APPLICATION OF BIOTECHNOLOGY IN WASTE WATER TREATMENT

APPLICATION OF BIOTECHNOLOGY IN WASTE WATER TREATMENT

ABSTRACT    

                      

Most of the industrial effluents contain biodegradable substances which can be treated by conventional biological treatment methods such as activated sludge process, aerated lagoon and aeration pond. The effluents generated from pulp and paper, chemical, pharmaceutical, dyeing and dye manufacturing industries can not be treated by the conventional methods due to the presence of recalcitrant compounds. The white rot fungi, which are initially identified to have the ability to degrade lignin, can be used for the treatment of effluent, generated from these industries. It is observed that the white rot fungi have a non-specific enzyme system, which oxidizes the recalcitrant compounds present in the effluent. in this paper, application of this fungal treatment for removal of colour of waste water from pulp plant and dying industries have been attempted using white rot fungus trametes versico                                                                                                                                                                                                           

INTRODUCTION

Due to rapid industrialization and urbanization a lot of chemicals manufactured and used in day to day life which includes dyes, pesticides insecticides and other chemicals, find their way in the waste water generated from industries where such compounds are manufactured and processed. These compounds are not easily amenable to conventional biological treatment process such as activated sludge, aerated lagoon and oxidation ponds. Effluents discharged from pulp mill and dying wastewater are highly coloured due to the presence of lignin-related compounds and dyes respectively.

Many synthetic dyes have been used increasingly in textile and dyeing industries because of their case and cost effectiveness in synthesis, fineness and variety in colour compared to that of natural dyes.  Number of dyes are manufactured which include several varieties of dyes such an acidic reactive, basic disperse, azo, diazo, anthraquinone based and Meta complex dyes. The toxicological and ecological aspects of these dyes are complex to evaluate. Some of the dyes are toxic carcinogenic and mutagenic. 

Processes like dying and printing are done cloth industries. The chemicals used in dying are napthol, reactive colour, vats, pigments sulphurates, binder. HCL, Acetic acid, sodium nitrite and urea white for printing, pigment colours, reactive colours, binders. Dying and finishing wastewater from the textile industries are generally necessary to affect adequate removal of contamination.

Many methods of colour removal from dyeing and textile industries such as chemical coagulation, chemical oxidation, electrochemical irradiation, ozonation and adsorption are available  but not implemented in the industrial scale either due to cost or being environmentally unsound. The ability of the white rot fungi to degrade a wide range of products of synthic chemicals, many of which are recalcitrant to biodegradation has been reported. Treatments of hazardous waste xenobiotic compounds, organo-pollutants and mechanism by which the white rot fungi degrade pollutant have also been revived.

The white rot fungus, Tramets versicolor has a non-specific enzyme system which oxidizes the recalcitrant compounds. It has been used for the decolorisation of paper and pulp mill effluents biodegradation of azodyes, and polycyclic aromatic hydrocarbon compounds, acenaphthene and acenaphthylene. In the present investigation, the removal of colour from pulp mill effluent and dye from aqueous solution by the white rot fungus Trametes versicolor MTCC138 grown under different culture conditions is reported.

What Is biotechnology?

It is a technology which employs biomaterial and biological principles to produce beneficial product of human need.It is the effective use of technology by using biological agents for well being of human kind.

CHARACTRISTICS OF PULP AND PAPER INDUSTRIES

 Pulp and paper is a major polluting industry in India. The effluent from the pulp plant of a paper mill is dark brown in colour and contains chlorinated organic compounds formed due to usage of chlorine and its derivates in the pulp bleaching process. The chlorinated organic compounds are identified as potentially hazardous. Carcinogenic, mutagenic, persistent and bioaccumulative sample collected at site were brought to laboratory analyzed for various parameters like COD, BOD SS and pH etc. as per standard methods by AAHHA (1981).

The conventional biological treatment system currently used in the pulp and paper industry such as activated sludge process, aerated lagoon, anaerobic lagoon, stabilization ponds etc. are successful in reducing the biochemical oxygen demand (BOD)from the effluent whereas colour and chlorinated organic compounds are not removed. Colour can be removed by precipitating with metal salts of aluminum, ferric and ferrous. By using these metals salts experiment reports are high removal efficiency. Salts remove color but retain its own colour. Mixed culture used in the biological treatment system are capable of metabolizing soluble sugars and some low molecular in the effluent, leading to reduction of BOD but lacks in an enzyme system capable of oxidizing colour causing compounds (chloro-lignin).

Water pollution and other environmental regulations in India are beginning to require industry to substantially reduce the colour of effluents from industries aesthetically unacceptable, reduce the light transmission through the contaminated waterways thereby reducing the photosynthesis which will lead to depletion of dissolved oxygen and pose a health hazard to the aquatic life in the receiving water bodies.

MATERIAL AND METHODS

a) Culture:

The white rot fungus culture, trametes versicolor MTCC 138 was procured from Institute of Microbial Technology, Chandigarh, India. The organism was maintained on agar slants containing yeast extract (5g/L), glucose (10g/L) and agar=agar (15g/L) and maintained at 4⁰c. The p^H of the medium before solidification was adjusted to 5.8.

b) Medium Composition:

The basic growth medium composition consists of 10g/L Glucose: 1g/L KH₂PO_4:1.75 g/L NH₄CL:0.5g/L KCL; and 0.5g/LMgSO₄7H₂O. The initial p^H of the medium was adjusted to 4.5.

c) Pulp mill effluent:

           

The effluent samples used for the present studies procured from Tamilnadu, Newsprint and paper Limited, Kagithapuram (Tamilnadu), India. The highly coloured effluent from pulp plant utilizing bagasse as the raw material was collected in airtight plastic cans (30L) and stored at 4±1^oC.The characteristics of effluents were determined according to standard methods for the examination of water and wastewater. 17^th edition APHA, Washington D.C. except for colour, and are reported in table 1.

