Industrial Textile Wastewater Treatment Research Articles

Treatment of industrial textile wastewater by the solar photoelectro-Fenton process: Influence of solar radiation and applied current

This work addresses the removal of Acid Blue 29 (AB29) textile dye by a solar photo-electro-Fenton (SPEF) process. Ten liter AB29 solutions containing 100 mg L−1 total organic carbon (TOC), 0.5 mM Fe2+ and 0.05 M Na2SO4 at a pH of 3.0 were electrolyzed by applying current densities of 25 and 50 mA cm−2 in a pilot plant built in our laboratory. The pilot plant was composed of an electrochemical filter press cell with a dimensionally stable anode (DSA-type) and an air-diffusion cathode coupled to a solar photo-reactor.AB29 was completely mineralized by SPEF at the end of electrolysis, while the solution achieved decolorization in short periods of time on sunny days. Reaction intermediates, such as aromatic compounds, carboxylic acids and inorganic ions, were found during the oxidation process. Solar irradiation favors the mineralization of the dye in cost and efficiency compared to other electrochemical methods. Moreover, the treatment of an industrial textile effluent containing AB29 by SPEF produced mineralization greater than 90% on sunny days.

Novel hydroxyapatite-based bio-ceramic hollow fiber membrane derived from waste cow bone for textile wastewater treatment

Industrial textile wastewater is toxic due to the presence of recalcitrant color pigments and poisonous heavy metals. In this study, the hydroxyapatite (HAp)-based bio-ceramic hollow fiber membranes (h-bio-CHFM) were developed via the combined phase inversion and sintering technique. It was found that the properties of the developed h-bio-CHFMs were greatly affected by the HAp content of the ceramic suspension, and sintering temperature. The h-bio-CHFM with the sintering temperature of 1200 °C exhibited the long rod-shaped HAp particles and the smallest pore size (0.013 μm). High removals of color (99.9%), COD (80.1%), turbidity (99.4%) and conductivity (30.1%) were achieved using the h-bio-CHFM sintered at 1200 °C with stable high flux of 88.3 L/m2h. Remarkably, the h-bio-CHFM sintered in the temperature range of 1000–1200 °C also demonstrated excellent adsorption ability towards heavy metals with 100% removals. The results of this study show the potential of the h-bio-CHFM for the efficient industrial textile wastewater treatment applications.

Using scrap zero valent iron to replace dissolved iron in the Fenton process for textile wastewater treatment: Optimization and assessment of toxicity and biodegradability

A Fenton like advanced oxidation process (AOP) employing scrap zerovalent iron (SZVI) and hydrogen peroxide (H2O2) was studied for industrial textile wastewater treatment from a textile manufacturing plant located at Medellín, Colombia (South America). The wastewater effluent studied contains a mixture of organic compounds resistant to conventional treatments. The effect of initial pH and SZVI concentration and H2O2 concentration were studied by a response surface methodology (RSM) Box-Behnken design of experiment (BBD). The combined SZVI/H2O2 process led to reductions of 95% color, 76% of chemical oxygen demand (COD) and 71% of total organic carbon (TOC) at optimal operating conditions of pH = 3, SZVI = 2000 mg/L and [H2O2] = 24.5 mM. Molecular weight distribution measurement (MWD), ultraviolet–visible (UV–Vis) spectroscopy, HPLC, biodegradability and toxicity were used to characterize the pollutants after the treatment process finding that the resulting effluent was polluted mostly by low molecular weight carboxylic acids. A remarkable biodegradability enhancement of the effluent was evidenced by a BOD5/COD ratio increase from 0.22 to 0.4; also, the SZVI/H2O2 process successfully reduced the toxicity from 60% to 20% of dead A. Salina crustaceans.

