Landfill Site Visit

This past week, the group went on a site visit to a landfill that serves the industrial area of Villacidro, a small commune in the south of Sardinia of approximately 14,000 inhabitants. The facilities include a MSW plant, sewage plant, photovoltaic stations and wind farms. The photovoltaic arrays are on the roofs of buildings and on the ground of the facility. The landowner, CIV, intends to expand solar capacity in coming years. 

The MSW and sewage plants are operated by Villaservice Spa. After a presentation from one of the site-engineers, he gave us a tour of the grounds. To ensure our health and safety, Villaservice required us to wear a Hazmat-like suit, air mask and gloves while touring the facilities. The putrid odor was an all-encompassing. Birds flocked over mounds of loose trash and corpses of dead rats scattered the grounds. Even though I was covered from head to toe in protective clothing, I felt as though I the grime had penetrated through. 

The walls throughout the site were plastered with safety signage.

The landfill has been divided into three sectors: the first sector of the landfill was active between 1993 and 2006. In 2008, this sector was capped and has since been utilized for biogas extraction. The biogas is stored in the spherical structure below.

This sector of the facility contains approximately 0.8Mm^3 of unsorted MSW, sewage sludges and local process wastes. The second sector, started in 2006, accepts residual wastes, sewages sludges and local process wastes. This sector has the same 0.8Mm^3 capacity as the first sector. With current projections, the second sector will continue to accept waste until 2018, after which it too will be capped and utilized for biogas extraction.

The third sector, an anaerobic plant, deals exclusively with organic waste. Initially, a dry treatment uses an electromagnet to separate recoverable metals from the organic fraction. The organic material then goes through a wet treatment to separate the slurry into light and heavy debris. Finally, a digester processes the organic slurry through a three stage centrifuge process. The output from the third centrifuge stage goes to a composting plant, after which it is sold at market value.  

The tour culminated in a climb to the top of the landfill, from where we could observe the working face, groundwater monitoring wells and wind turbines.

On Thursday, a guest lecturer came to speak on mine area remediation in Sardinia. According to the speaker, a quarter of land in Sardinia has been impacted by former mining activity, which can potentially limit economic development. Communities, such as Buggerru on the western coast of Sardinia, have built parking lots and futbol fields on mining waste. Iglesias in particular has the highest amount of mine waste in Sardinia. Human bio-monitoring has found communities members living near the abandoned mine sites to have augmented levels of metals and metalloids, most likely due to inhalation. The riverbed in the San Giorgio area has become a slightly diluted mine waste. The lecturer maintains that mine waste contains salvageable material, such as zinc. Closing the metal loop through recovery would align with EU sustainability goals.