Biofilter Process is a newly developped biological treatment technique, which is divided into submerged and non-submerged two styles.The typical submerged technique is BAF (Biological Aerated Filter) ,while the non-submerged ones include artificial rapid infiltration and constructed wetland etc.
      BAF filter technique is a kind of aerobic biological treatment,which has a relatively high efficiency with its high hydraulic loading,high volume loading,high biofilm activity, double functions of biological degradation and SS interception,and no need of secondary sedimentation tank after biological treatment unit.
      However, since BAF filter technique needs to be aerated for removing BOD, ammonia nitrogen,which has not get rid of the disadvantage of high energy consumption. Besides, it needs granular fillings as the biological carrier, such as ceramic microsphere,coke,activated charcoal etc, which correspondingly raises the investment in construction.