scholarly journals Removal of Dyes by Aqueous Mixed Coagulants

2005 ◽  
Vol 5 (1) ◽  
pp. 52
Author(s):  
Peik Yin Ooi ◽  
Tjoon Tow Teng ◽  
A. K. Mohd Omar ◽  
N. A. R. Nik Norulaini

Alum, MgCl2, and mixtures of alum and MgCl2 have been used as coagulant to remove coloring matter in the reactive dye Levafix Brill Blue EBRA. The jar test was used to determine the effectiveness and the optimal condition of the coagulation process in terms of pH of the coagulation process, coagulant dosage, percentage color removal, and floc settling time. Coagulant dosages of 1,000-5,000 ppm were studied. The treatment of textile industry wastewater was done in the treatment plant of a printing mill. The results showed that coagulation by MgCl2 and alum occurs at the removal pH ranges of 10.5-11.0 for MgCl2 and 4.0-6.0 for alum. The mixtures of MgCl2 and alum gave two distinct effective color-removal zones at pH 4-5.5 and pH 8-9.5. The addition of alum to MgCl2 shifted the optimal pH of MgCl2 from 10.5-11. 0 to 8. 0-9.5. The alum dose of 1,000-3,000 ppm in the coagulant mixture increased by 10-25 % the color removal in the alkaline zone. Floc settling time was found to (a) increase with coagulant dose and (b) take longer in the acidic color-removal zone than in the alkaline zone. The presence of alum increased the floc settling time in the alkaline zone. The study done at the treatment plant of a printing mill showed similar results. A mixture of 60% MgClz and 40% alum at an average dosage of 2,800 ppm gave a color removal of 97% and reductions of 88% for COD and 69% for suspended solids. Keywords: Chemical coagulation, color reduction, mixed coagulants, and textile waste.

2007 ◽  
Vol 42 (1) ◽  
pp. 54-62 ◽  
Author(s):  
Pei Wen Wong ◽  
Tjoon Tow Teng ◽  
Nik Abdul Rahman Nik Norulaini

Abstract The coagulation-flocculation method was used to treat aqueous solutions containing varying ratios of commercial disperse and reactive dyes. The effectiveness of this method was assessed using such coagulants as alum, polyaluminium chloride (PACl) and MgCl2, and an anionic coagulant aid. The jar test method was used to measure the effects of pH and coagulant type and dosage on colour removal and chemical oxygen demand (COD) reduction. The effect of coagulant aid on floc settling time was also measured. The results showed that the coagulant dosage needed to achieve optimum colour removal and COD reduction increased as the percentage of reactive dye in the mixture increased. Alum and PACl performed effectively in a lower pH range (pH 3.8 to 5.2), whereas MgCl2 performed effectively in a higher pH range (pH 10.4 to 10.9). PACl was more effective than MgCl2 and alum, achieving >99% colour removal and 96.3% COD reduction using a smaller quantity of the coagulant. The addition of coagulant aid improved floc settling time. These results show that PACl is more effective than MgCl2 and alum in removing both colour and COD in the treatment of the industrial textile wastewater samples.


2014 ◽  
Vol 977 ◽  
pp. 270-273
Author(s):  
Ming Li ◽  
Yan Zhen Yu ◽  
Guang Yong Yan

A response surface methodology (RSM) was used for the determination of optimum coagulation process conditions for disperse navy blue dye wastewater treatment. The experimental design was Box-Behnken design (BBD) with three operational variables: coagulant dosage, pH value and settling time. The influence of these three independent variables on the chroma removal was evaluated using a second-order polynomial multiple regression model. Quadratic model was predicted for the response variable and the maximum model-predicted chroma removal efficiency was 95%. Based on surface and contour plots, the optimum conditions were obtained to be coagulant dosage of 70.98 mg/L, pH value of 7.46, and settling time of 15.80 min with the actual chroma removal efficiency as 93%.


Author(s):  
Bruno Rodrigues dos Santos ◽  
Roselene Maria Schneider ◽  
Adriana Garcia do Amaral ◽  
Milene Carvalho Bongiovani ◽  
Ednaldo Antonio de Andrade

Effluents generated in landfills are difficult to treat and require different forms of treatment to reach the necessary polishing for disposal. Leachate is usually treated in stabilization ponds where pollutants are significantly removed, but it might not be enough for disposal. Thus, we aimed at evaluating the applicability of the natural coagulant Tanfloc SG and the chemical coagulant PAC, with the addition of the anionic flocculation auxiliary polymer (PA), in the coagulation / flocculation processes as a post-treatment of landfill effluents. The tests were carried out by means of a jar test, with coagulant dosage ranging from 0 - 1,250 mg.L-1 and pH values ranging from 5 - 9, in three decantation times. The results showed that both Tanfloc SG and PAC are efficient in clarifying the effluents, even though they act well in different dosage values of coagulants and pH. The polymer dosage did not generate significant improvements in the variations of the variables studied, however, in some experiments it was shown to expand removal range in regards to some variables. The PAC coagulant showed to be efficient in the removal of suspended solids, dissolved materials, colloidals and humic substances, and Tanfloc SG acted mainly in the removal of solids. 


