System Analysis of Bio-Natural Gas from Large-Scale High Organic Load Wastewater in China

The demand for renewable alternatives to natural gas as a fuel for industries and residential consumers has been growing fast. Bio-natural gas is expected to play an important role in green energy transition and climate change. Large amounts of high organic load wastewater are discharged from coking, pharmaceutical, papermaking, printing and dyeing, petrochemical, and food processing industries. Bio-natural gas could be produced from high organic load wastewater using anaerobic digestion or membrane bio-reactor and biogas upgrading technologies. This study performs a comprehensive analysis of bio-natural gas produced from high organic load wastewater (BNGWW) in China. The status quo is compared with the potential use of this alternative, coupled with a techno-economic analysis of production technologies, energy policies, and opportunities and challenges. A model is proposed to estimate the provincial BNGWW demand in China from 2016 to 2020 and the decomposed demand across 42 sectors from 2016 to 2019. Factors influencing BNGWW potential are analyzed under the changes of time, region, and sectors. The result shows that BNGWW demand is affected mainly by natural gas prices, industrial scale, and chemical oxygen demand of organic wastewater. Some provinces in East China, Central and Southern China, and Xinjiang have high BNGWW potential. The agricultural and food processing industry has the highest production potential. Challenges and barriers to the development of BNGWW have also been highlighted.