Industrial textile wastewater treatment via membrane photocatalytic reactor (MPR) in the presence of ZnO-PEG nanoparticles and tight ultrafiltration

In the present study, the degradation of industrial textile wastewater (SDWW) was investigated using a membrane photocatalytic reactor (MPR) in the presence of zinc oxide capped with polyethylene glycol (ZnO-PEG) nanoparticles and polypiperazine-amide (PPA) tight ultrafiltration membrane (UF-PPA). The optimum operating conditions of MPR were obtained under initial pH 11, 0.10 g/L of ZnO-PEG nanoparticles, and 75% dilution of SDWW. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) analyses confirmed that ZnO-PEG nanoparticles and the UF-PPA membrane have great potential as an alternative treatment to meet the stringent discharge limits. The mechanisms of membrane fouling for the optimum operational condition were investigated using model fitting according to the Wiesner and Aptel equations. It was revealed that cake formation occurred rapidly at both stages of the fouling mechanism. Hence, it is believed that this integrated approach has a great potential to be implemented in the industrial textile wastewater treatment sector to ensure the environmental cleanliness for future generations.

A review of the existing and emerging technologies in the combination of AOPs and biological processes in industrial textile wastewater treatment

The textile industry is known as releasing huge amounts of wastewater contaminated by a large spectrum of chemicals. There are several units (e.g. printers, mercerizing machines, finishing machines, dyers) within a dye house that generate different types of effluents, some of which (mostly dyers) work in batch mode. As a result, the wastewater composition varies significantly in concentration and time. Due to this, textile wastewater treatment can be very complicated. The recent trend in the textile industry is on-site wastewater treatment and the process water recycling. This review paper presents the recent developments in Advanced Oxidation Processes (AOPs), biological processes and their combinations for industrial textile wastewater. Most studies only investigated the mixed wastewater originating from the plants, without a deeper consideration on the effluents generated by different units within the dye house. Due to an extreme variation of the textile wastewater quality, the strategy of the division of the wastewater into separated streams according to their biodegradability is highly recommended. Particular attention has been paid in this review to the comparison of cost effectiveness of wastewater treatment processes. The presented considerations are based not only on a literature survey of the last 20 years but also on exemplified industrial cases of the application of AOPs and biological process in textile factories in Poland.

Reduction of adsorbed dyes content in the discharged sludge coming from an industrial textile wastewater treatment plant using aerobic activated sludge process

Dye mass balance study at full-scale industrial textile wastewater (ITW) treatment plant showed that 1.5 ton of excess waste sludge, containing 304.5 Kg of dyes, are daily produced and discharged in landfills. Therefore, this by-product of activated sludge process (ASP) presents a serious environmental problem. In this work, a laboratory and pilot scale investigations were carried out to optimize aerobic biodegradation efficiency to reduce the amount of residual adsorbed dye that will be found in the waste sludge. The resistance of acclimated biomass to the toxicity of ITW was studied in 2.5 L batch reactors using different dye to biomass (D/B) ratios of 0.102, 0.25 and 0.72 g CODS/g VSS. Results of respirometric analyses showed that acclimated activated sludge (AS) biomass is able to treat ITW at high D/B ratio of 0.72 g CODS/g VSS. Moreover, biodegradation kinetic study using Monod law showed that COD and color removal were better for the highest D/B ratio. The half saturation coefficient of heterotrophs for indigo dye (KSind) of 20.01 g/m3 showed high affinity between biomass and dye molecules. Optimization of the process at pilot-scale with different hydraulic retention time (HRT) of 2–5 days, and different sludge recycling rates (SRR) of 220–680 m3/d, showed that high HRT of 5 days and a SRR of 0.22 allowed the best dye biodegradation efficiency (95%). Application of the best conditions at full-scale reduced significantly (89%) the amount of the discharged dyes from 304.5 Kg/d to 33 Kg/d. Results were numerically validated using a mathematical model based on the activated sludge model 1 (ASM1).

