Introduction to a Large-Scale Biogas Plant in a Dairy Farm

This article describes a large-scale biogas plant in a dairy farm located in the Tongzhou District of Beijing. It is has a treatment capacity of 30t manure and 30t wastewater per day, a total of 60t/d with a residence time of 20 days. Input material undergoes mesophilic fermentation inside the digester, which also directly stores the biogas above the slurry within the same tank. This storage method has been found to be advantageous for large scale biogas plants in China. Along with biogas production, this particular plant also adopted a combined heat and power (CHP) system. CHP systems burn biogas for generating, but they also convert the excess heat into electricity. In this case study, the CHP system generates 160kw of electricity. These comprehensive systems can provide heat, clean electricity and organic fertilizer, which can result in economic, social and energy saving benefits. Due to these multiple benefits, CHP systems are commonly used when dealing with large scale livestock biogas projects.