Material Recovery Facilities - MRFs

Generic information

In many towns and cities these days, each householder is provided with at least two bins, maybe more, for recycling. When one deposits materials into the bin dedicated for recyclates, they are collected by the refuse/recycling collections crews and taken to the MRF (Materials Recovery Facility).

The MRF comprises a large shed or several industrial buildings in a complex, where waste with several types of recyclable wastes ('co-mingled' - as sorted by the householder) is sorted further, bulked up into load sizes suitable for transport, made ready for collection and transportation, sold, stored, and shipped to the buyers including some of the original manufacturers.

The Materials Recovery Facility is made up of a series of conveyor belts and a mix of manual and automatic procedures to separate the materials and remove the items that are not needed.

In order to collect dry, packaging waste separately from mixed waste that contains organics, there are several options that subsequently affect the MRF configuration. In particular:

• Two-bin collection system: this system includes one bin for mixed dry packaging waste and a second bin for the rest of the waste (mixed wastes including also organic wastes). It is the simplest system that can be applied and it requires the least effort from the citizens.
• Three-bin collection system: This system is similar to the one described above, but there is also a third bin, aiming at a certain material, usually paper (which is easily recycled and has good after sale prices) or, organic waste that is collected in order to be composted in a dedicated facility. Such systems are a bit more complex and require citizens’ participation to be successful.
• Multiple-bin system: Such systems include more than three bins, for example: paper/cardboard, other dry packaging waste, organic waste and rest waste. Such systems require a very good design of the collection system: location of bins, frequency of collection, different trucks depending on the materials, good design of the routes as well as high participation from the citizens.
• Green Points: Dedicated areas where several bins are placed and citizens bring their packaging waste materials and dispose it to the respective bin (usually Green Points are combined with a two or three-bin system).

The practice all over the world has indicated that in order to recover dry recyclables that can be then sold and return to the production cycle, it is almost obligatory to organize at least a two-bin collection system. Otherwise the materials are to a great extend “dirty” and even if a Mechanical Treatment Facility is used, the purity of the products is low. Additionally, such a system helps in “purifying” the organic fraction of the wastes, thus increasing the options for its use after treatment.

The more bins are used, the simpler the MRF configuration becomes. In multi-bin collection systems MRFs are actually storage areas, where a minimum number of workers remove unwanted material (e.g. large objects) and then the recyclable material is baled and stored.