Addition of composite adsorbent Zeliac to a riverbank filtration system can enhance the removal of micropollutants in polluted river water. This paper aims to investigate the potential use of Zeliac to remove pollutants, such as total coliform, Escherichia coli, suspended solids (SSs), UV254 and colour, from the Sungai Kerian River. Two columns filled with Zeliac of different granular sizes were established and continuously run for 15 days. Maximum SS removals of 93% and 98% were recorded for Zeliac with granular sizes of 1.18–2 mm and 0.42–0.6 mm, respectively. Meanwhile, 99%–100% of total coliform was removed from the system, and no E. coli was detected in the effluent up to 15 h of the experiments. High removal efficiencies were also recorded for UV254 (>80%) and colour (>90%). Granular size showed no significant effect on the removal of the selected parameters, especially total coliform and E. coli. Zeliac showed good potential as an adsorbent to improve water treatment.