Conversion of an Aerated Lagoon to an Activated Sludge System, 1996 Environmental Conference Proceedings

Kieffer Paper Mills operated an 80 admtpd mill producing packaging grade paper products from old newsprint utilizing a conventional ASB for wastewater treatment until 1992. In 1992, Kieffer and Ahlstrom installed a new 140 admtpd recovered fiber market pulp mill using sorted mixed office waste furnish. The increased COD and BOD load from the existing operation, plus the new mill, overloaded the existing treatment system. To meet state mandated discharge limitations to the East Fork White River, a small tributary, a change in the effluent treatment system would be required. A low cost solution was needed to solve the problem without putting too great a financial burden on the small mill. Ahlstrom Aquaflow was contracted to modify the ASB system for operation as an Activated Sludge Process. This was accomplished by changing the air distribution and increasing total aeration capacity in the existing lagoon and adding a new secondary clarifier and return sludge system to complete the conversion to activated sludge operation. Waste sludge was dewatered on the existing recovered fiber pulp mill belt dewatering press. The original “polishing lagoons” following the ASB were eventually bypassed after it was found that water quality actually deteriorated between the new secondary clarifier and the river outfall.