If there is one machine found in almost every sorting plant in the world, it is the trommel screen, also called a rotary drum screen. The reason is simple: it splits waste by size, and size is the first criterion by which a mixed flow can usefully be separated. Everything small, soil, broken glass, organic residue, leaves on one side. Everything large and still recoverable moves on.
A trommel screen is a perforated cylindrical drum mounted on an incline. Material enters at the upper end, and rotation combined with the tilt tumbles it continuously. That tumbling is essential: it breaks up clumps and gives every piece several chances to find an opening. See the full range of waste sorting equipment and where each machine sits in the flow.
Key Advantages of a Trommel Drum Screen
• Two fractions from a single pass, a trommel screen separates fine material, which falls through the openings, from coarse material, which exits the end of the drum, with no additional machine.
• Tumbling breaks up clumps, the continuous movement of material inside the drum separates pieces stuck together, which a flat screen cannot do on wet waste.
• Mesh size to order, panels can be ordered between 10 and 100 mm and can be replaced, so the same drum adapts if your flow or the destination of the fractions changes.
• Adjustable residence time, inclination and rotation speed control how long material stays in the drum, which is the trade-off between throughput and screening precision.
• Robust construction, the drum handles abrasive and wet material, and the screen panels are replaceable parts, so wear does not mean replacing the whole machine.
• Throughput from 10 to 50 tonnes per hour, three diameters and four drum lengths cover everything from a small municipal plant to a continuous industrial flow.
Technical Specifications, Trommel Screen
| Parameter | Ø1.8 × 6 m | Ø2.5 × 8 m | Ø3.0 × 10 m | Ø3.0 × 12 m |
|---|---|---|---|---|
| Drum diameter (m) | 1.8 | 2.5 | 3.0 | 3.0 |
| Drum length (m) | 6 | 8 | 10 | 12 |
| Indicative throughput (t/h) | 10 | 25 | 40 | 50 |
| Installed power (kW) | 11 | 18.5 | 30 | 37 |
| Indicative weight (t) | 15 | 25 | 30 | 35 |
| Mesh size (mm) | 10–100 | 10–100 | 10–100 | 10–100 |
| Screen material | Carbon or stainless steel | Carbon or stainless steel | Carbon or stainless steel | Carbon or stainless steel |
| Inclination | Adjustable | Adjustable | Adjustable | Adjustable |
Throughputs are indicative, calculated for mixed municipal waste at typical moisture with a mesh of roughly 80 mm. A smaller mesh or wetter material reduces the real throughput. The final configuration is set from the composition of your waste.
Applications for the Rotary Drum Screen
• Municipal waste sorting plants, separating the fine fraction, which goes to biological treatment or landfill, from the coarse fraction containing recyclables.
• Landfill reclaimed waste, recovering cover soil and the inert fraction from already deposited waste, to free up landfill space.
• Composting, screening mature compost for a uniform product, removing the remaining contaminants.
• Construction waste, grading rubble into size fractions for recycled aggregate production.
• Alternative fuel production, preparing the high calorific fraction by removing fine and inert material.
• Biomass and green waste, screening wood chip and material from green space maintenance.
How It Works
Material enters the inclined drum at the feed end. The drum rotates, and the combination of rotation and tilt makes the waste tumble and advance at the same time. Pieces smaller than the mesh fall through the openings and are collected underneath as the undersize fraction. What does not pass keeps advancing and leaves at the far end as the oversize fraction. The longer the drum, the more chances the material has to find an opening, so screening is more complete. The steeper the inclination, the faster material passes, so throughput rises but precision falls. Setting these two parameters is the practical way to balance a trommel screen.
Selection Guide
The choice starts from two questions. First: what throughput must the line sustain? That decides diameter and length, roughly Ø1.8 × 6 m for around 10 tonnes per hour, up to Ø3.0 × 12 m for 50 tonnes per hour. The second question is more important and more often ignored: at what size do you want to cut the flow? The mesh decides what leaves on each side. For separating the organic fraction from household waste, 40 to 80 mm openings are usual. For screening mature compost, this drops to 10 to 25 mm. For preparing alternative fuel, the range moves up to 80 to 100 mm. If your flow is likely to change over time, it is worth ordering a spare set of screen panels.
Frequently Asked Questions
What mesh size should I choose?
It depends on what you want to separate, not on the size of the machine. For pulling the organic and fine fraction out of household waste, 40 to 80 mm is the usual range. For final compost screening it drops to 10 to 25 mm. For preparing the combustible fraction it goes to 80 to 100 mm. Because panels are replaceable, you can start with one configuration and adjust it after the first months of operation.
What is the difference between a trommel screen and a star screen?
A trommel screen sieves through fixed openings in a rotating drum, and it is the most versatile solution on mixed waste. A star screen sieves between rotating elastic discs that clean themselves, so it performs better on very wet or sticky material that would blind the openings of a drum. Many plants use both, at different points in the flow.
How much does throughput drop if the material is wet?
Noticeably, and by how much depends on composition. Wet waste clumps and tends to cover the screen openings, so the same machine screens less and less precisely. That is why the table figures are given for typical moisture, and real sizing is done from an analysis of your waste rather than from a catalogue.
Can the screen panels be replaced?
Yes, they are designed as replaceable parts. They can be changed both for wear and to alter the mesh size when the flow or the destination of the fractions changes. It is one of the reasons a trommel screen stays useful for many years.
Is the equipment supplied new?
Yes. We supply new units only, made to order for your application, with complete technical documentation.
What maintenance does a trommel need?
Periodic inspection of the screen panels for wear and blinding, checking the support rollers and the drive system, lubricating the bearings and cleaning the drum interior. On wet waste a screen cleaning system is also fitted to keep throughput steady.
Why URSTAG?
URSTAG is a premium brand of recycling equipment, with over 15 years of experience. You don't just get a machine, you get a solution engineered by specialists, built from top-tier components and backed by a team that supports you from design through commissioning.
• European engineering, every machine and every complete line is designed by our engineering teams in Europe, with a focus on reliability, safety and energy efficiency.
• Premium components, we build on motors and automation from industry leaders: Siemens, Schneider Electric, ABB, WEG, SEW-Eurodrive, NORD Drivesystems and Bonfiglioli.
• Over 15 years of experience, we know how materials and machines behave in real-world operation, and we configure each solution for your flow and volume.
• New equipment, configured for you, we supply new units, made to order for your application, with complete technical documentation.
• Delivery, installation and training included, we handle transport, commissioning and operator training, with support throughout the equipment's life.
As a premium brand, URSTAG relies on European engineering, top-tier components and experience. You choose a partner that supports your production long term, with equipment built to run reliably in demanding industrial environments.
