Effects of Retention in Effluent from a Wastewater Treatment Plant on Deposition of <i>Escherichia coli</i> in Packed-Bed Columns

Abstract

The transport of pathogenic bacteria from wastewater treatment facilities in subsurface has attracted extensive concerns over recent decades, while the impact of effluent water chemistry remains unclear. The influence of retention time in effluent from a municipal wastewater treatment plant on bacterial surface properties and deposition of Escherichia coli strains in saturated quartz sand packed-bed columns was investigated in this paper. Retentions in effluent significantly altered bacterial surface properties, such as zeta potential, surface charge and hydrophobicity, subsequently changed their deposition rate coefficients and attachment efficiencies in quartz sand packed-bed columns. Under low ionic strength conditions, bacterial deposition onto quartz sand grains was in agreement with the predictions of DLVO theory, in which the secondary energy minimum was demonstrated to be predominant.