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Granada Eco-Center: technology at the service of efficient material recovery

Granada Eco-Center, in Alhendin (Granada), with a nominal capacity of 450,000 tons per annum, is totally automated and is one of the leading facilities in waste recycling at the national level, and had a 10.8% waste recovery rate on inputs last year.

The plant features 4 treatment lines that process 30 tons per hour and has 10 AUTOSORT automated sorting units.

The Granada Eco-Center is located in the city of Alhendin, approximately 15km from the capital city of Granada. The complex is 890,500 m2, and consists of a plant for biological mechanical treatment, a plant for sorting light packaging, a plant for leachate treatment and a plant for refining compost.

Granada Eco-Center provides direct employment to 190 persons and treats the MSW (municipal solid waste) generated by 144 municipalities (812,000 inhabitants), as well as containers selectively collected throughout the entire province (923,000 inhabitants). The Eco-Center’s MSW recovery rate in 2015 was 10.80% of facility inputs, which is equivalent to 38,525 tons of materials recovered. On top of this, 5,670 tons of packaging were recovered, which is a yield of 72.5% for this material.

The plant has 4 treatment lines with a processing capacity of 30 tons per hour. These 4 lines are grouped in pairs (2+2) so that the plant works symmetrically with two different types of material at the same time, which also increases process stability and versatility.

The latest renovations carried out at the Granada Eco-Center have made it a model at the national level and a good example of how process automation and inclusion of the most advanced treatment technologies are decisive factors for waste management efficiency and improvement. One of several technological improvements implemented is TOMRA´s  AUTOSORT sensor-based sorting equipment.

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 metioned 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.”

The advantages of sensor-based technology

Among the benefits which the installation of TOMRA´s AUTOSORT has generated for performance and work at the facility, Alonso emphasizes: “the lower maintenance and cleaning costs, as well as greater ease of use and cleaning of the equipment. In addition, other considerations are the equipment’s great ease of use, stable and increased sorting performance, versatility in order to sort new products demanded by the market, the ability to change products to be sorted or to reconfigure the material sorting chute, ease of instruction configuration in the same optical separator when handling different streams (MSW, light containers, etc.) or when emptying the unit after the cleaning shift, setting the configuration to “do not blow” for all the optical separators or for cleaning out the recirculation circuit, and setting the configuration to “do not blow” in the first optical separator in the recirculation circuit.”

On the other hand, there is still margin for efficiency improvements at the Granada Eco-Park through the installation of more cutting-edge TOMRA Sorting equipment. According to Ricardo Alonso: “Other streams have been uncovered with sufficient quantities of recoverables which warrant the installation of sensor-based automatic separation. These include cardboard recycling and recirculation of recoverables (mainly Tetra-Pak) in the flat fraction stream; cleaning equipment for the organic fraction prior to composting; consistent sorting of recoverables (including metals and plastics) which exist in the fraction (particle size Ф50-80 mm) for their subsequent incorporation into the facility’s already existing automatic sorting stream, and recovery of glass during processing,” he concludes.