Abstract:
The studies were concerned in biological-decolorization of molasses wastewater by aceticacid bacteria No.PB103. At first, the optimal conditions such as carbon sources, nitrogen sources, pHand inoculum size, were determined for highest decolorization yield. The results showed that theoptimal concentration of carbon sources, nitrogen sources, pH and inoculum were glucose 3%, yeastextract 0.5%, pH 6 and 2 ml of inoculurn in 20 ml of synthetic molasses wastewater (7.6 x 103,respectively. The decolorization yield, COD removal efficiency and BOD, removal under aboveoptimal condition were 78.31 %, 45.71% and 33.28% respectively. The COD and BOD,concentration in influent were 23,104 and 557.64 mg, respectively.When the stillage and molasses wastewater from anaerobic pond were investigated, it wasfound that the molasses wastewater from anaerobic pond that was supplemented with nutrients couldbe easier decolorized than both nutrients supplemented stillage and non-nutrients supplementedstillage. The decolorization activity of acetic acid bacteria in supplemented and non-supplementednutrients stillage were 32.33% and 9.77%, respectively. But the decolorization activeity, BOD, andCOD removal efficiencies of molasses wastewater from anaerobic pond that supplemented withnutrients were 75.38%, 33.33% and 64.29 %, respectively. The effluent COD and BOD, from aboveexperiment were 15,384 and 1,990 rng, respectively.For the determination of molecular weight distribution, the results showed that the largemolecular weight pigment in both molasses wastewater (stillage and molasses wastewater fromanaerobic pond ) were reduced when it was cultivated with acetic acid bacteria No.BP103. And thelarge molecular weight pigment in nutrients supplemented molasses wastewater could be removedeasier than in non-nutrient molasses wastewater.For the continuous decolorization process, acetic acid bacteria showed the decolorizationactivity at 74.47% within 4 day cultivation And the BOD, was reduced to 544.53 mgtl. But thedecolorization activity of the system was decreased after 8 day cultivation. For the semi-continuousdecolorization process,acetic acid bacteria showed the decolorization activity higher than continuoussystem. The decolorization activity was the highest ( 84.99%) after 21 day cultivation. And this simicontinuousdecolization process could be operated with the stable decolorization activity even thesystem was replaced for four times.