1. Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610065, People's Republic of China
2. Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu 610041, People's Republic of China
3. Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture and Rural Affairs, Chengdu 610041, People's Republic of China
4. Department of Environment, College of Architecture and Environment, Sichuan University, Chengdu 610065, People's Republic of China