Dry Mixed Recycling Baler: Processing Co-Mingled Recyclables

By:     Conor Murphy

What Dry Mixed Recycling Is and Why It’s Challenging to Bale

Dry mixed recycling (DMR), also known as co-mingled or co-mingling recycling, is a collection stream that combines multiple dry recyclable materials in a single container rather than asking the producer to separate them at source. Paper, cardboard, plastic bottles, plastic film, aluminium cans, and steel tins may all arrive together in a single DMR collection, requiring sorting downstream before baling and onward sale to reprocessors.

The DMR approach is widely used in both commercial and local authority collections because it simplifies the producer’s waste segregation task. Instead of maintaining five separate collection streams, the producer puts all dry recyclables in one container. The sorting happens at a materials recovery facility (MRF) or at a sorting facility before the material is baled by type.

For businesses managing their own DMR stream (a commercial operation collecting dry recyclables from across their premises in a single stream before processing), and for waste operators and councils running MRF operations that handle DMR from collections, the baling challenge is handling variable, mixed material efficiently while producing bales that meet reprocessor specification requirements.

Gradeall manufactures balers for DMR applications across the full capacity range, from the multi-materials baler for operations processing several material types in sequence to the GH600 and GH500 horizontal balers for high-throughput MRF applications. Manufactured from Dungannon, Northern Ireland, with nearly 40 years of manufacturing experience and equipment in over 100 countries, Gradeall’s DMR baling equipment is designed for the variable material conditions of real-world mixed recycling streams.

The Material Quality Challenge in DMR Baling

The central challenge of DMR baling is that the commercial value of the output depends entirely on the quality of the sorted input. DMR that is well-sorted before baling (each bale containing a single material type at acceptable purity) produces commercially valued bales. DMR that is poorly sorted or heavily contaminated produces low-value or unmarketable bales that may cost more to dispose of than they generate in income.

Contamination sources in DMR. Food contamination is the primary value-destroyer in DMR bales. Cardboard and paper with significant food residue, plastic bottles that haven’t been emptied, and food-contaminated film all reduce the value of the bale stream they enter. DMR collections that include significant food contamination are more expensive to sort and produce lower-grade output.

Cross-material contamination. Plastics in a cardboard bale, cardboard in a plastics bale, or metals in a paper bale all reduce the value of the primary material. The sorting stage must achieve sufficient separation to produce bales that meet the purity specifications of the relevant reprocessors.

Non-target materials. Materials that should not be in a DMR stream at all (general waste, batteries, electrical items, materials too small to be sorted by automated sorting equipment) create problems throughout the processing chain. Good producer education and clear collection instructions reduce non-target material rates.

DMR Processing Approaches: Sort Then Bale

The standard approach to commercial DMR processing is sort then bale: the mixed incoming material is sorted by type and the sorted streams are then baled separately. This is the MRF model: automated sorting systems (NIR scanners, optical sorters, ballistic separators) separate the mixed input into material streams that feed dedicated balers.

For smaller commercial operations without the investment in automated sorting, manual sorting ahead of baling achieves a similar result at lower throughput. A sorting line with dedicated collection positions for each material type allows staff to separate the DMR stream into cardboard, paper, clear PET, HDPE, aluminium, and steel before each stream accumulates to baling quantity.

The multi-materials baler is the right equipment for an operation running a manual sort line with multiple material streams of moderate volume. It processes each sorted stream in sequence, producing separate bales for each material type with one machine rather than requiring a dedicated baler per stream.

The twin-chamber baler suits operations where two streams are generated simultaneously at volumes that justify parallel processing rather than sequential baling runs.

High-Throughput DMR Baling at MRF Scale

At MRF scale, the volumes of sorted material arriving at the baling stations are high enough that throughput is the primary equipment specification driver. A cardboard station at a busy MRF handling 50,000 tonnes per year of input needs baling capacity that can keep pace with the sorted cardboard output from the automated sorting system.

Horizontal balers are the standard configuration for MRF-scale baling because they can be fed continuously from conveyor systems, produce large-format mill-size bales that maximise collection vehicle payload, and run at throughput rates that match MRF processing speeds.

Gradeall’s GH600 provides high-throughput baling appropriate for MRF applications. Its continuous-feed design, large bale format, and robust construction suit the demanding continuous-use conditions of MRF operations. The GH500 covers the mid-range throughput requirement between a high-capacity vertical baler and the GH600.

For MRF operators, the baler’s integration with infeed conveyors is a key specification requirement. Gradeall’s conveyor systems support integration of baling equipment into MRF processing lines, providing the material feed path from the sorting stations to the baler loading point.

Bale Specification Requirements for DMR Output

The reprocessors who purchase DMR output bales have specific requirements for the bales they will accept. These requirements vary by reprocessor and by material but typically address:

Purity. The percentage of the target material in the bale by weight. Cardboard bales need to be predominantly cardboard with minimal plastic or other non-paper content. PET bales need to be predominantly clear PET with minimal HDPE, coloured PET, or non-plastic content. Purity requirements are set by the reprocessor and reflect their processing capability; lower purity material requires more cleaning and produces lower-grade output.

Moisture content. Wet material reduces bale quality and weight. Maximum moisture content specifications (typically 12 to 15 percent for paper and cardboard) are applied by many reprocessors. Wet material from DMR collections stored outdoors or in uncovered facilities may fail moisture content specifications.

Bale dimensions and weight. Reprocessors specify acceptable bale dimension ranges and minimum bale weights. Bales outside these ranges may be rejected or subject to a handling surcharge. The baler specification must produce bales within the required ranges consistently.

Absence of prohibited materials. Batteries, liquids, glass, and other prohibited materials that can damage processing equipment or create safety risks at the reprocessing facility are grounds for bale rejection. Quality management at the sorting stage prevents prohibited materials from entering the baled output.

The Commercial Realities of DMR Baling

DMR baling income is subject to the same commodity market dynamics as single-stream baling but with additional complexity: each material in the sorted output has its own price, and the overall economics depend on the revenue mix across all output streams compared to the total processing cost.

In periods of strong commodity markets, DMR sorting and baling operations generate significant positive income from multiple streams simultaneously. In weak markets, some streams may have negative value (a disposal cost rather than a selling price), which can make the overall economics of a DMR operation challenging.

The investment case for DMR baling equipment in a commercial or MRF operation needs to include a realistic assessment of through-cycle economics across both strong and weak commodity market conditions, not just a projection based on current market prices.

“DMR processing is where waste management becomes genuinely complex, because the economics depend on markets that move substantially,” says Conor Murphy, Director of Gradeall International. “The equipment needs to handle variable material reliably and produce consistent quality output. We design our balers for exactly that requirement, and we help operations understand the equipment specification that gives them the best chance of consistent output quality across all market conditions.”

Contact Gradeall International to discuss DMR baling equipment specification for your operation.

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