Synthetic Textile Wastewater Research Articles

Effect of High-Rate Aeration in the Electrocoagulation Treatment of Pharmaceutical and Synthetic Textile Industrial Wastewater Effluents

Despite the extensive literature on the effects of implementing aeration in the electrocoagulation (EC) treatment of industrial wastewater, few studies evaluate the performance of this technique at high aeration rates. In this work, we present the outcomes derived from EC treatment of pharmaceutical and synthetic textile wastewater effluents in two lab-scale reactors with and without aeration, each equipped with different electrode combinations of aluminium and iron (Al/Al, Al/Fe, and Fe/Fe). In the non-aerated EC reactor, maximum chemical oxygen demand (COD) reductions of 56% and 80% were achieved for the pharmaceutical and textile effluents, respectively, with up to 100% removal of turbidity and colour with the Al/Al combination. The installation of high-rate aeration to prevent sludge accumulation on the electrode surface markedly reduced residence times and enhanced the COD removal in the pharmaceutical effluent. However, this implementation potentially reduced the process efficiency for thesynthetic textile effluent as prolonged operation led to flocculation breakdown and subsequent re-dissolution of the contaminants in the water.

Evaluation of Integrated Anaerobic/Aerobic Conditions for Treating Dye-Rich Synthetic and Real Textile Wastewater Using a Soda Lake Derived Alkaliphilic Microbial Consortia

Textile industry wastewater (WW) has intense color, high chemical oxygen demand (COD), pH, and salinity, making it challenging for conventional treatment. Soda lakes, with high alkalinity and salinity, host diverse microbes capable of textile dye degradation. This study evaluated anaerobic/aerobic reactors using alkaliphilic microbial consortia from Lake Chitu, an Ethiopian soda lake, for treating synthetic and real textile WW. The experimental setup consisted of a first-stage anaerobic reactor followed by a second-stage aerobic reactor, operating continuously with a predetermined flow rate and hydraulic residence time. After evaluating synthetic WW, real textile WW was collected in two batches (rounds I and II). The treatment setup removed 99% of the dye color for synthetic WW, 98% for round I, and 96% for round II. COD removal was 87% for synthetic WW, 86% for round I, and 93.37% for round II. TKN removal reached 90% for synthetic WW, 91% for round I, and 96% for round II at a steady state. Residual COD and TKN values met the final effluent discharge standards. GC–MS and IR analyses revealed that dyes were broken down into intermediate organic compounds under anaerobic conditions and further degraded into smaller molecules under aerobic conditions. This integrated reactor approach effectively removes dyes and enhances COD and TKN removal. The study’s novelty lies in evaluating both synthetic and real textile WW using integrated reactors under alkaline conditions in a continuous process, inoculating alkaliphilic consortia, without pre-enrichment or external nutrient addition to real WW. The study provides insights into the effectiveness of alkaliphilic microbial consortia derived from soda lakes for treating textile WW using integrated reactor conditions. Reactor microbiome characterization is needed to further explore microbial diversity and community structure.

Advanced chitosan-based composites for sustainable removal of Congo red from textile wastewater

The non-biodegradable Congo red (CR) dye which is widely used in textile industries has poses carcinogenic risks due to its complex reactions that may generate benzidine. Effective treatment of industrial effluent containing CR dye is imperative. This study assessed chitosan (Cs) and chitosan/fly ash (Cs/Fa) composites for biosorbing CR dye from synthetic textile wastewater. Fly ash varied in the range of (1:0.25–1:1) with chitosan to assess adsorption performance. Characterization techniques included FTIR, SEM, EDX, BET, and zeta potential analyses. Response surface methodology guided the determination of optimal variables. The study examined Cs and Cs/Fa dosage (A), time (B), and initial dye concentration (C) effects on CR removal. Incorporating fly ash substantially cut adsorption costs by 50% while enhancing dye removal up to 85% at pH 6. Improved acidic stability of chitosan (Cs/Fa 1:0.75) was notable. Chitosan (Cs) exhibited a high Congo red removal efficiency of 98% while the chitosan/fly ash (Cs/Fa) composites showed a substantial removal efficiency of 94%. Optimal conditions were 2 g L−1 of adsorbents, initial CR concentration of 40 mg L−1 for 120 min. Freundlich isotherm model best described adsorption behavior. Pseudo-second-order kinetics correlated significantly (R2 = 0.999). This study showed the potential of Cs and Cs/Fa bio-composites for effective textile wastewater treatment.

