4.4 Bioremediation Methods

59

The indigenous population of Phragmites australis has been extensively studied

for textile wastewater remediation and primarily for the removal of acid orange 7 dye

[22]. Aquatic plants have the ability to degrade azo dyes, such as Azolla pinnata and

Lemna minor. Some studies have showed improved phytoremediation capabilities

in the presence of plant microbes and their associated microorganisms, due to their

transformation ability of organic and inorganic compounds, biological weathering,

element cycling, formation of fungal minerals, and interaction between fungi and

clay [23]. Combination technologies include the effects of plants and microorgan-

isms, which may also contribute to the degradation of certain textile dyes. According

to reports, when used in combination with the salt-tolerant bacteria Gracilibacillus

sp., both Sesbania cannabina Pers and alfalfa plants can degrade effluent containing

acid scarlet GR or acid red B dyes [24]. However, most of the research on dye

phytoremediation is carried out on the laboratory bench, and there are few reports

on the pilot scale of dye wastewater treatment. Table 4.4 lists the potential of

different wild/native plants and their dye remediation properties [25, 26].

Table 4.4

Phytoremediation performances of various indigenous/wild plants for textile

dyes and effluents.

Sl. no.

Name of the plant

Dye/effluent

Decolorization (%)

1.

Alternanthera

philoxeroides

Remazol Red

100

2.

Pogonatherum crinitum

Effluent

74

3.

Nasturtium officinale

Acid blue 92

78

4.

Ipomoea hederifolia

Scarlet RR

96

5.

Typha angustifolia

Reactive blue 19

70

6.

Bouteloua dactyloides

Effluent

92

7.

Petunia grandiflora

Brilliant blue G

86

8.

Azolla filiculoide

Basic red 46 and Acid blue 92

90 and 80

9.

Lemna minor

Methylene blue and Acid blue

92

80.56 and 77

10.

Portulaca grandiflora

Reactive blue 172

98

11.

Glandularia pulchella

Green HE4B and Remazol

Orange 3R

92 and 100

12.

Aster amellus

Remazol Red, Remazol Orange

3R

96 and 100

13.

Typhonium flagelliforme

Brilliant blue R

65

14.

Blumea malcolmii

Malachite green, Red HE4B,

Methyl orange, Reactive red

2, and Direct red 5B

96, 76, 88, 80,

and 42

15.

Phragmites australis

Acid orange 7

68 and 98

16.

Bacopa monnieri

Reactive and direct azo dyes

90–100

Sources: Rahul et al. [25]; Shanmugam et al. [26].