Use of Microbes for Black Liquor Clarification
Gaikwad Bhaskar G.1*, Magdum Anagha G.2
1C.E. Division, National Chemical Laboratory, Pune-411008, India
2Y.M.College, Bharati Vidyapeeth Deemed University, Kothrud
*Corresponding Author E-mail: bg.gaikwad@ncl.res.in
ABSTRACT:
Effluent from pulp and paper industry called as black liquor (BL). Black liquor contains salts and organic material. It is dark coloured and hazardous in nature. Precipitation of black liquor (BL) was studied. Different concentrations of hydrochloric acid attempted. 0.73, 1.46, 1.82, 2.19, 2.55, 2.92 % HCl was used. Precipitation observed. pH, residue amount and decolorization were studied. 2.55, 2.92% HCl were able to precipitate the black liquor (BL) to a maximum level. pH of the supernatant was 6.0 and 5.0 respectively. We have studied biodegradation of this undiluted black liquor at different pH 5 and 6. Different bacterial and yeast cultures were used for screening. 18 cultures used for biodegradation of black liquor at pH 6.0. Cell concentration was 2.5% (wet weight basis). 80% black liquor used. Biodegradation was carried out at 280C for 24h under shaking condition. Candida utilis NCIM 3055 has shown 9.81% decolorization. We have used pH 5.0 for screening at 280C for 24h under shaking condition. 21 cultures were used for screening. Among the 21 cultures, Pseudomonas putida NCIM 2205, Pseudomonas testosteronii NCIM 5099 and Saccharomyces carlsbergensis NCIM 3455 have shown 27.74, 37.74 and 24.57% decolorization. Pseudomonas testosteronii NCIM 5099 has shown maximum decolorization. It has produced clear liquid after treatment.
KEYWORDS: Pollution, black liquor, growth, decolorization, yeast, bacteria etc.
Effluent from pulp and paper industry is colored and toxic. It is called as sulphite waste liquor or black liquor. It should be treated to get a clear solution. It has done by chemical treatment and microbial treatment. A single method is not useful to solve this problem. The combination of both chemical and microbial method is used for solving this problem. Many researchers have reported a study on this [Kumar et al. (2014)1, Tyagi et al. (2014)2, Negrao et al. (2015)3, Hooda et al. (2015)4, etc.]. In this paper, we have studied treatment of black liquor by the chemical method and microbial method.
MATERIALS AND METHODS:
Chemicals and Cultures:
Chemicals from Hi-Media, Mumbai and S.D. Fine Chemicals, Mumbai were used for an experiment. Cultures brought from NCIM (National Collection of Industrial Microorganisms), Pune.
Growth:
Bacterial cultures maintained on Nutrient –agar medium (beef extract 10, NaCl 5, peptone 10 g/L, pH 7.0, agar 20g/L.) at 40C. Yeast cultures maintained on MGYP-agar (Malt extract 0.3, glucose 1, yeast extract 0.3 and Peptone 0.5 %, pH adjusted to 6.5. 2.0% agar used). Bacterial cultures were grown in nutrient broth. Yeast cultures were grown in MGYP. Pre inoculum used for growth. Growth was carried out at 280C, 220 rpm for 24h. Cells were centrifuged and used for the study.
Analysis:
Biodegradation:
Biodegradation of 80% BL was done using 2.5% cells. It was done at 280C, 220 rpm for 24 h. Colour was determined. BL of pH 6.0 and 5.0 used in the study.
Experimental
We have precipitated black liquor and solution obtained after separating precipitate used for biodegradation.
Precipitation of Black liquor
Table 1: Precipitation of undiluted BL: pH of supernatant
|
HCl conc. (%) |
pH |
|
0 |
11.39 |
|
0.73 |
10.5 |
|
1.46 |
9.6 |
|
1.82 |
9.13 |
|
2.19 |
8.0 |
|
2.55 |
6.0 |
|
2.92 |
5.0 |
Undiluted black liquor was taken. Diluted HCl added. It mixed well and kept for 1h at 280C for 1h without shaking. Centrifuged it and supernatant analysed. The residue weighed. pH has shown in table 1. Effect of HCl concentration on precipitation and decolorization plotted in figure 1.
Figure 1: Effect of HCl concentration on precipitation and decolorization
Biodegradation of BL at pH 6.0
18 cultures (bacterial and yeast) used for the study. Biodegradation of 80% BL pH 6.0 was done using 2.5% cells. Biodegradation carried out at 280C, 220 rpm for 24 h. Colour was determined.
Biodegradation of BL at pH 5.0
21 cultures (bacterial and yeast) were used for the study. Biodegradation of 80% BL was done at pH 5.0 using 2.5% cells. The reaction was carried out at 280C, 220 rpm for 24 h. Colour was determined. Results are in table 2. The comparison has shown in figure 2.
