Jan 29, 2016

Gaining Great Gravel

Austrian gravel plant sees increase in product quality after adding filter press

Gaining Great Gravel

With no wastewater treatment system in place, Flatscher Erdbau & Schotterwerk GmbH faced a number of challenges that were threatening the company’s business.

A nearly full disposal pond, with slurry too fluid to transport but too thick to pump, had led to an acute shortage of both disposal space and water for the gravel-washing process.

To turn existing waste streams into new business opportunities, the gravel plant needed:

  • reliable and efficient treatment technology uniquely suited for moderately sticky filter cake;
  • a closed-loop filter system to decrease dependency on groundwater; and
  • optimized filter cloth washing, thickener interface, and related ancillaries for specific slurry conditions.

An evaluation of four potential partners led to a clear conclusion: Andritz Separation was the supplier of choice, with efficient technology for handling the customer’s urgent wastewater treatment challenges.


To maximize reliability, an advanced sidebar filter press with long tiltable frames was installed. A filter cloth washing device with a high-pressure pump, a control system and a drip tray were added, optimized with an additional thickener interface and adjusted to boost throughput. Rather than pumping waste into a disposal pond as before, the new wastewater treatment plant made it possible to recover water for a more thorough gravel washing process, and thus obtain a cleaner, more valuable product. The slurry itself, which was previously disposed of, now has a much better consistency that makes it easy to treat and mix with other materials.


Thanks to its new wastewater treatment facility, the gravel plant has replaced most of its water and waste losses with an up-front investment in future efficiency. Relieved of the need for sludge disposal and with less demand for groundwater resources, overhead costs have been substantially reduced. At the same time, the company’s revenue streams have never been stronger. A cleaner gravel product secures approximately 15% higher prices, while the filter cake with 80% dry substance content can now also be sold to local customers, as it is ideal for use in road construction. This complete closed-loop system has allowed the plant to overcome its limited resources, providing a reliable platform for profitable business in the years to come. 

Andritz Separation Inc.


1010 Commercial Blvd. S.

Arlington, TX 76001

United States

Phone: 817.465.5611

Fax: 817.468.3961


[email protected]