Actual Textile Wastewater Research Articles

Advanced treatment of actual textile dye wastewater by Fenton‐flocculation process

AbstractTo improve the performance of actual textile dye wastewater treatment, an advanced treatment combining the Fenton and flocculation processes was developed. The parameters affecting decolorization in the Fenton‐flocculation process, including initial pH, H2O2 dosage, Fe2+dosage, reaction temperature, reaction time, and flocculant dosage, were examined. With the optimal Fenton‐flocculation condition parameters, more than 95 % COD removal, 99 % colour removal, and 99 % turbidity removal were obtained. UV‐visible spectra of raw water and supernatant were further obtained after the Fenton‐flocculation process, and results demonstrated that the chromophoric groups and the conjugated system in the dye molecular structure were destroyed. All these results confirmed that the Fenton‐flocculation process was a favourable and effective post‐treatment method for actual textile dye wastewater.

Effectiveness on color and COD of textile wastewater removing by biological material obtained from Cassia fistula seed


 
 
 Nowadays, natural polymeric materials extracted from plants are the new alternatives for synthetic chemicals in water and wastewater treatment. The aim of this study is to evaluate the ability of Cassia fistula seed gum (CFG) as a coagulant aid with PAC in the treatment of textile wastewater. Jartest experiments were carried out to identify the optimal parameters of coagulation-flocculation for removing color and COD in synthesis wastewater containing Methyl blue and RB21 dyes, including pH, settling time, PAC dose, the optimal CFG dosage in comparing with the cationic polymer. After that, actual textile wastewater was treated by using PAC, PAC plus cationic polymer, and PAC plus CFG for evaluating the role of CFG. CFG supplementation has assisted the process effects at nearly 98% color, 85% COD for RB21 and 90% color, 70% COD for MB at the best dose of CFG 0.15 mL and 0.1 mL, respectively. The optimized parameters for the coagulation of real textile wastewater using PAC were pH = 6 and dose = 0.6 mL can removal 66% of color. By adding CFG to PAC, the efficient of treatment was increased about 70% even at the lower dosage of PAC and CFG (0.5 mL for each reagent). The yield of combining PAC and polymer was a little bit lower than PAC and CFG, for instant 68% color was decreased at the same condition. These achievements demonstrated a workable substitute of natural products such as Cassis fistula seed gum for synthetic chemical products in coagulation-flocculation process.
 Hiện nay các loại vật liệu sinh học chiết xuất từ thực vật đang được nghiên cứu ứng dụng trong xử lý nước và nước thải thay cho các chất hóa học. Mục tiêu của nghiên cứu này là đánh giá hiệu quả của việc sử dụng gum được chiết xuất từ hạt cây Muồng Hoàng Yến (MHY) làm chất trợ keo tụ trong xử lý nước thải dệt nhuộm. Thí nghiệm Jartest được tiến hành nhằm xác định các điều kiện tối ưu cho quá trình xử lý nước thải tổng hợp chứa thuốc nhuộm Methyle Blue (MB) và RB21 bao gồm pH, thời gian lắng, liều PAC, liều gum MHY và liều polymer. Sau đó tiến hành xử lý nước thải thật với các điều kiện thích hợp đã xác định nhằm đánh giá vai trò của gum MHY. Gum MHY làm tăng hiệu quả của quá trình xử lý, đạt gần 98% đối với độ màu, 85% COD đối với RB21, 90% độ màu và 70% COD đối với MB với liều lượng tương ứng là 0,15 mL và 0,1 mL. Các thông số tối ưu cho quá trình xử lý trên mẫu nước thải thật là pH = 6, liều PAC = 0.6 mL có thể làm giảm 66% độ màu. Bổ sung gum MHY làm chất trợ keo tụ giúp gia tăng hiệu quả xử lý màu lên 70% dù với liều lượng rất thấp là 0,5 mL. Hiệu suất xử lý khi sử dụng kết hợp PAC và polymer thấp hơn trong trường hợp sử dụng PAC và gum MHY, cụ thể khoảng 68% độ màu được xử lý ở cùng một điều kiện. Những kết quả này cho thấy tiềm năng của việc sử dụng các vật liệu gum tự nhiên nhằm thay thế cho các hợp chất hóa học trong các quá trình keo tụ tạo bông để xử lý nước thải.
 
