This study employed a novel approach, utilizing recycled alumina flocs after coagulation/flocculation (C/F) as a catalyst in catalytic ozonation (CO), along with the auxiliary catalyst sodium zeolite (Na-Z), where alumina produces hydroxyl radicals, and zeolite enhances molecular ozone reactions. This synergistic strategy focuses on treating contaminated canal water, recognizing that the presence of various pollutants can reduce the efficacy of a singular catalyst type. In the current investigation, alum, Na-Z, and rice husk (RH) were applied as a coagulant, catalyst, and filter media in C/F, CO, and filtration processes respectively. Four treatment technologies (C/F, O3, O3/Na-Z, and RHF) were studied independently and in four different combinations (O3–C/F, C/F–O3, C/F–O3/Na-Z, and C/F–O3/Na-Z–RHF) for the first time and their efficacious performance was evaluated. It was revealed that the combination-IV (C/F–O3/Na-Z–RHF) was a more efficient and economical treatment than others. This novel integrated treatment C/F–O3/Na-Z–RHF has remarkable removal efficiency of 99 %, 99 %, 85 %, 93 %, 100 %, 89 %, and 93 % for TSS, turbidity, COD, BOD5, fecal coliforms, cadmium, and copper respectively, under optimized working conditions. Also, treated canal water complied with the studied irrigation water quality guidelines. Notably, this efficient treatment combination halved the treatment time compared to others, potentially reducing the electrical energy demand of 11.45 kWh.m−3 and the overall operational treatment cost of 1.62 USD.m−3. Hence, the application of this efficient hybrid treatment system contributed to recycling canal water for agricultural use, livestock, and pasture watering, playing a crucial role in mitigating the water crisis.
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