Technical Bulletin No. 0090: Evaluation of Bio-oxidation Pilot Plant Studies at Pulp and Paper Mills
There has been an increasing demand from regulatory agencies for the secondary treatment of waste effluents from pulp and paper mills. This treatment is for the purpose of removing Biochemical Oxygen Demand (BOD) which may deleteriously reduce the oxygen levels in the receiving waters where dilution is inadequate. The economically feasible methods of reducing soluble and finely divided BOD are biological in nature. Of these biological methods, modifications of the activated sludge process appear to offer the best solution at this time with regard to efficiency and capital construction costs. A number of mills are currently experimenting with these bio-oxidation processes on a pilot plant scale. The results of these operations, which are summarized in the following report, show that a variety of mill effluents can be handled by this type of treatment. They also indicate that a variety of operating conditions and aeration techniques may be successfully employed. Several important aspects of bio-oxidation remain to be resolved before this method can be generally recommended for full-scale treatment of pulp and paper mill wastes. These include disposal of waste sludge, color intensification, and economic considerations. National Council research is currently being; concentrated on these factors.