User:Valeria magnolfi/sandbox

ORION is a small scale innovative automated system of Anaerobic digestion (AD). A first prototype was developed in June 2015 by an international team of researchers with the support of the European Commission under the Research for Small and medium-sized enterprises associations Theme of the 7th Framework programme. The purpose of this system is to reduce storage, transport as well as landfilling or incineration of biodegradable waste produced by European Agro-food and HORECA SMEs such as restaurants, hotels, markets and fisheries. ORION is a compact machine including a grinder, a digester, an energy management unit and a sensor and automation module. The digester volume varies in the range 3 - 30 m³ depending on the available organic load. It can treat 80-1000 kg/day of biodegradable waste including mixed food and vegetables, cheese whey, salmon waste, seaweed and restaurant waste. The system is equipped with control tools based on Fuzzy logic and advanced sensors such as electronic noses and tongues, keeping under control the digester performances through remote monitoring and storage of more than 80 process and component status variables. As a result of the digestion process, the AD system produces biogas containing 50-65 % Methane. The latter is exploited by the energy management unit to ensure an adequate temperature to the biological process and directly used on-site. ORION's estimated energy production on daily basis is 1.5 –7.5 Nm³ biogas/m³.

General context
Restaurants, hotels, markets, fisheries and other small to medium size agro-food industries industries have to manage large quantities of organic waste: the industry produced 239,871,940 tonnes of organic waste in 2006. EU established a 35% landfill diversion target for biodegradable waste at 2016, taking 1995 levels as baseline Landfill Directive. Municipal waste recycling target is 50% at 2020 and MS should take measures to encourage environmental friendly treatment of bio-waste such as anaerobic digestion and composting. These options are turning more and more convenient due to high incineration costs. But composting is not applicable to putrescible fraction including meat, fish and starch residues and large scale anaerobic digestion plants requires huge amounts of organic input to be viable. Besides, on site small scale anaerobic digestion of organic waste can be a good solution from an economic, environmental and hygienic point of view.

Technology details
The Orion system includes a grinder, a digester, an energy management unit and a sensor and automation module.

The only end-user interface is with a convenient waste grinder. The grinder reduces the organic matter to be digested to small particle and mix it. A Programmable Logic Controller controls the moment to pump it to the digestion module while an automatic periodic self-cleaning cycle is provided to pump the ground organic matter from the grinding to the digestion module.

The digester is composed by a “head” and a “body”. The head collects the biogas produced in a gasholder and it contains operation and measurement equipment. The body includes a mixing chamber called jabot and a methanation tank. The jabot receives the organic matter from the grinding and it feeds the methanation tank at regular intervals. The anaerobic digestion occurring in the methanation tank can thus be assimilated to an infinitely stirred process with suspended biomass. The intelligent selection of surface materials further contributes to optimise the conditions of the microrganisms which are responsible for the biogas production. The digester is heated and continuously kept at a constant temperature through an hot water bath, surrounding the methanation tank. The digestion module includes all the connecting to the devices necessary to its functioning, apart from some peripheral devices (grinding unit, combustion module, buffer tanks).

The energy management unit includes a small, certified biogas boiler running only on steady state biogas stream and a heat exchanger for the hot water bath. The system is provided with a natural gas boiler working during start-up or transient digester operation. In addition a small natural gas assisted flare deals with poor quality or intermittent biogas for environmental and health and safety reasons. The system is equipped with a simple PLC, relays and switches allowing the automatic functioning of the gas and water circuits. Detectors for CO, HC and temperature are linked to warning/cut off systems. An hazard and operability study has been undertaken to maximise the boiler safety.

A sensor module has been developed in order to autonomously gather essential information on the dynamics of the digestion process. Three different sets of sensor arrays have been integrated in the sensor module. A first set of commercial Ion selective electrodes monitors pH, ORP and ionic concentration of the effluent resulting from the digestion. A second set of commercial electrochemical and infrared sensors measures the composition of the produced biogas. A third set of custom developed conductive polymer sensors responds to the acetic and propionic acid contained in the effluent. The system is completely automatic and does not require any operation from the end user. An automation module (client side) is responsible for controlling the digester, taking decisions on the inputs received from the sensors. The server side of the automation module monitors and centralises the data from all the clients.