Resuspension of Escherichia coli and MS2 bacteriophage from bed sediment in irrigation canals

Sediments are known to be potential reservoirs of pathogenic microorganisms that can influence the microbial quality of the overlaying water. A set of laboratory experiments was conducted to investigate the resuspension of Escherichia coli and the MS2 virus from bed sediment to the overlaying water in irrigation canals. Consequently, their concentration in moving water is dependent on flow properties (e.g., velocity, shear stress) and the size of bed sediment. When bed material is sandy loam, their quantity in water increases with the shear stress on bed surface. However, for a sandy bed, their presence in water has no apparent correlation with flow properties. The amount of MS2 virus in water was greater at low flow velocity and shear stress than Escherichia coli because the size of the MS2 virus is much smaller. Finally, an empirical relation was formulated for calculating the maximum allowable Escherichia coli concentration in sandy loamy bed sediment.