Operating Experience at Lake Utopia Paper Increases Confidence in UASB Process, 1994 Environmental Conference Proceedings

Michael Smith, Andre de Vegt, Pierre Fournier

Lake Utopia Paper Company – located in St. George, New Brunswick, Canada – produces 450 tons of corrugated medium from neutral sulfite semi-chemical pulp and recycled fiber. The process generates a concentrated waste stream that requires treatment prior to discharge into the L’Etang Estuary. Effluent treatment consists of a primary clarifier followed by two 1520 m(3) BIOPAQ upflow anaerobic sludge blanket reactors. Post-treatment is achieved with an aerated lagoon which is currently in the process of being converted to an activated sludge system, for fish toxicity removal purposes.

The treatment system underwent an extended startup period. Poor upfront solids removal resulted in sub-optimal performance by the UASB. Over the past two years, the anaerobic reactor has performed at or above expected levels. Volumetric loading rates of over 20 kg COD/m(3).d result in COD and BOD reductions of 55 and 80% respectively, through the UASB. A biogas production rate of 15,100 m(3)/d enables the mill to off-set some of its oil consumption at the plant boilers. Furthermore, steady operation of the anaerobic reactor has allowed the estuary to begin to sport its compliment of marine life.

This paper will present a description of the treatment plant and operating data over the past two years.