The aerated grit trap is a very important element in mechanical wastewater treatment. Its task is not only to reliably remove the grit from the wastewater flow but also to retain particulate lipophilic substances (grease) to prevent floatable particles from settling or overflowing in downstream treatment systems.
Fine grit of a grain size ≥ 75 µm can usually not be separated by conventional aerated longitudinal grit traps as the rising air counteracts the continuous sedimentation of small particles. Very long, wide and voluminous structures are already required if you want to remove grit of a grain size ≥ 100 µm.
The new HUBER Grit Trap GritWolf® we will present for the first time at IFAT 2018 sets new standards. The screen is the result of a development based on a wealth of experience in grit and grease removal gathered over many years.
Steering away from space-consuming aerated longitudinal grit traps, the HUBER GritWolf® consists of an aerated chamber and a separate unaerated chamber. In the first smaller chamber the wastewater is exposed to fine-bubble aeration. Floatable particles float to the water surface where they accumulate forming bigger agglomerates. A paddle system removes the agglomerates from the grit trap surface just before the outlet. The second chamber is unaerated and equipped with so-called ‘stacked plates’. Due to the deep flow approach and the advantages of a lamella separator, the GritWolf® reliably removes 90% of the grit of grain size ≥ 75 µm.
The new HUBER Grit Trap GritWolf® is available in different sizes for flow rates from 44 l/s (1 MGD) to 876 l/s (20 MGD) and requires much less space than conventional systems. The grit trap tank is usually made of concrete, stainless steel tanks for a flow of up to 175 l/s (4 MGD) are however available as an option . The HUBER GritWolf® can also be integrated into existing grit trap chambers. The horizontal grit conveyor, the lamella packages and the paddle system for grease removal are manufactured from corrosion-resistant material.
The grit is removed axially from the HUBER Grit Trap GritWolf® by a time-controlled horizontal screw conveyor. Even large ‘sand dunes’ occurring under stromwater conditions (stormwater flushes) are evenly dosed into the suction area of the grit pump. Clogging in conical grit sumps or wear on scrapers are a thing of the past. A grit pump delivers the grit-water mix into a HUBER Coanda Grit Washer RoSF4 that produces clean grit in a proven way, thus perfecting the entire grit treatment system.