 

Application of the removal of pollutants from textile industry wastewater in constructed wetlands using fuzzy logic

ABSTRACTThere are more than a hundred textile industries in Turkey that discharge large quantities of dye-rich wastewater, resulting in water pollution. Such effluents must be treated to meet discharge limits imposed by the Water Framework Directive in Turkey. Industrial treatment facilities must be required to monitor operations, keep them cost-effective, prevent operational faults, discharge-limit infringements, and water pollution. This paper proposes the treatment of actual textile wastewater by vertical flow constructed wetland (VFCW) systems operation and monitoring effluent wastewater quality using fuzzy logic with a graphical user interface. The treatment performance of VFCW is investigated in terms of chemical oxygen demand and ammonium nitrogen (NH4-N) content, color, and pH parameters during a 75-day period of operation. A computer program was developed with a fuzzy logic system (a decision- making tool) to graphically present (via a status analysis chart) the quality of treated textile effluent in relation to the Turkish Water Pollution Control Regulation. Fuzzy logic is used in the evaluation of data obtained from the VFCW systems and for notification of critical states exceeding the discharge limits. This creates a warning chart that reports any errors encountered in a reactor during the collection of any sample to the concerned party.

Novel wedge structured rotating disk photocatalytic reactor for post-treatment of actual textile wastewater

A wedge structured rotating disk photocatalytic (PC) reactor was used for post-treatment of actual textile wastewater collected after activated sludge treatment. Compared with a conventional planar disk, the wedge structured disk had larger surface area and exhibited better light utilization efficiency. Treatment conditions such as pH and rotating speed were optimized. The COD content in effluent was reduced from 380mgO2L−1 to 109 and 56mgO2L−1 respectively after 3h and 5h treatment at pH 6.0 and rotating speed of 20rpm. The effect of anions (NO3−, SO42− and Cl−) in actual textile wastewater on treatment was investigated. Benefit from high light utilization efficiency, the wedge rotating disk reactor could compensate COD removal inhibition caused by anions. A 1.5V voltage was also applied to perform photoelectrocatalysis process to further improve the performance, and no additional electrolyte was needed. COD in effluent was reduced to as low as 75mgO2L−1 after 3h treatment. In addition, this reactor was used to treat other water samples including the actual textile wastewaters collected before activated sludge treatment (initial COD of 880mgO2L−1) and after activated carbon adsorption post-treatment (initial COD of 108mgO2L−1). Experimental results suggested that wedge structured rotating disk photocatalysis process was stable, efficient and worth further scale-up investigation.

Adsorption of textile dye onto modified immobilized activated alumina

The study describes the synthesis of modified immobilized activated alumina (MIAA) and its application for the removal of textile dye from aqueous media. Immobilization was carried out by using the sol–gel method while modifications were made during the synthesis by adding powder activated alumina. Batch adsorption experiments were carried out at 20±1°C to see the effect of different parameters like contact time, stirring rate, initial concentration of the dye and dose of MIAA. The removal efficiency of Cibacron reactive yellow dye with an initial concentration of 400mg/L was greater than 90% for 90min contact time. Langmuir and Freundlich adsorption isotherms were applied which fitted the data with an R2 value of 0.99. The maximum adsorption capacity of MIAA was 25mg/g at the initial dye concentration of 400mg/L. MIAA can be regenerated thermally and chemically with the dye removal efficiency remained above 85% during the first 4 regeneration cycles. Thermal regeneration was achieved in a muffle furnace at 450°C while chemical regeneration was done by immersing MIAA in 0.1M NaOH solution for 2h. MIAA also proved effective for the adsorption of dyes from actual textile wastewater giving a removal efficiency of 75%.

Electrochemical oxidation of textile industry wastewater by graphite electrodes

In the present article, studies have been performed on the electrochemical (EC) oxidation of actual textile industry wastewater by graphite electrodes. Multi‐response optimization of four independent parameters namely initial pH (pHo): 4–10, current density (j): 27.78–138.89 A/m2, NaCl concentration (w): 0–2 g/L and electrolysis time (t): 10–130 min have been performed using Box‐Behnken (BB) experimental design. It was aimed to simultaneously maximize the chemical oxygen demand (COD) and color removal efficiencies and minimize specific energy consumption using desirability function approach. Pareto analysis of variance (ANOVA) showed a high coefficient of determination value for COD (R2 = 0.8418), color (R2 = 0.7010) and specific energy (R2 = 0.9125) between the experimental values and the predicted values by a second‐order regression model. Maximum COD and color removal and minimum specific energy consumed was 90.78%, 96.27% and 23.58 kWh/kg COD removed, respectively, were observed at optimum conditions. The wastewater, sludge and scum obtained after treatment at optimum condition have been characterized by various techniques. UV‐visible study showed that all azo bonds of the dyes present in the wastewater were totally broken and most of the aromatic rings were mineralized during EC oxidation with graphite electrode. Carbon balance showed that out of the total carbon eroded from the graphite electrodes, 27–29.2% goes to the scum, 71.1–73.3% goes into the sludge and rest goes to the treated wastewater. Thermogravimetric analysis showed that the generated sludge and scum can be dried and used as a fuel in the boilers/incinerators.

