140 t/h
of material into the hopper
Construction and Demolition
Demolition waste
Swiss
H2M
Water and sludge treatment plant for washing natural and recycled materials.
500 m³/h
water flow rate
35 t/h
of solids to the filter press
H2M, based in Vufflens-la-Ville in the Canton of Vaud, is a Swiss company and part of the Holcim Group, specialising in the treatment, recycling and recovery of excavation materials and mineral waste from the construction sector. The company processes excavated soils and demolition debris into certified recycled materials, including recycled aggregates, for reuse in infrastructure projects. Its washing plants support compliance with Swiss environmental requirements while reducing landfill disposal and the use of virgin resources.
The project challenges
Turbid water
Two separate effluent streams had to be treated, each with different physicochemical characteristics — one generated by washing natural aggregates and the other by washing recycled materials.
Chemical decontamination
A key requirement was to reduce hexavalent chromium concentrations in the recycled material by converting Cr(VI) to trivalent chromium, Cr(III).
Sludge management
The two sludge streams — from natural and recycled materials — had to be processed using a single filter press while keeping the dewatered materials separate for subsequent handling
Tecnoidea’s process-engineering approach
Compact plant
To reduce the footprint and integrate the system into the existing production site, the entire plant was arranged vertically across three levels.
Gravity-fed milk-of-lime dosing
A monolithic milk-of-lime unit with a 65 m³ silo was installed for automatic dosing without pumps. The elevation difference between the unit and the sludge tank enables gravity-fed dosing, simplifying the hydraulic circuit and reducing the risk of pipe blockages.
Filter-press cleaning
The filter press was fitted with a core-blow system that uses water and compressed air to clear residual sludge from the central feed duct and associated wetted parts automatically.
Results
Variable feed material
The plant was deliberately sized with reserve capacity to handle variations in the incoming material, including both natural and recycled aggregates.
Material decontamination
The chemical treatment reduces hexavalent chromium concentrations and supports separate handling of the treated fractions in accordance with applicable Swiss requirements.
Longer component life
The core-blow system reduces residual sludge build-up, supporting stable operation and extending filter-cloth service life.