When wastewater infiltrates into the soil, groundwater may be contaminated. If the distance from source of pollution to point of groundwater abstraction is small, there is a real chance of abstracting pathogenic microorganisms. In this book, the transport of Escherichia coli in aquifers under saturated conditions is studied. Starting point is the well known colloid filtration theory. Straining or physical sieving, geochemical heterogeneity, variable deposition rate coefficients, and preferential flow mechanisms are then included in the theory. The case of Sana'a, the capital of Yemen, served to evaluate the importance of bacteria transport processes in a field situation. This book is useful for hydrogeologists concerned with microbiological contamination of aquifers.

Arsenic, manganese and iron in drinking water at concentrations exceeding recommended guideline values pose health risks and aesthetic defects. Batch and pilot experiments on manganese adsorption equilibrium and kinetics using iron-oxide coated sand (IOCS), Aquamandix and other media have been investigated and modeled. Effect of manganese and iron loading on manganese removal and rate of oxidation of adsorbed iron and manganese have been studied. Aquamandix and IOCS demonstrated iron and manganese adsorption capacity that increases with increasing pH under oxic and anoxic conditions. Manganese loading and low filtration rate using feedwater with no nitrite favour non-uniform development of catalytic manganese oxide on media that subsequently enhances manganese removal.