An integrated batch‐type Fenton oxidation‐electrocoagulation‐adsorption system for <scp>COD</scp> and chromium removal from tannery wastewater

Abstract Background Leather industry wastewater and processing by‐products from coconut coir pith require immediate intervention, as they pose a significant threat to the ecosystem. This study explores the use of coconut coir pith processing waste for the development of activated carbon (AC) adsorbent and Fe 3 O 4 /AC based Fenton catalyst, followed by integrating them with electrocoagulation and adsorption processes for the removal of chemical oxygen demand (COD) and chromium from the tannery wastewater. Results The surface area (AC‐507.51 m 2 /g, Fe 3 O 4 /AC–210.06 m 2 /g) and field emission scanning electron microscopy analysis validated the formation of pores on the AC after KOH activation, and the decrease in the surface area endorsed Fe 3 O 4 /AC composite formation. The initial chemical oxygen demand and chromium concentration of raw (Pvm Raw) and equalization tank (Pvm EQ) tannery wastewater were 4000 and 120 mg/L, 3360 and 148 mg/L, respectively. The results revealed that overall, 85.6% and 88.57% of COD and 99.35% and 98.28% of chromium were removed after the integrated Fenton oxidation‐electrocoagulation‐adsorption treatment of Pvm Raw and Pvm EQ. Conclusion The findings highlight the potential of coconut coir pith processing waste derived activated carbons and Fe 3 O 4 /AC as an efficient and sustainable material for adsorption and Fenton oxidation processes. Further, the batch‐type integrated Fenton oxidation‐electrocoagulation‐adsorption processes showed significant efficacy in COD and chromium removal from the tannery wastewater. In conclusion, the value addition of waste materials for the construction of integrated reactors could be a promising solution for the solid and liquid waste management process. © 2026 Society of Chemical Industry (SCI).