Biological Groundwater Denitrification: Laboratory Studies

Laboratory denitrification studies were conducted in a sand column using sucrose as a biodegradable carbon source. The denitrification capacity of the system was followed for more than one year. Column efficiency was dependent on the flow rate and on the carbon to nitrogen ratio in the treated water. After a few months of operation, visible accumulation of gas in the active zone was accompanied by a marked decrease in column permeability. Vacuum treatment restored permeability to its original level; only partial recovery was achieved by simply allowing the slow natural release of gas. He suggest that under the conditions tested, clogging resulted from the accumulation of microbiologically produced gas.