In this study, the applicability and the advantages of the downflow floating medium filter (DFF) in wastewater treatment were examined. The experimental results indicated that the DFF with in-line flocculation addition is a good pretreatment unit to reduce phosphorus load (up to 80-89% removal). The DFF also resulted in uniform filterable-flocs of 32-42 µm throughout the filter run. Thus it can also successfully be used as a flocculator. The backwashing of floating medium was achieved with a small quantity of water and at low backwash velocity. The introduction of floating medium filter bed on top of a coarse sand filter unit (CSF) increased the filter run time and removal efficiency (more than 87 and 94% of NH3-N and T-P removal respectively), particularly at a low filtration rate (5 m3/m2.h).
Application of downflow floating medium flocculator/prefilter (DFF) - coarse sand filter (CSF) in nutrient removal
H. H. Ngo, S. Vigneswaran; Application of downflow floating medium flocculator/prefilter (DFF) - coarse sand filter (CSF) in nutrient removal. Water Sci Technol 1 April 1996; 33 (8): 63–70. doi: https://doi.org/10.2166/wst.1996.0153
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