Printing Wastewater Treatment Research Articles

Advanced Approaches in Dyeing and Printing Wastewater Treatment: A Comparative Study of Physical and Chemical Methods

This thesis presents a comprehensive analysis of various physical and chemical methodologies for treating dyeing and printing wastewater, which is a significant environmental concern in the textile industry. It delves into physical techniques like ultrafiltration, nanofiltration, reverse osmosis, and magnetic separation, evaluating their efficiency in removing contaminants and the challenges faced, such as membrane fouling and the requirement for high-quality magnetic seeds. The study also explores chemical methods like electrochemical oxidation and photocatalytic oxidation, highlighting the advancements in electrode materials and the use of TiO2 catalysts in degrading pollutants. A comparison is made between the effectiveness, operational constraints, and economic viability of these methods, emphasizing the need for optimizing existing technologies and developing hybrid systems that integrate the strengths of individual techniques. This research aims to contribute to the ongoing efforts on enhancing wastewater treatment efficiency, reducing environmental impact, and promoting sustainable practices in the textile industry. This work serves as a reference for future research on wastewater treatment, offering insights into developing more effective, cost-efficient, and eco-friendly solutions.

Preparation of lotus-leaf-like carbon cathode for the electro-Fenton oxidation process: Hydrogen peroxide production, various organics degradation and printing wastewater treatment

To develop an electro-Fenton (EF) oxidation process for highly efficient organics degradation, a carbon cathode with lotus-leaf-like super-hydrophobic surface was prepared using ordinary graphite powder as an electro-catalyst material, polytetrafluoroethylene (PTFE) as an adhesive agent, boric acid (H3BO3) as a pore-forming agent, and using copper wire meshes to shape the surface morphology. The obtained results show that the carbon cathode with a lotus-leaf-like morphology led to an evident increase in hydrophobicity, which greatly enhanced hydrogen peroxide (H2O2) production performance. In the air-aerated Na2SO4 solution (pH = 2.8), the cathode prepared under optimized conditions yielded 527.5 mg L−1 H2O2 within 60 min with an observed current efficiency (CE) of 35.1 %. The developed EF oxidation process exhibited the strong oxidation ability for the degradation of several organics including rhodamine B (RhB), methylene blue trihydrate (MBT), p-nitrophenol (p-NP) and tetracycline (TC). What's more, the treatment of one real printing wastewater by this EF system presented the chemical oxygen demand (COD) removal of 76.8 % and the total organic carbon (TOC) removal of 73.5 %, and concurrently enhanced the biodegradability evidently. In addition, it was found that chloride ion (Cl−) might have an adverse effect on organics degradation due to the meaningless H2O2 consumption caused by HClO and ClO−. The results of this study indicate that the developed EF process can be used not only for the efficient removal of organic pollutants, but also as a pre-treatment before biological treatment for the enhancement of biodegradability.

Study on printing wastewater treatment by decomposition reaction H<sub>2</sub>O<sub>2</sub> catalyzed of complex between ion Ni<sup>2+</sup> and citric acid

In this article, the results of the research on organic pollutant treatment in the wastewater of printing processes on fabric by H2O2 under the catalytic role of the complex between ion Ni2+ and Citric acid (H4L) were presented. The condition of pH, H4L/Ni2+, H2O2, Ni2+ concentration has been explored to get the optimal conditions for improving COD efficient treatment. The results provide the solutions of the homogeneous complex catalysts in the industrial wastewater treatment at room temperature and atmosphere.

Application of Electrocoagulation for Printing Wastewater Treatment: From Laboratory to Pilot Scale

This study reports for the first time the application of electrocoagulation (EC) from laboratory to pilot scales for the treatment of printing wastewater, a hazardous waste whose treatment and disposal are strictly regulated. The wastewater was taken from three real printing companies with strongly varying characteristics. The treatment process was performed in the laboratory for operational optimization and then applied in the pilot scale. The weight loss of the electrode and the generation of sludge at both scales were compared. The results show that the raw wastewater should be diluted before EC treatment if its COD is higher than about 10,000 mg/L. Pilot scale removal efficiencies of COD and color were slightly lower compared to those obtained from the laboratory scale. At pilot scale, the effluent CODs removal efficiency was 81.9 – 88.9% (final concentration of 448 – 992 mg/L) and color removal efficiency was 95.8 – 98.6% (final level of 89 – 202 Pt-Co) which proved the feasibility of EC treatment as an effective pre-treatment method for printing wastewater as well as other high colored and hard-biodegradable wastewaters. Keywords: Printing Wastewater, Electro-Coagulation, Laboratory Scale, Pilot Scale, Industrial Wastewater

