A Study on Bacterial Transport Through Subsurface Media

Abstract

Groundwater is a natural source on which everyone depends on it for fulfilling their daily needs. Increasing of the demand of clean water due to urbanisation and industrialisation force the urban people extract more from groundwater. Eventually, the recharge of groundwater occurs through precipitation, adopting various mechanism of artificial recharge of surface water and wastewater. During this process, there is a possibility of transport of existing microbes towards the aquifer and make it contaminant. Several processes in the soil environment independently or in combination works and control the fate and transport of microbes through sub-surface media. Therefore, in order to understand these processes, the present study investigates the transport of E. coli through one-dimensional vertical columns packed with three different types of porous media under various moisture content conditions. Column experiments were conducted to understand the influence of different factors such as media type, media size, media depth, minerals present in media, and presence of fertilizer in media in bacterial transport under variable moisture content conditions. E. coli suspensions were pumped through the columns, and effluent samples were collected to determine bacterial viability using the MTT protocol. Results were analyzed using Breakthrough Curves (BTC), which provided insights into peak concentrations, time to peak, and tail concentrations of E. coli. Several numbers of experiments were conducted by systematically varying the influencing factors and observed that particle size, travel distance, porosity, particle surface condition and types of mineral present in the particle are the parameters affecting the mechanism of bacteria transportation through the subsurface media. It is also observed that the sorption mechanism during the transport of E. coli through porous media is being affected by the presence of aluminium oxide. The present study also explored the effect of adding fertilizer to the porous media on the