An efficient biotreatment process for polyvinyl alcohol containing textile wastewater

The aim of this work was to optimize the biodegradation of polyvinyl alcohol (PVA) containing actual textile wastewater for a sustainable treatment solution. The isolated microbial consortia of effective PVA degrader namely Candida Sp. and Pseudomonas Sp., which were responsible for symbiotic degradation of chemical oxidation demand (COD) and PVA from desizing wastewater. In the process optimization, the maximum aeration was essential to achieve a high degradation rate, where as stirring enhances further degradation and foam control. Batch experiments concluded with the need of 16 lpm/l and 150 rpm of air and stirring speed respectively for high rate of COD and PVA degradation. Optimized process leads to 2 days of hydraulic retention time (HRT) with 85–90% PVA degradation. Continuous study also confirmed above treatment process optimization with 85.02% of COD and 90.3% of PVA degradation of effluent with 2 days HRT. This study gives environment friendly and cost effective solution for PVA containing textile wastewater treatment.

Preparation, characterization and coagulation behaviour of a novel inorganic coagulant – polyferric(III)-magnesium(II) sulfate

A novel coagulant, polyferric(III)-magnesium(II) sulfate (PFMS), was prepared. The preparation technology was optimized and the optimized PFMS product was used to treat actual textile wastewater. The performance of PFMS was evaluated and compared with those of conventional coagulants. X-ray diffraction and infrared spectrometry show that PFMS is a macromolecular composite polymer of ferric and magnesium based on –OH bonds. The coagulation performance of PFMS is better than those of PFS, PAC, and PFC. The coagulation mechanism of PFMS in treating actual textile wastewater is primarily driven by charge neutralization at low dosages and co-precipitation netting at high dosages.

Photocatalysts and Photoreactors for Treatment of Industrial Effluents

Development of photocatalysts and photoreactors for treatment of industrial effluents is considered important to harness solar energy for environmental clean up. The photocatalytic method of decolorization of textile dyes utilizes UV component of sunlight (3-5%) and the only solid phase (TiO2catalyst) can be recycled on a technical scale. Moreover, the method does not produce any sludge unlike adsorption and coagulation methods. These attributes of the photocatalytic method are attractive for possible application in industry. Our group is presently working on pilot scale photoreactors and exploring feasibility of industrial application of this technique. We have developed a few TiO2based photocatalysts (P-25 TiO2, ZnO, TiO2(bulk) and rare earth metal (In2O3, Nd2O3, Yb2O3and Sm2O3) doped TiO2), photo catalyst bearing supports (e.g., acrylic sheet) and photoreactors (annular immersion well type, falling film type and shallow slurry photoreactors) for use with UV & sunlight. We have carried out a few tests with Solar Slurry Photoreactor (SSPR) in field using actual textile wastewater with encouraging results. The SSPR developed under this study was capable of decolorizing textile wastewater under specified conditions approximately with a treatment rate of 9.0 Lh-1. The reactor area exposed to sunlight was approximately 1 m2. Thus, a reactor having 18-20 m2exposed area would treat about 1.0 m3textile wastewater at a rate approximately equal to180 Lh-1. The present data suggest that it may be possible to apply this technique initially for the color treatment of textile wastewater from small dyeing operations. However, the details of techno-economic feasibility need to be assessed beforehand. The proposed book chapter would present details of all the above-mentioned efforts. It would be targeted to bring out inadequacies associated with the photocatalytic technology for wastewater treatment.

Utilization of silica gel waste for adsorption of cationic surfactant and adsolubilization of organics from textile wastewater: A case study

The use of silica gel waste (SGW) as an adsorbent was found to be a very attractive alternative for removal of cationic surfactant (CS) from industrial (textile) wastewater. In the present work, the actual textile wastewater containing 362mg/l CS (in terms of CTAB) was treated by SGW in both batch and continuous modes. In batch mode, the optimum adsorbent dose and equilibrium time were found to be 10g/l and 30min respectively. Under optimized conditions, high removal efficiency of CS was achieved (~87%) and subsequent solubilization of other organic pollutants was found to occur through adsolubilization. The adsorption followed the Freundlich isotherm model. The breakthrough and exhaust times were found to be 6.5 and 13h respectively for a column of depth 50mm, maintaining the loading rate at 1.22m3/m2/h. The value of adsorption rate coefficient (K) and adsorption capacity coefficient (N) were found out. Regeneration of SGW after its exhaustion was efficiently done using 18% hydrochloric acid. The use of a solid waste of a factory as an adsorbent for removal of cationic surfactant and subsequent adsolubilization of organics made the process very cost effective alternative for textile wastewater treatment.

