Barcelona, Spain) on the day the ex

Barcelona, Spain) on the day the experiments started and origi- nated from a door-to-door collection system. In the home experiments the OFMSW used was the organic waste produced by the families themselves. The waste average composition was similar to that of the OFMSW produced in other parts of Catalonia and Spain (Agència de Residus de Catalunya, 2006 Ruggieri et al., 2008). Specifically, the OFMSW presented the following general properties: moisture content of 62.3 ± 5.7%, 70.6 ± 9.1% (in dry basis) and pH was 6.1 ± 0.2.
2.6. Analytical methods
organic matter Water content, dry matter (DM) and organic matter (OM) con- tent were determined according to standard procedures (The US Department of Agriculture and The US Composting Council, 2001).
To obtain the Dynamic Respirometric Index (DRI), microbial respiration was measured as O2 consumption in a dynamic respirometer built by Ponsá et al. (2010), which was based on the methodology described by Adani et al. (2006). The DRI represents the average rate of oxygen uptake during a 24 h period of maximum biological activity observed during the respirometric assay (nor- mally this rate is achieved 24–48 h after starting the test) and it reports the material stability degree (Adani et al., 2004; Ponsá et al., 2010). It is expressed in mg of O2 consumed per g of OM (or DM) per hour and measured in triplicate assays. A complete description of the dynamic respiration index methodology and its values can be found everywhere (Ponsá et al., 2010; Barrena et al., 2011).
2.7. Economic balance
The economic balance was estimated by relating the experi- mental difference found between the weights of the OFMSW col- lected per year through the aerated (AB–CB) and the conventional (nAB–nCB) system and considering the waste tax refund and the OFMSW treatment costs. The balance presented in this work shows the results for a municipality of 4999 inhabitants (small-size municipality) with a door-to-door collection system assuming an average value of OFMSW collected of 0.332 kg inh