Comparison of sludge settling velocity and filtration time after electrocoagulation process in treating industrial textile dyeing wastewater: RSM optimization

Electrocoagulation process (EC) is one of the best economic methods for industrial textile dyeing wastewater treatment; however, produced sludge is the main problem of this method. So sludge settling velocity (SSV) and filtering time (FT) of sludge are effective on area requirement and operating costs. Effect of four operational parameters including electrodes type, pH, current density and electrodes distance was investigated on SSV and FT. Decolorization and chemical oxygen demand (COD) removal of wastewater were checked. The results showed the more effect of electrodes type rather than of variable parameters. SSV and FT were 0.02–0.14 cm/min, 0.2–8.34 min for Al electrodes and 0.05–1.55, 0.42–2.78 min for Fe electrodes at all conditions. Also decolorization and COD removal were 62–94.5, 14.74–36.74% for Al electrodes arrangement and 83.91–94.59, 24.6–44.45% for Fe electrodes arrangement. Comparison between Al and Fe electrodes showed that Fe electrodes were better than Al for filtration and settling after EC process. Fe electrodes have high impact on SSV and FT, but have no effect on decolorization and COD removal. Optimum condition was initial pH of 7.43, current density of 5 mA/cm2 and electrodes distance of 0.5 cm, which SSV, decolorization and COD removal were 1.72 cm/min, 83.78 and 35.48%, respectively.

Treatment of industrial dyeing wastewater with a pilot-scale strengthened circulation anaerobic reactor

We developed a pilot-scale strengthened circulation anaerobic (SCA) reactor (with an effective volume of 27 m3) and applied to the treatment of industrial textile wastewater. The treatment performance and the working mechanism were studied systematically and the key operational parameters were identified. The results demonstrated that a stable and excellent chemical oxygen demand removal efficiency of 62.7% and a maximum chromaticity removal efficiency of 73.5% were obtained at an optimal reflux ratio of 4. Interestingly, the bio-degradability was evidently improved after the SCA reactor treatment. The high throughput sequencing analysis indicated that the diversity of the bacteria or archaebacteria before the treatment was slightly higher than that after the treatment, which may be attributed to the production of certain toxic intermediates and/or characteristic pollutants during the treatment. Enzyme activity test and COD removal show that numerous microorganisms still maintained active in the anaerobic granular sludge even in a severe environment.

Coagulation-flocculation sequential with Fenton or Photo-Fenton processes as an alternative for the industrial textile wastewater treatment

In this study, the industrial textile wastewater was treated using a chemical-based technique (coagulation-flocculation, C-F) sequential with an advanced oxidation process (AOP: Fenton or Photo-Fenton). During the C-F, Al2(SO4)3 was used as coagulant and its optimal dose was determined using the jar test. The following operational conditions of C-F, maximizing the organic matter removal, were determined: 700 mg/L of Al2(SO4)3 at pH = 9.96. Thus, the C-F allowed to remove 98% of turbidity, 48% of Chemical Oxygen Demand (COD), and let to increase in the BOD5/COD ratio from 0.137 to 0.212. Subsequently, the C-F effluent was treated using each of AOPs. Their performances were optimized by the Response Surface Methodology (RSM) coupled with a Box-Behnken experimental design (BBD). The following optimal conditions of both Fenton (Fe2+/H2O2) and Photo-Fenton (Fe2+/H2O2/UV) processes were found: Fe2+ concentration = 1 mM, H2O2 dose = 2 mL/L (19.6 mM), and pH = 3. The combination of C-F pre-treatment with the Fenton reagent, at optimized conditions, let to remove 74% of COD during 90 min of the process. The C-F sequential with Photo-Fenton process let to reach 87% of COD removal, in the same time. Moreover, the BOD5/COD ratio increased from 0.212 to 0.68 and from 0.212 to 0.74 using Fenton and Photo-Fenton processes, respectively. Thus, the enhancement of biodegradability with the physico-chemical treatment was proved. The depletion of H2O2 was monitored during kinetic study. Strategies for improving the reaction efficiency, based on the H2O2 evolution, were also tested.

