Browsing by Author "Dilini, L.M.L."

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    A Biological Treatment for Color Removal in Distillery Effluents
    (Uva Wellassa University of Sri Lanka, 2013) Dilini, L.M.L.; Premathilake, M.M.S.N.; Udagedara, D.T.
    Distilleries are one of the industries generating enormous amount of wastewater which is about 10–15 L of effluent for the production of 1 L of alcohol. The fermentation of carbohydrates present in molasses is carried out by yeasts, which yields ethyl alcohol. The pH of the raw molasses is adjusted to 4 - 4.5 to prevent bacterial growth and then fermented liquor containing alcohol is degasified and alcohol is separated, leaving behind the waste called “spent wash”. The spent wash is the major polluting waste of the distillery, which has very high Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) values. The COD often crosses and BOD reaches7×10 mgL (Goel, 2006).The waste is dark brown in color due to caremalization of some sugar. It also contains nearly 2% of the dark brown recalcitrant pigment called melanoidin, which does not get degraded easily by microorganisms, posing a great difficulty in its removal. Molasses has very high quantity of fermentable sugars. These sugars react with amino acids and undergo Maillard reaction and then polymerize to form melanoidin, which is a major color containing compound in the distillery effluent. Putrescible organics like skatole, indole and other sulfur compounds produces obnoxious smell in the effluent and when it comes in contact with high temperature, becomes more toxic to aquatic biota. The waste has substantial quantities of dissolved solids and suspended solids with high . The pH of spent wash remains in the acidic range varying from 3 to 5.4 (Goel, 2006). The distillery waste also has high quantities of potassium along with sulphates. Melanoidin containing distillery effluents require pretreatment before safe disposal into the environment, because the direct disposal causes serious soil and water pollution by inducing coloration and eutrophication problems in aquatic environments- which leads to reduction of sunlight penetration in water bodies. Additionally, it in turn decreases both photosynthetic activity and DO concentration affecting the normal life cycle of aquatic fauna and flora (Goel, 2006). Further, it causes reduction in soil alkalinity, inhibition of seed germination and damage to vegetation upon land disposal. Treatment of distillery wastewaters by physical or chemical methods was found not feasible due to the high cost and generation of secondary pollutants. But compared to them biological treatments are more economical and environmental friendly. Many fungi species have the ability of removing color from wastewaters. Especially white rot fungi exhibit extensive bioremediation activities that are mainly based upon their capabilities to produce extracellular lignin modifying enzymes (Pant and Adholeya, 2007). In this research we studied several white rot fungi activity towards decolorization of distillery effluents. Methodology Ten polyporusbasidiomycetes white rot fungi species were collected for distillery waste water treatment from Matara area.Effluent was collected from Pelwatte distillery inButtala. Effluent was dark brown in color, semi liquid and a dense material. About 5mm squares were cut from collected basidiocarps and placed on PDA plates and were incubated for 7 days. Among them, five fungal species were selected for the experiment due to their rapid growth. Above efficiently growing five fungal specieswere isolated using streak plate method. Streaked cultures were incubated again for 7 days.Then, using these cultures new plates were prepared by spread plate method incubatingagain for seven days.
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    The Biological Treatment for Color Removal of Distillery Effluent
    (Uva Wellassa University of Sri Lanka, 2013) Dilini, L.M.L.
    Distillery effluents should treat before disposal into the environment.Spent wash is the major polluting waste of distillery industry.These effuents may cause severe soil and water pollution, specially in aquatic environments. It reduces the sunlight penetration causing decreased photosynthetic activities. Various studies have been carried out on removing these effluents from the water bodies, using physical and chemical methods. But these methods are very hard,could be very expensive and could be destructive to the environment. In this study we used biological method to remove these effluents from aquatic systems which is more economical and environmentally friendly. In this study we planned to remove the colour by using five polyporus fungal species that is commonly found inMatara area. Basidiomycetes decomposing fungi has exhibited extensive bioremediation activities that are mainly based upon their capabilities to produce one or more extracellular lignin-modifying enzymes which have thepotential to decolorize distillery effluent.In this study over the fivepolypores fungal species were collected and cultured. The absorbance was mesuared for seven days, after 5 days incubation period. Results revealed that most of fungal species were removed up to 50% of color.The most efficient color reducing fungal species was fungal "C" (Lenzites botulin). Key words: Polyporusfungal, spread plate; streak plate, ligninolitic enzymes, liquid broth