Designing a 30 Ton-Per-Hour (TPH) Municipal Solid Waste (MSW) pretreatment line requires precise machinery sequencing. Incorrect equipment placement leads to severe screen blinding, material wrapping, and lost recovery of high-value recyclables.

A common question among EPC contractors and facility designers is: Should the bag opener be placed before or after the primary trommel screen?

Direct Answer: Bag Opener MUST Precede Trommel Screening

In a standard household MSW line, the bag opener machine must always be installed BEFORE the trommel screen.

Engineering Reasons for Placing Bag Opener First:

1. Screen Blinding Prevention: Unopened plastic bags roll along the interior of a trommel screen drum without discharging their contents. This causes “trampolining,” where unbagged organic waste passes straight through the drum without being screened.
2. Particle Size Liberation: Over 60% of recyclable PET bottles and aluminum cans are encased inside secondary trash bags. Ripping bags open at Stage 1 liberates these items so the trommel screen can fractionate them by size.
3. Optimized Trommel Loading: Opening bags homogenizes the material bed depth entering the trommel drum, maintaining uniform rotation balance.

Recommended Equipment Sequence for a 30 TPH Line

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