Textile Industry Wastewater Treatment Research Articles

Performance evaluation of shell and tube heat exchanger through ANN and ANFIS model for dye recovery from textile effluents

ABSTRACT Performance of Shell and Tube Heat Exchanger for treatment of textile industry wastewater as a secondary treatment process is reported. An Adaptive Neuro-Fuzzy Inference System and Artificial Neural Network models were used for predicting the accuracy of the process. Condensate flow (m3/hr), feed inlet temperature (°C) and steam flow (kg/cm) for textile effluents were used to predict the condensate temperature (°C). The accuracy of the developed model was validated using Absolute Mean Relative Error, Root Mean Square, and Absolute fraction of variance. The different combinations of input parameters were determined with preceding parameters of the model. Comparison of the models indicated the advantage of ANFIS model over ANN model. Seventh configuration values of ANN reported 0.971%, 1.175%, and 0.9456 of the Absolute Mean Relative Error, Root Mean Square, and Absolute fraction of variance respectively. Similarly, the ANFIS reported 0.381%, 0.532%, and 0.9998 of the Absolute Mean Relative Error, Root Mean Square, and Absolute fraction of variance respectively. ANFIS model was found to be more effective in predicting the condensate temperature with a high Absolute fraction of variance R2 = 0.9998 the results were in line with the experimental data. In the present study the complication of nonlinear process has been resolved using ANFIS modeling technique. The treated water could be recycled using this process. Optimization of the process parameters helps in minimizing water consumption and offers economic benefits for wastewater treatment.

Self-forming dynamic membrane bioreactor for textile industry wastewater treatment

The robustness of anaerobic dynamic membrane bioreactor (AnDMBR) for synthetic textile wastewater treatment was investigated. Textile wastewater may contain high concentrations of NaCl and sulfate, hence their impact on the AnDMBR performance was investigated in detail. A dynamic membrane was formed on a 20-μm pore sized nylon support layer at a constant flux of around 8 LMH. In the absence of sulfate addition, total and filtered (soluble) COD averaged 96 ± 49 mg/L (91% removal) and 75 ± 35 mg/L (93% removal), respectively. Sulfate addition increased total COD in the permeate to 222 ± 68 mg/L (79% removal). Average SS concentration was lower than 30 mg/L in the permeate although its concentration in the bioreactor reached 10 g/L. Throughout the AnDMBR operation dye removal averaged >97%. Sludge filterability, which was assessed by specific resistance to filtration, supernatant filtration, capillary suction time and viscosity, decreased after sulfate addition. Organic and inorganic matters in the dynamic layer were characterized by SEM-EDS and FTIR analyses.

Synergistic degradation of acid blue 113 dye in a thermally activated persulfate (TAP)/ZnO-GAC oxidation system: Degradation pathway and application for real textile wastewater

The performance of a binary persulfate activation system based on the simultaneous use of heat (TAP) and ZnO coated granular activated carbon (ZnO-GAC) catalyst was investigated for the degradation of Acid Blue 113 (AB113) azo dye and the treatment of textile industry wastewater. FESEM, XRD, FTIR, EDX-mapping and BET analyses confirmed the successful loading of ZnO nanoparticles onto the GAC substrate. The effect of five independent variables on AB113 removal in the TAP/ZnO-GAC oxidation system was optimized by a 5-level full central composite design (CCD). All experiments were performed in a 6250 mL volume reactor. Adequacy and validity of the proposed model were confirmed with p-value < 0.0001 and R2 = 0.9994. The optimum values for solution pH, reaction time, persulfate (PS) concentration, ZnO-GAC dosage, and solution temperature were obtained to be 4.7, 50 min, 4.2 mM, 2.5 g/L, and 70 °C, respectively. Under these conditions, the maximum removal efficiency of AB113 in PS/ZnO-GAC, TAP, and TAP/ZnO-GAC oxidation systems was 26, 83 and 94.2%, respectively. The synergistic effect of ZnO-GAC on TAP oxidation system reduced the apparent activation energy by approximately 83%. The naphthalen-1-ol, phthalic acid, malonic acid, ethane-1,2-diol, and oxalic acid were the most abundant intermediates produced during AB113 degradation. Radical scavenging experiments showed that SO4·- was the predominant radical species in the TAP/ZnO-GAC system. The optimized TAP/ZnO-GAC process effectively improved the biodegradability of real textile wastewater samples (BOD/COD>0.4).

