Application of poly aluminum chloride and alum as catalyst in catalytic ozonation process after coagulation for the treatment of textile wastewater.

Textile wastewater is ranked highly contaminated among all industrial waste. During textile processing, the consumption of dyes and complex chemicals at various stages makes textile industrial wastewater highly challenging. Therefore, conventional processes based on single-unit treatment may not be sufficient to comply with the environmental quality discharge standards and more stringent guidelines for zero discharge of hazardous chemicals (ZDHC). In this study, a novel approach was followed by recycling Poly aluminum chloride (PACl) and Alum as a catalyst for the first time in the catalytic ozonation treatment process leading to a nascent method after using them as a coagulant in Coagulation/Flocculation. In the current investigation, six different combinations were studied to remove turbidity, TSS, COD, BOD5, color, and biodegradability (BOD5/COD ratios) of wastewater. Moreover, Central Composite Design was implied using RSM in Minitab software. During the combination of treatment processes, it was found that the pre-coagulation/flocculation with coagulant PACl followed by post-catalytic ozonation with recycled PACl, a more effective treatment than others. The optimum R.E of turbidity, TSS, COD, and color were 84%, 86%, 89%, and 98%, respectively. Moreover, a decrease in toxicity and increase in biodegradability (BOD5/COD ratio from 0.29 to 0.54) was observed as well. The electrical energy demand and operational costs of treatment processes were estimated and compared with other treatment processes.

Treatment of leachate through constructed wetlands using Typha angustifolia in combination with catalytic ozonation on Fe-zeolite A.

Leachate control and management is a major challenge faced during solid waste management as it may pollute surface and groundwaters. In the current research, constructed wetlands (CWs) vegetated with Typha angustifolia plant in combination with catalytic ozonation by ferrous (Fe)-coated zeolite A was studied for the treatment of leachate. The CWs treatment with 9 days detention reduced the chemical oxygen demand (COD) and biochemical oxygen demand (BOD) up to 75.81% and 69.84%, respectively. Moreover, total suspended solids (TSS), total dissolved solids (TDS), and total kjeldahl nitrogen (TKN) removal of 91.16%, 33.33%, and 25.22% were achieved, respectively. The Fe-coated zeolite A catalytic ozonation further reduced the COD up to 90.7%. Comparison of the processes showed the effective performance of the combined process (CW/O3/Fe-zeolite) with 97.76% COD reduction of leachate. It is, therefore, concluded that the studied combined process (CW/O3/Fe-zeolite A) was more efficient as compared with single ozonation and CW alone, hence it can be implied for the leachate treatment in real conditions.

Catalytic ozonation for the removal of reactive black 5 (RB-5) dye using zeolites modified with CuMn2O4/gC3N4 in a synergic electro flocculation-catalytic ozonation process.

This study aims to investigate the decolourization efficiency of reactive black 5 (RB-5) dye by using CuMn2O4/gC3N4 coated zeolites (zeolite 4A) for the first time in a hybrid electro-flocculation-catalytic ozonation process. A comparison between various treatment options such as electro-flocculation, electro-flocculation in the presence of a catalyst, and catalytic ozonation in combination with electro-flocculation was explored. Moreover, the effect of different factors such as pH, time, catalyst dose, ozone dose, radical scavenger, and voltage has been studied in each treatment option mentioned earlier. The results indicated that the best treatment option was found to be catalytic ozonation in combination with electro-flocculation with removal efficiency (RE) of 90.31% at pH 10 after 30 min of the treatment process. The hydroxyl radical scavenger effect indicated that the synergistic catalytic process follows a radical mechanism. It is therefore concluded that CuMn2O4/gC3N4-zeolite catalysts in synergic electro-flocculation-catalytic ozonation process may be effectively used for the treatment of textile wastewaters.