Anaerobic treatment of recycled paper mill effluent with the internal circulation reactor
Anaerobic effluent treatment using the BIOPAQ® UASB (Anaerobic Upflow Sludge Bed) process has been used on a large variety of effluents from the pulp and paper industry. Newly developed sludge bed reactors which allow higher upflow velocities have been successfully introduced into the pulp and paper industry. An example of such a reactor is the internal circulation reactor (BIOPAQ® IC reactor). This paper presents the design and operational performance data of IC reactors treating effluent at three different recycled paper mills. Stable process performance was achieved despite large fluctuations in COD load and COD concentrations.