Influence of media size on operational stability of UBAF
滤料粒径对给水曝气生物滤池运行稳定性的影响

Up biological aerated filter(UBAF) was applied for the treatment of source water in Liuwuzhou.Effect of media size on the variation of head loss as well as the removal efficiency of NH3-N and CODMn was evaluated.The results showed that UBAF with media size between 3 and 5 mm was suitable for the removal of NH3-N and CODMn.However,because of the great head loss which also varied significantly before and after back wash,this media size was not favorable for UBAF operation.UBAF with media size between 6 and 10 mm made good performance,and the removal efficiencies of CODMn and NH3-N were 73.8% and 18.6%,respectively,which meet the requirement of the Sanitary Standard for Drinking Water(GB5749-2006).The head loss was low(below 0.4 m) after operating for 24 h.And the variation of head loss before and after back wash was minimal(below 5 cm).Additional test demonstrated that media broken might result in the change of size gradation and the head loss increased subsequently.