Effect of inoculation on the biodegradation of butterfat-detergent mixtures in fixed-film sand columns

The purpose of this work was to investigate the feasibility of biodegradation of butterfat using an aerobic sand column system. Two bench-scale sand columns were inoculated with lipolytic microorganisms to colonize the sand with an active biofilm, and two uninoculated columns were used as controls. Butterfat was fed daily to the columns in artificial wastewaters that were supplemented with a detergent to provide emulsification. Sand columns exhibited physical infiltration, trapping butterfat in the sand, and resulted in an apparent high degree of COD and BOD5 removal from the effluent. Accumulation of biomass on the sand grains was demonstrated by measurement of ATP. Biomass accumulated in the columns over the 259-day experiment. At the end of the experiment, the amount of biomass was comparable in inoculated and uninoculated columns. Uninoculated columns were shown to lag behind inoculated columns by about 100 days in COD removal.