Figure 2: Comparison of results of best cultures.
A= Pseudomonus putida NCIM 2205, B= Pseudomonus testosteronii NCIM 5099,
C= Sacchromyces carlsbergensis NCIM 3455
Table 2: Biodegradation of black liquor (BL) at pH 5.0
|
Cultures |
NCIM no. |
Biodegradation (%) |
|
Alcaligenes sp. |
5085 |
0 |
|
Arthrobacter viscosus |
2451 |
7.27 |
|
Candida shethiae |
3500 |
20.61 |
|
Candida magnoliae |
3470 |
0 |
|
Candida utilis |
3055 |
11.81 |
|
Escherichia coli |
2569 |
12.71 |
|
Escherichia coli |
2067 |
16.81 |
|
Pacchysolan tannophilus |
3504 |
19.29 |
|
Pseudomonas fluorescens |
5101 |
3.5 |
|
Pseudomonas fluorescence |
5100 |
9.31 |
|
Pseudomonas oleovoran |
2867 |
22.45 |
|
Pseudomonas putida |
2205 |
27.74 |
|
Pseudomonas resinovoran |
2599 |
23.03 |
|
Pseudomonas solarisolan |
5103 |
8.33 |
|
Pseudomonas sp. |
2304 |
7.35 |
|
Pseudomonas sp. |
2667 |
19.91 |
|
Pseudomonas syringae |
5102 |
19.54 |
|
Pseudomonas testosteronii |
5099 |
37.74 |
|
Pseudomonas testosteronii |
5098 |
18.32 |
|
Sacchromyces carlsbergensis |
3455 |
24.57 |
|
Sacchromyces cerevisiae |
3077 |
2.45 |
RESULTS AND DISCUSSION
As HCl concentration increased, pH decreased (table 1). As HCl concentration increased precipitation and decolorization increased (figure 1). pH caused precipitation of salts and lignin which in turn reduced colour. At certain point, precipitation reached maximum level. The amount of HCl may vary batch to batch because every batch has its own characteristics. We have used pH 6 and 5 for the screening of cultures for biodegradation of black liquor. At pH 6 (2.55% HCl), colour changed from dark black to dark brown. 18 cultures used at pH 6.0. One culture (Candida utilis NCIM 3055) has shown 9.81 % decolorization. This indicated that some inhibitory components were in excess which inhibited most of the cultures. At pH 5.0 (2.92% HCl), we got brown colour (table 1). 21 cultures used for screening at pH 5.0. Pseudomonas putida 2205, Pseudomonas testosteronii 5099, Saccharomyces carlsbergensis NCIM 3455 have shown 27.74, 37.74, 24.57% decolorization respectively (table 2). Results of best cultures are compared in figure 2. All have shown clear liquid. Pseudomonas testosteronii NCIM 5099 has shown maximum 37.74% decolorization. Colour of black liquor reduced significantly. Therefore, it is the best culture.
A bacterial mixture of Klebsiella sp., Alcaligens sp., Cronobactor sp. was able to decolourise pulp and paper industry effluent to 55% in 14h [Kumar et al. (2014)1]. 64.3% decolorization of black liquor reported by Tomar and Mittal (2014)6 where they used Aspergillus niger. Liu et al. (2014)7 studied biodegradation of black liquor. They used acid for precipitation of BL. They observed 85.07% anaerobic biodegradation in upflow sludge bed reactor. Rajwar and Rai (2015)8 observed 73% decolorization of BL using mixed fungal cultures. Yadav and Chandra (2015)9 studied biodegradation of lignin. They observed 80% reduction in colour of paper mill wastewater using the mixed culture of Bacillus subtilis GU 193980 and Klebsiella pneumonia GU 193981. Decolorization of kraft liquor was studied by Fonseca et al. (2015)10. They used laccase from Phlebia brevispora BAFC 633. Biodegradation of pulp and paper effluent was studied by Hooda et al. (2015)4. They observed 47% decolorization by Brevibacillus agri RJH-1.
CONCLUSION:
Precipitation of BL was done. 2.55, 2.92 % HCl were able to precipitate maximum level. Biodegradation of BL studied at pH 6.0, 5.0. 21 cultures used for screening at pH 5.0. Pseudomonas putida 2205; Pseudomonas testosteronii 5099; Sacchromyces carlsbergensis NCIM 3455 have shown 27.74, 37.74, 24.57% decolorization respectively. All have shown clear liquid. Pseudomonas testosteronii NCIM 5099 has shown maximum decolorization. Colour of black liquor reduced significantly. Therefore, it is the best culture.
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Received on 17.03.2016 Modified on 04.04.2016
Accepted on 30.04.2016 © AJRC All right reserved
Asian J. Research Chem. 9(4): April, 2016; Page 182-184
DOI: 10.5958/0974-4150.2016.00029.8