Effect of Calcination Temperature on the Performance of Pd-Based Catalysts

It is difficult to biodegrade organic waste-water, which is treated by catalytic wet oxidation method. The catalyst Pd-Fe-Co-Ce/FSC (ratio 1:1:1:3), and the calcination time was 3 h, and the calcination temperatures were set to 400, 550, 700, and 850 °C, respectively. When the calcination temperature was 550 °C, the experimental results show that: when Pd-Fe-Co-Ce/FSC (ratio 1:1:1:3) is added with, the pH of wastewater is reduced, and then the pH will rise again; the Pd-Fe-Co-Ce/FSC (ratio 1:1:1:3) catalyst has good decolorization effect at 4 calcining temperatures, which can reach 92.7% - 97.9%, and 36.6% - 41.8% higher than the blank without catalyst; the best treatment effect is when the calcination time is 3 h and the calcination temperature is 550 °C. The addition of Pd-Fe-Co-Ce/FSC (ratio 1:1:1:3) after treatment of printing waste-water, its COD removal rate increased significantly, and the final effluent percentage reached 71.7% - 88.8%.

Treatment of real printing wastewater using electrocoagulation process with titanium and zinc electrodes

Electrocoagulation (EC) has numerous benefits over traditional coagulation. It is noteworthy that most researchers have studied EC using either iron electrodes or aluminum electrodes. The key objective of this study is to investigate the performance of the EC process with zinc and titanium electrodes for treating real printing wastewater through several experimental conditions. Experiments were done through batch systems. The effects of the operating variables, inclusive of varying current densities (CDs), spacing between electrodes, electrolysis time, and varying electrode materials (titanium and zinc) on the efficiency of the removal of different parameters were studied. Oil and grease, total dissolved solids (TDS), and chemical oxygen demand (COD) were among these parameters. The highest removal efficiency for COD after 90 min using a zinc electrode was approximately 50 % attained at 20 mA/cm2. For the titanium electrode, after 90 min, the highest removal efficiency for COD was 46 % attained at 15 mA/cm2. For the removal efficiency of TDS, the zinc electrode performance was better than that of the titanium electrode for every CD. After 90 min, the optimal TDS removal efficiencies were 9 % and 19 % for titanium and zinc electrodes, respectively. The titanium electrode offers the maximum efficiency of removal for oil and grease. The highest efficiencies of removal were attained at a separation distance of 4 cm. At a CD of 15 mA/cm2, the best COD elimination efficiencies using the titanium electrode at the separation distances of 6, 4, and 2 cm were 24 %, 47 %, and 30 %, respectively. At a CD of 15 mA/cm2, the best COD removal efficiencies using the zinc electrode at the separation distances of 6, 4, and 2 cm were 27 %, 41 %, and 38 %, respectively. In both the zinc and titanium electrodes, following the experiments, corrosion occurred in the anodes, which is evidence that the process of treatment took place. The EC performance was observed to be much better than that of conventional coagulation during the treatment of printing wastewater. Zinc and titanium electrodes demonstrated a good capability of removing pollutants when used in the EC process.

Coagulation and adsorption as pretreatments of thin-film composite-forward osmosis (TFC-FO) for ink printing wastewater treatment.

This study investigated the performance of coagulation with ferric chloride (FeCl3.6H2O) and adsorption with activated carbon used as pretreatments prior to thin-film composite-forward osmosis (TFC-FO) filtration of ink printing wastewater. Wastewater samples were collected from a printing factory located in Chao Phraya river basin where zero liquid-discharge standards are regulated. The FO filtration unit was operated in co-current mode with the cross-flow velocity of 600 mL/min using 2 M NaCl as draw solution. The FO membrane achieved 83.9-91.0% chemical oxygen demand and 91.2-99.9% color rejections. FO filtration of raw wastewater, coagulation-treated wastewater, and coagulation and adsorption-treated wastewater resulted in 56.3%, 49.0% and 46.1% of flux decline in 150 min. Scanning electron microscopy and Fourier transform infrared spectrometry results revealed that cake formation caused by colloidal particles and pore blocking from precipitation were the major fouling mechanisms. Cake-enhanced concentration polarization also promoted adsorption of color and pigments at the membrane surface. Both fouling mechanisms were successfully mitigated by adsorption following coagulation pretreatment. Overall, the combined pretreatments and FO have potential for the effective treatment and reuse of ink printing wastewater.

