Performance of an Upgraded Activated Sludge System with a Biological Selector Treating High-Strength Pulp Mill Wastewater, 2001 Environmental Conference Proceedings

Kar Munirathinam, Dave Weeden, Eric Bolin--Buckeye Lumberton operates a 140-ton per day cotton fiber pulp manufacturing facility in Lumberton, North Carolina. The wastewaters generated from the production plant are being treated in the activated sludge process. Due to some historical compliance issues with BOD and TSS, which occurred primarily in the winter months, the wastewater treatment facility (WWTF) was evaluated to define potential operational changes and upgrades that would allow achievement of the permit limits consistently. The WWTF was upgraded with an aerobic biological selector to improve sludge settling characteristics.

The aerobic selector significantly improved the sludge settling characteristics, which allowed an increase of the MLSS concentration in the aeration basin during the winter months without solids carry over in the final effluent. The average BOD removal was 99.10 percent with a maximum value of 99.82 percent. The BOD removal wasconsistent throughout the year with no impact of low temperature during the winter months due to higher operating MLSS concentration in the aeration basin. The final effluent BOD and TSS loads were significantly lower than the permit limits. The defoamer and flocculant chemical usage was significantly reduced after the WWTF upgrade.