Suchergebnisse

International audience ; During the last years, a big strength has been put on organic resources recovery in order to achieve our aspiration towards a "Recycling Society" and climate stabilisation. Energy, nutrients and organic matter needs have thus driven sustainable management of resources and wastes and promoted new technological developments. In this context, biological processing of organic wastes and the use of natural resources to recover nutrients as phosphorus, to produce soil improvers and to supply energy is of great interest. However regulations on the management of organic resources waste are fragmented. So the current legislation in Europe might be not sufficient to achieve the stated objectives of its effective management. Moreover there is an open question on the tools that can be used to assess the efficiency of management systems for organic resources and waste which lead to the adequate processes selection. Especially the increasing use of Life Cycle Assessment tools has to be carefully addressed with a special focus on the considered indicators and the local applicability of the results. Following the ORBIT conferences tradition, ORBIT2012 deals with all aspects of organic resources and waste management with a special focus on the assessment of technologies with environmental, social and economical point of view. A large place is given to climate change and decision making tools between waste treatment options. Traditional themes as energy recovery (Biofuels, biogas, hydrogen production), biological treatments (composting and anaerobic digestion) and also mechanical biological treatment still remain central issues that are discussed in order to improve technologies and product quality, especially for land application. More local approaches such as home and community composting are also discussed as they may represent solutions that have to be considered in an integrated organic waste management plan which includes prevention. Special emphasis is also laid on EU policies and strategies for ...

International audience ; In France, like in all developed countries, the amount of solid wastes generated per year has increased continuously since the 1960's. To hold back this trend, waste policies have been set up, as illustrated by current EU waste policy and its five main priorities: prevention, reuse, recycling, recovery and disposal. Composting can be defined as the process whereby aerobic micro-organisms convert organic substrates into compost: a hygienic, biostable product that can be beneficially applied to land (Haug, 1993; Mohee & Mudhoo, 2005). Therefore, it fits perfectly with the fourth priority, recovery, which fosters extraction of useful material or energy from wastes. In this context, interest towards composting has increased continuously during the last few years. During treatment, micro-organisms breakdown organic matter and produce carbon dioxide, water and heat. Heat generated by biological activity modifies moisture content and temperature conditions. These changes result in the appearance of a temperature peak in first days of treatment and most pathogens are killed by the high temperatures reached (around 70-80°C), turning waste into a hygienic product. Among the various physical parameters taking part in the composting process, thermal conductivity seems to be of major importance, and could be used as an indicator to follow heat transfers within the organic matrix. However, as all physical parameters involved in the process, the initial preparation of the substrate (adjustment of moisture content or C/N ratio, addition and mixing with bulking agent …) has an influence on the physical parameters involved in the process (such as bulk density, Free Air Space or air permeability) and thus, on thermal conductivity. Moreover, difficulties often occur in composting experiments because the effects of compaction on physical properties are ignored, or information about these effects is lacking. As soon as the pile of waste is built, the settlement of the composting matrix begins. This ...

International audience ; In France, like in all developed countries, the amount of solid wastes generated per year has increased continuously since the 1960's. To hold back this trend, waste policies have been set up, as illustrated by current EU waste policy and its five main priorities: prevention, reuse, recycling, recovery and disposal. Composting can be defined as the process whereby aerobic micro-organisms convert organic substrates into compost: a hygienic, biostable product that can be beneficially applied to land (Haug, 1993; Mohee & Mudhoo, 2005). Therefore, it fits perfectly with the fourth priority, recovery, which fosters extraction of useful material or energy from wastes. In this context, interest towards composting has increased continuously during the last few years. During treatment, micro-organisms breakdown organic matter and produce carbon dioxide, water and heat. Heat generated by biological activity modifies moisture content and temperature conditions. These changes result in the appearance of a temperature peak in first days of treatment and most pathogens are killed by the high temperatures reached (around 70-80°C), turning waste into a hygienic product. Among the various physical parameters taking part in the composting process, thermal conductivity seems to be of major importance, and could be used as an indicator to follow heat transfers within the organic matrix. However, as all physical parameters involved in the process, the initial preparation of the substrate (adjustment of moisture content or C/N ratio, addition and mixing with bulking agent …) has an influence on the physical parameters involved in the process (such as bulk density, Free Air Space or air permeability) and thus, on thermal conductivity. Moreover, difficulties often occur in composting experiments because the effects of compaction on physical properties are ignored, or information about these effects is lacking. As soon as the pile of waste is built, the settlement of the composting matrix begins. This ...