Modification Technique Influence on the Adsorption Capability of Organobentonites for Reactive and Direct Dyes

In this study, the adsorption of reactive and direct dyes from synthetic textile wastewater using organobentonites modified by two different routes was studied. Except for the drying step, the synthesis conditions were the same, and organobentonites were synthesized by employing a cationic surfactant at a level corresponding to the entire cation exchange capacity of bentonite under microwave irradiation. In the final step, the samples were dried using either a freeze dryer or an air dryer. The structural characteristics of the organobentonites were determined via XRD and FTIR analyses. The obtained equilibrium data indicated that the adsorption process fitted to the Langmuir isotherm model for both dyes. Although the results indicated that both organobentonites adsorbed two of the dyes, the freeze-dried sample could serve as a more effective adsorbent for removing reactive and direct dyes from wastewater.

WITHDRAWN: High crystallinity nano-biochar synthesized from lotus leaf wastes for uptake of dye molecules from synthetic and real wastewater

This article investigates the potential of lotus leaves-derived nano-biochar in eliminating methyl violet (MV) dye from synthetic and real textile wastewater. The surface of nano-biochar was characterized by TEM, BET, FTIR, XRD, DLS, and FESEM analyses. The BET surface area of nano-biochar was 456.3 m2.g-1, demonstrating an excellent specific surface area. The highest biosorption efficiency and maximum biosorption capacity of MV were 96.3% and 526.3mg/g, respectively, which were obtained at pH 10, equilibrium time of 200min, adsorbent concentration of 0.5g/L, MV ion concentration of 150 ppm, and temperature of 50oC. Also, the mechanism of the biosorpiton process shows that the process is endothermic. Based on R2 and RSME error values, the biosorpion process followed the pseudo-first-order and Langmuir models, indicating that monolayer biosorption of MV molecules on the biochar surface is dominant. Besides, nano-biochar was successfully reused in three steps with high efficiency. The impact of interference ions such as methylene blue, methyl orange, crystal violet, and brilliant blue on MV sorption was investigated and the outcomes revealed that nano-biochar has a remarkable ability to simultaneously eliminate these dye molecules. Additionally, nano-biochar could eliminate COD, BOD5, turbidity, TDS, and EC from a real textile wastewater with high efficiency. Overall, biochar nano-powder, owing to its high reusability, high sorption capacity, easy synthesis, and low-cost, can be considered an ideal option for industrial application.

468 https://doi.org/10.31881/TLR.2024.010 Decolourization of Synthetic Wastewater Related to the Textile Industry Using Photo-Fenton

The artisanal textile industry plays a vital role in the economy by providing a wide variety of products. However, this sector generates large quantities of wastewater containing a diversity of organic compounds, including dyes that, when released into the environment, contribute significantly to water pollution. In this research, samples of synthetic wastewater containing green aniline were subjected to decolourization using the photo-Fenton process. Synthetic textile wastewater was prepared at a concentration of 40 mg/L, and a calibration curve was established. During the treatment, ferrous sulfate (at concentrations of 50 and 150 mg/L) and H2O2 (at concentrations of 0.5 and 1.0 g/L) were added to 1 L of the synthetic effluent in a stirring medium (at 1000 rpm) and exposed to solar radiation for 1, 2, or 3 hours, while maintaining a pH of 3. To quantify the degree of decolourization, absorbance was measured at the beginning and end of the treatment using a colourimeter. The optimal conditions for Fe2+ concentration, H2O2 concentration, and treatment time, with an initial concentration of 40 mg/L, were found to be 150 mg/L, 1.0 g/L, and 3 hours, respectively. Under these conditions, the percentage of decolourization reached 97.546%. The study demonstrated that the concentration of Fe2+ and treatment time, as well as the interaction between Fe2+ concentration, H2O2 concentration, and treatment time, significantly influenced the degree of decolourization. Conversely, the concentration of H2O2 and other interactions did not exhibit significant influence.

