Biological Denitrogen in Floating Media Deep Bed Filtration Process

A synergetic process for simultaneously filtration and denitrogenation in two cascaded deep beds was studied for advanced treatment of secondary effluent. Both the deep beds were up-flow and packed with 2 m height of 3~4 mm polystyrene foam pellets. The first bed was assembled an aerator in its bottom for nitration, and the second bed was added methanol in its influent for denitrificaion. When HRT=1~2 hr, the efficiency of ammonium removal and nitrate was 90% and 95% respectively. Turbidity of the effluent was less than 1 NTU. It was also found that backwashing had important effects on system operation.