Author(s):  
Dimas Frananta Simatupang ◽  
Gimelliya Saragih ◽  
Martin Siahaan

One of the first steps in processing river water into drinking water is by removing the turbidity of the river water. Turbidity can be removed by adding a chemical called a coagulant. This study aims to obtain data on how the effect of using coagulant dosage variations in reducing turbidity and iron content in raw water at the water treatment plant (IPA) PDAM X. The study was conducted using the jar test method to determine the dose of aluminum sulfate coagulant in reducing turbidity and colorimetric method using visible spectrophotometry to determine iron content that meets quality standard criteria. The results showed that the higher the coagulant dose, the lower the turbidity and iron content of the raw water. Coagulant doses with up to 30 ppm were able to reduce turbidity with an efficiency of 92.67% and reduce iron levels up 96.10%.


2009 ◽  
Vol 4 (2) ◽  
Author(s):  
H. Nagare ◽  
T. Aso ◽  
S. Yoshida ◽  
K. Ebie

Focusing on the improvement of removal efficiency of humic substances by coagulation, coagulation-flocculation processes were applied not only once but more than twice to the water being treated, and the effect of repeated coagulation was evaluated in jar-tests. With more than the critical dosage of PACl (15 mg/l), approximately 30% of color removal was attained in typical one-pass treatment, whilst maximum 65% removal was achieved by repeating the coagulation twice. Repeating coagulation enhances the coagulation process to achieve higher color removal efficiency, and can reduce the coagulant dosage.


Author(s):  
Bukola M. ADESANMI Yung-Tse HUNG and Howard H. PAUL

The interference of synthetic dye in the water bodies and environment poses a risk to both human and environmental health. Due to the recalcitrant nature of dye and presence of many other pollutants in industrial wastewater, efficient method of treatment of industrial effluent is required to address the lingering problem over the years. To address this major concern, experimental was carried out on synthetic dye and flour wastewater treatment by coagulation-flocculation while varying operating parameters (dosage, concentration, coagulant type etc.). The effectiveness of coagulation-flocculation process for the removal of Naphthol Green B in a mixture of dye wastewater and flour wastewater at different concentrations (50 ppm, 100 ppm, 150 ppm, 200 ppm) was investigated. Using 3 coagulant (FeCl3, FeSO4 and Al2(SO4)3), color removal efficiency was also investigated. The effectiveness of the coagulation process was measured for transmittance and absorbance as indices using UV-Vis Spectrophotometer. Also, the total organic carbon (TOC) was measured. Transmittance and absorbance values of 99.6% and 0.001 respectively were achieved post treatment. Ferric Chloride and Aluminum Sulfate gave better results than Ferrous Sulfate which gave the poorest transmittance and absorbance values indicating reduced color removal efficiency. The results of this study revealed that coagulation process is an efficient preliminary treatment for appreciable suspended particles and color removal from dye wastewater. It also showed the impact of coagulant dosage, dye strength and combined wastewater samples on the removal efficiency and resulting effluent quality.


2019 ◽  
Vol 8 (4) ◽  
pp. 1490-1494

This work deals with investigation of effectiveness of adsorption and coagulation on removal of color of simulated acid dye solutions. Dye stuff belonging to acid group is employed and batch tests were conducted with three coagulants (Calcium hydroxide, Ferric sulphate and Aluminium chloride) to access feasibility and also to study the optimum values for coagulant dosage, RPM, pH and time. The study clearly indicates that dye effluent responds effectively to Ferric sulphate. The removal is probably due to physicochemical mechanism of coagulation and flocculation and/or chelating complexation type reactions and color removal at lower pH ranges may be either due to physicochemical coagulation or chelating complex formation reactions. The study clearly indicates that there is significant reduction in the chemical dosage requirements and in some cases a further increase in color removal. From the above studies it may be concluded that some of the Acid dye stuffs are suitable for their color removal using various coagulants. In this study we have used commercial carbon as well as activated carbon prepared from sawdust (agriculture waste), and performed the same experiment by varying the variables (coagulant dosage, RPM, pH and time), the studies shows that in the process of coagulation the percentage color removal is more than when compared to that of adsorption.