THE EFFECT OF IMMOBILIZED ENZYME ON TEXTILE WASTEWATER

Textile wastewater has a complex composition characterized by high dye content and chemical oxygen demand. Therefore, textile wastewaters have serious environmental impacts, such as aesthetic degradation, and carcinogenic properties. Treatment and the recovery of textile wastewater are important due to their high volume and toxicity. The effects of peroxidase enzyme immobilized on magnetic chitosan-clay beads of synthetic textile wastewater were investigated in a batch reactor. System performance was determined by chemical oxygen demand (COD) and color. The batch reactor was operated in three different pH (5, 7, 10), temperatures (25, 35, 45 °C), and reaction times (0-5-10-20-30 min.) with synthetic textile wastewater. As a result, COD and color removal efficiencies were determined as 44% and 56%, respectively, corresponding effluent concentrations are 1442 mg/L, 450 Pt-Co. The results of this study show that using the enzyme immobilization process is an effective method to remove color and COD concentration from textile wastewater.

Removal of Remazol Black B dye using recirculation batch electrocoagulation

Textile industry wastewater mainly contains high concentration of organic matter including the active dye of Remazol Black B. This wastewater effluent needs to be properly treated before discharge into water bodies. Electrocoagulation is one of physico-chemical methods that can be used as an alternative of wastewater treatment in the textile industries because it has a good efficiency in removing colour. A wide range of pH measured in the textile industry wastewater (i.e., 3.9-14) may affect the effectiveness of electrocoagulation process. Other factors that affect electrocoagulation process were current intensity and wastewater flow. This study aims to determine the optimum of electrocoagulation process in the recirculation batch method using recirculation batch reactor. The applied current tested were 10 A, 15 A and 20 A, with flow rate of 2 L/min, 3 L/min, and 4 L/min. A synthetic textile wastewater was prepared with a Remazol Black B dye colour concentration of 10 ppm, 3 g/L of NaCl, and pH of 11. The parameters tested periodically in this study were pH, TDS and removal of colour and COD. Result of this study showed that by increasing the electric current strength and decreasing the flowrate, efficiency of pollutants removal was increased. Highest removal percentage of COD and colour were 100% and 88,78%% with current strength of 20 A, and flow rate of 2 L/min, the final pH was 11,4, whereas total dissolved solid fluctuated (i.e., 1785 mg/L– 1902 mg/L).

DYESTUFF REMOVAL FROM SYNTHETIC TEXTILE WASTEWATER USING OLIVE LEAF

The textile industry is one of the sectors where water use is high. Textile wastewater contains a high percentage of dyestuffs. Dyestuffs prevent photosynthetic activities in water and disrupt the ecological balance in water. Treatment of dyestuffs is very important for the prevention of water pollution and for the health of living things. There are several methods for the treatment of wastewater containing dyestuffs. In this study, it was aimed to remove dyestuff from synthetic textile waste water by using olive leaf by adsorption method. The effects of initial pH, amount of adsorbent, contact time and temperature on adsorption were investigated. According to the data obtained, optimum conditions were determined as pH 2, 0.25 g of adsorbent, 2 hours of contact time, and a temperature of 25 °C. When the experimental data were applied to the kinetic models, it was observed that they conformed to the pseudo-second-order rate equation. The data obtained at the end of the experiments were applied to the Langmuir and Freundlich isotherm models. It was observed that the data obtained with olive leaf conformed to the Freundlich isotherm. The reaction for the olive leaf is an exothermic and occurs spontaneously, according to thermodynamic analysis. Negative entropy indicates a decrease in disorder in adsorption.

