Greater recovery and fewer sorting personnel
The plant currently has 10 AUTOSORT units: 4 units on the rolling sorting chute for two processing lines, another 4 units on the rolling sorting chute for the other two processing lines, and two optical separators for recirculation and extraction of cardboard from the rolling fraction for the 4 lines.
As Ricardo Alonso Perez, Waste Services Engineer for the Government of Granada, explains: “With the introduction of AUTOSORT, recovery of cardboard from the rolling fraction has increased by approximately 0.8-1.0% for total facility inputs.” Currently, in a discrete processing shift of 7 hours 20 minutes, between 5 and 7 tons of good-quality cardboard are recovered in this stream.”
With respect to recovery of other recyclables through the afore mentioned rolling fraction recirculation process, such as PET, PEAD or Beverage Cartons (Tetra-Pak), etc., “the advantage is not so much in the increase in recyclables as it is in the reduction of triage personnel working on the ejection stream in the quality control chamber, which has allowed us to phase out 3 operators per shift and relocate them to strengthen other production functions in the plant, such as in the primary and secondary chambers.”
The recirculation circuit in the rolling fraction stream
After the two optical separator chutes in which PET, PEAD, Plastic Mixes and Tetra-Paks are separated, and after passing through the quality control chamber, all material ejected from the rolling fraction stream is directed to a new optical recirculation chute, in which all remaining recoverables from this stream (PET, PEAD, Tetra-Pak, aluminum, ferrous metals and cardboard) are blown by a 2,000mm-wide AUTOSORT. This yields two streams:
The unblown fraction which falls onto the general ejection belt in the facility, and passes through a small quality control chamber, which recovers, apart from any cardboard which may have escaped, rolling recyclables which are difficult or unrecoverable by the automatic separator (bottles with liquid, bottles filled with air which may have rolled on the accelerating belts, as well as black-colored materials which are not detectable via the near-infrared sensor (NIR). Afterwards, this stream no longer has any material of value and is directed to the landfill via a transfer facility.
The blown fraction which passes through a second AUTOSORT unit, 1,000mm wide, which generates two new streams: a blown fraction of cardboard, which passes through quality control triage prior to being stored in a warehouse, and an unblown fraction (recyclables excluding cardboard), which is returned to the ballistic separators for another pass through the automatic separating chutes.
Ricardo Alonso Perez notes that, “The Granada Eco-Park is a hybrid facility and is set up to process MSW as well as light containers. As such, the operation of this recirculation circuit during processing of Light Container waste is an important point. In this case, blowing of the cardboard is replaced by blowing of the Plastic Mix fraction (or Mix), which produces, on the one hand, a recirculation of recoverables (blown by the first optical recirculation separator and not blown by the second separator), similar to MSW mode. On the other hand, this yields a new sorting point for the Mix fraction (blowing by the first optical recirculation separator and blowing by the second separator of the Mix fraction), given that the presence of cardboard in the rolling fraction when Light Containers are processed is so small that it is sorted by manual triage in the quality control chamber prior to the recirculation chute.”