The hybrid process with eco-friendly materials for the treatment of the real textile industry wastewater

The present study represents the application of a hybrid process to a pretreated real textile wastewater. Hybrid process includes electrocoagulation, adsorption, and photo Fenton- like oxidation methods. In our previous study, electrocoagulation (EC) method was investigated and the optimum conditions were determined. Nearly 35% total organic carbon (TOC), 18.6%, chemical oxygen demand (COD), 90% turbidity, and 50% color removal efficiencies were achieved by the EC step. In this study adsorption and photo Fenton- like oxidation were applied sequentially to the effluent of EC step. Walnutshell and corncob agricultural wastes were used for the preparation of the activated carbon. After adsorption step, the removal efficiency of the TOC was found to be nearly 75% and color, turbidity, and total dissolved solids achieved the standards for irrigation water. Also, the removal efficiency of the COD was found as 27%. For adsorption, Langmuir isotherm model fit better and the second order kinetic model was found to be the best model. The BiNiO3 catalyst with corncob support material was effective for the photo Fenton- like oxidation method. The optimum conditions were selected as 0.75 g/L BiNiO3/corncob based catalyst loading and pH = 7–7.5. At the end of the hybrid process, 87% TOC, 49% COD, 96% turbidity, approximately 90% color and 95–97% suspended solids removals were achieved. The hybrid system was effective to achieve the irrigation water standards except for salinity and COD. Agricultural wastes used in preparation of catalysts and adsorbents were promoted to be innovative, environmentally friendly and economical.

A microporous polymer ultrathin membrane for the highly efficient removal of dyes from acidic saline solutions

Membranes with excellent water permeance and high dye removal efficiency are highly desired for textile industry wastewater treatment. However, the high acidity and salinity in such wastewater impose great challenges in dye removal efficiency for conventional polyamide-based membranes. This study presents a type of acid-tolerant polyarylate (PAR) nanofiltration (NF) membrane that tackles such challenges. The PAR active layer is produced via interfacial polymerization using 5,5′,6,6′-tetrahydroxy-3,3,3′,3′-tetramethyl-1,1′-spirobisindane (TTSBI) and isophthaloyl dichloride (IPC) as monomers, and formed on top of a single-walled carbon nanotube (SWCNT) nanofilm. The supporting SWCNT layer contributes to the ultrathin thickness of the PAR active layer and the extremely high membrane permeating flux of ~210 L m−2 h−1 bar−1, while the inclusion of TTSBI monomer grants the PAR active layer surface negatively charged that makes a high dye rejection of >99% at a wide range of feed solution pH and salinity possible. Furthermore, a high selectivity for dye and NaCl was observed with a stable NaCl retention of ~10%, when the membrane is tested at a pH ranging from 2 to 9 and feed NaCl concentration ranging from 1000 to 5000 ppm. The PAR NF membrane is therefore a promising tool for the highly efficient treatment of acidic and high salinity textile dye wastewaters.

Combination of TiO2 microreactor and electroflotation for organic pollutant removal from textile dyeing industry wastewater

Photocatalytic degradation techniques have been widely used for the treatment of high organic content wastewater. The use of TiO2 photocatalytic activity combined with electroflotation process to treat a wastewater is still very rare and needs to be understood. This study proposed the UV/TiO2/Electroflotation process as a new method for the treatment of textile dyeing industry wastewater. The performance of UV/TiO2/Electroflotation microreactor system to remove the chemical oxygen demand (COD) was compared with that of other microreactor systems for the experiments conducted at different hydraulic retention times (HRTs) of 13, 30 and 60 min. The results showed that the COD removal efficiency of Florescent microreactor is lower than that of Florescent/TiO2 microreactor and then is lower than that of UV microreactor and then is lower than that of UV/TiO2 microreactor and then is lower than that of UV/TiO2/Electroflotation microreactor. Three microreactor systems of UV, UV/TiO2 and UV/TiO2/Electroflotation with their HRT of 60 min are capable of removing more than 90% of COD from the wastewater containing dyes. The efficiencies of COD removal by the UV/TiO2/Electroflotation microreactor are approximately 25% higher than those by the UV/TiO2 microreactor and are more than 81% higher than those by the UV microreactor, using the HRTs of 15 and 30 min. The use of UV/TiO2/Electroflotation process could be useful for the treatment of high organic content wastewater to contribute to advanced wastewater technology needed in the future.