Treatment of textile dye wastewater by peroxymonosulfate activation using facilely prepared Fe3O4@TiO2 heterogeneous photocatalyst

AbstractIn this study, Fe3O4@TiO2 was synthesized by a facile precipitation–impregnation method and applied as a magnetic photocatalyst for degrading synthetic and actual textile dyeing wastewater in the presence of peroxymonosulfate (PMS). In Rhodamine B (RhB) degradation, the removal efficiency reached 99.86% (for RhB) and 93.67% (for color) under optimal operating conditions of 80 mg L–1 RhB, 0.5 g L–1 PMS, 0.5 g L–1 Fe3O4@TiO2, at pH 6, and after 30 min of UVA irradiation. The influence levels of anions on the RhB removal and decolorization were in the order of Cl− < SO42− < CO32− < PO43−. In addition, the Fe3O4@TiO2 composite exhibited good applicability for treating other dyes (e.g., 99.6% of tartrazine and 60.3% of methylene blue after 30 min) in water and actual textile dyeing wastewater with high color (70.3% after 5 min) and COD removal (71.4% after 120 min). The radical scavenging tests indicated the role of reactive oxygen species in the order of O2•− ∼ 1O2 > h+ > SO4•− > HO• for RhB degradation but O2•− > h+ > 1O2 > SO4•− > HO• for decolorization. These results suggest the potential application of PMS activation using Fe3O4@TiO2 in the photocatalytic treatment of textile and dyeing wastewater with the dominant role of O2•−.

Joint Multi-Optimization of an Extremophilic Microbial Bioanode for Mitigation of Mixed Hazardous Azo Dyes in Textile Synthetic Wastewater

Bioelectrochemical systems (BESs), rather than physicochemical processes, are used for wastewater remediation, electricity production, and zero carbon dioxide emission. Textile effluents contain organic and inorganic compounds that can fuel BESs. The main goal of this study was to understand the interplay between the anode material, its surface area, the potential applied to the working electrode (WE), and the concentration of the co-substrate, and how these factors lead to the formation of highly efficient thermohalophilic bioanodes (THB) retrieved from Chott El Djerid (SCD) hypersaline sediment for the treatment of synthetic textile wastewater. To this end, twenty-seven bioanode formation experiments were designed using a Box-Behnken matrix and response surface methodology to understand concomitant interactions. All experiments were conducted in electrochemical reactors of final volume 750 mL inoculated with 80% of enrichment medium containing three azo dyes at a concentration of 300 ppm and 20% of biocatalyst microbial SCD source, at 45 °C. The optimal levels were predicted using NemrodW software as carbon felt (CF) anode material, 6 cm2 anode surface, 7 g/L glucose concentration, and −0.1 V applied potential. These theoretical results were experimentally validated, using maximum current output of 5.23 ± 0.30 A/m2, decolorization rate of 100%, and a chemical oxygen demand (COD) removal rate of 96 ± 1%. Illumina Miseq results revealed that bacterial community harbored the bioanode was dominated at phylum level by Firmicutes (67.1%). At the species level, the biofilm was mainly colonized by Orenia metallireducens species (59.5%). Obtained findings show a promising application of THB in the degradation of recalcitrant molecules as well as for the energy recovery.

Decolorization of azo Direct Blue 71 dye in aqueous solutions using sequential upflow anaerobic sludge blanket reactor and UV/H2O2 process

In this research, decolorization of synthetic textile wastewater was investigated by upflow anaerobic sludge blanket (UASB) reactor and advanced oxidation UV/H2O2. In the acclimation phase, an 18 L UASB reactor with a discharge of 18 cm3/min was fed with a colorless synthetic wastewater for 40 days. Then the reactor was fed with wastewater containing Direct Blue 71 as the coloring agent at 6 consecutive steps with concentrations of 10, 50, 100, 200, 300 and 400 mg/L. In the first step, the removal efficiency was the least due to the low inflow dye concentration. However, by further increment of dye concentration in the influent to greater than 200 mg/L, the removal efficiency gradually increased and reached above 80 %. Since the treated effluent from steps 4–6 did not meet regulations, it was discharged into a UV/H2O2 reactor for further treatment. The results showed that with increasing H2O2 concentration, the removal efficiency increased, although excessive increase in H2O2 concentration reduced the removal efficiency. The pseudo-first order kinetic model was in good agreement with the degradation data with the optimal reaction rate constant at a concentration of 2225 mg/L of H2O2.

