Recovering and Recycling Sand from Sewage
March 16, 2022
It was an ingenious invention – using a fluid bed to recover pure sand from sewage. In the early 1990’s HUBER SE developed their fluid bed RoSF4 Grit Washing Classifier after several years of research and development.
The driver for this new technology was to meet the demands of tightening landfill disposal criteria and the associated cost increase. Not only did this technology meet the goal of achieving the highest quality sand/grit possible but many Water Utilities in Germany found opportunities to recycle this byproduct in applications including using as road base.
The final product from the RoSF4 Grit Washer is clean sand/grit with 90% dry solids and almost no residual organics. The technology is well proven in over 2000 sites around the world, including some 20 sites across ANZ.
In Germany the Federal Soil Protection Act (BBodSchG) standardizes the specifications for the remediation of contaminated sites whilst the Federal Soil Protection and Contaminated Sites Ordinance (BBodSchV) defines the values and requirements for recycled materials sourced from numerous byproducts including sewage.
Essentially with proper treatment, which is achieved by the RoSF4 Grit Washer, the regulations allow for the reuse of sand/grit within road base, construction products and land reclamation.
Australia and New Zealand sewage treatment plants produce somewhere in the order of 25,000 – 40,000 tons of sand/grit each year and the vast majority can realistically be sustainably recovered in the HUBER RoSF4 and beneficially reused.
The sustainability and circularity impact associated with grit reuse is significant and would:
- relieve many landfills of unnecessary waste,
- reduce truck movements and associated carbon emissions
- allow for the return of a carbon rich stream to the head of the treatment plant to aid denitrification and increase biogas production.