Municipal Solid Waste screening

A disc screen is the ideal choice for screening MSW because it separates the waste without clogging on plastic, film and rags, whereas traditional technology tends to wrap and jam. In many developing markets MSW is not source-separated: organics, flexible plastic, textiles, wet paper and inerts arrive mixed in a single wet stream. Ecostar’s DDS (Dynamic Disc Screening) technology uses hexagonal or octagonal Hardox discs with a jolting motion that keeps the material agitated and opens the waste bed, so fines pass through while long or stringy material is pushed to the oversize instead of winding around the shafts. The cut size is adjusted in real time by changing shaft speed, up to ±30%, without stopping the plant to swap screens.

MSW screening is needed where waste is not separated at source because the waste reaches plants as a single mixed stream: mechanical screening is the first step to recover materials and cut the volume sent to landfill. A screening system splits MSW by size into a fine fraction and a coarse one, giving two manageable streams to work on downstream. Ecostar mobile screens can operate directly at the waste site, in 2 or 3 fractions: Hextra, a mobile screen up to 200 t/h in TRACK and HOOKLIFT versions, and Nhexa, a compact tracked mobile screen up to 50 t/h, move to the site without first building a fixed plant. This lets countries without established infrastructure leapfrog straight to advanced treatment solutions, adopting modern processing without passing through inefficient intermediate models.

For excavated landfill waste, an Ecostar 3-fraction disc screen works directly on the material as it is, eliminating the need for an upstream shredder, unless the waste contains massive bulky items or heavy industrial tarps that require a rough pre-opening.

This is because the screen and shredder serve entirely different functions: the shredder merely reduces particle size, whereas the 3-fraction disc screen actively classifies the material into three distinct streams: fines (soil/grit), coarse, and oversized recyclable in a single pass. Utilizing an Ecostar screening machine instead of adding a primary shredder brings three major advantages: a compact single-pass process, vastly reduced capital and operating costs, and, above all, the preservation of the material structure. This last point is vital for recovery: a primary shredder would pulverize old glass and plastics, embedding grit into the waste and ruining its recycling or fuel (RDF) potential. In contrast, the disc screen’s dynamic, jolting movement gently strips the decomposed soil matrix away into the fines, isolates mid-sized materials, and leaves large plastics and textiles intact in the oversize fraction for clean recovery.

A disc screen separates MSW without clogging on plastic, film and rags, whereas a traditional technology tends to wrap and jam. In many developing markets MSW is not source-separated: organics, flexible plastic, textiles, wet paper and inerts arrive mixed in a single wet stream. Ecostar’s DDS (Dynamic Disc Screening) technology uses hexagonal or octagonal Hardox discs with a jolting motion that keeps the material agitated and opens the waste bed, so fines pass through while long or stringy material is pushed to the oversize instead of winding around the shafts. The cut size is adjusted in real time by changing shaft speed, up to ±30%, without stopping the plant to swap screens.

The screen does not clog with plastic, bags and rags in MSW: the Ecostar disc screen is built to minimise wrap on these materials. the Ecostar disc screen is built to minimise wrap on plastic, bags and stringy material. The discs work with a jolting motion, so plastic film does not roll up on the shafts the way it does on traditional screens. For the hardest MSW streams, full of bags and strapping, HDDS (Hyper Dynamic Disc Screening) technology adds a dedicated fin that catches long material and carries it to the oversize, cutting downtime for cleaning.

MSW screening produces at least two fractions while the cut size is adjusted in real time, up to ±30%, by changing shaft speed. The Ecostar range covers every plant size: Hexact, a modular static screen starting at 2 m and reaching up to 200 t/h; Hextra, a mobile screen up to 200 t/h in TRACK and HOOKLIFT versions; Nhexa, a compact tracked mobile screen up to 50 t/h, with cut sections from 15 to 150 mm, suited to small and medium throughput or tight spaces.

Ecostar’s DDS disc screen uses up to 70% less energy than traditional screening systems. The saving comes from the low pulling force of the discs: the motor is 7.5 kW per 4 m of screening surface, a low figure for moving a heavy, wet stream like MSW. Fewer clogs also mean less downtime and less maintenance, for a lower operating cost per tonne over the whole life of the plant.