The influence of structural topology of additively manufactured PEGDA monolith on adsorption performance for textile wastewater treatment

AbstractWith the rapid advancement of three dimensional (3D) printing technology that offers flexibility to achieve desired surface area and permeability for wastewater applications, structural topology design has the potential to significantly improve the adsorption performance. This present work involves fabricating the green water technology with four different complex monolithic structural designs (Kagome, gyroid, Fischer, and body‐centered cubic [BCC]) with specific surface areas varied from 19.4 to 39.84 mm2 via digital light processing (DLP) technique. All the monolithic structures with different structural topologies were grafted with chitosan to evaluate their adsorption performance in a batch process. The influence of different structural topology on the adsorption performance and efficiency was evaluated at an optimal temperature of 60°C with optimum pH of 6.3 for a reaction time of 2 h using synthetic methyl orange (MO) dye and textile wastewater. Results indicated that the body‐centered cubic (BCC) design exhibited the highest MO adsorption capacity (12.71 mg/g), with the highest permeability (2.57 10−7 m2) and surface area (39.84 mm2). Additionally, a direct relationship was found between the surface area and the permeability of the adsorbent as well as adsorption strength. Fifty percent of color and 2.46% of chemical oxygen demand (COD) removal efficiencies were achieved to verify the adsorbent feasibility in actual application. The present work mainly establishes the feasibility of 3D printing in fabricating different monolithic structures, which enables future topology optimization for improved wastewater management.

Treatment of synthetic textile wastewater containing Acid Red 182 by electro-Peroxone process using RSM

The Azo dyes are primarily utilized in textile industries. Treatment of textile wastewater because of the presence of recalcitrant dyes using conventional processes is greatly challenging and ineffective. So far, no experimental work has been conducted on the decolorization of Acid Red 182 (AR182) in aqueous media. Hence, in this novel experimental work, the treatment of AR182 from the Azo dyes family was explored using the electro-Peroxone (EP) process. For the optimization of operating factors, including AR182 concentration, pH, applied current, and O3 flowrate in the decolorization of AR182, Central Composite Design (CCD) was utilized. The statistical optimization presented a highly satisfactory determination coefficient value and a satisfactory second-order model. The expected optimum conditions by the experimental design were as the following: AR182 concentration at 483.12 mg.L−1, applied current at 0.627,113 A, pH at 8.18284 and O3 flowrate at 1.13548 L min−1. The current density is directly proportional to dye removal. However, increasing the amount of applied current beyond a critical value has a contradictory impact on dye removal performance. The dye removal performance in both acidic and highly alkaline environments was negligible. Hence, ascertaining the optimum pH value and conduction of the experiment at that point is critical. At optimum points, the decolorization performance in predicted and experimental conditions for AR182 were 99 and 98.5%, respectively. The outcomes of this work clearly substantiated that the EP can be successfully utilized for the decolorization of AR182 in textile wastewater.

Electrocoagulation process for the decolorization of wastewater containing Reactive Red 195 and CFD simulation of the hydrodynamic in a continuous-flow single-channel reactor

Abstract The highly colored textile effluents require efficient treatment before being released into the environment. In this study, a continuous-flow single-channel reactor operating in closed- circuit was used to apply electrocoagulation for the treatment of synthetic textile wastewater. First, the characterization of the hydrodynamic within the reactor is evaluated by Computational Fluid Dynamics simulation using the k-ε turbulence model (Comsol Multiphysics®). Apart from a non-uniform distribution of the velocities inside the reactor, no particular anomaly was observed. Second, the decolorization efficiency was examined under various current intensities, electrolysis times, and initial dye concentrations. By operating under a current intensity of 100 mA instead of 50 mA, the required electrolysis time to achieve a decolorization efficiency of 80% decreased by 40%, while the specific electrode consumption remained slightly unchanged at about 0.19 kg Al·kg−1. At a current intensity of 100 mA and an electrolysis time of 26 min, and the increase in the initial dye concentration from 10 to 50 mg·L−1 the decolorization efficiency decreased remarkably while the specific electrode consumption was kept constant at about 0.15 kg Al·kg−1 dye removed. The knowledge obtained through this study can be used for the transposition from batch to continuous mode.

