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Bioefficacy Potential of Textile Effluent Adapted Bacterial Strains for COD Reduction

发布时间:2018-01-01
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Bioefficacy potential of textile effluent adapted bacterial strains for COD reduction

Cleaner production is the need of an hour for sustainable development. Textile industry in particular becomes one of the culprits to be considered in terms of damage it causes to the environment. The strategic approach for cleaner production has gained momemtum in recent years for environmental protection and preservation of ecological resources from excessive depletion and, has shown its ability to decrease environmental pollution, preserve natural resources (Li et al., 2011). The current problem faced with industrial waste waters is absence of treatment prior to its being released into environment .Industrial effluents urban runoff, direct disposal of untreated textile effluent into adjoining water bodies specially the drains, fertilizers and animal wastes constitute the major reservoir of contaminants (Jaishree and Khan, 2014 ). Excessive usage of enormous volumes of water and chemically different types of synthetic dyes contributes to water pollution caused by textile industry. The major constituents of textile based effluents are several types of chemicals such as dyes, dispersants, leveling agents, acids and alkali (Olukanni et al., 2006) that are discharged into water bodies without treatment which increases the chemical oxygen demand (COD) and biochemical oxygen demand (BOD), alters the pH and gives the water bodies (rivers) intense colourations. Coloured wastewater from textile industries is considered to be the most polluting in almost all industrial sectors (Andleeb et al., 2010). Sanganer textile industry which is one of the largest handloom manufacturing zone from western India covers more than 154 block printing units. It is because of the toxic nature of effluents generated by textile cluster, it has gained much attention (Talware et al., 2008). Effluent from these industries is being discharged without treatment into agricultural fields and used for irrigational purposes and pollutes both ground water and soil due to the percolation of some water soluble pollutants (Pande et al., 2009). COD being one the major pollution indicator reflects the quality of water both in terms of its use for irrigational purposes and release into adjoining surface waters. The fact has been established that untreated textile waste water has very high COD( Sharma et al., 2013; Goyal et al., 2013; Paul et al.,2012;Agarry and Ajani, 2011; Varma and Sharma, 2011; Rao and Prasad, 2010). Sanganer being one of the major textile clusters of Rajasthan is deprived of an Effluent Treatment Plant (ETP), the waste water generated from textile and dyeing units is directly introduced into the adjoining surface water and primarily is used for irrigational purposes. Studies pertaining to reduction in COD by indigenous micro flora have been well established both nationally and internationally. (Sharma et al., 2010) studied the effect of indigenous bacteria on simulated textile effluent in terms of COD reduction and dye degradation. (Fakhruddin et al., 2010) studied the effect of algae and aquatic macrophytes on COD reduction of textile effluent collected from post discharge of equalization tanks and witnessed a decrease of 69% in COD. (Musa and Ahmad,2010) studied the effect of indigenous bacteria on waste water of pineapple industry in terms of reduction in COD by microcosm analysis. Keeping in view, the above cited facts, our study is aimed to characterize the untreated textile effluent and to isolate and identify a potential bacterial strain the effect of which would be studied to minimize the level of COD through microcosm analysis.

Methodology

COD reduction by indigenous bacterial strains: COD determines the amount of oxygen required for the chemical oxidation of organic matter and presence of non biodegradable matter It is also an important pollution indicator which reflects the chemical quality of effluent. In the present study, bioefficacy of an autochthonous bacterial strain has been accounted.

Inoculum preparation: A loopful of pure culture of all strains TexA, TexB, TexC, TexD, TexE, Cons T was inoculated into Nutrient Broth (NB) with the following composition (gm/l): peptone-5, meat extract-1, yeast extract-2, Nacl-5, ,pH-7) and incubated as described earlier. Growth kinetics of all the strains was studied till a desired O.D.660= 0.6 was attained (Suizhou et al., 2006) .Different inoculums were prepared by varying the concentration from 0.1%, 0.5% and 1%.

Microcosm analysis: Microcosm analysis of untreated textile effluent was carried out in accordance with protocol devised by Musa and Ahmad, 2010. The effluent sample was equally distributed (400 ml each) into a set of 3 erlenmeyer flasks (1000ml capacity) and labeled as I, II and III A separate flask containing only the effluent sample was maintained as negative or abiotic control .In flask I, 0.1 % (v/v) inoculums was added, to flask II, 0.5 % (v/v) inoculum was added and to flask III, 1 % (v/v) inoculums was added whereas flask IV was devoid of inoculum. All the flasks were labeled as

  • Tex A 0.1%(I)
  • Tex A 0.5%(II)
  • Tex A 1%(III)
  • Tex Ct (IV)
  • Tex B 0.1%(I)
  • Tex B 0.5%(II)
  • Tex B 1%(III)
  • Tex Ct (IV)
  • Tex C 0.1%(I)
  • Tex C 0.5%(II)
  • Tex C1%(III)
  • Tex Ct (IV)
  • Tex D 0.1%(I)
  • Tex D 0.5%(II)
  • Tex D 1%(III)
  • Tex Ct (IV)
  • Tex E 0.1%(I)
  • Tex E 0.5%(II)
  • Tex E 1%(III)
  • Tex Ct (IV)
  • Cons T (0.1%)(I)
  • Cons T (0.5 %) (II)
  • Cons T (1.0 %) (III)
  • Tex Ct (IV)

