to medium amounts of wastewater from 10 to 300 l/s. Basically, a Complete Plant consists of two main components: screen and grit trap. As an option, other systems can be added, such as screenings treatment units, aeration systems or a grease trap.

Since 2000, mechanical state-of-the-art wastewater treatment has additionally comprised a grit washing plant so that the screen, grit trap and grit washer are usually mentioned in the same breath. In case of conventional installations with ‘independent’ units the optimal arrangement is easy to achieve because the screen, grit trap and grit washing plant can simply be combined to a complete system as necessary. In case of Complete Plants, however, the combination of all three steps is more difficult because the screen, grit trap and grit washing unit are directly connected hydraulically.

We now have managed to integrate our intelligent and patented grit washing system in the grit trap of a Complete Plant. The grit washer is arranged directly behind the grit trap and fed directly from the horizontal grit removal screw of the grit trap. Inside the grit washer, grit and organics are separated in a typical upflow process. We use our extremely efficient hydrostatic pressure meter, which is well proven in thousands of ‘big’ grit washing plant installations. The major advantage of this hydrostatic system is that the grit washing plant continues to wash and discharge grit even during feeding. The discharged treated grit is statically dewatered and collected in a container with a loss on ignition of normally below 3%. The washed out organics are dosed into the effluent from the Complete Plant to avoid the accumulation of organic particles.

With this innovation we enable also small wastewater treatment plants with a flow of less than 100 l/s to treat their grit at low cost before its disposal or utilisation.