Saline Sediments as a Suitable Source for Halophilic Inoculums to Degrade Azo Dyes in Synthetic and Real Textile Wastewaters by Microbial Electrochemical Systems

The treatment of textile wastewater (TWW) loaded with recalcitrant azo dyes in bioelectrochemical systems (BES) rather than in physicochemical processes is a low-cost and environmentally friendly process. The main objective of this study is to investigate the potential of different saline sediments collected from extreme Tunisian environments for the formation of bioanodes capable ofsimultaneous azo dyes degradation and electric current generation in synthetic (STWW) and real textile wastewaters (RTWW) characterized by a varied composition of azo dyes and a high salinity. The obtained bioanodes and anolytes were studied comparatively by electrochemical, microscopic, analytical, and molecular tools.Based on the UV–visible spectra analysis, the breakdown of the azo bond was confirmed. With RTWW, the BES achieved a chemical oxygen demand (COD) abatement rate of 85%with a current density of 2.5 A/m2. Microbial community analysis indicated that a diverse community of bacteria was active for effluent treatment coupled with energy production. At the phylum level, the electrodes were primarily colonized by proteobacteria and firmicutes, which are the two phyla most involved in bioremediation. The analysis of the microbial community also showed the abundance of Marinobacter hydrocarbonoclasticus and Marinobacter sp. species characterized by their high metabolic capacity, tolerance to extremophilic conditions, and role in hydrocarbon degradation.

Phosphorus recovery from phosphonate-contaminated wastewater by nonthermal plasma treatment prior to adsorption on granular iron-coated sand

Phosphonate contamination of water resources has drawn much attention. Advanced oxidation combined with phosphorus recovery is considered as a promising solution, but the development of a cost-efficient process remains challenging. This work demonstrates an effective two-step process including a plasma-based oxidation of phosphonate, followed by phosphate adsorption on granular iron-coated sand (ICS). In the first step, a tandem reactor configuration, which consists of a dielectric barrier discharge (DBD) plasma chamber and an ozonation chamber, was used to transform 1-hydroxyethane-1,1-diphosphonic acid (HEDP) to Ortho-phosphate (Ortho-P). When lava rock was added as a packing material in the ozonation chamber, the Ortho-P production was enhanced by 10–35%, due to an increased exposure of reactive species (O3,OH and O2•-) by 120%, 20% and 30%, respectively. The use of O2 as carrier gas in the plasma reactor resulted in the highest Ortho-P production efficiency (86%), followed by Ar (48%), N2 (21%) and air (13%). Humic acids present in the wastewater can compete with phosphonates for reactive species, decreasing the Ortho-P production efficiency by 30%. In the second step, ICS granules were used to adsorb the produced Ortho-P. The final recovery efficiency of Ortho-P from synthetic and real textile wastewater was 85% and 53%, respectively. The treatment performance of this novel two-step process is better compared to that of ozone-based AOPs, while the associated operational treatment costs are still somewhat higher. This indicates that optimizing energy consumption is still the biggest challenge for further industrial applications of nonthermal plasma-based AOPs.

Decolourisation of Real Industrial and Synthetic Textile Dye Wastewater Using Activated Dolomite

Textile effluent accounts for 22% of the total industrial wastewater produced in Malaysia. Due to their ubiquitous use in organic dyes, inefficiently treated textile wastewaters pose environmental and health hazards. Colour, chemical oxygen demand, biochemical oxygen demand, toxic metals and microbes are the commonly targeted water quality parameters in untreated textile fluids. Furthermore, their non-biodegradability and high colour intensity may reduce aquatic diversity by blocking the sunlight. Recently, physical treatment, principally adsorption, has been conducted. Dolomite has additional features, such as performing as a heavy metal and microbe remover. This study employed dolomite for treating textile dye wastewater from a commercial textile manufacturer and synthetic effluent containing methyl orange. Different sizes of dolomite were activated at different temperatures and subsequently added to the water samples in varying amounts. After 2 h of agitation at 100 rpm and sedimentation for 24 h, their absorbance reading was taken. Their morphological, decolourisation percentage, chemical oxygen demand reduction percentage and bacterial growth post-treatment were examined. Despite variances in dolomite’s capacity to decolourise colours, the treatment proved effective in decolourising dyes, removing chemical oxygen demand and reducing bacterial growth. The most significant percentages of decolourisation observed were 98.7% for real textile dye wastewater (RTDW) and 78.0% for synthetic textile dye wastewater (STDW), while for chemical oxygen demand, reductions were 66.7% for RTDW and 73.9% for STDW, respectively. As for microbe growth inhibition, the highest growth reduction percentages were 99.7% and 98.6% for RTDW and STDW, respectively.

