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 Abeer.T. A. H. AL-Abdaly; Dr. K. K. Al-Ahmady Volume 22, Issue 1, February 2014, Page 97-109 10.33899/rengj.2014.87020 Show Article PDF 0 K