The municipality of Milan covered by Amsa comprises 1.281 million citizens, and first introduced door-to-door collection of household biowaste in November 2012 for one quarter of the city of Milan. The scheme was expanded to the entire city over four stages, and was fully implemented by June 2014. Compostable bags and 120-litre brown bins are used for collection from houses (smaller 35-litre brown bins are available on request). Small 10-litre aerated kitchen baskets, designed with an airy structure to minimise odours and anaerobic decomposition, are used in apartments. Biowaste is collected twice a week.
The waste management organisation coordinated activities with the City of Milan. Census data from the area were used to prepare the service setup. A software model was used to determine logistics requirements, based on factors such as bin weights, vehicle loads, route distances, crew productivity, etc. The model was validated using data from trial runs.
Following implementation of the plan across three quarters of the city, the recycling rate for food waste rose from 35 % in 2011 to 48 % in 2014, equating to 90 kg per capita per year. Composition analysis at the start of the service showed that just 3.8 % of the food waste fraction comprised non-compostable (contaminant) material. This increased to 5.1 % eight months into the campaign, but dropped back down to 3.7 % after the quality awareness campaign.