Integrated electrochemical processes for textile industry wastewater treatment: system performances and sludge settling characteristics

Textile wastewater containing toxic dyes needs efficient treatment before being released into the environment. Certain dyes are known or presumed to have carcinogenic potential for humans. In this work, hybrid electrochemical processes including electrocoagulation (EC) alone and combined with electro Fenton (EF), anodic oxidation (AO) and peroxi-coagulation (PC) were tested to treat real textile wastewater using a batch reactor. A sequential EC and EF (EC-EF) process was found to be more effective. The experimental results indicated that the effectiveness of the treatment decreases in the following order: EC-EF > EC-AO > EC-PC > EC. EC-EF results showed a decrease in chemical oxygen demand (COD, 97%), total organic carbon (98%), total suspended solids (98%), and the concentration of metal species; showing that the treatment of such wastewater type can be achieved by combined EC-EF process in a one-pot bench-scale reactor. The electrical energy consumption, the iron dissolution, and the biological oxygen demand/COD ratios of EC and EC-EF processes were evaluated. Characterization of the sludge generated during EC treatment at current density of 20 mA cm− 2 was carried out. Precipitation, adsorption, and electrochemical oxidation/reduction of organic dyes and metallic ions occurred during the treatment. This investigation shows the efficiency of combined EC-EF to treat textile wastewater.

Treatment of Textile Industry Wastewater using Microbial Fuel Cell

Recent research have found out that Bio Electrochemical Systems (BES) are proving to be efficient in both power generation and in waste disposal. The best example for a BES is a microbial fuel cell. The microbial fuel cell (MFC) uses the organic and the inorganic materials in the wastewater to produce electricity by the action of the microbes on them. Thus the MFC’s can be used for both bio-electricity generation and wastewater treatment. The power generation and the efficiency of the MFC depends on various factors like the type of bacteria, type of electrode used and organic content in the effluent. Experiments were carried out to treat textile industry wastewater using Microbial Fuel Cell. Graphite was used as anode, stainless steel and aluminium mesh were used as cathode. Influence of cathodes on power production and COD reduction on process has been critically examined. The maximum power density and COD reduction were observed in graphite and stainless steel electrode system

WASTE TO PRODUCT: BISOLUM-BRICKS, INCORPORATION OF WWTP SLUDGE OF TEXTILE INDUSTRY INTO BRICKS FOR WALL PAIRS

The disposal of WWTP sludge is one of problems in textiles industry, which requires serious attention to find a way out. Utilization of sludge from the textile industry wastewater treatment, according to the Republic of Indonesia Goverment Regulation No.110 year 2014, can be used as a mixture of brick raw materials, must consider the availability of technology, meet environmental quality standards and meet technical requirements for use.Environmental feasibility refers to Goverment Regulation No.110 year 2014, carried out with TCLP toxicity tests on raw materials for soil, WWTP sludge and brick products. Acute toxicity test LD 50, carried out on brick products in which using a mixture of WWTP Sludge. Technical feasibility is carried out by testing the quality of brick products in accordance with solid brick Nasional Indonesian Standard (SNI) for wall pairs.Research results prove the toxicity test on raw materials and brick products with a mixture of up to 60% of waste, still meets the requirements of TCLP and LD.50 according to GR No.110 year 2014. Test the quality of bricks at the use of 40% and 60% mixture of sludge still meet Nasional Indonesian Standard (SNI 15-2094-2000) solid red brick for wall pairs.

Synthesis and Characterization of Activated Sludge/Zeolite Adsorbent for Lampung Textile Industry Wastewater Treatment

The present study reports a green synthesis method for ordered adsorbent material for Lampung Ethnic Textile Industry (LETI) wastewater treatment from activated sludge rubber industry and clipnotilolite (natural zeolite). LETI wastewater is containing about 70 mg/L of Chromium; 63,600 mg/L of COD and 36, 500 mg/L of BOD. It has also high colour intensity and complex pollutants. Adsorbent can reduce Chromium heavy metal significantly. Activated sludge/zeolite adsorbent was calcined by furnace at 600°C for 15 min. It was activated by 10% wt/wt of NaOH and 1 molar of HCl. The material properties of calcined activated sludge/zeolite adsorbent was characterized by FT-IR, BET and SEM. Results showed that structure interaction processes occured between activated sludge and zeolite clipnotilolite. The BET analysis results showed that surface area, pore volume and average pore size respectively are 932 m2/gram; 0.6 cc/gram; and 258.87 Å.

