ANAEROBIC DIGESTION OF FOOD WASTE: USING THE MODEL ADM1 TO SIMULATE ITS PERFORMANCE AND ASSESS ITS POTENTIAL AS A WASTE MANAGEMENT OPTION

摘要

Annual food waste arisings in the UK alone are estimated to be 12-20 million tonnes. This figure in combination with the environmental impacts of food waste landfilled, have called the need of new options to be introduced for its treatment. Due to its readily biodegradable nature and high energy potential, anaerobic digestion has been considered as an attractive option for its treatment. However, the nature of food waste composition can be problematic to digestion performance. Performance in AD is normally assessed against process stability, energy generation and digestate quality. Food waste can be highly variable depending on its source and this can be a cause for instabilities. Co-digestion with sewage sludge has been suggested as an alternative and improvement to the digestion process. The high carbon availability and low nutrients concentration are the key characteristics that make food waste a desirable substrate for digestion with sewage sludge, a substrate poor in soluble organic material. As little evidence exist on the suitability of substrates for digestion and in general on digester process performance, over different design and operating conditions, the Anaerobic Digestion Model 1 (ADM1), developed by the IWA Anaerobic Digestion Modelling Task Group, was assessed as a tool to simulate AD and part of an evaluation of the potential of food waste digestion with and without sewage sludge. This model is the most widely used in the field of anaerobic digestion processes. Therefore the aim of this work was to assess the potential of the ADM1 to simulate the anaerobic digestion of food waste with and without sewage sludge in order to assist decision making on the management and operation of anaerobic digestion facilities as well as in policy.