Comparative assessment of biological treatment and green chemistry approaches for industrial-scale textile wastewater remediation.

The textile sector releases dirty wastewater into the environment, which poses serious health and environmental concerns across the globe. The present study evaluated the textile wastewater treatment using two methodologies: biological treatment using polyvinyl alcohol (PVA) gel and a green chemistry strategy with Azadirachta indica leaf extract combined with polyaluminum chloride (PAC) solution. The physicochemical parameters such as BOD, COD, TDS, TSS, and pH levels were measured three times a week and compared with World Health Organization (WHO) standards. Toxic effects of both treated and untreated wastewater were evaluated by measuring the concentrations of heavy metals (Cr, Cd, and Pb) and inorganic salts (phosphate, ammonium, and sulfate) in the wastewater samples. The results of this comparison study demonstrated that both treatment procedures dramatically decreased pollutant loads, with the green chemistry method displaying greater efficacy. This method reduced the pH from 12.5 to 6.6, the COD from 855 to 47 mg L-1, the TDS from 5200 to 1500 mg L-1, the TSS from 1600 to 110 mg L-1, and the BOD from 340 to 20 mg L-1. Biological treatment improved several measures, but TDS and pH levels stayed above the permissible limits, while the green chemistry approach was found to be more effective at removing Cr, Cd, and Pb from the textile wastewater. Cr went from 1.3 to 0.233 mg L-1, Cd went from 0.147 to 0.030 mg L-1, and Pb went from >0.01 to 0.347 mg L-1. However, none of these levels reached WHO standards (Cr: 0.05, Cd: 0.003, and Pb: 0.01 mg L-1). Salts: phosphate went down from 4.433 to 1.233 mg L-1, ammonium went down from 8.733 to 3.3 mg L-1, and sulfate went down from 429 to 220 mg L-1. Overall, the A. indica + PAC green chemistry treatment proved more efficient than biological treatment alone, offering a cost-effective, eco-friendly, and scalable solution. However, advanced or integrated methods are recommended for achieving full compliance with international discharge standards.