Mixed Waste Processing

As the name indicates, a mixed waste processing (MWP) facility manages unsegregated refuse; it separates some material out to be recycled before the remainder is sent for disposal. Separation can be performed by different methods: (1) manually by handpickers as waste runs across a conveyor, (2) mechanically by automated equipment designed to extract recyclables, or (3) some combination of manual and mechanical means. As an example of technology used in a MWP facility, an automated system may have a large magnetic separator to remove ferrous metal from the waste stream. MWP facilities may sort a range of materials including cans, bottles, and paper; the array of materials recycled varies with the facility. MWP facilities differ from material recovery facilities (MRFs) in that they accept commingled garbage; MRFs accept "clean" recyclables already segregated from the rest of the waste stream.

Pros and Cons of Mixed Waste Processing

As with many solid waste management options, mixed waste processing offers a number of advantages and disadvantages, as listed below:



  • 100% participation in a recycling program.
  • Easy for residents.
  • Achieves minimum threshold of recycling with little effort from community.
  • Can be efficient system for removing ferrous material from the waste stream.
  • Waste material can be baled for landfill disposal or shredded for incineration.
  • Compared to curbside recycling, the public is less informed about waste reduction issues and may feel less ownership of a recycling program.
  • Materials are missed by sorting processes.
  • Recyclable materials may be con- taminated and, thus, more difficult to market.
  • Limited range of recyclable material collected.
  • Source reduction is not emphasized.
  • Some worker health and safety concerns.
  • Potential odor problem.

The first four advantages occur because MWP does not require public participation. However, this lack of public involvement in separating recyclables from waste can also translate into a disadvantage: participation in source-separation recycling programs acts as an educational tool that can, in turn, benefit waste reduction efforts. The other disadvantages result from general technical limitations inherent in MWP. When garbage is mixed, the value and recyclability of some materials may be reduced by contamination (such as newspaper) or breakage (such as glass). Also, only a fraction of potentially recyclable materials are recovered by hand-pickers with a conveyor system unless worker-to-conveyor-speed ratios are high. However, another benefit of MWP is that after processing but before disposal, the waste can be baled to conserve landfill space or shredded for incineration.

Recycling Rates and Costs

In addition to these advantages and disadvantages, costs and recycling rates are critical factors in the selection of a waste management option.

In assessing its solid waste management options, a local government should determine the recycling rates it can achieve under various options and cost scenarios. These factors should be considered along with the advantages and disadvantages of MWP noted above.

Blue Bag Recycling

"Blue bags" can be used to increase recycling rates of a MWP system. In a blue bag program, participants put recyclable materials in a special blue plastic bag. This bag is then collected along with the regular garbage. A MWP facility can then segregate all blue bags from other waste and better manage this pre-sorted, cleaner material. Also, blue bags can offer straightforward recycling options for certain materials in office and industrial areas.

A blue bag program requires a mechanism for distributing or selling bags to residential, office, and industrial users. If the bags are sold, the price should be comparable to that for regular plastic garbage bags, if possible. Blue bag programs require close coordination with the MWP facility operators and comprehensive educational efforts. If the public is not properly educated about the importance of segregating recyclable materials into the blue bags, a MWP facility faces the danger of undermining such a program as people may believe that recyclables will be adequately sorted whether or not they participate. Also, blue bag programs in North Carolina have not achieved high participation rates.

Local governments that establish blue bag programs are in the unusual position of paying high tipping fees, perhaps $38/ton, to recycle segregated materials that otherwise could be more economically managed. A final concern about blue bag programs was raised by one North Carolina local government official who remarked that many blue bags burst while in compacting trucks.

Waste Reduction Before the MWP Facility

Local governments and other waste generators incur significant costs for every ton of material sent to a MWP facility; however, substantial cost savings (as well as increased recycling rates) can be realized if waste is minimized through source reduction and pre-facility recycling. For example, Pitt County, N.C., has an excellent recycling program centered around staffed collection centers; the county is planning to send only its garbage to a MWP facility while its source-separated recyclables are sold to regional recycling markets. In the absence of a comprehensive recycling program, pre-facility recycling could involve special recycling programs for materials not recycled by the MWP facility or for valuable items in the waste stream. Source reduction can be an even more cost-effective option than recycling and should be part of any solid waste management program.

Contract Concerns

Although a MWP facility may be a beneficial part of an integrated solid waste management program, local governments should carefully consider clauses in contractual agreements that could inhibit future waste reduction efforts. Note that the following recommendations may also apply to other solid waste contractual agreements that address options such as landfilling and incineration.


Despite some attractive features, the recycling efforts of a MWP facility alone will not enable a local government to reach a significant waste reduction rate or North Carolina's 40-percent waste reduction goal by the year 2001. Although it may be a beneficial component of an integrated waste management strategy, MWP does not end a local government's responsibility to develop complementary waste reduction and recycling programs.

The NC Division of Pollution Prevention and Environmental Assistance (DPPEA) at (919) 715-6500 can provide information on waste reduction activities that local governments can implement or more information on MWP. The table below lists contacts and telephone numbers of North Carolina MWP facilities. Also, in its continuing effort to help local governments evaluate options, DPPEA will conduct further research into MWP as well as other solid waste management options.

Mixed Waste Processing Facilities in North Carolina



Month/Year Began

Tons Processed Per day

Recycling Rate, 94-95, %

Recycling Rate, 95-96, %

Contact and Telephone

High Point Materials Recovery Facility

High Point





Perry Kairis, (910) 883-3215

Haywood County MWP Facility

Haywood County





Jack Horton, (704) 452-6625

Addington Environmental MRF

Montgomery County





Ken Lowder, (910) 576-3697

Appalachian Second Resource

Onslow County





David Clarke(910) 455-8645

BCH Energy Project (VEDCO)






John Davis, (910) 483-0863

1Much of the recycling at this facility occurs at the front-end of the facility before materials enter sorting lines. Actual residential recycling rate is less than 1 percent.

2The facility no longer processes mixed waste.

3As of January 1997, this facility has temporarily closed because of financial and maintenance problems.

The North Carolina Division of Pollution Prevention and Environmental Assistance provides free, non-regulatory technical assistance and training on methods to eliminate, reduce, or recycle wastes before they become pollutants or require disposal. Contact DPPEA at (919) 715-6500 or 800-763-0136, FAX (919) 715-6794, or E-Mail nowaste@p2pays.org for information about our services and/or assistance with your waste reduction program.


This document is intended to offer information and guidance for waste reduction and management. Compliance with environmental and occupational safety and health laws is the sole responsibility of each business. All legal and regulatory references within this document are intended for informational purposes only. Businesses should contact the appropriate legal and regulatory authorities for current interpretation and implementation of regulatory requirements. Mention of a vendor or manufacturer does not represent an endorsement by the State of North Carolina. Neither the State of North Carolina nor the authors are responsible for practices or procedures implemented by individual firms.

DPPEA-97-04. January 1997.