Clogging of microbial denitrification sand columns: Glas bubbles or biomass accumulation?

Denitrification studies were conducted in sand columns in order to differentiate between the effects of gas and biomass accumulation on the clogging of the interstitial spaces, and to optimize conditions for prolonged operation. Four biodegradable carbon sources were used: sucrose, acetate, formate and ethanol. The results suggest that it is the accumulation of biologically produced gas that causes clogging of the columns. Of the four carbon sources tested, formate brought the lowest accumulation of gas and the highest permeability levels in the column.