2021 ◽  
Author(s):  
Bahareh Bavar

Wastewater containing fats, oils and grease (FOG) is problematic in several ways: foul odors, blockage of sewer lines, interference with the proper sewage treatment operation and excess amount of FOG that can lead to certain fines for responsible wastewater generator. In this paper, the magnetic coagulation process is used to destabilize the oily wastewater emulsions while assisting with the oil floc formation. The oil/magnetic powder flocs were subsequently deposited and removed with the assistance of magnetic field. Preliminary investigations were devoted to calculations of optimal magnetic field. Preliminary investigations were devoted to calculations of optimal magnetic powder proportions were devoted to calculations of optimal magnetic powder proportions of various sizes and their oil sorption capacity. The results from the jar test confirmed the effectiveness of the magnetic coagulation procedure. It was demonstrated that the magnetic coagulation process with optimum amount of magnetic powder of 12 g/L could remove 94.2% of FOG, 96.9% of total suspended solids (TSS), and 86.7% of chemical oxygen demand (COD) on average.


2018 ◽  
Vol 250 ◽  
pp. 06007 ◽  
Author(s):  
Siti Nor Aishah Mohd-Salleh ◽  
Nur Shaylinda Mohd-Zin ◽  
Norzila Othman ◽  
Nur Syahirah Mohd-Amdan ◽  
Fitryaliah Mohd-Shahli

Treatment on the generated landfill leachate is crucial as it can cause serious toxicological effects and environmental hazards, particularly when the unfavorable contaminants are left accumulated for a long period of time. The purpose of this study was to determine the optimum coagulant dosage of polyaluminium chloride (PAC) in selected dosage ranges (2250-4500 mg/L) and to analyse the ideal pH of leachate sample (pH 3-10). PAC was tested on stabilized leachate taken from Simpang Renggam Landfill Site (SRLS), by investigating the percentage removals of five significant parameters, which were suspended solids, chemical oxygen demand (COD), ammonia, and heavy metals (iron (Fe) and chromium (Cr)). The removal efficiency was determined by a series of experiments using jar test. From the obtained results, it was found that 3750 mg/L and pH 7 were the optimum conditions for PAC dosage and sample pH, respectively. The conventional optimization test showed satisfactory results for suspended solids, COD, Fe, and Cr at 95%, 53%, 97%, and 79% respectively, but had low removal on ammonia at 18%. It can be concluded that the coagulation-flocculation process has the potential to be applied as a primary treatment for stabilized landfill leachate in Malaysia.


2013 ◽  
Vol 60 (1) ◽  
Author(s):  
Norzita Ngadi ◽  
Noor Yahida Yahya ◽  
Nabilah Muhamad

Dalam kajian ini, poliacrylamid (PAM) dan polialuminium klorida (PAC) telah digunakan sebagai bahan pengental untuk merawat air sisa industri tekstil. Eksperimen ini telah dijalankan dengan menggunakan ujian balang. Kesan dos, kelajuan percampuran dan masa pemendapan ke atas keberkesanan proses flokulasi telah dikaji. Air sisa yang terawat dianalisis untuk penyingkiran warna, pengurangan COD dan pengurangan kekeruhan. Keputusan yang diperolehi menunjukkan bahawa PAM adalah lebih baik daripada PAC dalam merawat air sisa tekstil. PAM mencatatkan penurunan parameter tertinggi, iaitu 6 NTU untuk kekeruhan, 744 mg / l untuk COD, dan scala kurang daripada 0.5 untuk warna. Prestasi tebaik PAM dicapai pada dos 0.07 g dan apabila proses flokulasi dijalankan pada 200 rpm kelajuan percampuran dan 30 min masa pemendapan. Kajian ini juga mendapati bahawa parameter operasi yang dikaji (iaitu dos, kelajuan percampuran dan masa pemendapan) tidak banyak mempengaruhi ke atas penyingkiran warna, dan penurunan kekeruhan dan COD apabila PAC digunakan sebagai bahan pengental. Kata kunci: Pengelompokan; poliacrylamid (PAM); polialuminium klorida (PAC); air sisa tekstil In this study, polyacrylamide (PAM) and polyaluminum chloride (PAC) was used as a flocculant to treat industrial textile wastewater. The experiment was conducted using a Jar test experiment. The effect of dosage, mixing speed and settling time on the performance of the fflocculation process was investigated. The treated textile wastewater was analyzed by its color removal, turbidity and COD reductions. The results obtained showed that PAM performed better in treating the textile wastewater compared to PAC.PAM recorded the highest reduction of parameters, which are 6 NTU for turbidity, 744 mg/l for COD, and scale less than 0.5 for colour. The best performance of PAM was achieved at dosage 0.07 g and when the flocculation process was conducted at 200 rpm of mixing speed and 30 min of settling time. It was also found that the investigated operating parameters (i.e. dosage, mixing speed and settling time) did not influence much on removal of color and reduction of turbidity and COD when PAC was used as flocculant. Keywords: Flocculation; polyacrylamide (PAM); polyaluminum chloride (PAC); textile wastewater


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