Removal of color from textile dyeing wastewater by foam separation

The feasibility of foam separation for color removal from direct dyes-containing wastewater was assessed using actual textile wastewater as the research system and cetyl trimethyl ammonium bromide (CTAB) as the collector. The influences of liquid loading volume, air flow rate, surfactant concentration, and initial pH on the removal efficiency and reuse of CTAB in the foamate were studied. The results indicated that using CTAB as a collector for foam separation can provide good foaming quality and effectively remove color from textile wastewater. Under optimum operational conditions (liquid loading volume 450 mL, gas flow rate of 500 mL/min, CTAB concentration 20 mg/L, and an initial pH of 7.0), the removal efficiency reached 88.9%. The residual dye content met the discharge standard for the dyeing and finishing textile industry (GB4287-92) published by the Ministry of Environmental Protection of the People's Republic of China. Using recycled foamate in untreated wastewater, the removal efficiency of 87.5% was obtained with CTAB concentration 10 mg/L of the wastewater.

Color removal from textile wastewater by using treated flute reed in a fixed bed column

This study investigated the ability of acid treated flute reed to adsorb color (dye) from synthetic reactive dye solutions, and actual dyeing and printing textile wastewaters in a laboratory scale fixed bed column. The effects of particle size, initial reactive dye concentration, bed depth and flow rate on adsorption performances were examined. The results from experiments with synthetic reactive dye solutions showed that the volume treated (until the breakthrough occurred) increased with decreasing particle size, influent reactive dye concentration and flow rate, and increasing bed depth. The bed depth service time model was suitable for describing the experimental data. The treated flute reed was able to reduce color efficiently, 99% for dyeing textile wastewater with ten adsorption columns in series and 78% for printing textile wastewater with a single adsorption column. The difference in the numbers of columns used for the two types of actual textile wastewater led to a substantial discrepancy in suspended solids removal, 99% for dyeing wastewater and 12% for printing wastewater. Similar pH and chemical oxygen demand (COD) results were obtained for the two types of textile wastewater. The acid pretreatment of flute reed resulted in dramatic decreases in pH after the adsorption and very acidic effluents (pH 3). Increases of COD after the adsorption due to organic leaching from the treated flute reed were observed. A different pretreatment method to solve these pH and COD problems is needed before flute reed can be used in practice.

Degradation of Textile Dyes, Dyebaths and Dyeing Wastewater by Homogeneous and Heterogeneous Sonophotolysis

AbstractThe degradability of an azo dye (C.I. Acid Black 2), synthetic and real dyebaths, and actual textile dyeing wastewater were investigated using a homogeneous and heterogeneous Advanced Oxidation Processes (AOPs) in combination with power ultrasound (US). The components of the homogeneous process were US, short wave UV-C and ferrous ions, and those of the heterogeneous were US, short wave UV-C, ZnO and H

Enhanced treatment of practical textile wastewater by microbubble ozonation

In this paper, microbubble technology was employed to increase the mass transfer rate of ozone and enhance the ozone oxidation of practical textile wastewater. Experiments were performed using a microbubble generator and a bubble contactor, which is commonly used in ozonation system, for comparison. The microbubble generator produced a milky and high intensity microbubble solution, which could reach a higher oxygen transfer rate at a lower input gas flow rate. A volumetric oxygen transfer rate (VOTR) of 0.086–0.413 kg/m 3 h and a total mass transfer coefficient of 0.1072–0.4859 min −1 were obtained at airflow rates of 0.02–1.5 dm 3/min. During the ozonation of practical textile wastewater by using the microbubble system, the input ozone could be almost completely utilized, and the rate of decolorization and organic reduction were much faster than those of the bubble contactor. For the practical textile wastewater tested, the time required for 80% removal of color was about 140 and 280 min by ozone microbubble and conventional bubbles, respectively. The chemical oxygen demand (COD) removal efficiency in the microbubble system was higher by 20%. The results revealed that in addition to the enhancement of the mass transfer of ozone, microbubbles could improve the oxidation of actual textile wastewater.