Bioefficacy of selected strain in terms of COD reduction: The simulated effluent samples were analyzed for COD reduction by dichromate reflux method at an interval of 5 days till a period of 20 days for all inoculum concentrations (0.1 %, 0.5 % and 1%) of Tex A bacterial strain and compared with negative control . The decrease in COD was expressed in terms of percent reduction by the formula:

% COD reduction= Initial COD-Final COD X 100

Initial COD

COD reduction: Microcosm analysis was carried out by standardizing the O.D.660 =0.6 of the isolate.

  • Table represents COD reduction by Tex A strains inoculated at different concentrations (0.1%.0.5% and 1.0%) in effluent sample at an interval of 5 days with a final time of experiment being 20 days. Maximum reduction in COD was observed on 20th day with 1% (v/v)

Figure and represents COD at 0th day and 20th day.

  • Table represents COD reduction by Tex B strains inoculated at different concentrations (0.1%.0.5% and 1.0%) in effluent sample at an interval of 5 days with a final time of experiment being 20 days. Maximum reduction in COD was observed on 20th day with 1% (v/v)

Figure and represents COD at 0th day and 20th day.

  • Table represents COD reduction by Tex C strains inoculated at different concentrations (0.1%.0.5% and 1.0%) in effluent sample at an interval of 5 days with a final time of experiment being 20 days. Maximum reduction in COD was observed on 20th day with 1% (v/v)

Figure and represents COD at 0th day and 20th day.

  • Table represents COD reduction by Tex D strains inoculated at different concentrations (0.1%.0.5% and 1.0%) in effluent sample at an interval of 5 days with a final time of experiment being 20 days. Maximum reduction in COD was observed on 20th day with 1% (v/v)

Figure and represents COD at 0th day and 20th day.

  • Table represents COD reduction by Tex E strains inoculated at different concentrations (0.1%.0.5% and 1.0%) in effluent sample at an interval of 5 days with a final time of experiment being 20 days. Maximum reduction in COD was observed on 20th day with 1% (v/v)

Figure and represents COD at 0th day and 20th day.

  • Table represents COD reduction by Tex A strains inoculated at different concentrations (0.1%.0.5% and 1.0%) in effluent sample at an interval of 5 days with a final time of experiment being 20 days. Maximum reduction in COD was observed on 20th day with 1% (v/v)

Figure and represents COD at 0th day and 20th day.

Tex A: Enterobacter sp.

Tex C: Serratia spTex D: Sarcina sp.

Tex E: Pseudomonas spConsD: Consortium.

Strain

Enterobacter sp

Initial COD

(mg/l)

0th day

( mg/l)

5th day

( mg/l)

10th day

( mg/l)

15th day

(mg/l)

20thday/Final COD (mg/l)

Tex A 0.1%(I)

670

560

400

240

180

134

Tex A 0.5 %(II)

670

512

379.2

198

96

92

Tex A 1.0%

(III)

670

480

352

96

80

77

Tex Ct

(IV)

670

656

631

624

613

603

Table : Microcosm analysis for COD reduction of untreated textile effluent by Enterobacter sp.

Strain

Serratia sp

Initial COD

(mg/l)

0th day

( mg/l)

5th day

( mg/l)

10th day

( mg/l)

15th day

(mg/l)

20thday/Final COD (mg/l)

Tex C 0.1%(I)

670

659

567

378

267

210

Tex C 0.5 %(II)

670

558

438

367

245

198

Tex C 1.0%

(III)

670

523

416

322

146

134

Tex Ct

(IV)

670

663

645

624

621

592

Table : Microcosm analysis for COD reduction of untreated textile effluent by Serratia sp

Strain

Sarcina sp

Initial COD

(mg/l)

0th day

( mg/l)

5th day

( mg/l)

10th day

( mg/l)

15th day

(mg/l)

20thday/Final COD (mg/l)

Tex D 0.1%(I)

670

625

579

546

462

337

Tex D

0.5 %(II)

670

572

476

397

350

325

Tex D

1.0% (III)

670

423

390

212

117

113

Tex Ct

(IV)

670

666

632

627

619

612

Table : Microcosm analysis for COD reduction of untreated textile effluent by Sarcina sp.

Strain

Pseudomonas sp

Initial COD

(mg/l)

0th day

( mg/l)

5th day

( mg/l)

10th day

( mg/l)

15th day

(mg/l)

20thday/Final COD (mg/l)

Tex E 0.1%(I)

670

587

487

336

270

236

Tex E 0.5 %(II)

670

518

439

338

256

202

Tex E 1.0%

(III)

670

484

423

330

228

178

Tex Ct

(IV)

670

636

630

625

600

590

Table : Microcosm analysis for COD reduction of untreated textile effluent by Pseudomonas sp.

