A forefront technology for waste sorting: optical reader in the treatment plant located in Bologna with an overall recovery capability of 70%
In the Bologna area, Herambiente manages all the plants for the waste treatment, recovery and disposal. Given the increasing amount of waste from separated collection and the need to improve their treatment, Herambiente decided to build a high performing plant, with state-of-the-art technology of mechanical treatment. The 2 lines of the plant (1 for paper fractions and 1for the plastics), are able to guarantee a high efficient process. The result is a plant with a treatment capacity of 100.000 tons per year, with a high average overall recovery percentage (70%).
The plant has the only technological equipment of its kind in Italy, with optical readers and a ballistic separator: the optical reader uses visible light and infrared sensors to identify the various types of materials which are then separated using a jet of compressed air. Optical identification of incoming waste makes the sorting process up to 3 times quicker and more accurate than the traditional sorting systems, yielding higher percentages of recovered material. The main advantages of the new system include rewarding the general public’s effort to separate their waste for collection, and returning higher quality recycled waste to the market. A more performing sorting plant leads to an improved separated collection and increase the rate of recyclable/recoverable material; citizens can be considered the most relevant stakeholder. The benefits of this initiative are addressed to the entire community

Resources needed

The investment for the technological upgrading of the plant was about 11 mln of euros, entirely supported by Herambiente, which is the largest company in the waste treatment industry.

Evidence of success

Herambiente Granarolo plant is able to treat up to 12 ton/h of paper waste and up to 8 ton/h of plastic waste; the 2016 average amount treated is 70.000 tons a year. The fractions recovered comply with the highest standars prescribed by the national packaging material consortia, and also required by the national and internationals markets.

Difficulties encountered

During the project, a challenge encountered was the knowledge gap of the staff, due to the use of the technology: specific professional training and teaching activities were carried out; experienced colleagues from other nearest company plants were temporary relocated in order to share knowledges

Potential for learning or transfer

Subjects that are potentially interested in this practice are companies or municipalities responsible for the waste collection and treatment.
The most relevant aspect that can be significantly transferred is the kind of technology: the waste sorting systems based on optical readers. This system, combined with manual and other mechanical operations (such as rotating sieves, ballistic sieves, magnets, etc.) can ensure adequate product uniformity of each recovered fraction by eliminating scraps and materials not amenable to recovery and guarantees a significant overall recovery percentage (70%).
Financial resources could be an obstacle to the implementation of this technology, but the material deriving from this kind of sorting system has a very high quality so it has also a high economic value. This factor should be taken into consideration from companies involved in waste trade or from a Municipality which manages directly the waste from its community
Main institution
Emilia-Romagna, Italy (Italia)
Start Date
January 2011
End Date


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