Iron (Fe) and manganese (Mn) degrade drinking-water aesthetics and foul infrastructure, particularly in decentralised systems with limited operational control and routine maintenance. This study develops and evaluates KJ25 EcoPellets, a calcined clay-biomass composite granular medium, for Fe and Mn removal using continuous-flow column filtration. Batch screening identifies the optimal formulation comprised brick-making clay blends (Common Brick Mix 25% and Harvest Cream 75%) with agricultural residues (2% sugar cane mulch and 2% sorghum stubble) as pore formers. KJ25 was benchmarked against conventional media (sand, pumice, Filtralite®) in mono- and dual-media column configurations. At an influent of 10 mg L −1 Fe and 10 mg L −1 Mn, KJ25 removed 98.8% Fe and 46.2% Mn. Column filtration (0.7 m bed; 52 mm internal diameter; 2.5-10 m h −1 ) showed sustained Fe removal for KJ25 (0.6-2 mm) (∼95-100% across rates), whereas a KJ25 (2-4.75 mm) exhibited reduced Fe stability at 10 m h −1 . Mn removal was rate-sensitive and remained the limiting endpoint: mono-media KJ25 (0.6-2 mm) achieved ∼45-50% Mn removal (vs ∼30% for KJ25 (2-4.75 mm) and 90% at 10 m h −1 with ∼45% of Mn removal at 10 m h −1 , while improving operability by reducing backwash velocity required for ∼30% expansion and lowering 3 min backwash water volumes to 4.02-4.64 L compared with 7.02 L for fine KJ25 mono-media (∼35-45% reduction). Overall, KJ25 offers lower headloss, robust Fe removal, improved Mn control, and favourable operability for decentralised drinking-water treatment. • KJ25 EcoPellets achieved 95–100% Fe removal at 2.5–10 m h −1 in column studies. • Mn removal reached ∼45–50% at 10 mg L −1 under similar conditions. • Dual-media beds maintained >90% Fe removal at 10 m h −1 . • Both mono- and dual-media demonstrated lower headlosses. • Backwash water demand reduced by ∼35-45% relative to fine KJ25 mono-media.
Balasooriya et al. (Thu,) studied this question.