Automation of light packaging treatment process at the “Las Dehesas” MSW treatment plant in the Valdemingómez Environmental Complex (Madrid)

The new automated facility consists of a modification of two light packaging lines at the “Las Dehesas” MSW Treatment Plant, which forms part of the Valdemingómez technology park (Madrid).


The automation of the two lines gives each line a capacity of 7.2 t/h for the treatment of part of the packaging fraction. The design objectives of the two automated lines that form part of the Las Dehesas plant are as follows:

• Maximum operating flexibility
• High degree of automation of the facility
• High design capacity to ensure operations throughout the
service life of the facility
• Maximisation of recoverable products
• Minimisation of reject
• High process efficiency
• High uptime and technical availability of the facility
• Flexibility in terms of selecting recoverable products sorted, and the quality and quantities of these products

Mechanical treatment lines and sorting

The waste in the reception pit is unloaded into the treatment lines. The facility is fitted with two overhead cranes, each of which is equipped with an electro-hydraulic orange peel grab. The treatment lines are fed by means of the two orange peel grabs. The orange peel grabs are also used to remove bulky items that could cause clogging of the treatment lines. The pretreatment and sorting process has the objective of recovering all possible recoverable by-products in the waste packaging and mixed fractions fractions, by means of both automatic and manual sorting. The following is a description of the entire pretreatment and sorting process. This description is structured in accordance with the different operating areas. When the waste is deposited on one of the treatment lines by the feed conveyors, the process of separating recyclables begins.

Bulky waste sorting area

The feed conveyors enable the waste to be carried up to the new primary sorting trommels, which have a screen size of 400 x 400 mm. These trommels separate bulky items from the waste stream. Items of more than 400 mm are collected by a conveyor belt and sent to the bulky waste shredding area, subsequent to undergoing manual sorting of recoverable materials, such as large pieces of cardboard, scrap metal and wood. The separated materials are deposited into open containers.

Organic matter sorting area

The underflow from the bulky waste trommel screen is collected by two previously existing conveyor belts, which are reversible to enable the new bag opener to be bypassed if necessary. These
two-way conveyors feed the bag openers. Once the material has gone through the bag openers, it is unloaded onto previously existing conveyor belts, which in turn deposit it onto a further
two existing belts. These two-way belts feed the previously existing double trommels.

These secondary sorting trommels have two different mesh sizes. The screen of the first section has a diameter of 80 mm,
while the screen of the second section has a diameter of 200 mm. This second trommel section separates two fractions. The fraction of less than 200 mm is sent to the lower conveyor of the manual sorting booth and the fraction of over 200 mm is sent to the upper conveyor of the booth. These units have a slight grade of 2% to facilitate better separation of the material.

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Plant Report published in: #54 FuturENVIRO October 2018