Performance of Nanofiltration Membrane for Printing Wastewater Treatment

Almost every manufacturing process is the major origin of wastewater with certain characteristic. Printing facility provides a wide range of waste component that is harmful to the environment and people. Those harmful waste component contains high concentration of heavy metals and dye. This paper presents one of the most promising methods to remove the heavy metals and dyes from a printing wastewater before discharging to the environment. The feasibility of commercially available NF270 membrane to treat both heavy metals and dye was thoroughly investigated. The study was carried out using a cross-flow nanofiltration membrane system at operating pressure and temperature set at 5 bar and 24 ˚C, respectively. Experimental results showed that the permeate flux of NF270 is decreased from 6.2 to 5.0 L/m2.h after 1-h operation. Whilst, the rejection of both iron and zinc ions could be obtained up to 96.9% and 97.8%, respectively. Additionally, almost complete elimination of colour (99.6%) could be achieved using NF270 membrane. Thus, it can be concluded that the commercial NF270 membrane is promising in removing both heavy metal ions and dye from printing wastewater.

Application of a full-scale electrocatalytic reactor as real batik printing wastewater treatment by indirect oxidation process

Batik printing wastewater is mainly characterized by toxic dyes; hence an effective treatment technology with simple operation is needed as a suitable solution. Electrochemical-based advanced oxidation process is a simple and easy method to degrade dyes without generating any harmful sludge as by-products. A full-scale electrocatalytic reactor was constructed as a sub-set of 6 tubes (1.2m3) to treat actual batik printing wastewater; Ti/RuIrO2 electrode is designated as anode and stainless steel plate as cathode. The electrodes were positioned vertically with electrode gap of 30mm and evenly installed inside the tubes. Surface-area-to-volume ratio (S/V) was 6.28m−1. Each tube was equipped with single motor mixer using a fan belt. Optimum operational parameters were investigated, i.e., hydraulic retention time (30, 60, 90, 120, 150 and 180min), electrolyte (salt) concentration (2500, 3000, 3500, 4000mgL−1) and initial pH (3, 5, 7, 9); color and COD was used as indicators of process efficiency. Reactor achieved a complete decolourization and COD reduction of 60.8% at potential of 5V, HRT of 120min, salt concentration of 4000mgL−1 and pH 5. Three intermediate products were detected after electrodegradation with particular m/z values of 388, 300, and 256. The specific design and configuration of reactor employed in this research resulted in voltage and energy losses of 15.35% and 15.25%, respectively.

Optimization of Operating Conditions on Ceramic Printing Wastewater Treatment with Coagulation and Sedimentation Method

The ceramic printing wastewater was treated with coagulation sedimentation method by adopted AlCl3 polymerization (PAC) as a coagulant. In order to optimize the wastewater treatment of operating conditions, with absorbance, turbidity and conductivity for testing index, the PAC dosing quantity, stirring time, stirring intensity and influx water pH value on the influence of the wastewater treatment. The results show that the wastewater absorbance and turbidity with PAC dosing quantity increase, mixing time extension and stirring intensity increase present reduced trend, with the water pH increases present first decreases trend of increase; Proper operating conditions of wastewater treatment: PAC dosing quantity 90 mg/L, mixing time 15 min, mixing strength medium speed and influx water pH value is about seven. On this condition, ceramic printing wastewater treatment of effluent decolorization rate reached 86.9%, turbidity removal rate reached 92.5%, conductivity is 2.05 x 103 s/cm.

Influence of Influent pH on Ceramic Printing Wastewater Treatment

Investigated the influence of absorbency, turbidity and suspended substance in printing wastewater treatment by regulating the pH value of water treatment. Firstly, was acidified the wastewater samples to 5, 4, 3, 2, then alkalize them to 8、9、10、11、12. Calculated decolorization removal, turbidity removal and the suspended substance removal. The results show that, the decolorization removal and the turbidity removal were low after acidification. While after alkalized treatment the decolorization removal and the turbidity removal were all rise. The decolorization removal and turbidity removal increased following with the increase of pH of samples that first acidified and then alkalized. And it was the most obvious when the pH was 12. When the wastewater samples first acidized the pH to 4 and then alkalized the pH to 12, the dispose effects was the best. In these conditions, the decolorization removal and turbidity removal could reach 57.7 % and 72.8 %. After acidification, the suspended solids removal came down followed with the rise of pH value. As the water samples in same acidification value and then alkalized, with the increase of pH, the suspended solids removal first rose and then came down. It could get the best dispose effects at the pH 11, the suspended solids removal could reach 41.4 %.

