Removal and inactivation of 'E. Coli' from water using copper modified natural zeolite

Zeolite was used as a base material that was coated using relatively safe heavy metal based biocides. Cu2+-modified zeolite (Z-Cu2+) showed promising results for E. coli removal/inactivation in stormwater, but copper leaching from the media was significant. We therefore aimed to optimise the modification conditions of Z-Cu2+ and reduce copper leaching, while maintaining the E. coli removal efficiency. Preliminary column study showed that CuO-coated Z-Cu2+ at 180 degreesC (ZCu2+/ CuO-180 degreesC) was good at E. coli removal ( 2 log reduction), and reduced mean copper leaching to 0.9 mg/L. Meanwhile, 0.6% loss of initial copper loading from Z-Cu2+/CuO-180oC was monitored during the whole experiment period, which is considerably lower than the 8.3% loss of copper from the virgin Z-Cu2+. However, leaching higher than AGWR-ADW was observed from this media when source water has salinity around 500 muS/cm. Calcination of Z-Cu2+ at 400 degreesC (ZCu2+- 400 degreesC) reduced copper leaching to 0.11 mg/L, while maintaining its inactivation ability, but without notably better removal efficiency.