Treatment feasibility of nssc pulping effluent using uasb reactor

Abstract

The safe disposal of black liquor generating from NSSC pulping section of the paper mills is one of the challenging issue in the developing countries. A treatment feasibility study was conducted on a laboratory scale UASB (upflow anaerobic sludge blanket) reactor running on continuous flow basis for about 30 weeks at neutral pH and at constant temperature of 33oC. It is observed that about 35% of black-liquor COD could be reduced at a hydraulic retention time of 38 hours and at an organic loading rate of 2.75 kg-COD/m3-day. The average gas production and methane gas conversion at optimum conditions was observed to be 0.17 m3/kg-CODrem-day and 0.88 L-CH4/g-CODrem-day, respectively. The overall methane composition was noticed to be 61% of the biogas. This study suggests that the post-treatment of NSSC pulping effluent is required to meet the safe effluent disposal standards.