A. Sabzali and  M. Nikaeen and  B. Bina,  Evaluation of Cigarette Filters Rods as a Biofilm Carrier in Integrated Fixed Film Activated Sludge Process.   journal   = {International Journal of Industrial and Manufacturing Engineering}, [online]. World Academy of Science, Engineering and Technology.
    March 2011, vol. 51(3). 583 - 588
    [viewed 28 January 2022]. Available from: https://publications.waset.org/pdf/7934.