Source: Florida DEP
Key Objectives of MRF Design
MRFs must be designed to produce clean, consistent, marketable products from heterogeneous materials that contain some level of contamination. Designing, constructing and equipping a new MRF, or redesigning an existing facility, requires an efficient integration of automated technologies and manual labor. When designing a MRF, the following are generally considered some of the key objectives in order to maximize efficiency and cost-effectiveness:
- Maximize material throughput.
- Maximize material recovery and minimize processing residue.
- Maximize automation and minimize manual labor.
- Create a safe environment for workers.
- Produce consistent streams of quality recovered materials.
- Optimize system performance and reduce downtime.
Types of MRFs
A MRF is a processing facility where materials are sorted and prepared for marketing either to end users (manufacturers) or to other facilities for additional processing. Configuration of the MRF processing line will vary depending upon how materials are received.
- Source separated – Incoming recyclables have been sorted by type at the point of collection, e.g., drop-off and curb-sort collection programs. Some processing might be needed to further sort materials, such as separating steel cans from aluminum cans and sorting glass by color, but the primary purpose of the facility is to remove contaminants and prepare the material for marketing, often by baling, flattening, or crushing.
- Dual stream – Recovered materials are received in two streams, typically fiber (newspaper, magazines and catalogs, mixed paper, cardboard, etc.) and commingled containers (plastic, glass, metal, and sometimes aseptic containers). Separation of materials is accomplished by a combination of automated equipment and manual sorting.
- Single stream – Recovered materials are received in a single stream, with fiber and commingled containers combined. The first stages of processing typically utilize equipment that separates the material into two streams (fiber and containers), which are further sorted using equipment similar to that used in dual stream MRFs.
- Mixed waste – Unsegregated mixed waste is processed using various technologies to separate mixed recyclable materials from waste. Recyclable materials are then processed using equipment similar to a single stream MRF. Some mixed waste MRFs process the entire waste stream, while others target commercial waste or loads rich in recyclables. Most try to minimize the amount of wet or organic waste being processed.