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In light of the adoption of recent global policies and strategies for a more sustainable food waste management system and a greater control of environmental impacts, this study describes a circular bioeconomy plant model, currently operating in South Italy, for treatment and enhancement of organic fraction of municipal solid waste. The key basis for plant activity is dry anaerobic digestion of separately collected organic fraction of municipal solid waste (SC-OFMSW) followed by digestate composting process. Biomethane for use in the transport sector is obtained by biogas cleaning and upgrading, while high-quality compost for organic farming is produced by digestate composting. Plant activities are completed by the transformation of part of the produced waste into refuse derived fuel (RDF) to be allocated to waste-to-energy plants and the treatment of odour emissions which allows the recovery of ammonium sulphate as a fertilizer. A rooftop photovoltaic system supplies most of electric energy needed by the plant. For plant activities relative to 2020, carbon footprint was equal to -112 kg CO

The effects of the temporary increase of organic loading rate (OLR) combined with the simultaneous decrease of hydraulic retention time (HRT) on the stability of a pilot scale dry anaerobic digester were investigated. The separately collected organic fraction of municipal solid waste in mesophilic conditions (T = 40°C) was treated. The objective of this study was to verify whether it is possible to feed the digester for short periods, about three consecutive weeks, with higher OLRs and lower HRTs than those considered optimal without generating process failure or long-term instability. Starting from stable operation at a daily OLR of 10.0 kg of total volatile solids (TVS) for digester volume and an HRT of 23 d, the reactor was fed with an OLR of 10.8, 11.7 and 12.5 kg TVS m-3 d-1 corresponding to an HRT of 21, 19 and 18 d, respectively. It was observed that after using an OLR of 10.8 and 11.7 kg TVS m-3 d-1 for 3 weeks with satisfying results, it was possible to restore stable operating conditions at an OLR of 10.0 kg TVS m-3 d-1 in a short time. Otherwise, after using an OLR of 12.5 kg TVS m-3 d-1 the anaerobic digestion was deeply unbalanced and quickly failed. In this latter case, however, it was possible to fully recover and restore the stable conditions of the process within two months.

In this paper, performance analysis over two years&rsquo, operation of an industrial anaerobic digestion (AD) plant of a separately collected organic fraction of municipal solid waste is presented. The continuous plug-flow AD plant is still regularly operating and it has been fully operational since September 2018. Since then, it has been supplied with 40,000 t/y of pretreated separately collected organic fraction of municipal solid waste from municipalities of the Calabria region in Southern Italy. The AD process is carried out in a mesophilic regime at 40 &plusmn, 0.5 &deg, C, using a constant hydraulic retention time (HRT) of 22 days and a substrate with average total solids and average total volatile solids of 30.0% and 22.2%, respectively. In the last two years, the plant produced an average of 191 m3 and 860 m3 of biogas per tonne (t) of organic input material and of total volatile solids, respectively, with an average methane specific production of 508 m3/t (total volatile solids). The average CH4 percentage in the biogas was of 59.09%. The obtained results came out from the combination of high organic content of separately collected organic fraction of municipal solid waste, optimized pretreatment system and operating conditions adopted.

In this paper, a preliminary study of anaerobic digestion of organic fraction of municipal solid wastes (OFMSW) in presented with the aim to compare the performances of both wet- and dry-type reactors. The treatment of OFMSW via anaerobic digestion (AD) producing biogas is a process that is receiving a growing interest because two different needs can be coupled: the request of sustainable municipal waste treatments and increasing demand renewable energy. This paper aims to offer experimental results comparing batch test and continuous experimental reactors under different conditions of humidity and solid content. Results show that both the investigated configurations may be used for converting OFMSW into a high quality biogas and that the increase of dry matter in the continuous process still allows to achieve significant biogas production rates. A slight reduction of the methane content was observed (less than 5% relative) that can be also related to the change in the level of volatile fatty acids. These results are very promising in supporting the possibility of operating an industrial scale plant with a dry-process without affecting the system performance.

Nowadays, an important contribution to the sustainable industrial growth might come not only from the development of new materials but also from the re-design of process engineering, which leads to the development and the re-designing of more compact and efficient new processes in many areas of applications. As already done in large part of processes in Nature, membrane operations can serve in molecular separations, chemical transformations, water and energy transfer between different phases. Indeed, these technologies well fit the principles of this design philosophy and this is testified by the various applications of membranes in chemical and petrochemical industry and many are the successful examples of processes that have moved from lab-scale to pilot plant up to a demonstration unit in refinery. The main aim of this chapter is to show the main applications of membrane technology in the petrochemical industry and the related current research trends, focusing on the impact that membrane technology can have on the process sustainability.