Mine Wastewater Treatment Using Cassia fistulaPlant Parts as Bio-coagulants

Conventional uses of synthetic coagulants in wastewater treatment are costly, pose serious health risk to end-users, and pollute aquatic environments with nonbiodegradable materials. This study examined the potential of Cassia fistulaplant parts at different dosages to decontaminate mine wastewater. A 3 × 3 factorial arrangement of treatments involving three C. fistulaparts (seeds, leaves, and roots) at three dosages (50 mg L−1, 100 mg L−1, and 150 mg L−1) was adopted using jar test experimental procedures. Dosage and C. fistulaparts had significant effects on heavy metal concentrations and water physico-chemical properties (p< 0.0001). Bio-coagulants at the three dosages significantly lowered levels of copper, cadmium, and iron compared to alum (100 mg L−1). Only 150 mg L−1of C. fistulaleaves significantly reduced arsenic content within the WHO standards. C. fistularoots at 50 mg L−1and leaves at 50 and 100 mg L−1reduced Fe content of the wastewater by more than 99%, though residual Fe content for bio-coagulant treatments were still above the WHO guidelines. Root extracts at 50 mg L−1dosage more effectively reduced conductivity to within EPA acceptable limits. Similarly, 50 mg L−1leave extracts resulted in 99% reduction in turbidity and total suspended solids, though residual turbidity was still above the WHO recommended limit. Leaves and roots of C. fistulaat varied dosages can effectively decontaminate wastewater due to the varied amounts and composition of functional groups in these parts. C. fistulaparts offer a cost-effective option of purifying polluted mine wastewater and increasing quality water availability.