Inventory and tertiary treatment of effluent from textile industries in Bangladesh (original) (raw)
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Treating textile effluents by coagulation – flocculation methods using different dosing compositions
Pelagia Research Library, Advances in Applied Science Research, 2012, 3 (4):2514-2517, 2012
This paper discusses fast yet simple method of treating effluents of textile industry by simple chemicals. Textiles industry produces substantial toxic, often loaded with color (from residues of reactive dyes and chemicals), acidic and alkaline contaminants having high pH, high concentration of organic materials etc, which requires proper treatment before being released into the environment. Removal of such toxic materials from waste water is more important because the presence of small amounts of dyes in effluent disposed into the land and river water reduces the depth of penetration of sunlight into the water environment, which in turn decreases photosynthetic activity and dissolved oxygen (DO). The adverse effects can spell disaster for aquatic life, soil, and detrimentally affects the water quality. In this research work different coagulants like Alum, Lime, Ferrous Sulphate, Ferric Chloride, and poly-electrolytes for flocculation were employed to select the most suitable composition which has optimal removal efficiency. Settling characteristics of the flocs formed in the coagulation process were studied at laboratory scale. Parameters such as colour, COD, Hardness, Total Dissolved Solids (TDS), and Total Suspended Solids (TSS), and settled sludge volume have been studied. The optimal coagulant dose volume and pH were determined by comparing the effectiveness of these coagulants [Amirtharajah, A. M., et. al]. Results showed that coagulant like lime eliminated colour and COD effectively. However ferrous sulphate was chosen as effective coagulant for colour removal as it required lowest coagulant dose, minimum settled sludge volume and maximum decolourization. It was also observed that higher percentage of suspended solids was removed by using a combination of iron salts with lime at pH 10 to 11 as compared to alum in a very short time period.
2015
Coagulation and flocculation are most widely methods used for dye and pollution removal from various wastewaters. The aim of this study is efficiency comparison of inorganic coagulant (Alum and Ferric Cchloride) for treatment of textile factory wastewater. The appropriate coagulant was selected at optimum condition for treatment of textile's factory wastewater by measuring of dye, COD, BOD5 and TSS parameters. The different pH (4, 5, 6, 7, 8 and 9) was used for determine the optimum pH. Totally, 240 samples were collected and exanimated according the standard methods of wastewater and water tests. Results showed that the ferric chloride has more removal efficiency than alum in removal of COD, TSS and dye. The most removal of COD, TSS and dye using alum was obtained 36, 19 and 68.8 while for ferric chloride was obtained 72, 60 and 98 respectively. The optimum pH 7 and 5 were obtained for alum and ferric chloride respectively. Based on the results, it can be concluded that COD, TS...
Industrial wastewater turbidity removal using coagulation flocculation process
2017
Textile and tannery wastewaters contain highly toxic and organic biorefractory compounds and have adverse effects on human health. Jar-test experiments are conducted in order to assess the efficiency of coagulants salts on the treatment of these industrial wastewaters. For this purpose iron chloride (FeCl3), and aluminum sulfate (Al2(SO4)3) have been used. The results indicate that iron chloride achieves more than 93% of tannery wastewater turbidity removal and produces two times less sludge than alum; while alum allows 95% of textile wastewater turbidity removal and produces less volume of decanted sludge than iron chloride. Alum can be recommended on the removal of turbidity from textile wastewater. However, for an efficient turbidity removal from tannery wastewater, iron chloride is suitable.
International Journal of Integrated Engineering, 2019
Large quantities of dyes are currently being used in fabric and textile industries. High concentrations of COD (150-10 000 mg/ L) and colours (50-2500 pt. co) are released in the effluent as the end product [1]. Therefore, it is a compulsory for the fabric and textile industry to undergo wastewater treatment as either a physical, chemical or biological process to maintain the quality of water as stated by Environmental Quality Act 1974 (Act 127). Concerns
Study on coagulation and flocculation for treating effluents of textile industry
Acta Scientiarum. Technology, 2013
This study investigated the optimization of time of coagulation, flocculation, and sedimentation of the chemical coagulant, aluminum sulfate and natural coagulant, Tannin. It was performed an economic analysis of the process, checked the removal efficiency of color, turbidity, COD, and treatment characterization using metals, BOD 5 , and total solids. The tests were conducted in Jar Test, using different mixing and sedimentation times. The time required to provide the rapid and slow mixing were 2 and 20 minutes, respectively, for the investigated coagulants, with optimum concentration of 400 mg L-1 for Tannin and 600 mg L-1 for Aluminum Sulfate. For the analyzed parameters, the percentage of removal, according to the best optimization test were 93.12, 99.06 and 99.29% for COD, color, and turbidity, respectively, using the coagulant aluminum sulfate, and 94.81, 99.17 and 99.65% for COD, color and turbidity, respectively, using the coagulant Tannin.
