Every year, 150,000 tons of scrap and non-ferrous metal are processed by the family business of the Gratz brothers in the municipality of Edt bei Lambach in Upper Austria, where 75 employees take care of the environmentally conscious processing and disposal of industrial waste, old cars, electronic and household scrap.
The company is the only scrap processor in Austria that operates its own wastewater treatment plant. At the plant, all of the surface water from the six hectares of fully surfaced land owned by the company is collected and purified before being discharged into the sewage system.
Controlled by a level measurement system, the wastewater flows from the three retention basins in the wastewater treatment plant, which together hold 1700 m³, into two lamella clarifiers. The addition of a VTA system product and of a liquid polymer ensures the formation of sufficiently large, shear-stable floc, which settles optimally in the lamella clarifiers. From there, the solids are passed to a downstream sedimentation tank, where they are largely dewatered with a chamber filter press before being incinerated.
New dosing system for an optimum result
Until now, the polymer was discharged directly into the wastewater between the retention basin and the lamella clarifier without maturing the solution. Although this achieved good blending, the method could not fully exploit the potential of the polymer. Because without sufficient maturation, polymer consumption increases while at the same time the result deteriorates.
Now, the inline mixer previously in operation has been replaced by a two-chamber dosing system from Eurodos. The 2KT-1000 tower system ensures optimum maturation of the polymer used there – the basis for excellent settling behaviour and economical operation of the treatment plant.
Field report from the VTA Group’s scientific journal “Laubfrosch”, issue 74