Dose-Optimized Evaluation of Lignocellulosic Coagulants and Ferric Chloride for Primary Treatment of Textile and Tannery Wastewaters

This researches the dose–response efficacy of two lignocellulosic coagulants (sawdust and rice husk) in comparison with ferric chloride for textile and tannery wastewaters treatment. The jar tests were conducted using six different doses of the coagulants (0, 2, 4, 6, 8, and 10 grams per 250 milliliters of wastewater) following a completely randomized factorial design, with each test repeated three times to ensure reliable results. The efficiency of the coagulants was evaluated based on several types of key parameters: pH, electrical conductivity (EC), turbidity, total suspended solids (TSS), total dissolved solids (TDS), hardness and extracts concentration into chloride, phosphate and to cadmium had been measured. The data demonstrated the influence of the coagulant type and dose on almost all parameters, as well as multiple wastewater × coagulant interaction effects (p ≤ 0.05). In general, sawdust proved to be better than rice husk and ferric chloride when applied for all physico-chemical properties and pollutant removal excepting pH adjustment, the turbidity, reduction in solids and cadmium removal^^. The maximum doses, especially 10 g, gave the highest enhancements for both wastewater kinds. The results demonstrate that lignocellulosic coagulants, especially sawdust, are feasible and economical substitutes for the conventional inorganic metal salts as primary treatment agents to textile and tannery industries which are confronted with increasing environmental demand. Importantly, the research indicates possible application of agricultural waste by-products by large water treatment industries.