Upgrading of an activated sludge plant with floating biofilm carriers at Frantschach Swiecie SA to meet the new demands of year 2000

Frantschach Swiecie S.A., the largest Pulp & Paper producer in Poland and o ne of the larger in Europe, chose to upgrade the existing WWTP with a new f loating biological bed equipped with an advanced steering system. The disch arge from the WWTP will be one of the lowest in Europe, 4 kg COD/tonne prod uced pulp, and is already below the future goals for the European Union. Th e new demands have been reached with an advanced steering system controllin g three selective biological reactors operating in series and/or parallel. Each biological reactor is operating at specific conditions to decrease sel ected organic compounds. The new floating biological bed, FlooBed(R), is an upgraded activated sludge system with floating carriers covered with a thi n biological film. The FlooBed(R) reactor is a progress from fluidised beds and modified activated sludge plants. The activated sludge plant as such has not been rebuilt. The improvement of the activated sludge process is that the wastewater now is saturated with oxygen and new micro-organisms are created before the entry to the existing activated sludge plant. The FlooBed(R) reactors are installed in a volume that is 50% of the former activated sludge plant volume and the reduction of COD has increased from 51 to 90%: The operational costs for the FlooBed(R) are 17 EUR/tonne reduce d COD where 7 EUR is electricity and the remaining part is added chemicals. (C) 1999 Published by Elsevier Science Ltd on behalf of the IAWQ. All righ ts reserved.