Adsorption and Removal of Methylene Blue from Aqueous Solution Using Sterile Bract of Araucaria angustifolia as Novel Natural Adsorbent

The aim of this work was to study the adsorption and removal of methylene blue from aqueous solution using sterile bract of Araucaria angustifolia as novel natural adsorbent. Raw and boiling-treated sterile bract samples were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, and point of zero charge. The contents of humidity, ash, total extractive content, lignin and cellulose were 13.20, 3.30, 7.12, 44.45 and 30.92%, respectively. The methylene blue adsorption mechanism in the sterile bract was evaluated using non-linear Langmuir, Freundlich, Redlich–Peterson and Sips isotherm models, whereas the adsorption kinetic was evaluated using pseudo-first- and pseudo-second-order kinetic models. The methylene blue removal efficiencies of the raw and boiling-treated bracts were 98.59 ± 0.01 and 99.90 ± 0.01%, respectively, after 480 min. The best adsorption efficiency was found within 480 min of contact, 5.0 g of adsorbent with 500 mesh granulometry, pH = 6, initial adsorbate concentration of 150 mg L−1 and temperature of 292 K. The maximum methylene blue adsorption capacities of the raw and boiling-treated bracts according to the non-linear Langmuir isotherm model were 125.34 and 138.65 mg dye per gram bract, respectively. The kinetic fit depends on the solution pH, determination coefficient and Chi square test statistic. From thermodynamic results, it was concluded that the adsorption process is favorable, spontaneous (ΔG 0). Overall, the sterile bract of Araucaria angustifolia could be applied as low-cost alternative adsorbent for the treatment of textile industry wastewater.

Novel pilot scale photocatalytic treatment of textile & dyeing industry wastewater to achieve process water quality and enabling zero liquid discharge

This paper presents a novel end-to-end pilot scale photocatalytic treatment of real textile & dyeing industry effluent, which involved innovative approach in primary treatment, followed by Heterogenous Photocatalysis (HP) involving nano-TiO2/UV as secondary treatment and suitable filtration leading to treated water meeting process water quality enhancing water re-use efficiency. This enables Zero Liquid Discharge (ZLD); which is the need of the hour in tackling problems of point source pollution and Water Conservation in developing countries like India. Overall treatment led to complete degradation and mineralization of organic pollutants and dye stuff thereby achieving adequate treatment, complete decolourization and deodorization of the effluent and almost hundred times less quantities of sludge residues in comparison to those obtained in conventional treatment methods. The nature and elemental composition of sludge residues, as investigated using Energy Dispersive X-ray (EDX) elemental analysis, confirms complex organic dye components mineralized and nature being non-toxic. The complete treatment took place in 5 h without any kind of bioremediation method, which further highlights highly efficient and fast treatment coupled with small footprint. Overall cost of treatment is estimated to be around 1.55 USD/m3. Such an innovation in wastewater treatment is expected to bring a revolution in developing countries, which are grappled together with problems of rapid industrialization, urbanization, regulatory compliances and environmental challenges.

Removal of cationic dye (Methylene Blue) from aqueous solution by adsorption on two type of biomaterial of South Morocco

Abstract Industrial water pollution has become a very serious problem in many countries. This pollution can cause a variety of environmental effects. To reduce the negative effects of these industrial pollutants, various wastewater treatment methods, in particular physico-chemical treatment, have been developed, specially, the adsorption technique. This study aims to use the new biodegradables adsorbents with two type of Moroccan cactus (Naturel (NC) and Dried Cactus (DC)) in a physico-chemical process of adsorption, for the treatment of textile industry wastewater, and the comparative study of adsorption capacity of these adsorbents was presented. In this study, the adsorption tests were carried out using Methylene Blue, and the results showed a remarkable elimination of this cationic dye. The two adsorbents were characterized with Fourier transform infrared spectrophotometer (FTIR), and scanning electron microscope (SEM). The effects of contact time, adsorbent mass and pH were investigated in a batch-adsorption technique. The experimental results of two adsorbents showed that the Methylene Blue adsorption is related to the solution pH of 5.4 and the ambient temperature. Experimental isotherms of adsorption equilibrium results were validated accurately by Langmuir and Freundlich models. The adsorption capacities fitted by the Langmuir model are 3.44 and 14.04 mg/g using NC and DC respectively. All results showed that these adsorbents could be employed as low-cost alternative for removal of cationic dyes from industrial wastewater.

Exploration of Performance Kinetics and Mechanism of Action of a Potential Novel Bioflocculant BF-VB2 on Clay and Dye Wastewater Flocculation.

