A Review of Biological Aerated Filters (BAFs) for Wastewater Treatment

Abstract

Biological aerated filters (BAFs) can combine ammonia, carbonaceous matter, and solids removal in a single-unit process. Biological nutrient removal (N and P) can also be accomplished. Removal rates based on reactor volume for carbonaceous BOD, ammonia, and nitrates of up to 4.1 kg BOD m⁻³ day⁻¹, 1.27 kg NH3-N m⁻³ day⁻¹ and 5 kg NO3-N m⁻³ day⁻¹, respectively, are normally reported. The small footprint and adaptability of BAFs allows them to be used in upgrading established works, especially those in built up areas where space is at a premium. Although many configurations are available, including upflow and downflow, sunken, and floating media, the process still requires some optimization, especially with regard to media type, backwashing rates, and aeration control to decrease power consumption. Key words: biological aerated filter; wastewater treatment; submerged media bioreactor; carbonaceous matter removal; nitrification