2017
In this research, the potential of aluminum-based water treatment residual (WTR) discharged from the water treatment plant has been evaluated as a coagulant for color removal from cationic and anionic dye solutions. The sample of water treatment residuals (WTR) was collected from water treatment plant (Nigdi, Pune) where Poly Aluminum Chloride (PAC) is used as coagulant in the coagulation/flocculation process. The effects of initial pH, initial dye concentration and WTR dosage were studied. The results have shown that maximum color removal of 81.08, 77.88 and 72% for anionic dye and 94.54, 91.77 and 84.53% for cationic dye were obtained at initial dye concentrations of 25, 50 and 75mg/L, respectively, at pH 3.0 and WTR dose of 120mg/L. Although lower amount of WTR were required for the removal of dyes from wastewater, the reuse of WTR as a low cost material can offer several advantages such as higher efficiency of cationic an anionic dye color removal and economic savings on overall...
—A textile is the major source of water consumption and waste water pollution, there are various treatment techniques to remove color and waste water textile pollution. Coagulation flocculation is the widely used method to remove pollution from textile due to suspended particles .in this research the two coagulant were selected that is Alum and ferric chloride in order to select the suitable ones with optimum removal effiency in terms of color. the research shown that When the PH is varied it has been seen that improved color removal were obtained by reducing the PH to 5.0 also it has been observed that at PH 5.0 the incremental increase of PH is 78% and lowest value was at 48% in case of Alum and in the case of Fecl3 the maximum percentage removal for color removal was 79-80%.Color is the main attraction of any fabric no matter how excellent its constitution, if unsuitably colored it is bound to be a failure as a commercial product. Sustainability of the environment has become a focus; hence the need for improvement and monitoring of textile waste water discharges, for which major concern is color. Color in textile dyeing and finishing effluents is as a result of large amounts of dye stuffs left during the dyeing stages and inefficient dyeing processes often resulting in unfixed forms.
In this study, coagulation-flocculation process was used to treat detergent wastewater with ferric chloride as coagulant. The improvement of the process by using polyelectrolytes and clay minerals (montmorillonite and bentonite) as coagulant aids was also investigated. The results of the wastewater characterization showed that the concentration of organic matter expressed as chemical oxygen demand (COD) was as high as 24.3 g/L while the biochemical oxygen demand was low. Chemical treatment can be considered as a suitable option for treatment of detergent wastewater due to the low ratio of BOD 5 /COD. Coagulation/flocculation and precipitation studies were performed in a conventional jar-test apparatus. The coagulant dosage of ferric chloride ranged between 0.5 g/L and 3 g/L, whereas the concentrations of polyelectrolyte and clay minerals varied between 5-75 mg/L and 25-750 mg/L, respectively. The optimal condition was obtained at the dosage 2 g/L ferric chloride at pH 11 with the COD removal efficiency of 71%. Addition of coagulant aids provided higher removal efficiencies. Using clay minerals at the dose of 500 mg/L with ferric chloride provided 84% of COD removal and the removal efficiency of COD increased with using polyelectrolyte, resulting in an efficiency of 87%. The maximum removal efficiency was obtained with the addition of polyelectrolyte and it was found that the ferric chloride combination with coagulant aids, at certain pH and agitation speed, provided higher removal efficiencies compared to coagulation with ferric chloride alone.
Journal of Hazardous Materials, 2010
In this study, performance of a waterworks sludge (FCS: ferric chloride sludge) for the removal of acid red 119 (AR119) dye from aqueous solutions were investigated. For this purpose, response surface methodology (RSM) was applied to optimize three operating variables of coagulation/flocculation process including initial pH, coagulant dosage and initial dye concentration. The results showed that the decrease of initial pH was always beneficial for enhancing dye removal and no re-stabilization phenomenon was occurred even at the used maximum FCS dosage. It seems that iron hydroxides of the FCS could neutralize the negative charges on dye molecules or cause to the trapping of the dye ones. Therefore, the sweep flocculation and/or the charge neutralization might play key roles in the enhancement of dye removal. The optimum initial pH, FCS dosage and initial dye concentration were found to be 3.5, 236.68 mg dried FCS/L and 65.91 mg/L, respectively. Dye removal of 96.53% is observed which confirms close to RSM results. Therefore, it can be concluded that reusing the FCS as a low-cost material into the coagulation/flocculation process in wastewater treatment plants can offer some advantages such as high efficiency for AR119 dye removal and economic savings on overall treatment plant operation costs.