C&D screening

In construction and demolition waste, the patented technology DDS Ecostar (Dynamic Disc Screening) separates the heavy inert fraction (rubble, brick, concrete, aggregate) from the light fraction such as film, plastics, wood, paper and textiles, delivering a clean, calibrated aggregate.

Separation is performed by shafts of flat-profile hexagonal or octagonal Hardox discs that move the material forward while keeping a constant gap. This dynamic action prevents long, stringy materials from wrapping around the shafts and stops wet fines from clogging the screening apertures: it is the same anti-wrapping and anti-clogging behavior that lets the screen run continuously even on wet C&D. The result is a clean cut that sends the light fraction to oversize and returns the inert material as undersize, ready for the next recycling stages.

To cease to be classified as waste, a recycled aggregate must be calibrated into defined fractions and highly refined (no plastic, wood, gypsum, light materials). Screening is the stage that determines these two physical requirements.

Across the EU, an aggregate ceases to be waste once it meets defined quality criteria and contaminant limits and is destined for permitted uses (End of Waste). In Italy, for example, this is governed by Ministerial Decree 28 June 2024, no. 127, with CE marking required for most applications.

Within this process, DDS Ecostar addresses the physical requirements: it produces consistent particle-size fractions (10, 30, 50, 80, 100, 200 mm) and, by separating the light fraction, reduces contamination of the output. End of Waste compliance also depends on the chemical characterisation and documentation required by the decree, but clean, calibrated screening is the prerequisite that makes the aggregate suitable for higher-value reuses such as road sub-bases, embankments and the production of aggregates for concrete.

It depends on volumes and site logistics. For high-capacity fixed plants, the choice is the Hexact Ecostar stationary screen, which processes up to 150 t/h of shredded C&D in structured recycling lines.

For demolition sites, temporary yards or operations that move between locations, the answer is a mobile screen: Hextra Ecostar for large outputs on the move, and Nhexa Ecostar when a compact machine that is easy to transfer between sites is needed. For C&D, the reference technology is DDS Ecostar: fixed or mobile, separation quality doesn’t change with the format — only where and how you work changes.

Yes. DDS Ecostar is designed to work both dry and in the presence of moisture, mud and clay content: conditions typical of demolition material.

The flat disc profile and the dynamic action of the shafts prevent wet fines from sticking and blocking the screening apertures, a common limitation of traditional technologies when the material is not perfectly dry. This lets the plant maintain operational continuity even in rainy seasons or with un-dried stockpiles, with no downtime for cleaning and no drop in separation performance

The DDS Ecostar discs are made of Hardox, a high-strength anti-wear steel chosen precisely to withstand the abrasion and impact of inert material, ensuring reliability and durability over time.

Routine maintenance and, above all, correct initial setup also matter: calibration suited to the incoming material reduces stress and extends component life. That is why Ecostar supports the customer during commissioning and trains operators in the correct use of the screen, keeping performance consistent and reducing downtime over time.

Because, for the same throughput, the DDS Ecostar disc screen takes up less space and consumes less energy than a drum screen: it separates the material by letting it flow over the disc shafts with low traction force, instead of continuously rotating the whole drum together with the material inside it. The drum screen operates by tumbling the material inside the cylinder at a speed of approximately 0.3–0.5 m/s, whereas Ecostar’s DDS technology allows the material to be processed on the discs at a speed of 1–1.5 m/s

Added to this is cut flexibility: DDS allows the screening section to be varied on site (in the order of ±30%) and multiple fractions (10–200 mm) to be obtained on the same machine, adapting the particle size to market demand for the aggregate without replacing components.