Content and distribution of iron in river sediments at borehole site Rb-6/P-5d in area of Belgrade water supply

Abstract

The current problem of water supplying systems for large cities with quality drinking water be‐ comes more and more complex every day. Consumption is growing rapidly due to an increase in the number of inhabitants, an increase in per capita consumption, and a number of large water consumers, such as industry and agriculture. For many cities, including Belgrade, the main source of drinking water is groundwater. The captured groundwater of Belgrade water source is formed in alluvial deposits of the Sava River and layers of Pleistocene age, previously formed from torrential flows of melted glaciers. Beside the limiting factor of the "capacity of the site", during the exploitation of the wells, due to the rapid ageing of wells, reducing of the capacity of the well and screen is observed (Dimkić, 2017). Reducing of the capacity of the well and screen happens due to hydrogeological, hydrological, hydraulic factors, as well as geochemical, mechanical and biological processes that take place in the collector of groundwater. Interaction of these factors leads to the formation of "deposits" (e.g. Majkić‐Dursun et al., 2015), which causes clogging the perforations on well screen structures and thus reduces the capacity of wells. Preliminary studies of water supply wells of the Belgrade groundwater source indicated to the increased content of iron in the deposits which causes clogging the filter perforations. The aim of this research is to determine the content of iron in individual lithological layers, as well as the distribution of iron content along the stratigraphic column, particularly in the aquifer, as a potential source of iron and the causative agent for the formation of the deposits on the well screen. These studies are part of the activities on the definition of the mechanism of transport of iron from the primary lithological setting, as well as on elucidation of the mechanism responsible for the precipitation of iron‐bearing deposits (i.e. iron minerals) on the well screen.