A review of the materials utilized in the design and fabrication of biogas digesters

This work aims to discuss the different materials used in the construction and fabrication of biogas digesters, which are critical for sustainable energy generation. The study analyzes a broad spectrum of materials, including civil construction materials such as bricks, sand, stone, and concrete, thermoplastics like polyvinyl chloride, polyethylene, and high-density polyethylene, composite materials, and metallic substrates such as steel. These materials play a vital role in the structural integrity and functionality of biogas digesters, fulfilling various purposes depending on their properties. The main aim of this review is to consolidate and compare the properties inherent to each material, discuss the attributes of their designs, and outline their specific applications for the development of biogas digesters. The methodology involves a qualitative analysis of existing research, highlighting the techniques of adapting various materials that could accelerate the development of biogas technologies. Furthermore, the review examines the biogas production process within digesters made from materials such as stones, cement, thermoplastics, and ferrous alloys, which are also used for gas storage. Our findings indicate that small-scale, domestic biogas digesters predominantly use cement-based materials due to their rigidity, robustness, and long service life. In contrast, material selection for large-scale or commercial biogas plants is influenced by a complex relationship between the properties of the materials and the environmental factors, considering the distinct physical, electrical, and thermal characteristics of each material. Nevertheless, plastic-based digesters emerge as a promising alternative in regions facing logistical challenges, attributed to their chemical resistance, flexibility, and recyclability.