Reactive Blue Dye Removal by Membrane Distillation using PVDF Membrane

Background/Objectives: Membrane distillation (MD) is a thermally driven water separation process which has lately attracted the attention from the academics and industries due to its lower energy requirement relative to pressure driven process. The aim of this paper is to study the performance of self-fabricate hollow fiber membrane in reactive blue dye removal by membrane distillation technique. Methods/Statistical Analysis: In this work, the potential use of polyvinylidene fluoride (PVDF) for reactive blue dye removal was study by direct contact membrane distillation (DCMD). The membranes were produced by phase inversion spinning method with 1-methyl-2-pyrrolidone (NMP) solvent and ethylene glycol (EG) additive. The membranes were characterized in term of membrane morphology, porosity, liquid entry pressure and hydrophobicity. Findings: Relative to the pristine membrane, PVDF membrane with additive was discovered to be possessed enhanced membrane characteristics, i.e. higher liquid entry pressure and larger pore size. In terms of membrane stability, the experimental results demonstrated that the PVDF membranes with EG as additive were able to generate consistent flux, while maintaining a superior rejection rate of reactive blue dye. Application/Improvements: The result in this work shown that PVDF membrane with EG as additive possesses a superior permeate flux performance and rejection rate which suggested that this membrane possesses the prospect to be applied in the industrial textile wastewater treatment.

Application of Iron Electrode in Textile Industry Wastewater Treatment Using Electro-fenton Technique: Experimental and Statistical Study

The application of synthetic colors in textile industries and their entry into the water and groundwater is an environmental problem because of being very toxic material. The synthetic colors which are used in textile dyeing (plyacrilic and polyester) are usually dispersing colorants. They derive the azo and anthraquinone chemicals. Electro-Fenton process is an efficient technique which can degrade the recalcitrant wastewaters. The main goal of the present study was to examine the effect of iron electrodes (as a cheap and available material) on industrial textile wastewater treatment by electro- Fenton technique. The experiments were conducted to evaluate the effects of reaction time, current density, pH, H 2 O 2 /Fe 2+ molar ratio and volume ratio of H 2 O 2 to textile wastewater (TW) (ml/l) on the process. Response surface methodology (RSM) was used to consider the effects of five independent variables on the COD and color removal from the wastewater and optimize the operating conditions. The optimum conditions were obtained at reaction time of 71.74 min, current density of 40.11 mA/cm 2 , pH 2.84, H 2 O 2 /TW of 2.03 (ml/l), H 2 O 2 /Fe 2+ molar ratio of 3.89 for COD removal of 76.33%. Furthermore, optimum conditions were found at reaction time of 75.97 min, current density of 67.04 mA/cm 2 , pH 2.98, H 2 O 2 /TW of 1.69 (ml/l), H 2 O 2 /Fe 2+ molar ratio of 2.98 for color removal of 79.33%.

The potential of direct contact membrane distillation for industrial textile wastewater treatment using PVDF-Cloisite 15A nanocomposite membrane

This work demonstrates the feasibility of employing direct contact membrane distillation (DCMD) for treating industrial textile wastewater for clean water production. Experimental results showed that the in-house fabricated polyvinylidene fluoride-Cloisite 15A polymer–inorganic nanocomposite membrane is robust and able to treat the industrial effluent by reducing at least 89% of the initial values of the water quality parameters measured. However, the membrane permeate flux was reported to decline almost 50% in the first few hours of the 40-h treatment process before reaching water flux of 13–22kg/m2h. It is believed that the initial flux decline is mainly caused by the foulants accumulated on the membrane outer surface that increases mass transfer resistance of water molecules and reduces water productivity. With respect to separation characteristics, the DCMD process has shown better performance for COD and color removal in comparison to the other commonly used pressure-driven membrane processes. Further improvement on the membrane surface properties is necessary to reduce fouling propensity and pore wetting caused by the surfactants and other foulants in the textile wastewater. This is of particular importance for long-term operation of DCMD process.

