Degradation of BOD and Foam in a Paper Mill Aerated Lagoon by Biological Methods, 1992 Environmental Conference Proceedings

A bleached kraft pulp mill in the southeastern U.S. had been experiencing problems in meeting their NPDES permit level of BOD discharge (7037 kg/day). They also had complaints concerning waste pond foam blowing into a nearby park and a card dealership in the surrounding community.

A biological program using a mixed microbial formulation to augment the existing biomass was implemented in mid-August, 1991. The criteria for success for this program were the reduction of BOD and the elimination of foam. In less than 2 weeks, the BOD had decreased

significantly, and it continued to decrease until the end of the month. During this period, the level of foam, 20-30 cm on the aeration lagoon was dramatically reduced by approximately 90% in just 2-3 days after the beginning of the program. Currently, the mill is in full operating control, and discharging approximately one-half as much BOD as the permit allows.

The field trial resulted in significantly decreased BOD discharge, and dramatically reduced foam levels in the aeration basin. The correlation of black liquor (organics) to BOD is shown, and is documented by laboratory studies and field data.