Constortium

Tex D

Initial COD

(mg/l)

0th day

( mg/l)

5th day

( mg/l)

10th day

( mg/l)

15th day

(mg/l)

20thday/Final COD (mg/l)

Cons D 0.1%(I)

670

560

450

376

317

300

Cons D

0.5 %(II)

670

480

396

192

129

101

Cons D 1.0%(III)

670

476

324

193

88

72

Cons Ct

(IV)

670

666

637

612

604

599

Table : Microcosm analysis for COD reduction of untreated textile effluent by Cons D

Wastewater from industrial plants such as textile, electroplating and petroleum refineries can contain various substances that tend to increase the chemical oxygen demand (COD) of the wastewater. Various local agencies have placed limits on the allowable levels of COD in industrial wastewater effluent. It is desired to develop a process suitable for treating the wastewater to meet the regulatory limits. Various methods are available for COD reduction in industrial wastewater such as precipitation, incineration, chemical oxidation and biological oxidation. This project attempts to solvethe high concentration of COD in industrial wastewater using bacteria. The organic matter that contributed to COD in the wastewater will be degraded by the bacteria under aerobic conditions using batch process. The wastewater will be supplemented with an agricultural liquid waste for bacterial growth and metabolism. This will ensure the continual presence of bacteria to carry out degradation of organic matter in the wastewater.

The effect of bacterial consortium on COD reduction in dye contaminated soil sampled from vicinity of textile industry was studied by (Sharma et al, 2010). A similar study in which indigenous bacterial strains have been used for COD reduction has been investigated in effluent generated from pineapple industry has also been reported (Musa and Ahmad, 2010).

It is expressed as percent reduction which is calculated at regular intervals of 5 days. Microcosm analysis with an aim to reduce COD of textile effluent by bacteria and fungi isolated from textile dye contaminated soil has been reported. (Samuel and Ayobami, 2011). Reduction in COD of textile effluent by establishing aerobic –anaerobic bioreactor has been well accounted (Kassa, 2007).

Roy et al, 2010 collected effluents samples from post discharge of equalization tanks of local composite textile mills of Saver were treated with aquatic macrophytes, algae and their combination. They were found to be effective for the reduction of chemical oxygen demand (COD) and pH. Sixty nine per cent of COD was reduced with the combination treatment of Nostoc, Eichhornia crassipes and Pistia stratiotes. With the combination treatment of Nostoc and E. crassipes reduced 65 per cent COD in glass containers. pH was reduced from 11.2 to 8.6. Between earthen and glass containers, glass container was found to be more effective.

Wastewater that has been discharged from the pineapple industry contributes to high levels of Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and Suspended Solids (SS). The high levels of COD concentrations in wastewater are toxic to biological life and will affect aquatic environment. Currently, there are many methods that have been developed to treat pineapple industry wastewater such as ozonation, reverse osmosis and filtration. However, these conventional methods are costly and generate large amounts of sludge. Biological treatment may be a good alternative since its operational cost is less and it creates an environment friendly atmosphere compared to the conventional methods. In this study, the effectiveness of COD reduction involving a single bacterial culture D, G and I isolated from a pineapple industry wastewater were used in batch system. The COD reduction of pineapple industry wastewater was carried out using bacterial culture and pellet. The performance of these systems in reducing the COD level was monitored within 3 days. The COD reduction was analyzed using a Hach DR/4000 U spectrophotometer. The bacterial pellet D, G and I showed a maximal COD reduction of 87%, 77% and 94% respectively after 3 days exposure to wastewater. The wastewater treatment using bacterial pellet showed higher COD reduction as compared to treatment using whole bacterial culture. FESEM analysis showed that bacteria D, G and I appeared as rod shaped. (Musa et al, 2010)

Sharma et al, 2010 reports the potential of mixed bacterial population for the biodegradation of simulated textile dye wastewater. Two bacterial strains isolated from the dye contaminated soil of a local textile industry were used for the decolonization studies. The flasks having 100 ml of dye solution were inoculated with mixed bacterial cultures and incubated for the period of seven days under aerobic conditions in an incubator shaker and different growth conditions like nutrients, temperature and pH were optimized during the experimental setup. More than 70% colour removal from the wastewater samples was achieved after the incubation period of five days, and a little change in decolonization rate was observed thereafter. Majority of chemical oxygen demand (COD) was removed in the subsequent aerobic process. This study shows that it is possible to decolourize a high concentration of textile dyes by using Mixed Bacterial Consortia and a large number of pollutants can be removed up to a great extent.

Ajao et al, 2010 , reported immobilisation of Pseudomonas aeruginosa and Bacillus subtilis found to have degradative capacity was immobilized on agar-agar, which was transferred into bioreactor fitted with air sparger. The effluent was treated in the bioreactor. The immobilized cells significantly reduced COD to 200mg/I, BOD to 20mg/l, TSS 300mg/I that are upper limit for disposal into surface water. The result indicates overall % reduction in COD, BOD, Nitrate, Sulphate, Phosphates as 83%,97%,61.3%,62.8%,61.2% respectively.

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