Landfill gas emissions from a controlled site with different cover conditions

According to the European Landfill Directive (1999/31/EC) and the related Italian Legislation (‘‘D.Lgs. No.36/2003”), monitoring and control procedures of landfill gas (LFG) emissions, migration and external dispersions are requested. These procedures could be particularly interesting in the situation of a controlled landfill presenting old and active sections with different cover conditions (i.e., temporary and/or final covers). In this context, a significant case-study situation is represented by the “Fano” controlled landfill for non-hazardous waste (Marche Region, Central Italy), which is owned and operated by the ‘‘ASET” public multi-utility group since the year 1978. Over this long operation time, the “Fano” landfill site has been progressively structured with different waste placement sections. As far as the summer 2010 status is concerned, the “Fano” landfill is comprehensive of diversified sections/sub-sections with particular cover conditions. Precisely, the oldest and inactive Section ‘’1” is equipped with a final, composite cover system consisting of non-compacted clay layer, compacted clay layer, geotextile-geonet-geotextile layer, and top soil. Particularly in summer 2010, the top soil of Section “1” was naturally covered by spontaneously growing and dense herbaceous vegetation. Differently, the subsequent and inactive Section ‘’2” is comprehensive - as for the summer 2010 status - of three parts with diversified cover conditions: (1) the predominant areal portion named Sub-section ‘’2A”, presenting since the end of summer 2007 a temporary artificial covering system (1 mm HDPE overlying a 50 cm clay layer) as permitted by the Italian landfill legislation for waste isolation from precipitation; (2) the smaller Sub-section “2B”, having solely the clay layer without the HDPE; and (3) the south-eastern portion named Sub-section “2S”, which during the period March-June 2010 was characterised by the deposition of about 9,400 ton of sea-sediments dredged from the Fano harbour. Finally, the active Section “3”, in operation since the year 2008, is disaggregated in the following portions: (1) the main Sub-section “3B”, which presents a temporary non-compacted clay cover; and (2) the smaller and double portion named Sub-section “3A”, which consists of two lateral parts of a long slope temporarily covered during the year 2010 with a geomembrane (HDPE). Interestingly, specific monitoring campaigns of LFG diffuse emissions have been annually carried out at the “Fano” landfill since the year 2005 with the non-stationary variant (i.e., with instantaneous location on ground surface) of the static accumulation chamber technique. The paper presents some elaborations of the monitoring data of the overall campaigns 2005-2010. In particular, the discussion is primarily focused on the campaign carried-out at the “Fano” landfill site during the summer 2010 when the site sections/sub-sections were simultaneously characterised by the aforementioned different cover options. The evaluation of LFG emissions with the static chamber approach at the “Fano” landfill site has permitted to individuate some relevant effects attributable to possible types of landfill cover.