“Modeling of Mass Transfer Coefficient in Rotating Biological Contactor With Perforated Discs (RPBC)”. Al-Khwarizmi Engineering Journal 11, no. 4 (December 31, 2015): 20–27. Accessed May 3, 2024. https://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/271.