The wastewater reclamation is the need of today's world. Advanced oxidation processes (AOPs) are considered as a good option for removing recalcitrant organic materials in wastewater by oxidation reactions with powerful, non-selective hydroxyl radical (OH•). Ozone alone does not cause complete oxidation of some refractory organic compounds and has a low reaction rate. The ozone is combined with H2O2, UV light, catalyst, ultrasound to enhance the generation of hydroxyl radicals to increase the efficiency of the treatment process. The ozone-based AOPs have been proved to be effective in detoxifying an ample range of industrial effluents containing recalcitrant organics, pharmaceutical products, pesticides, phenols, dyes, etc. Ozone based AOP processes such as O3/UV, O3/H2O2, O3/Fe (II), O3/metal oxide catalyst, O3/activated carbon, O3/ultrasound, O3/Fenton, photocatalytic ozonation were discussed. A review of ozone-based AOP processes as a combination of ozonation with other techniques for the degradation and mineralization of recalcitrant organics present in the industrial/municipal wastewater based on the recently published work were reported.

Recent advances in ozone-based advanced oxidation processes for treatment of wastewater- A review

Detoxification of water and wastewater by advanced oxidation processes

Degradation of nitrogen-containing hazardous compounds using advanced oxidation processes: A review on aliphatic and aromatic amines, dyes, and pesticides.

Recent trends and developments in Fenton processes for industrial wastewater treatment - A critical review.

A copper-based catalyst supported on carbon microspheres prepared by using the spray drying method has exhibited interesting Fenton-like catalytic properties for the degradation of Methyl Orange, Methyl Blue, and Rhodamine B in aqueous solution. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) data suggested that the catalyst consisted of copper particles covered by cuprous oxide. The influence of initial pH, reaction temperature, dosage of catalyst, and H2O2 concentration on the catalyst performance were investigated. Under optimum reaction conditions, the Behnajady–Modirshahla–Ghanbery kinetics model was observed to fit well with the experimental data. It was also observed that hydroxyl radical (HO•) formed from the reaction between hydrogen peroxide (H2O2) and cuprous (Cu+) species was responsible for the dye degradation under acidic conditions. This work provides new insights into the mechanism and kinetics of low-valence copper–carbon composite Fenton-like catalyst for degrading org...

Degradation of Organic Dyes over Fenton-Like Cu2O–Cu/C Catalysts

This study has focused on the treatment of real tannery effluent using different advanced oxidation processes in lab and pilot scale studies. Periodic monitoring was conducted for five months to identify the performance at different stages of treatment in the CETP. Monthly monitoring analysis shows that ratio of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) were about 0.1–0.25. It was observed that even after physicochemical treatment the sample had a low biodegradability index (BDI). For this reason, more efficient methods of advanced oxidation processes like Fenton, Ozonation have been experimented with primary settling tank (PST) effluent to improve the biodegradation in the successive activated sludge process and secondary settling tank (SST) effluent to remove the residual inorganics. Sample collection and analysis were performed using standard methods of analysis. Pollutant removal efficiency was measured in terms of reduction in COD and Total Organic Carbon (TOC). The purification effect obtained by Advanced Oxidation Processes (AOPs) was better in Ozone when compared to Fenton. A three step process of (coagulation + aeration + O 3 ) resulted in 80–90% reduction of COD. Coagulation, extended aeration followed by ozonation was recognized as the best method of treatment of tannery wastewater. Lab scale and pilot scale studies were done with real tannery wastewater effluents and the economics of the treatment processes were evaluated.

K.P. Sakthivel

Papers

Advanced oxidation processes for the treatment of tannery wastewater

Improved treatment of tannery wastewater treatment plant effluent using polymeric coagulants