This study explores production of an efficient bioflocculant; BF-VB2, by strain Bacillus sp. TERI VB2 and proposes its potential application in wastewater treatment. One milligram of BF-VB2 can effectively flocculate 1980.0 mg ± 5.0 mg of kaolin particles leading to 99.0% ± 0.5% enhancement in flocculation activity and 99.6% ± 1.0% reduction in turbidity; in less time. BF-VB2 when applied for treatment of textile dyeing industrial wastewater revealed reduction in dye color (82.78% ± 3.03%), COD (92.54% ± 0.24%), TSS (73.59% ± 0.71%), and chloride ions (81.90% ± 0.716%). The best-fit kinetic model (for both COD removal, and dye decolorization) was pseudo-first order with regression coefficient of 0.98 and 0.95, and rate constant of 4.33 × 10-2 and 1.83 × 102, respectively. Bridging due to presence of surface charges have been proposed as flocculation mechanism. From results obtained during test-tube studies, flocculation in larger volumes (0.01–5.0 L) was also performed to intend taking up BF-VB2 for in situ industrial wastewater treatment. This eco-friendly polysaccharide bioflocculant had longer shelf-life, stability to pH and temperature, cation-independence, and emerged to be more efficient than other flocculants assessed. This study proposed BF-VB2 as a potential natural flocculant candidate for industrial application.

Treatment of Textile Wastewater by Coagulation–Flocculation Process Using Gossypium herbaceum and Polyaniline Coagulants

The present study is carried out to evaluate the performance efficiency of biopolymeric and synthetic polymeric coagulants for the removal of color, chemical oxygen demand (COD), and turbidity from textile industrial wastewater. Shells of Gossypium herbaceum (GHC), a bio‐polymeric coagulant from bio‐waste, and polyaniline coagulants (PAC) (a synthetic polymeric) are chosen for the present study. A Box‐Behnken design (BBD) is employed for the optimization of the effects of the four process variables, such as pH, coagulation dose, contact time, and agitation speed, on the removal of color, COD, and turbidity of the wastewater. Fourier‐transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) are carried out to understand the functional characteristics and surface morphology of the coagulants. The maximum removal of color, COD, and turbidity with GHC is found to be 90.13, 72.96, and 85.48%, respectively, at pH 5.5, coagulant dose 2.2 g L−1, and contact time 35 min, while the maximum removal of color, COD, and turbidity with PAC is found to be 94.38, 91.45, and 89.36%, respectively, at pH 8.0, coagulant dose 1.6 g L−1, and contact time 35 min. The experimental results show that pH and coagulant dose influence the treatment efficiency of GHC and PAC. From the experimental observations, it is concluded that the performance of the biopolymeric coagulant is highly compatible in the treatment of textile industrial wastewater.

Investigation of immobilized filamentous fungi for treatment of real textile industry wastewater using up flow packed bed bioreactor

In this study, two filamentous fungi Aspergillus carbonarius M333 and Penicillium glabrum Pg1 were immobilized in macro porous polymeric support (MPPS) to treat real textile industry wastewater. The color and chemical oxygen demand (COD) removal efficiencies were tested in a batch and continuously operated up flow packed bed bioreactor. The protein concentration was also measured for different pH and MPPS amount. Wastewater inlet pH was tested between 4.5 and 6.0 and pH 5.5 was chosen optimum working pH in order to enhance the highest color and COD removal efficiencies. Moreover, MPPS amount was also tested from 1 to 9 pieces and the highest color and COD removal efficiencies were obtained with 9 pieces. The results showed that 98.2% decolorization and 69.8% COD removal efficiencies were obtained by batch experiments. However, 78.8% decolorization and 67.7% COD removal efficiencies were achieved by up flow packed bed bioreactor. The color and COD removal efficiencies were measured 78.8%, 72.1%, 70.2% and 67.7%, 62.5%, 60.0%, respectively, when the up flow packed bed reactor was operated repeatedly for 3 cycles. The immobilized fungi on MPPS were characterized by Scanning Electron Microscopy (SEM).

Songket Industry Wastewater Processing Using Electrocoagulation Method

The increment of Songket popularity as the traditional fabric from South Sumatra increases the production of Songket and the wastewater produced during the dying process. The dying process produces the reddish wastewater, and if it is disposed of directly into the environment, it will have a negative impact on the waters. The wastewater treatment of this reddish liquid is by electrocoagulation method. Electrocoagulation method is contaminants removal by electrical and chemical treatment system. The electrocoagulation method in this research was conducted in a batch where the wastewater was treated using 16.5 x 7.0 x 0.2 cm aluminum electrode. The parameters varied were the current density and processing time to determine the pH value, color intensity, BOD5, COD, TSS, and phenol levels. The optimum condition obtained from this study at a current density of 25 A/m2 with a processing time of 160 minutes. The effectiveness of Songket wastewater electrocoagulation was 67.28% for TSS, 54.13% for BOD5, 63.64% for COD, color intensity 79.21% and phenol content of 74.93% respectively. The result has fulfilled the quality standard of textile industry wastewater treatment.

