The pulp and paper industry produces effluents with large BODs and CODs. One of the specific problems that has not yet been solved is the strong black/brown color of the effluent, which is primarily due to lignin and its derivatives released from the substrate and dis-charged in the effluents, mainly from the pulping, bleaching and chemical recovery stages. The brown color of the effluent may increase water temperature and decrease photosynthesis, both of which may lead to decreased concentration of dissolved oxygen. Chemical recovery is not carried out in small paper mills due to economic reasons. Several methods have been tried for the removal of chloroorganic materials, but all are quite expensive and are not feasible in common practice. Physical and chemical methods of removing chloroorganic materials, although quite effective in decolourization of pulp and paper mill effluents, are unattractive for industrial applications because of the high costs.
Biological treatment systems are particularly attractive, since in addition to colour they also reduce the BOD and COD of the effluent. Among various microorganisms used in the SuperX and SuperXL have proved their potential in the lignin/phenolic wastewater treatment. We have proved ideal organisms for decolourization as well as for the reduction of absorbable organic halides (AOX) and the chemical oxygen demand (COD). Several researches have also shown that kraft mill effluents can be partly decolorized by SuperX and SuperXL culture.
Our SuperX and SuperXL culture produce isoenzymes, including lignin peroxidise and MnP-dependent peroxidises (MnPs) and laccases, which are capable of degrading lignin as well as the chlorinated lignin’s found in pulp bleaching effluents demonstrated that purified lignin peroxidise and man-ganese peroxidise were effective in the decolourization of kraft bleach plant effluent and observed the decolourization of olive mill waste waters by these two purified enzymes. The results are assessed in terms of colour removal, reduction of COD and increase in the inorganic chloride content.