Municipality of Zanica – The "ex discarica Cuter” Landfill

Environmental Remediation
Between 2014 and 2016, Riccoboni SpA was employed by the Municipality of Zanica (Bergamo) to remove and dispose of the acid sludge at the “ex discarica Cuter” landfill) in the area called Cucco, and to make the site safe. The project was funded by the Region of Lombardy, in order to remedy what was potentially an extremely hazardous situation for the local residents and environment, one that had already led to the European Commission including the site in its list of non-compliant hazardous waste disposal sites and bringing legal proceedings against Italy for failure to fulfil its obligations.

The aim of the project was to remove the acid sludge and the surrounding saturated soil, located in a former quarry pit used until the mid-1970s for the illegal disposal of hazardous waste, treat it, dispose of it and, lastly, make the area of the pit safe. Over time, the high acidity of the sludge had, in fact, led to the contamination of the soil that had been used to partially fill the pit.

The operation was carried out by erecting a tent inside the depression, where tanks were constructed to treat the acid sludge using calcium oxide and sawdust. Once the degree of acidity had been sufficiently reduced, the waste was removed and transported to final disposal sites, which, in the case of the acid sludge, due to its excessively high hydrocarbon content, consisted of an incineration and energy recovery plant. Lastly, the area was restored and made safe, so as to prevent any deep percolation of rainwater; this involved installing a non-permeable barrier (clay and non-woven fabric sheeting) at the bottom of the pit, filling the depression with granular material and covering with a layer of sand, a polyethylene geomembrane and a top layer of arable soil. This completed the restoration, thereby putting an end to the legal proceedings.

Overall, the project involved the removal, stabilisation and subsequent disposal of 6,075 tons of acid sludge and 9,850 tons of contaminated soil. The principal contaminants found were total petroleum hydrocarbons, lead, and sludge with an extremely high degree of acidity.