Ecological analysis of a typical farm-scale biogas plant in China

The aim of this work was to present the common anaerobic digestion technologies in a typical farm-scale biogas plant in China. The comprehensive benefits of most biogas plants in China have not been fully assessed in past decades due to the limited information of the anaerobic digestion processes in biogas plants. This paper analyzed four key aspects (i.e., operational performance, nonrenewable energy (NE) savings, CO2 emission reduction (CER) and economic benefits (EBs)) of a typical farm-scale biogas plant, where beef cattle manure was used as feedstock. Owing to the monitoring system, stable operation was achieved with a hydraulic retention time of 18-22 days and a production of 876,000 m(3) of biogas and 37,960 t of digestate fertilizer annually. This could substantially substitute for the nonrenewable energy and chemical fertilizer. The total amount of NE savings and CER derived from biogas and digestate fertilizer was 2.10x10(7) MJ (equivalent to 749.7 tce) and 9.71x10(5) kg, respectively. The EBs of the biogas plant was 6.84x10(5) CNY center dot yr(-1) with an outputs-to-inputs ratio of 2.37. As a result, the monitoring system was proved to contribute significantly to the sound management and quantitative assessment of the biogas plant. Biogas plants could produce biogas which could be used to substitute fossil fuels and reduce the emissions of greenhouse gases, and digestate fertilizer is also an important bio-product.Geosciences, MultidisciplinarySCI(E)SSCI中国科学引文数据库(CSCD)0ARTICLElincong@cau.edu.cn; mengjing@pku.edu.cn3375-384