Kutai Clay Granules for Reducing Escherichia coli and Coliform Bacteria in Hospital Wastewater

Abstract

Aims: This study evaluated the capacity of activated Kutai clay granules to reduce Escherichia coli and coliform bacteria in hospital wastewater and to characterise the clay by particle composition and cation-exchange capacity (CEC). Study Design: Laboratory experimental study comparing untreated hospital wastewater with four Kutai clay doses. Place and Duration of Study: Hospital wastewater was obtained from Abdoel Wahab Sjahranie Hospital, Samarinda, Indonesia, and laboratory analyses were performed using facilities associated with Mulawarman University. The study period was not reported in the source manuscript. Methodology: Activated Kutai clay granules were heated at 121°C for 30 minutes. Four doses (2.5, 5.0, 7.5, and 10.0 g) were separately added to 100 mL of hospital wastewater. Samples were stirred at 2500 rpm for 5 minutes and allowed to settle for 1–3 minutes. E. coli and coliform concentrations were measured using the Most Probable Number (MPN) method. Clay particle composition and CEC were also determined. Results: Kutai clay contained 59.0% clay, 26.0% silt, and 15.0% fine sand, with a reported CEC of 19.03 meq/100 g. Untreated wastewater contained 1.1 × 10⁵ MPN/100 mL of both E. coli and coliform bacteria. After treatment, all four clay doses produced a reported concentration of 3.0 × 10² MPN/100 mL for both indicators, corresponding to 99.73% removal. No dose-response difference was observed in the reported measurements. Conclusion: Under the reported laboratory conditions, Kutai clay granules substantially reduced E. coli and coliform concentrations in hospital wastewater. Because all tested doses yielded the same reported endpoint, the lowest dose (2.5 g/100 mL) may warrant further evaluation for treatment efficiency. Replicated experiments, statistical analysis, and physicochemical characterisation are needed before scale-up or routine application.