Preparation of Polysilicate Aluminium Ferric (PSFA) Using Effluents and its Application on Banknote Printing Wastewater Treatment

Based on the concept of “waste control by waste”, a kind of inorganic polymeric flocculants which was called Polysilicate Aluminium Ferric (PSFA) was made from bentonite, wastewater containing Al3+, wastewater containing Fe3+ and sulfuric acid under normal temperature conditions, and it was adopted to treat banknote printing wastewater. The experiment results revealed that the maximal Chemical Oxygen Demand (COD) removal efficiency of 95.52% with residual COD of 3571mg/L and color removal efficiency of 96% with residual color of 40 times could be achieved at the optimal dosage of 48g/L wastewater, a number of big and dense alum flocs appeared quite fast, the flocs and water could be obviously separated in a short time, the pH of coagulating effluent of which color was light green was about 4.01, the effects of coagulation were very well.

Dyeing and printing wastewater treatment using fly-ash coated with chitosan

Printing and dyeing industry is a considerable source of environmental contamination. In this study treatment of printing and dyeing wastewater with a new type of sewage treatment agent, fly-ash coated with chitosan particles (FCCP), was examined. The effects of pH, stirring time, sedimentation time and temperature on color, COD, turbidity and NH3-N removal were determined. The optimum dosage of FCCP and the influence of individual factors on removal efficiency were tested. The optimum parameters determined using the L16(45) orthogonal experiment were as follows: FCCP (weight ratio of chitosan to fly-ash 1:6) dosage, 4 g·L−1; temperature, 35°C; pH, 4. The stirring time and sedimentation time were 20 min and 5 h, respectively. Under these optimum conditions, the color, COD and NH3-N removal ratios were 97%, 80% and 75%, respectively.

Decolorization of triphenylmethane, azo, and anthraquinone dyes by a newly isolated Aeromonas hydrophila strain

A broad-spectrum dye-decolorizing bacterium, strain DN322, was isolated from activated sludge of a textile printing wastewater treatment plant. The strain was characterized and identified as a member of Aeromonas hydrophila based on Gram staining, morphology characters, biochemical tests, and nearly complete sequence analysis of 16S rRNA gene and the gyrase subunit beta gene (gyrB). Strain DN322 decolorized a variety of synthetic dyes, including triphenylmethane, azo, and anthraquinone dyes. For color removal, the most suitable pH and temperature were pH 5.0-10.0 and 25-37 degrees C, respectively. Triphenylmethane dye, e.g., Crystal Violet, Basic Fuchsin, Brilliant Green, and Malachite Green (50 mg l(-1)) were decolorized more than 90% within 10 h under aerobic culture condition and Crystal Violet could be used as sole carbon source and energy source for cell growth. The color removal of triphenylmethane dyes was due to a soluble cytosolic enzyme, and the enzyme was an NADH/NADPH-dependent oxygenase; For azo and anthraquinone dyes, e.g., Acid Amaranth, Great Red GR, Reactive Red KE-3B, and Reactive Brilliant Blue K-GR (50 mg l(-1)) could be decolorized more than 85% within 36 h under anoxic condition. This strain may be useful for bioremediation applications.

Dyeing and printing wastewater treatment using a membrane bioreactor with a gravity drain

A laboratory-scale membrane bioreactor (MBR) with a gravity drain was tested for dyeing and printing wastewater treatment from a wool mill. The MBR was operated with continuous permeate by gravity and without chemical cleaning for 135 days. Results showed that excellent effluent quality could meet the reuse water standard in China. The average concentrations of COD, BOD5, turbidity and color in the effluent were 36.9 mg l−1, 3.7 mg l−1, 0.2 NTU and 21 dilution times (DT), respectively. The average removal rates of COD, BOD5, turbidity and color were 80.3%, 95.0%, 99.3% and 58.7%, respectively. The membrane flux increased with increasing of aeration intensity, and its increasing rate was related to pressure-heads. The higher the pressure-head, the greater the impact of aeration intensity on membrane flux. Statistical analysis also showed that both the pressure-head and aeration intensity significantly affected membrane flux. Due to its compact design, simple operation and easy maintenance, MBR with a gravitational filtration system hs low energy consumption and is cost-effective to build and operate. If the life expectancy of the membrane is set for 3–4 years and the membrane flux is set at 15 l/m2·h, such a MBR would be very competitive.