scholarly journals A Study on the Relative Performance of Different Coagulants and the Kinetics of COD in the Treatment of a Textile Bleaching and Dyeing Industrial Wastewater

2007 ◽  
Vol 7 (1 & 2) ◽  
pp. 49 ◽  
Author(s):  
Wilheliza A. Baraoidan ◽  
Lin Lin Tun ◽  
Pag-asa D. Gaspillo ◽  
Masaaki . Suzuki

Untreated wastewater from textile industries when discharged to nearby waterways would cause considerable health concerns to humans and animal life and to the host environment. They contain various chemicals such as dyes, detergents and surfactants, some of which are recalcitrant to biodegradation. Such wastewater can be better remediated by chemical treatment. The treatment of a textile bleaching and dyeing industrial wastewater was done by Coagulation and Flocculation Method using a jar test apparatus. Alum, polyaluminum chloride (PAC), and ferrous sulfate were used in separate runs as coagulants, while excelfloc 264 (a polyacrylamide copolymer) was used as flocculant. Preliminary tests were first conducted to determine the appropriate coagulation and flocculation agitation rates and settling time. The initial pH of the sample effluent was varied from 5 to 8 for alum coagulation, 5 to 8.5 for PAC coagulation and 9 to 11 for ferrous sulfate coagulation. The dosages of each coagulant and the excelfloc were varied from 200 to 1000 ppm, and 0.5 to 2.5 ppm, respectively. Experimental results showed that the optimum initial pH of the wastewater using alum, PAC, and ferrous sulfate were 7, 7.5, and 10, respectively. The optimum dosages of the coagulants were found to be 600ppm for alum and 800ppm for both PAC, and ferrous sulfate. The optimum flocculant dosages were 1.5ppm with alum, 1 ppm with PAC and 2ppm with ferrous sulfate. The highest percentage removal of COD, Total Suspended Solids (TSS), Total Dissolved Solids (TDS), chromium, and color were found to be 58.55%, 65%, 36.51%, 76.45%, and 78.96%, respectively, using alum: 65.4%, 67.5%, 35.84%, 44.92%, and 75.49%, respectively using PAC; and, 55.72%, 34.16%, 33.95%, 19.88%, and 48.56%, respectively, using ferrous sulfate. Among the three coagulants tried, coagulation with PAC gave the highest percentage of COD removal of 65.64% and TSS removal of 67.5% while alum gave the highest removal of both chromium and color at 76.45% and 94.49%, respectively. Rapid and slow agitation rates used were 240rpm for 1 minute and 40rpm for 20 minutes, respectively; while settling time was 30 minutes. Kinetics of the COD removal was studied at the optimum conditions. Kinetic model, determined by curve fitting with the coagulation/flocculation reaction, was observed to follow a first-order rate of reaction.

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


Phosphorous is one of the major nutrients contributing the increased eutrophication of lakes and natural waters. The concentration of phosphorus in domestic sewage is generally adequate to support aerobic biological wastewater treatment. Coagulation and flocculation processes can also to remove phosphorous from industrial wastewater.In this experimental study, an attempt is made to feasibility of natural coagulants like Cassia Alata, Calotropis Procera, Hyacinth bean, Banana leaves, Carcia Papaya, Acacia mearnsii, Jatropha Curcas, Cactus and Tamarind seeds on the decrease of Phosphorous from Industrial wastewater. The batch coagulation test was done to optimum graph was plotted between the removal efficiency all the chose coagulated. From the optimum trails, that the rate of phosphorous removal is more for hyacinth bean with a level of 75, trailed by casuarinas leaves with 74% and Banana leaves with 73%. Tamarind seed demonstrates the least Phosphorous expulsion from the wastewater with 56%. From the optimum trails, the Hyacinth bean can be utilized as a successful coagulant for the expulsion of phosphorus from the wastewater. In the optimum trails coagulation studies were carried out to investigate the factor like optimum dosage, pH, initial concentration of Phosphorous, Mixing time and the settling time which influences the removal of phosphorous by coagulation process. From the study, it might be inferred that the maximum percentage removal of phosphorous was acquired for the coagulant measurement of, pH of 8, the initial phosphorous concentration of, mixing time of and settling time of 45 minutes. It might be presumed that the Phosphorous removal from the industrial wastewater of 95% was conceivable when we kept up the optimum condition by the coagulation procedure..


