Landfill for Non-hazardous Waste in Ravenna (formerly Category I)

Compacting and re-covering of the waste with earth, stabilised organic fraction, fireproof and waterproof liner.

The leachate, or liquid waste, generated primarily by the infiltration of rainwater into the landfill site, is collected on a regular basis and then purified.
The drainage system, positioned above the waterproof tank liner, comprises a mineral drainage layer (gravel), a series of capture and collection pipes and an extraction system to carry the leachate in a pipe connected to all the sectors and which is transported to a system of storage tanks and reservoirs. It is subsequently channelled to the physicochemical treatment plant for purification treatment within the Section at 2.6 km S.S. 309.

The biogas produced by the landfill is captured by a horizontal and vertical collection system consisting of a drainage well which channels the biogas to the aspiration plant via a specific supply network at which point combustion is commenced to produce electricity (836 KWe installed) with the surplus biogas being transported to high-temperature flares for combustion.

A secondary waterproof mineral barrier comprising clay, and a lower waterproof HDPE geomembrane that is 2.5 mm thick. A primary waterproof mineral barrier comprising clay, an upper waterproof HDPE geomembrane that is 2.5 mm thick, a protective layer of the liner comprising geotextile and fine sand, and a drainage gravel layer (bottom drainage of the leachate).

Covering of the top portion takes place in two separate phases:

• temporary covering (estimated duration 10 years): comprises a biogas drainage layer and Bentonite geocomposite having a sealing function;
• definitive covering: this chosen technique is primarily determined by the fact that, being a landfill for municipal solid waste and similar waste, the creation of a final covering soon after completion of the various landfill operation phases is deemed risky and inconvenient. Intervening with a temporary covering while most of the settling and subsidence takes place ensures more effective isolation of the landfill site from the external environment as restoration and maintenance interventions are easier to carry out than when a final covering is in place.

The final covering of the embankments will, on the other hand, take place in a single step. Given the objective difficulty involved in the onsite storage of large amounts of drainage materials with controlled characteristics (washed gravel or sand for the most part) and given the difficulty involved in placing the sealing material (clay) on the embankments, evaluation of a final covering system using synthetic material is underway. This decision allows certain guarantees on the effective disposal capacity (water and biogas drainage) and on the sealing capacity with a significant reduction in the weight of the covering that benefits the stability of the landfill system.

The environmental matrices and emissions monitored as environmental surveillance of the potential impact of the operational management of the landfill are:

• rainwater;
• groundwater;
• surface water (receiving vessels);
• leachate;
• atmospheric particulate;
• monitoring of biogas composition;
• landfill emissions;
• air quality (Odorous substances);
• monitoring of leachate explosiveness on the management network;
• noise monitoring.