Integrated process of fungal membrane bioreactor and photocatalytic membrane reactor for the treatment of industrial textile wastewater

In this study, fungal membrane bioreactor (FMBR) and semiconductor photocatalytic membrane reactor (PMR) were used in order to test the efficiency of integrated fungal biodegradation and photocatalytic degradation of textile wastewater from reactive washing processes. It was found that color removal and chemical oxygen demand (COD) reduction efficiencies were 88% and 53% for photocatalytic degradation, respectively. TiO2 and ZnO were tested as semiconductor catalysts in the PMR and TiO2 showed better efficiencies than ZnO for both color and COD removal. However, it was attained that color removal and COD reduction efficiencies were about 56% and 60% for fungal biodegradation using Phanerochaete chrysosporium, respectively. Moreover, integrated system in which photocatalytic degradation was employed as a post-treatment application after fungal biodegradation process achieved high removal efficiencies for color and COD removal as 93% and 99%, respectively.

Optimization of coagulation-flocculation process for treatment of industrial textile wastewater using okra (A. esculentus) mucilage as natural coagulant

The use of natural coagulant in coagulation/flocculation treatment (CF) of wastewater shows many advantages over chemical agents, particularly biodegradability, low toxicity, low residual sludge production and low-cost. We investigate the coagulant activity of okra mucilage (Abelmoschus esculentus) as natural coagulant and their efficiency was compared to chloride ferric (chemical agent) in CF of textile wastewater. Optimization assays were conducted by the standard jar test method. The effect of pH, coagulant dosage and mucilage dosage on the percent removal of chemical oxygen demand (COD), turbidity and color were analyzed. A high removal of color (93.57%), turbidity (97.24%), COD (85.69%) was obtained using a low amount of the okra mucilage; 3.20mg L−1, 88.0mg L−1 Fe3+ at pH 6.0. The amount of Fe3+ can be reduced up to 72.5% (from 320.0 to 88.0mgL−1) and can increase the COD removal about 35.74% with addition of okra mucilage. The mucilage of residual okra has coagulant activity in the textile wastewater treatment and showed to be an available, biodegradable and non-toxic coagulant.

Membrane Processes for Dye Wastewater Treatment: Recent Progress in Fouling Control

The textile industry generates large volumes of effluents on a daily basis, which contains substantial loads of organic compounds, inorganic salts, and suspended impurities. Membrane filtration has become an essential part of advanced treatment plants for dye wastewater treatment. Prevention of membrane fouling is one of the critical objectives for making the overall treatment process commercially viable. Development in this area during the past decade is critically evaluated in this review. Recent developments in the primary, secondary, and tertiary treatment steps in textile wastewater treatment are outlined. The methods employed for measuring, modeling, and understanding membrane fouling processes are discussed. Specific efforts toward fouling control by (a) pretreatment stages of textile wastewater and (b) modifying and optimizing the membrane separation process parameters such as feed composition, hydrodynamic conditions, and membrane properties are then assessed. Fouling related investigations for microfiltration/ultrafiltration membranes, membrane bioreactors, reverse osmosis, and nanofiltration membranes with special focus on textile wastewater treatment are discussed. Recent efforts toward developing new membranes and cleaning processes for fouled membrane activation are also discussed. Pilot plant studies involving membrane separation in combination with other treatment processes are also summarized. Strategies evolved and experiences gained from the industrial scale textile wastewater treatment plants in India are discussed. The authors also summarize the opportunities and the challenges remaining at different stages of industrial textile wastewater treatment units.

