Potential of Cactus Cladodes as a Natural Biodegradable Composite in Wastewater Treatment for Stone-cutting Industries

Abstract

Using natural biodegradable polyelectrolytes of cactus (Ficus Indica) as a coagulation or flocculation agent for treating wastewater effluent of high turbidity has been investigated. This approach can be applied to recycling water as well as in the treatment of sludge prior to disposal to agricultural soils which in turn could be used in the field of soil remediation. The use of cactus cladodes powder (CCP) at an optimal dose of 140 mg/L was shown to meet the goal turbidity levels with enhanced recycled effluent quality of 45–98%, based on the optimized doses and turbidity results, which consequently cuts down on operating expenses and time. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) study evaluated the CCP binding mechanism. Experiments were compared with aluminum sulfate (Al₂(SO₄)₃) and ferric chloride (FeCl₃) coagulants. Major physico-chemical characteristics were measured, including pH, conductivity, turbidity, TDS, and the degree of coagulation with dosage changes. Assessment of coagulant efficiency with actual sample effluent from a stone-cutting factory with initial turbidities ranging from 100 to 400 NTU (Nephelometric Turbidity Unit) showed a comparable high turbidity reduction efficiency with cactus. Finally, coagulation kinetic studies were carried out using the batch method to study the effectiveness of the turbidity treatment. The first-order kinetic model provided a superior fit for the single coagulant dosage's coefficient of determination (R²).