A. H. AL-Abdaly, A. and K. K. Al-Ahmady, D. (2014) “Effect of the hydraulic detention time and the volumetric ratio of anaerobic to aerobic zone on the efficiency of the upgraded activated sludge units using (Bardenpho) system”, Al-Rafidain Engineering Journal (AREJ), 22(1), pp. 97–109. doi: 10.33899/rengj.2014.87020.