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Hera Group's regional biodigestor plant project


To complete the chain of separated collection of organic waste and make progress on achieving the targets of separated collection and compost and renewable energy production: these are the targets of Hera Group's “Biodigestor Plant Project”, which began its operational phase in early 2012 and aims to build one anaerobic biodigestor plant in each province in which the multiutility company manages the waste cycle. Five plants will be built in total: Modena, Ostellato (FE), Sant'Agata Bolognese (BO), Voltana (RA) and Rimini, in which, thanks to an airless fermentation process that simulates the digestive system of a cow, domestic organic waste resulting from separated collection can be transformed into high-quality compost and electricity via the production of biogas. The five biodigestor plants will be added to the existing one in Cesena (named Romagna Compost), the first of its kind in Italy, which is also operated by Hera Group.

The last few days of 2011 saw the issuance of the authorisations needed to construct the biodigestor plants at Rimini and Voltana (RA), which will supplement the existing composting plants. The construction work will therefore begin in the coming weeks, with a view to making the plants operational by the end of the year. This year should also see the completion of the authorisation process for the other sites, with work due to begin in 2013.

The project as a whole will involve total investment of over Euro 40 million for Hera Group, bringing the region's capacity for renewable-energy generation to more than 32 million KWh per year (around 6.5 million KWh per plant). In practical terms, this will mean meeting the annual energy needs of around 12,000 households (based on an average consumption per household of around 2,700 KWh), saving 17,000 tonnes of CO2 emissions.

Each biodigestor plant will treat organic waste resulting from separated collection by Hera in the relevant areas. Once it has reached the site, the ground-down organic waste is left in closed premises (like large garages). Here, via batch dry fermentation, methanogenic bacteria similar to those found in a cow's stomach carry out the digestion process, producing a methane-based gas which fuels engines that generate electricity. Another advantage of the process is the total absence of odours. By acting in the absence of oxygen, anaerobic bacteria can destroy all the substances that cause unpleasant odours and transform them into biogas. When the digestion process is complete, the material undergoes a composting phase so that it can ultimately be used as certified compost for organic farming.

The biodigestor plant project is particularly significant in light of the fact that the General Assembly of the United Nations, acknowledging the importance of energy for sustainable development, has designated 2012 the “International Year of Sustainable Energy for All”. The UN aims to raise awareness about the importance of increasing opportunities to access sustainable energy, energy efficiency and renewable energy sources at the local, national and international level.

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