A new photon kinetic-measurement based on the kinetics of electron-hole pairs in photodegradation of textile wastewater using the UV-H 2O 2FS-TiO 2 process

Actual textile wastewater and synthesized wastewater containing various textile dyes were photocatalytic degraded by the UVH 2O 2FS-TiO 2 process in an annular-flow photocatalytic reactor. In this process, a photon kinetic-measure was adopted to obtain constant rates of dyes decomposition. It was theorized that, by illumination at different UV frequencies, the electrons within the semiconductor were excited from the valence band to the conduction band, yielding the formation of electron-hole pairs which are the pre-requisites for photocatalysis. CPT (critical photonic time) exposure required to cause 90% of vibrations between the double and single bonds along the molecular chain of the dyes to be oxidized, was taken to measure the photocatalytic activities. The CPTs varied with the frequencies of the UV spectral areas. The derivatization of CPT from the first-order kinetic law was presented.

Simple physical treatment for the reuse of wastewater from textile industry in the Middle East

In this work, different treatment methods for wastewater from textile washing operations in the Palestinian territories were studied. The goal of the treatment process was to enable the textile industry to reuse the wastewater in textile washing through simple, efficient, and cost-effective methodologies. Actual textile wastewater samples from local textile factories were used and were found to be highly polluted. The study focused on three main processes; sedimentation, coagulation, and adsorption. While sedimentation was found to reduce the total suspended solids (TSS) of the wastewater, coagulation had the additional advantages of lowering the chemical oxygen demand (COD) and achieving higher filtration rates. Four coagulants were tested, ferric chloride, ferrous sulfate plus lime, aluminum sulfate, and aluminum sulfate plus lime. While ferric chloride failed to perform effectively as a coagulant, the other three coagulants were fairly effective. Finally, to further lower the COD of post-coagulation treated water, adsorption using activated carbon was studied. It was found that carbon was effective in reducing the COD of the wastewater using reasonable quantities, where up to 98% COD reduction was achieved using 6 g carbon/L.Key words: textile, wastewater, treatment, coagulation, sedimentation, adsorption.

Color removal from simulated dye water and actual textile wastewater using a composite coagulant prepared by ployferric chloride and polydimethyldiallylammonium chloride

In this study, a new composite coagulant, which was prepared by ployferric chloride (PFC) premixed with polydimethyldiallylammonium chloride (PDMDAAC), was adopted to treat the simulated dye water and the actual textile wastewater. The effect of coagulant dosage and pH of dye water on the color removal was examined. And the color removal results treated by the composite coagulant (PFC–PDMDAAC) were compared with those treated by PFC, PDMDAAC and PFC followed by PDMDAAC (PFC/PDMDAAC), respectively. The following results are discovered. Synergy between PFC and PDMDAAC increases zeta potential of PFC–PDMDAAC and reduces the effect of pH on zeta potential and Fe(III) species of PFC–PDMDAAC. Treatment with PFC–PDMDAAC is very effective in removing disperse blue HGL (98%) and reactive blue STE (86%). And small changes in the color removal efficiency of PFC–PDMDAAC are observed in all pH range. The color removal efficiency for disperse blue HGL and reactive blue STE is higher than 96% and 98% in the pH range 7.5–10.5, respectively. Furthermore, PFC–PDMDAAC is shown to be more effective in removing dye than that of PFC/PDMDAAC. Finally, the treatment of the actual textile wastewater has shown that PFC–PDMDAAC is a more effective coagulant.

Treatment of textile dyehouse wastewater by TiO 2 photocatalysis

The oxidative degradation of an actual textile dyehouse wastewater was investigated by means of photocatalysis in the presence of TiO 2. The UV-A-induced photocatalytic oxidation over TiO 2 suspensions was capable of decolorizing the effluent completely, as well as reducing chemical oxygen demand (COD) sufficiently (COD reduction generally varied between about 40% and 90% depending on the operating conditions) after 4 h of treatment. Two crystalline forms of TiO 2, viz. anatase and rutile, were tested for their photocatalytic activity and anatase was found to be more active than rutile. The extent of photocatalytic degradation was found to increase with increasing TiO 2 concentration up to 0.5 g/L TiO 2, above which degradation remained practically constant, reaching a plateau. Furthermore, textile effluent degradation was enhanced at acidic conditions (i.e. pH=3) and in the presence of hydrogen peroxide. To assess catalyst activity on repeated use, experiments were performed where the catalyst was recovered and reused; after three successive uses, TiO 2 had sufficiently retained its photocatalytic activity. Finally, the luminescent marine bacteria Vibrio fischeri was used to assess the acute ecotoxicity of samples prior to and after the photocatalytic treatment and it was found that ecotoxicity was fully eliminated following photocatalytic oxidation.