Living membrane bioreactor for highly effective and eco-friendly treatment of textile wastewater

The treatability of synthetic textile wastewater containing model dyes, such as reactive black and direct black dye (25.0 ± 2.6 mgdye/L), with chemical oxygen demand (COD, 1000 ± 113 mg/L), ammonia‑nitrogen (NH3-N, 140 ± 97 mg/L) and sulphate ions (SO₄2−, 1357 ± 10.86 mg/L) was investigated in this study using an innovative living membrane bioreactor (LMBR) using an encapsulated self-forming dynamic membrane (ESFDM). The key advantage of ESFDMBR is the self-forming of the biological filtering layer protected between two meshes of inert robust and inexpensive material. A laboratory scale bioreactor (BR) equipped with a filtering unit mounting polyester meshes with a pore size of 30 μm, operated at an influent flux of 30 LMH was thus used. After the formation of the biological living membrane (LM), the treatment significantly reduced COD and DOC concentrations to the average values of 34 ± 10 mg/L and 32 ± 7 mg/L, corresponding to reduction efficiencies of 96.0 ± 1.1 % and 94 ± 1.05 %, respectively. Throughout the LMBR operation, the colours were successfully removed from synthetic textile wastewater with an overall removal efficiency of about 85.0 ± 1.8 and 86.0 ± 1.9 % for direct and reactive dyes, respectively. In addition, the proposed system was also found effective in affording removal efficiency of ammonia (NH3) of 97 ± 0.5 %. Finally, this treatment afforded circa 40.7 ± 5.8 % sulphate removal, with a final concentration value of 805 ± 78.61 mg/L. The innovative living membrane, based on an encapsulated self-forming dynamic membrane allows a prolonged containment of the membrane fouling, confirmed by investigating the concentration of membrane fouling precursors and the time-course variations of turbidity and transmembrane pressure (TMP). Those final concentrations of wastewater pollutants were found to be below the limits for admission of the effluents in public sanitation networks in Italy and Tunisia, as representative countries for the regulation in force in Europe and North Africa. In conclusion, due to the low costs of plant and maintenance, the simple applicability, the rapid online implementation, the application of LMBR results in a promising method for the treatment of textile wastewater.

Coagulation Study on Extracted Algal Alginate from Red Algae as Natural Coagulant for Remediation of Textile Dye Congo Red

In the present study, extracted algal alginate from red algae as natural coagulant was used for removal of textile dye congo red (CR) from water. In developing countries like India, only about 10% of the wastewater being generated is treated, whereas the remaining 90% is discharged into the water bodies as it stands. Color and turbidity are the most common problems in the disposal of wastewater. The removal of color is one of the key challenges in wastewater treatment. For the coagulation process, the synthetic textile wastewater samples had CR concentrations of 50, 100, 150, 200, and 250 mg/L and varying initial pH of 4, 5, and 6. Different dosages of calcium and alginate (1, 2, 3, 4, 5, and 6 g/L) were used to perform the experiments. The obtained results exhibited that the effectiveness of color removal was higher at lower pH 4, and the calcium and alginate dosages are dependent on the CR concentration of the synthetic textile wastewater. These investigations demonstrating the higher efficiency of calcium alginate as a coagulant, where maximum color removal achieved over 95.05%. Increasing alginate dosages and residence times can enhance the performance of coagulation. Dye color is often present in real wastewater and needs to be removed before being reused or discharged to the environment.