With population growth and the development of industry, waste production is increasing exponentially and new types of waste are being generated. This dynamic raises key questions regarding the efficient and environmentally friendly treatments of these wastes. Biodegradable wastes such as food wastes and sewage sludge can be efficiently treated through anaerobic digestion. This process uses microorganisms to break down complex organic matter into biogas and it is the standard method for treating sewage sludge at wastewater treatment plants. A special case of anaerobic digestion is a process that treats two or more substrates and it is called anaerobic co-digestion. With the right conditions, the addition of cosubstrates can increase the biogas production, biogas quality and dewaterability of anaerobically stabilized sludge. Anaerobic co-digestion of sewage sludge and food waste can contribute to the energy neutrality of the wastewater treatment plant and decrease carbon footprint. However, a number of issues need to be resolved before anaerobic co-digestion of food waste and sewage sludge can be implemented, such as instability and inhibition of the process by increased ammonia nitrogen or acidification of the system, the variable composition of the substrates, methane emissions and the capacity of the anaerobic reactors.
The aim of the topic is to find the optimal technological arrangement and set the process conditions to ensure sufficient development of biogas of the required quality and to avoid undesirable effects of anaerobic co-digestion. By setting up the technology appropriately, it is possible to treat waste in an environmentally friendly way and at the same time to move towards energy self-sufficiency at wastewater treatment plants.
