Feasibility Study of running an Anaerobic Digestion Plant coupled with a Combined Heat and Power Plant near Paris, France, processing 50,000 tons of food waste per year

As human populations worldwide continue to expand, waste production and management solutions are being reexamined to address global climate change issues. The objective of this work was to determine whether constructing and running an anaerobic plant including electricity and heat production was a feasible project. The plant would be located near Paris, France, and process food waste. This work answers to both waste management and energy production related issues. Anaerobic digestion is a natural process during which organic matter is decomposed, producing biogas rich in methane and a digestate which can be utilized as fertilizer. This biogas is then combusted and its energy recovered. The first part of this study focuses on the process of anaerobic digestion itself. Important parameters are identified such as moisture, pH, temperature or C:N ratio of the material to process. A review of the current available technologies is conducted, identifying different operation modes. These operation modes can differ in several ways, such as the rate of feeding of the digester, the period of time the matter stays in the digester, or the number of stages the process is divided into (i.e. whether the digestion occurs in 1, 2, or more different containers). Also, the amount of methane obtained as output of the digestion process depends on the initial composition of the material. Previous studies made it possible to link different inputs with the expected quantity of methane produced. Based on research results and industrial data, a sizing model was developed. It calculates every flux of matter going in and out of a theoretical digestion plant. For a given input material, the model returns estimations of the biogas, energy, and fertilizer production. This model is applied for the project feasibility study, considering two different technologies: a wet and a dry process. The results obtained are used to conduct an economical and environmental analysis, before concluding on the feasibility of the project. Considering this specific project, the dry process is preferred from every point of view. Despite the extra costs generated, the project would be a sustainable waste management solution for the municipality, in line with present energetic and environmental concerns