2010 ◽  
pp. 141-147 ◽  
Author(s):  
Marina Sciban ◽  
Mirjana Vasic ◽  
Jelena Prodanovic ◽  
Mirjana Antov ◽  
Mile Klasnja

Coagulation and flocculation by adding chemicals are the methods that are usually used for removal of water turbidity. This study is concerned with the coagulation activity of extracts of various strains of bean. The aim was to ascertain if bean varieties influence coagulation activity. Active components were extracted from 1 g of ground sample with 100 ml distilled water. Contents of dry matter and nitrogen were specified in the solid samples, and the content of soluble nitrogen was determined in the extracts. These data were used to calculate the efficiency of extraction of nitrogen-containing compounds. The coagulation activity was assessed by jar test using synthetic turbid water, of the initial pH 9 and turbidity 35 NTU. The jar test was carried out by adding different amounts of extracts to model water, and stirring the content. After sedimentation for 1 h, residual turbidity was determined by turbidimeter and coagulation activity was calculated. The increment of organic matter concentration after the coagulation was also determined. These experiments confirmed that extracts of all investigated strains of bean could be used successfully as natural coagulants.


Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2031
Author(s):  
Ruben Miranda ◽  
Isabel Latour ◽  
Angeles Blanco

Effluent reuse is a common practice for sustainable industrial water use. Salt removal is usually carried out by a combination of membrane processes with a final reverse osmosis (RO). However, the presence of silica limits the RO efficiency due to its high scaling potential and the difficulty of cleaning the fouled membranes. Silica adsorption has many advantages compared to coagulation and precipitation at high pHs: pH adjustment is not necessary, the conductivity of treated waters is not increased, and there is no sludge generation. Therefore, this study investigates the feasibility of using pseudoboehmite and its calcination product (γ-Al2O3) for silica adsorption from a paper mill effluent. The effect of sorbent dosage, pH, and temperature, including both equilibrium and kinetics studies, were studied. γ-Al2O3 was clearly more efficient than pseudoboehmite, with optimal dosages around 2.5–5 g/L vs. 7.5–15 g/L. The optimum pH is around 8.5–10, which fits well with the initial pH of the effluent. The kinetics of silica adsorption is fast, especially at high dosages and temperatures: 80–90% of the removable silica is removed in 1 h. At these conditions, silica removal is around 75–85% (<50 mg/L SiO2 in the treated water).


Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1026
Author(s):  
Javier Tejera ◽  
Antonio Gascó ◽  
Daphne Hermosilla ◽  
Víctor Alonso-Gomez ◽  
Carlos Negro ◽  
...  

The objective of this trial was to assess the application of UVA-LED technology as an alternative source of irradiation for photo-Fenton processes, aiming to reduce treatment costs and provide a feasible treatment for landfill leachate. An optimized combination of coagulation with ferric chloride followed by photo-Fenton treatment of landfill leachate was optimized. Three different radiation sources were tested, namely, two conventional high-pressure mercury-vapor immersion lamps (100 W and 450 W) and a custom-designed 8 W 365 nm UVA-LED lamp. The proposed treatment combination resulted in very efficient degradation of landfill leachate (COD removal = 90%). The coagulation pre-treatment removed about 70% of the COD and provided the necessary amount of iron for the subsequent photo-Fenton treatment, and it further favored this process by acidifying the solution to an optimum initial pH of 2.8. The 90% removal of color improved the penetration of radiation into the medium and by extension improved treatment efficiency. The faster the Fenton reactions were, as determined by the stoichiometric optimum set-up reaction condition of [H2O2]0/COD0 = 2.125, the better were the treatment results in terms of COD removal and biodegradability enhancement because the chances to scavenge oxidant agents were limited. The 100 W lamp was the least efficient one in terms of final effluent quality and operational cost figures. UVA-LED technology, assessed as the application of an 8 W 365 nm lamp, provided competitive results in terms of COD removal, biodegradability enhancement, and operational costs (35–55%) when compared to the performance of the 450 W conventional lamp.


1977 ◽  
Vol 10 (2) ◽  
pp. 120-124 ◽  
Author(s):  
HARUO HIKITA ◽  
SATORU ASAI ◽  
HARUO ISHIKAWA ◽  
SHIGEYUKI HIRANO

2012 ◽  
Vol 518-523 ◽  
pp. 2745-2748
Author(s):  
Ling Yan Ren ◽  
Gang Xu

The paper adopted Coagulation-Fenton Oxidation Method on treating the wastewater of 6-nitro-1,2 diazonium oxygroup naphthalene-4-sulfoacid production process (i.e. 6-nitry wastewater), introduced the treatment effect of the combined technology used on 6-nitry wastewater, and studied the factors influencing the treatment effect, to determine the reasonable parameters of the technology on treating 6-nitry wastewater. The results showed that Using polyaluminium chloride (mass fraction 2%) as flocculant for treating 6-nitry wastewater, the COD removal rate reached up to 48.7%; Making Fenton reagent oxidation treatment on coagulation yielding water, under the best conditions for solution acidity controlled at pH3 or so, in the 100 mL wastewater, 30% hydrogen peroxide was 5.0 mL, 0.5 mol/L ferrous sulfate solution was 4.0 mL, reaction time was 60 min, the COD removal rate could reach 98% or more.


