IMPROVED BIOLOGICAL TREATMENT EFFICIENCY OF PULP MILL WASTE WITH CO-FEEDING STRATEGY ALONG WITH POLYHYDROXYBUTYRATE CO-PRODUCTION

Abstract

This study is focused on the use of pulp process waste as the medium for growth of Halomonas sp. MCC 2171. It was found that halophile is efficiently able to grow in the press filtrate that was produced during the dewatering stage of pulp. Initial characterization of pulp process waste shows that, it can be used as the suitable growth medium, without any further treatment. However, to enhance the reduction of organic content of the waste, co-feeding strategy was employed. Glycerol, a major by-product of the biodiesel industries was used as the co-substrate. Addition of glycerol not only increased the reduction of Biological Oxygen Demand and Chemical Oxygen Demand but also resulted in production of polyhydroxybutyrate (PHB). Further study was performed by addition of black liquor and crude glycerol in the press filtrate medium. Also assimilations of carbohydrate and lignin degradation products during growth of Halomonas sp. was observed in press filtrate medium. Thus using this strategy, it is possible to detoxify the press filtrate and conversion of some organic carbon compounds of pulp process waste into PHB and biomass. Treated wastewater can be recycled to the pulp washing stage which can improve the washing efficiency of pulp.