Recently industrialization has become one of the most promising contributors for economic development of Bangladesh. However, at the same time, industrial pollution has turned into one of the major problems for human being as well as for the environment. In order to understand the effect of textile effluent (TE) on environmental pollution, TE samples collected from North-west part of the capital of Bangladesh, Dhaka (Savar, Ashulia and Tongi area) were characterized biologically, biochemically and biophysically. Eight potential microorganisms were isolated (3 bacteria and 5 fungi) from the collected TE and two of them were used to de-colorization of TE significantly by bioremediation process. Among the various parameters checked here, some physicochemical properties like TDS, COD, BOD, DO and heavy metals like Cd and Cr were detected in quite high amounts. Altogether, our results indicate that TE is one of the serious pollutants, which could damage environment as well as water body severely.
Textile industries are considered as the key industrial sectors of Bangladesh as 78% of the total export earning comes from textile and textile related goods contributing 12% to GDP [
Textile effluents (TE) are highly responsible for organ damages, disorders in the respiratory tract, dysfunction of the heart, disorders in the nervous system, skin diseases, abnormalities in fertility and pregnancy. Besides the effects on human health, high concentrations of heavy metals in textile wastewater have a negative impact on the environment and water quality itself as well as on the biota living in the water bodies [
It has been reported that many bacterial and fungal species have the ability to decolorize and detoxify TEs by enzymatic degradation of organic materials through the process of bioremediation [
Textile effluents (TE) samples were collected from three northern industrial parts of Dhaka, Bangladesh. The zones were: Savar (Pakiza textile industry), Ashulia [Dhaka export processing zone (DEPZ)] and Tongi textile area. Two TE samples (sample 1 and sample 2) were collected from each of the three areas. Sample 1s were collected from the effluent discharge pipes of the industries, whereas, sample 2s were collected from the water bodies adjacent to the discharge points. The initial pH and temperature of effluent samples were determined and noted down immediately at the sampling site. All these samples were transported to the laboratory in an ice- packed chest box. Collected samples were stored at 4˚C until further use.
As Nutrient and YEPD [Yeast Extract (1.0%) Peptone (2.0%) Dextrose (2.0%)] Agar are the basal media (at pH 5.0) for screening of bacteria and fungi respectively, the diluted (up to 10 folds) TE samples were screened for the presence of bacteria and fungi on those media by following the method described by Barragán et al. [
After 24 hours of incubation, among all the eight microbial colonies only two colonies (S2A, S2B) were selected on the basis of highest growth activity for observing the effects of pH and temperature on TE de-colorization. The Mac-Cartney bottles containing different effluent samples were incubated for 1 - 7 days together with two different inoculums (S2A, S2B) both at 37˚C and at 42˚C for checking the decolonization effect as well as the reduction of pH from TE by bioremediation process by following methods of Idris et al. [
The physicochemical properties such as Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Electrochemical Conductivity (EC), Total Dissolved Solids (TDS), Total Suspended Solid (TSS), Dissolved Oxygen (DO) and four most commonly persistent heavy metal components content (Zn, Cu, Cd and Cr) was estimated by the standard method developed by Huq et al. [
Bangladesh is the second largest ready-made garments manufacturer country in the world. The money earned from exporting textiles is the single greatest source of economic growth of Bangladesh. These large numbers of textile industries discharge a huge amount of textile effluents everyday without proper treatment, which contain huge amount of toxic dyes and other chemical toxic substances that are poisonous for not only human, but also other creatures in this planet, including both the aquatic and the terrestrial environment [
Textile effluents (TE) samples were collected from three northern industrial parts of Dhaka, the capital of Bangladesh. The three sampling zones were selected which were located at Savar, Ashulia and Tongi textile area are shown in
Various collected samples were diluted where necessary, spread on agar media and then incubated at 37 and 42˚C for 24 hours. Three (C1, C2 and C3) different discrete colonies (3.5 ´ 108 colonies/ml) were found on nutrient agar plates which were considered as bacteria and five (C4, C5, C6, S2A and S2B) discrete colonies (2.5 ´ 108 colonies/ml) were found on YEPD plate which were considered as fungi based on their growth in selective media. The screening of microorganisms in Nutrient Agar and YEPD from the TEs are shown in
The effluent samples collected from the textile areas were blue in color, which indicate that TEs are not treated properly before release them from the industry. Because, they were pungent in smell and their initial pH during sample collection were around 10.0 and the temperature range of those samples was 31˚C to 35˚C. Therefore, we have decided to check the various physicochemical parameters like EC, TDS, TSS, DO, BOD, COD contents on TEs samples. The results are illustrated in
We also have checked whether TEs contain heavy metals or not. TEs sample collection and preparation for the
Strain code | Colony color, shape/size and growth | Gram staining | Microscopic view | Microorganism |
---|---|---|---|---|
C1 | Yellow, 0.7 - 1.3 cm in diameter, rapid growth | Gram Negative | Rod shaped | Bacteria |
C2 | Of White, 0.2 - 0.4 cm in diameter, slow growth | Gram Positive | Oval shaped | Bacteria |
C3 | White, 0.5 - 0.7 cm in diameter, rapid growth | Gram Negative | Rod shaped | Bacteria |
C4 | Red, raised, jelly like round colony | ND | Oval shaped | Fungi |
C5 | White, round oily colony | ND | Oval shaped | Fungi |
C6 | Of white oily, raised colony | ND | Rod shaped | Fungi |
S2A | White, raised, jelly like colony | ND | Oval shaped | Fungi |
S2B | Yellow, raised colony | ND | Oval shaped | Fungi |
ND = Not Determined.
detection of heavy metals content are explain in detail in the Materials and Methods. The results for the detection of heavy metals are shown in
Heavy metals content (ppm) in TEs | ||||
---|---|---|---|---|
Zn | Cd | Cu | Cr | |
Standard | 3.0 | 0.003 | 2.00 | 0.05 |
Ashulia | 0.6 | 0.004 | 0.30 | 0.10 |
Savar | 1.4 | 0.005 | 0.10 | 0.20 |
Tongi | 0.8 | 0.005 | 0.05 | 0.15 |
such incidence may cause serious health problems in near future [
After incubating the TE samples for 7 days both at 37˚C and 42˚C with two strains, significant de-colorization effect was observed. These changes were absent when compared TE with the color and pH of internal control (
This research was supported by Ministry of Education (17/10, M-15/2007/226), Bangladesh and the HEQEP
(W1, CP-3413) for publication cost of this manuscript which are hereby gratefully acknowledged.