Research on the national standard of the minimum allowable values of energy efficiency and energy efficiency grades for key sewage treatment equipmentHuang Jin, Wang Yueping, Zhang Xinheng, Chen Bin, Shi Ming, Ling Jianjun, Wang Wensheng, Wang Qijun, Zhang Xiaoxin and Lin LingE3S Web Conf., 53 (2018) 04010DOI: https://doi.org/10.1051/e3sconf/20185304010