Statistical optimization of industrial textile wastewater treatment by electrochemical methods

In this work, the Box–Behnken experimental design and the surface response methodology were applied for the optimization of the operational conditions of the electro-catalytic degradation of wastewaters, resulting from a local textile industry. The experiments were carried out in a laboratory scale batch cell reactor, with monopolar configuration, and electrodes made of boron-doped diamond (anode) and titanium (cathode). The multifactorial experimental design included the following variables: current density (i: 5–10 mA/cm2), pH (3–7), and submerged cathode area (CA: 8–24 cm2). To determine the process efficiency, the degradation percentage of: the chemical oxygen demand (%DCOD), the total organic carbon (%DTOC) and the color (%DC) were defined as response variables. The following optimal conditions for the electro-oxidation (EO) process were obtained: i = 10 mA/cm2, pH = 3 and CA = 16 cm2, reaching ca. 92 % of DC, 37 % of DCOD and 31 % of DTOC. The electro-Fenton (EF) and photo-electro-Fenton (PEF) processes were also evaluated at EO optimal conditions. For the EF process, with addition of iron (0.3 mM), the %DC, %DCOD and %DTOC was enhanced to 95, 52 and 45 %, respectively. For the PEF process (UV = 365 nm), it was possible to reach 98 %DC, 56 %DCOD and 48 %DTOC.

Development of an asymmetric carbon microfiltration membrane: Application to the treatment of industrial textile wastewater

Tubular carbon microfiltration membranes have been prepared using mineral coal powder (100μm average particle size) mixed with phenolic resin solution and organic additives. The porosity of the support can be sharply controlled by fixing the organic additives percentages, the particles size and the homogeneity of the carbon powder. A mesoporous active layer was deposited on the inner face of the carbon support by slip casting using a deflocculated slip made of mineral coal powder (1.76μm) suspended in a phenolic resin solution. An active layer with an average pore diameter of 0.60μm is obtained after carbonization under nitrogen atmosphere. The obtained membrane has very interesting characteristics regarding mechanical and chemical resistances. The application to the treatment of industrial textile wastewater shows good performances in term of permeate flux and efficiency (retention of COD and salinity of 50% and 30% respectively and almost a total retention of turbidity and color).

Applicability of a new pre-hydrated industrial grade polyaluminium salt for the decolourisation of textile wastewater

This study was conducted to assess the decolourisation and chemical oxygen demand (COD) reduction efficiency of a novel pre-hydrated aluminium salt as aluminium chlorohydrate (ACH) for the treatment of textile wastewater using coagulation/flocculation technology. Though, ACH belongs to the same group of polyaluminium salts, it is significantly different from polyaluminium chloride (PACl) in terms of the degree of hydration and alumina content and was used for the first time as a coagulant for the decolourisation of synthetic as well as real textile wastewater. The experimental results revealed that ACH is highly effective for the treatment of synthetic textile wastewater producing more than 99% of colour removal and 45% of COD reduction efficiency at a very low dosage of 200 mg L−1. The decolourisation of real textile wastewater was found to be very much in line with the results obtained for the treatment of synthetic textile wastewater. Superior decolourisation efficiency at a very low dosage as compared to that of the pre-established studies for real textile wastewater and least volume of easily dewatered sludge production makes ACH a novel and very promising coagulant for the treatment of industrial textile wastewater.

Treatment of Industrial Textile Wastewater Using Polyarcrylamide (PAM) and Polyaluminium Chloride (PAC)

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

Continuous electrochemical treatment of simulated industrial textile wastewater from industrial components in a tubular reactor

The continuous electrochemical treatment of industrial textile wastewater in a tubular reactor was investigated. The synthetic wastewater was based on the real process information of pretreatment and dyeing stages of the industrial mercerized and non-mercerized cotton and viscon production. The effects of residence time on chemical oxygen demand (COD), color and turbidity removals and pH change were studied under response surface optimized conditions of 30 °C, 25 g/L electrolyte concentration and 3505 mg/L COD feed concentration with 123.97 mA/cm 2 current density. Increasing residence time resulted in steady profiles of COD and color removals with higher treatment performances. The best column performance was realized at 3 h of residence time as 53.5% and 99.3% for COD and color removals, respectively, at the expense of 193.1 kWh/kg COD with a mass transfer coefficient of 9.47 × 10 −6 m/s.