2016 ◽  
Vol 74 (3) ◽  
pp. 564-579 ◽  
Author(s):  
Ceyhun Akarsu ◽  
Yasin Ozay ◽  
Nadir Dizge ◽  
H. Elif Gulsen ◽  
Hasan Ates ◽  
...  

Marine pollution has been considered an increasing problem because of the increase in sea transportation day by day. Therefore, a large volume of bilge water which contains petroleum, oil and hydrocarbons in high concentrations is generated from all types of ships. In this study, treatment of bilge water by electrocoagulation/electroflotation and nanofiltration integrated process is investigated as a function of voltage, time, and initial pH with aluminum electrode as both anode and cathode. Moreover, a commercial NF270 flat-sheet membrane was also used for further purification. Box–Behnken design combined with response surface methodology was used to study the response pattern and determine the optimum conditions for maximum chemical oxygen demand (COD) removal and minimum metal ion contents of bilge water. Three independent variables, namely voltage (5–15 V), initial pH (4.5–8.0) and time (30–90 min) were transformed to coded values. The COD removal percent, UV absorbance at 254 nm, pH value (after treatment), and concentration of metal ions (Ti, As, Cu, Cr, Zn, Sr, Mo) were obtained as responses. Analysis of variance results showed that all the models were significant except for Zn (P &gt; 0.05), because the calculated F values for these models were less than the critical F value for the considered probability (P = 0.05). The obtained R2 and Radj2 values signified the correlation between the experimental data and predicted responses: except for the model of Zn concentration after treatment, the high R2 values showed the goodness of fit of the model. While the increase in the applied voltage showed negative effects, the increases in time and pH showed a positive effect on COD removal efficiency; also the most effective linear term was found as time. A positive sign of the interactive coefficients of the voltage–time and pH–time systems indicated synergistic effect on COD removal efficiency, whereas interaction between voltage and pH showed an antagonistic effect.


2013 ◽  
Vol 64 (1) ◽  
Author(s):  
Norzita Ngadi ◽  
Nor Aida Yusoff

The study investigated the performance of chitosan and extracted pandan leaves towards treatment of textile wastewater by using flocculation process. Pandan leaves were extracted by using solvent extraction method. Flocculation process was conducted using a Jar test experiment. The effect of dosage, pH, and settling time on reduction of COD, turbidity and color of textile wastewater was studied. The results obtained found that chitosan was very effective for reduction of COD, turbidity, color and indicator for color. The best condition for COD and turbidity removal was achieved at 0.2 g dosage, pH 4 and 60 minutes of settling time. Under this condition, about 58 and 99% of COD and turbidity was removed, respectively. However, the results obtained using extracted pandan was opposite compared to the chitosan. Extracted pandan was not able to remove both COD and turbidity of the waste. 


Author(s):  
Mohammad Al-Hwaiti ◽  
Hamidi Abdul Aziz ◽  
Mohd Azmier Ahmad ◽  
Reyad Al-Shawabkeh

Adsorption techniques for industrial wastewater treatment rich in heavy metals and aqueous solutions of water-soluble such as Cl−, F−, HCO3−, NO3−, SO2−4, and PO3−, often include technologies for toxicity removals. The recent advancement and technical applicability in the treatment of chlorine and chlorinated compounds from industrial wastewater are reviewed in this article. Chlorine and chlorinated compounds are among the common discharged constituents from numerous industries. They can be carcinogenic or naturally toxic and can pose issues to aquatic ecosystems and human beings. Thus, elimination of chlorides and chlorinated compounds from water or wastewater is inevitable to get rid of the problem. Several techniques are being applied for the reduction of chlorine and chlorinated compounds in water. These include biodegradation, photochemical, adsorption, chemical, electrochemical, photo-electrochemical, membrane, supercritical extraction and catalytic method. Chlorine can react with various organic and inorganic micro-pollutants. However, the potential reactivity of chlorine for specific compounds is small, and only minor variations in the structure of the parent compound are anticipated in the water treatment process under typical conditions. This paper reviews different techniques and aspects related to chlorine removal, the types of chlorine species in solution and their catalyst, chlorine fate and transport into the environment, electrochemical techniques for de-chlorination of water, kinetics, mechanisms of reduction of chlorinated compounds, and kinetics of the electrochemical reaction of chlorine compounds. Keywords: Industrial waste, Kinetics, Wastewater, Water purification


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