Journal of Civil and Environmental Engineering

Aerobic Granules Formation in Dual-Layer Percolating Filters

Abstract

Christian Drakides and Meiling Lay-Son

Aerobic spherical granules were observed in zeolitic dual-layer intermittent percolating ï»¿filters ï»¿treating domestic septic tank effluent. The diameter of the granules ranged from 0.05 to 0.5 mm and when they predominate in the biofilms the mean SVI value was of 54 ml g-1 instead of 232 ml g-1 when they were absent. Flow behavior in these filters was characterized by the dimensionless Reynolds number. The values obtained (40