ISSN (0970-2083)

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DECOLOURISATION AND DEODOURISATION OF DILUTED SPENT WASH USING CHEMICAL AND BIOLOGICAL AGENTS

M. Vasanthy and C. Thamaraiselvi

P.G. and Research Department of Environmental Science, Govt. Arts College. Ariyalur, T.N., India

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Abstract

In India there are 290 distilleries producing 2.75 billion liters ol alcohol generating 45 billion liters ol waste water annually. The distiller) disposing waste water, in to the natural streams, on to the land (or agricultural land), pollutes the mother earth. Also it is essential to sustain the mother earth lor the future oT our next generation. The technology for treatment ol such a waste water is ol prime concern. Hence, the present study was locussed on dccolouri/ation and deodourisation ol spent wash using oxidixing. coagulating agents and biological material AM the treatment has shown complete odour removal. No colour removal has been noticed with powdered strychnus potatorum treatment. The result ol chemical treatment rexealed the highest colour removal than biological agents. Complete colour removal has been noticed when the 5% diluted spent wash treated with 1.5 g and 2 g of calcium hypo ehlorite (bleaching powder).

Keywords

Decolourisation, Deodourisation, Chemical and biological agents.

Introduction

Water is a vitally important commodity to all organisms. It is the medium which gave birth to the first primitive living molecules and withoul which lile can never exist. Many anthropogenic activities especially industrialization play a main role to pollute the aquatic ecosystem to a maximum. One such industry, distillery consumes large amount ol water and consequently generate huge quantities of spent wash.

The spent wash is ehacterised by the intense colour, objectionable odour. higher TDS, TSS, TS, HOD, COD, nitrate. chloride etc. (Nanjundaswamy et. al. 1998). Ramchandra and Singh 1999 have been reported that colour and odour poses a serious threat to the environment as the coloured waste allects the aquatic organism.light penetration and reduces the aesthetic value.

The colour is reddish brown to dark brown, due to the presence ol melanoidins and polyphenolie compounds (Kasturibai and Ganga 1996). The unpleasent odour caused by distillery spent wash has been Ibund due to the presence ol odour causing compounds such as hydrogen sulfide ammonia, mercaptans, amines, aldehydes, ketones. indole and skatoie has been reported by (Youngwoo et al. 1994). IHence the treatment of spent wash is utmost essential.

Materials and Methods

Physieo-chemical characterisation of distillery spent wash

The speniwash was collected Iron; a distiller) located al i rich). faimlNadu. The physico-chemical characiensitics such as pH, EC, TS, TDS, TSS, COD were determined (APHA 1989). The intensity of the colour was measured at 420 nm (max).

Dilntion of the distillery spent wash

Spentwash was diluted with distilled water to obtain the 5% dilution. This dilutions was prepared by diluting 5ml of spentwash to 100mL with distilled water.

Effect of oxidising agents and coagulating agents on colour and odour removal of 5 % diluted spent wash

About 100 mL of diluted spentwash was taken in 12 different conical flasks. Accurately 0.5g. Ig. 1.5g.2g. of calcium hypochlorile was added to the first four flask. Stirring was done immediately and left for 2 hrs.

Accurately 0.5 g, lg, 2g of calcium oxide was added to the another four flasks, mixed and left for 2 hrs.

About 0.5 mL, 1 mL, 1.5 mL.2 mL of Hydrogen peroxide was added to the remaining concial flasks stirred and left for 2 hrs.

After 2 hrs they were filtered and colour was detemined using spectrophotometer at 420 nm.

Effect of biological agents on colour and odour removal

About 100mL of spent wash was taken in 4 conical llask. Accurately 0.5g, Ig. 1.5, 2g of powdered stryclinus potatorum was added and mixed. Left for 2 hrs and filtered. The filtrate was subjected to colour analysis.

Result and Discussion

Physico chemical characterisation of spentwash

The characteristics of the distillery spentwash have been presented in 1 able 1 , I he colour and odour of the spcntwash is dark brown and unpleasant alcholic odour respectively, colour of the spent wash may be due to presence of mcianoidin pigments. Melaiioidins are formed due to decompositions products such as hvdroxv methyl funfural (Saxena and Rai, 2000).

Youngwuo at al. 1994) have reported the objectionable odour was produced by the anaerobe decomposition of compounds containing nitrogen and sulphide, mercuptans. amines, aldehydes, ketones. indole, and skatole. The pH of the spent wash was acidic which may be due to fermentation process and the total .solids, total dissolved solids were so high, which may be the reason for the higher BOD and COD. Hence the DO was nil.

Effect of oxidising agents and coagulating agents on colour and odour Removal of 5 % diluted spent wash

Complete colour removal has been noticed when the spent wash was treated with l.5g and 2g of calcium hypo chlorite. It was achieved by the oxidizing power of calcium hypochlorite. The oxidiz.ing agent may have oxidized the pigments imparting the colour.

icontrolpollution-distillery-spent-wash

Table 1 Physico chemical charactristics of distillery spent wash

icontrolpollution-oxidizing-agents

Table 2 Effect of oxidizing agents, coaulating agent and biological agents on colour and odour removal of diluted distillery spent wash

Diluted spent wash treated with calcium oxide has shown complete deodourisation and slight reduction of colour.The colour removal has decreased with decrease in amount of calcium oxide. It may be due to the hydoxy radicals which are generated capable of degrading the contaminants through oxidation (Inthorn et al. 2001). 5% diluted spent wash treated with 0.5 ml of H2O2 has resulted in no colour removal. It may be due to insufficient dosage of H2O2. Complete removal of odour has been achieved but only 10 % of colour removal have been noticed.

Effect of biological agents on colour and odour removal from the 5 % diluted spent wash

No colour removal was noticed and complete odour removal was noticed when 5 % diluted spent wash was treated with powdered Stryclinus potatorum. The coagulating property of the powdered strychnus potatorum (poly electroyte) has been already reported by Rangwala et al. I997.

Conclusion

Calcium hypo chlorite,hydrogen peroxide, Calcium oxide and powdered Strychnus potatorum were used lor the decolonisation and deodourisation. Chemical treatment has shown the highest reduction of colour when compared to biological treatment.But complete deodourisation has taken place by all the treatments.1 Henee.chemical treatments are better than biological treatment for the removal of colour and odour from the diluted spent wash wich has been diluted with distilled water.

References

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