In the Werdhölzli sewage treatment plant, sand trap material is produced in the mechanical stage of wastewater treatment. The sand trap material is largely freed from organic ingredients in a sand washing plant and filled into ERZ's own roll-off containers.

In addition, the incineration of sewage sludge in the fluidized bed furnace of the central sewage sludge recycling plant (KSV) in the Werdhölzli sewage treatment plant produces excess sand, which is provided in ERZ's own roll-off containers Flat.

This tender covers all services necessary for the transport and legally compliant disposal of sand trap material from the sand scrubber and surplus sand from the KSV fluidized bed furnace of the Werdhölzli sewage treatment plant in the period from 1 April 2023 to 31 March 2025.

Lot 1 – Legally compliant disposal of sand trap material from the sand scrubber

-Annual volume: approx. 690 tons

-Disposal in landfill type E and/or recycling of sand trap material

Lot 2 - Legally compliant disposal of excess sand from the fluidized bed furnace

-Annual quantity: approx. 200 tons

-Disposal in landfill type C