Municipality of Lacchiarella – The “ex fabbrica Omar” Site

Environmental Remediation

The remediation services entrusted to us by the Municipality of Lacchiarella (Milan) involved multiple operations, which made it possible to complete a reclamation programme for an area of 70 thousand sqm known as “ex Omar”, located at the heart of the Parco Agricolo Sud Milano (the Southern Milan Rural Park). It was a site that had been occupied, between the post-WWII period and the early 1980s, by a refinery. It then became the headquarters of a company that promised to transform toxic waste into petroleum, which was to become the focus of one of Italy's first large-scale investigations into illegal waste disposal. It left 60 thousand tons of hazardous liquid waste stored in tanks at the site. Analyses subsequently revealed that the principal contaminants were light and heavy hydrocarbons (in the soil) and hexane (in the groundwater).

Riccoboni SpA first operated at this site in 2002, when it was entrusted with the remediation—by making safe, storing and/or washing—of the contaminated gravel from “ex Omar” Lot 1. It returned from 2014 to 2017, to remediate the remaining sections of Lot 1 and the entirety of Lot 2. The work was begun in a negative-pressure tent, where the contaminated soil was stored in specially-constructed bays. Subsequently, the areas that were the site of the former refinery were remediated; this involved the removal and disposal of roofing containing asbestos, the selective demolition of several disused buildings and the demolition of both below-ground and above-ground reinforced concrete structures that interfered with the remediation efforts. The fractions of material that could be returned to a new position within the same site were crushed and recovered on-site using a mobile system located inside a negative-pressure tent. The “hazardous” and “non-hazardous” soil fractions that did not meet the criteria for disposal on-site (a total of over 50 thousand tons) were collected and sent for disposal off-site at authorised facilities.

To remedy the issue of water at the bottom of the excavation, a sheet pile retaining wall was erected in proximity to the nearby artificial canal, after which the base of the excavation was drained using a vertical well-point drainage system, with the water thus collected being treated immediately using an in-situ mobile system.

When the project was complete, the site was returned to the community completely covered over, with the original ground level restored. In 2018, the Municipality of Lacchiarella was therefore able to declare the remediation of the area complete and the environmental state of emergency—which had been in effect since 1995 and had caused the site of the former refinery to be included in the list of areas designated by the Italian government as Sites of National Concern ("S.I.N.")—resolved.