Compost screening for high quality organic fertilizers

No, it’s not an absolute requirement, but a technical limitation tied to efficiency. Traditional screens can process wet compost, but high moisture content causes blinding (clogging of the screening mesh) and the wrapping of plastics and other fibrous materials around the shafts. To avoid sharp drops in throughput and constant maintenance stoppages, many composting plants add a preliminary drying or biostabilization stage.

DDS (Dynamic Disc Screening) technology by Ecostar overcomes this trade-off: thanks to the flat-profile discs and the anti-wrapping system, the disc screen separates wet compost, even in an advanced state of decomposition, effectively without clogging the screening surface. This eliminates the need for thermal treatment or preliminary waiting times, optimizing plant space and speeding up the compost screening cycle.

Optimizing the separation of high-moisture compost requires dynamic screening technology capable of countering the sticky behavior of the material and the wrapping of fibrous and plastic fractions. In traditional screens, moisture causes the compost to form compact agglomerates that clog the screening meshes, while plastic and fibrous materials tend to wrap around the rotating shafts, leading to continuous downtime for cleaning and reduced throughput.

Hexact, Hextra and Nhexa Ecostar screens equipped with DDS technology, solve the problem on two fronts: the flat-profile discs break up compacted compost, while the free-floating sleeves prevent plastics from building up on the shafts, pushing them automatically toward the outlet. The result is the ability to screen high-moisture compost, even in an advanced state of decomposition, with high operational continuity and minimal cleaning intervention.

When screening wet compost, the biggest economic risk is that the fine organic fraction sticks to the oversize fraction and gets discarded along with the reject material: this means losing saleable finished product while also having to bear the disposal costs for material that would otherwise be quality compost.

DDS (Dynamic Disc Screening) technology by Ecostar reduces this product loss thanks to the jolting motion of the discs, which effectively separates the fine fraction from the coarse material. This is complemented by the feeding auger, developed specifically for this application, which ensures even distribution of material across the full width of the screen: a uniformly loaded screening surface improves separation and further limits the loss of usable material.

The Hexact, Hextra and Nhexa disc screens by Ecostar thus maximize the recovery of quality compost, reducing the volume of waste sent to disposal and the related impact on plant operating costs.

Plastic is the main obstacle to marketing compost: Regulation (EU) 2019/1009 sets the purity thresholds required for agricultural use, making plastic removal an essential step in the compost screening process.

DDS (Dynamic Disc Screening) technology by Ecostar separates the two fractions effectively: the fine organic fraction falls through the gaps between the discs (undersize), while plastic and fibrous material stays on top of the screening surface and advances toward the outlet (oversize). Real-time particle size adjustment via inverter, with a ±30% range, allows separation to be adapted to the specific characteristics of the material being processed, while the anti-wrapping system keeps screening efficiency constant over time, avoiding the contamination spikes typical of traditional screens prone to clogging.

The result is high-purity compost, compliant with regulatory limits and ready for sale.

Yes. Hexact by Ecostar is a stationary disc screen with a modular structure, designed precisely to grow alongside your plant: you start from a base section and add 2- or 3-meter modules up to a maximum screening surface of 10 meters.

Expansion is also possible later on, on a machine that’s already installed and operational: when compost volumes increase, you simply add the modules you need without replacing the entire machine, protecting your initial investment and eliminating the downtime associated with a full equipment changeover.

Hexact’s modular structure also reduces assembly time and transport costs for large screening surfaces, making this disc screen a scalable solution capable of adapting over time to the real production needs of a growing composting plant.

Energy consumption is one of the main cost items in a screening plant running extended shifts, and it becomes a decisive factor in technology selection for plants processing compost continuously throughout the year.

Hexact by Ecostar, the stationary screen with DDS (Dynamic Disc Screening) technology, is specifically designed to cut this cost item: the efficiency of disc screening allows the use of electric motors as low as 7.5 kW, with energy savings of up to 70% compared with traditional screening systems.
On a plant processing compost year-round, this difference in energy consumption has a significant impact on overall operating costs and considerably shortens the return on investment, making the Hexact disc screen an advantageous choice both economically and environmentally.