Effect of Fillings on Removal of Indicator Bacteria From Column of Simulated Wetland

In order to study effect of fillings on removal of indicator bacteria ( heterotrophic bacteria, coliforms group, fecal strep tococcus) , zeolite, anthracite, shale, vermiculite, ceramic filtermedia, gravel, blast furnace steel slag and bioceramic were chosen as fillings in columns of simulated wetland in a wastewater treatment experiment. Results show that anthracite and steel slagwere the highest in bacteria－removing efficiency, being 95，9% and 99，9% respectively, probably because the effluent from the two columnswas acidic and alkaline, respectively. Vermiculite and zeolite came next, while ceramic filtermedia and bio－ceramic followed in the rear. Correlation analysis revealed negative correlation existed between indicator bacteria removing efficiency and permeability of the six different fillings ( except steel slag and anthracite) , suggesting that filtration absorp tion is the mechanism of the fillings removing indicator bacteria，