Treatment of textile industry wastewater by electrocoagulation coupled with electrochemical advanced oxidation process

The present study deals with the treatment of real effluents, containing a mixture of reactive dyes (mainly methylene blue), by electrocoagulation (EC) coupled with electrochemical advanced oxidation processes (EAOPs) such as peroxi-coagulation (PC), anodic oxidation (AO), and electro-Fenton (EF), individually. To choose the right treatment process, the key criteria should be higher degradation efficiency and minimal energy consumption. Textile effluents are physico-chemical characterized and the operating parameters i.e. the initial pH, the current density, and the electrolysis time, were investigated. Wastewater treatment energy consumption was evaluated for each combined process. The results highlighted high efficiency of electrochemical processes in effective degradation of organic pollutants at the optimum operating conditions. Among the electrochemical advanced oxidation processes tested, sequential EC-EF treatment was being preferred and quite effective since it provided electro generated hydroxyl radical OH especially when using the boron-doped diamond. Thus, removals of 97%, 100% and 100% for, respectively, TOC, turbidity and color removal were achieved by using the EC-EF combined process. Energy consumption values were evaluated for textile dye decolorization as 0.45–1.5 kW h kg−1 of the removed TOC, depending on the applied current density. Regarding the efficiency level and the operating cost, the EC-EF combined process offers many advantages allowing the reuse of the treated water for other purposes.

On-site performance of floating treatment wetland macrocosms augmented with dye-degrading bacteria for the remediation of textile industry wastewater

Floating treatment wetlands (FTWs) are considered as cost-effective remediation options for various types of wastewater. Their effectiveness has been shown in several lab-scale and pilot-scale studies; however, there is a paucity of published data on pilot-scale systems treating genuine wastewater. This study aims to assess the performance of a pilot-scale system, carrying Phragmites australis in combination with three plant growth promoting and dye-degrading bacteria (Acinetobacter junii strain NT-15, Rhodococcus sp. strain NT-39, and Pseudomonas indoloxydans strain NT-38) for the treatment of textile industry wastewater (Interloop Limited, Faisalabad, Pakistan). Fifteen FTW macrocosms were established comprising plants and bacteria separately or in combination. Each unit was capable to carry 1000 L of the wastewater and the system was operated in a batch-wise mode for the period of 2 years. After a year of installation, performance of all FTWs units was optimal. A high removal in organic and inorganic pollutants was observed in the vegetated tanks, whereas combined application of plants and bacteria further enhanced the removal performance, i.e., chemical oxygen demand was reduced to 92%, biochemical oxygen demand to 91%, color to 86%, and trace metals to approximately 87% in the wastewater. The augmented bacteria displayed persistence in water as well as in the roots and shoots of P. australis suggesting a potential partnership with the host towards enhanced performance. Treated wastewater met the National Environmental Quality Standards (NEQS) set by the Government of Pakistan, thus, suggesting its discharge in the surface water without any potential risks. This pilot-scale study is a step forward towards sustainable remediation of the textile wastewater in the field.

Supercritical water gasification of wet sludge from biological treatment of textile and leather industrial wastewater

Activated sludge produced from biological treatment of textile and leather industrial wastewater was processed using hydrothermal gasification in order to produce fuel gas with high calorific value. The gasification experiments were performed in a batch reactor and the effect of temperature (400, 450, 500 and 550 °C), additives (KOH and dolomite) and reaction time (0, 30 and 60 min) was investigated. The gas yield increased with the increasing temperature. Hydrogen and methane compositions in the gas was between 42 to 57 vol%, while CO2 was between 30 and 40 vol%. The calorific value of the sludge was determined as around 16 MJ/kg, while after gasification the calorific value of the gas fuel produced was found to be 24.7 MJ/kg (24.3 MJ/Nm3) after 30 min. reaction time in the presence of KOH. The addition of dolomite did not affect the gas yield however, addition of KOH promoted the water-gas shift reaction and boosted hydrogen yield in the product gas. Around 70 wt. % of the sludge was converted into either gas or liquid with hydrothermal treatment.