                

      

Table1 CHARACTERISTICS OF PULP MILL EFFLUENT

Parameter	Range
PH	8.5-9.5
Colour concentration(pt-co units)	4500-4700
Total Solids(mg/L)	3200-3800
BOD (mg/L)	260-360
COD(mg/L)	4500-4800

COLOUR MEASUREMENTS

The colour of pulp mill effluent was measured according to National Council Of the paper industry For Air and Stream Improvement Standard Method (NCASI). The P^H of the original effluent sample was in the range of 8.5-9.5 and was adjusted 7.6 followed by filtration 0.45 µm filters. The absorbance of the filtrate was measured at 465 nm against distilled water using 1-cm light path cuvette in a UV spectrophotometer (shimadzu, Japan). PlatiniumCobalt Colour Units were calculated as follows.

           Colour units (CU) =500*A2/A2

Where,   

           A1-Absobance of sample at 465nm

           A2-absorbance500CU pt-co standard at 465nm.

a)      Dyes: 

           Remazol orange Remazol brown which are commonly used in industries, were selected for the study. Dyes were obtained from Colourchem, Mumbai, India.

b)     Dye measurements:

         The dye removal / disappearance was determined spectrophoto-meterically  by monitoring the absorbance at or near the wavelength (maximum absorbance )   for each dye i.e. at 490 nm and 480 nm forremazol orange and Remazol brown respectively.

EXPERIMENTAL

 The experiments on effect of varying concentrations of glucose and sucrose on colour and COD removal from pulp mill effluent (sample) were carried out in shake flasks (250ml). The basic nutrients were added to 100ml. of the effluent sample with varying concentrations of glucose (2.5to50g/L) and sucrose (2.5 to 25g/L). Similarly batch experiments were carried out in shake flask (250ml) containing10ml of aqueous solution containing the medium mentioned above and dyes with 250 and 500mg/L concentrations. The P^H of the effluent was adjust to 4.5(optimum) and autoclaved at 121^oC for 15 min. after autoclaving. The flaks were inoculated with the white rot fungus. Trametes versicolor kept in rotor shaker (180rpm). After 7 days, the effluents were withdrawn, filtered through 0.45µm filters and analyzed for colour and COD using methods mentioned earlier.

RESULTS AND DISCUSSION

       Treatments with pulp mill effluent from the pulp mill utilizing bagasse as the raw material are shown in Table 1. The effluent characteristics show more non- biodegradable substances, which were represented by the chemical oxygen demand (COD) of effluent. From the biochemical oxygen demand BOD/COD ratio of the effluent is less, which shows that the effluent is not suitable to conventional biological treatment.

Effect of glucose concentration

 

The effect of initial glucose concentration on colour removal efficiency is shown fig.1. In the present study, the maximum colour removal 92.3%was obtained at a glucose concentration of 50 g/L. From fig. 1. It is observed that the colour removal efficiency does not increase significantly after 15g/L of glucose concentration where about 85.2%were obtained. Also it is observed that the presences of easily metabolically sugars are required for the growth of fungus and colour removal which is supported by the earlier investigations. Colour removal is secondary metabolic process and the fungus requires glucose or cellulose for energy. Incubation with this fungus has not only reduced but also reduced COD of the effluent considerably The maximum COD removal of 78%was observed at the glucose concentration of 10g/L and further addition of glucose has increased COD of the treated effluent due to the presence of unmetabolisable glucose left with.

Effect of sucrose concentration

 

                 Fig. 2 Effect of sucrose concentration on removal of efficiency

              (P^H-4.5,NH₄CL 05g/L; Initial colour -4700 pt- Co and basic nutrients)

   The effect of initial sucrose concentration on colour removal efficiency is shown in fig.2 from fig 2, it is found that the maximum colour removal efficiency significantly. In the control fiask that is the flask without addition of sucrose showed no growth of fungus and hence there was no colour removal supporting the earlier statements that fungus requires easily biodegradable sugars for high growth. The maximum COD removal of 73.3%was obtained at the sucrose concentration of 5g/L and as mentioned earlier further addition of sucrose has increased the COD of treated effluent due to the presence of the unused sucrose.

CONCLUSION

  White rot fungus was found to be a suitable absorbent for the absorption of dye from aqueous solution. The data collected on the dye removal from aqueous solution with special reference to the ability of white rot fungus Trametes versicolor to remove remazol orange and remazol brown have been shown in Fig.3. it was observed that extensive removal of two dyes by the culture of Trametes versicolor as evidenced by the decrease in the absorbance of the culture medium. In the case of remazol brown, 97.6 and 98.7% co lour removal efficiencies have been attained at 250 mg/L and 500 mg/L dye concentration over a incubation period of 7 days respectively, whereas in case of remazol orange, decolourisation was only 70.4 and 81.3%.

Use of treated water in a place of fresh water reduces the fresh water demand in industry, there by reducing the chemical consumption and saving in fresh water cost.  

REFERENCES

1) Introduction to Environmental Biotechnology ’-by A.K.  Chatterji.

2) ‘Removal of colour from wastewater using Tramates Versicolor’ - Paper by S.V. Srinivasan and D.V.S.Murthy. (Journal IAEM. Vol.27, 260-264 (2000).

 3) www.atrp.gatch.edu/biosensor.html.

 4)  www.grzyby.pl/gatunki/trametesversicolor.html.

 5)  www.discoverlife.org/nh/tx/fungi