150,000 tonnes of scrap and non-ferrous metal per year are processed in the family business of the Gratz brothers in Edt near Lambach (Upper Austria). 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 metal processor in Austria to operate its own waste water treatment plant. All of the surface water from the six-hectare, fully paved company site is collected and cleaned there before being released into the sewerage system.
From the three retention basins of the wastewater treatment plant, which together hold 1700 cubic metres, the wastewater flows - controlled by a level measurement - into two lamella separators. The addition of a VTA system product and a liquid polymer ensures the formation of sufficiently large, shear-stable flocs that settle optimally in the lamella separators. From there, the solids are transferred to a downstream sedimentation tank, where they are largely dewatered using a chamber filter press and finally incinerated.
New dosing system for optimum results
Previously, the polymer was fed directly into the wastewater between the retention basin and the lamella separator without maturing the solution. Although this achieved good mixing, the potential of the polymer could not be fully utilised in this way. This is because without sufficient maturation, polymer consumption increases while the result deteriorates at the same time.
The previously operated inline mixer has now been replaced by a two-chamber dosing system from Eurodos. The 2KT-1000 tower system ensures optimum maturation of the polymer used - the basis for excellent settling behaviour and economical wastewater treatment plant operation.
Practical report from the VTA Group's knowledge magazine "Der Laubfrosch", issue 74