The influence of dewatering system on groundwater regime at NLMK Lipetsk

Abstract

The analysis of geological and hydrogeological conditions at the industrial site of Novolipetsk Metallurgical Plant (NLMK Lipetsk) was performed. It was determined that the hydrodynamic regime of groundwater at the industrial site changed in the course of construction and operation of the metallurgical facilities, as well as during creation of the Matyrskoe reservoir. An increase in the infiltration feed of aquifers was detected due to the process water leaks, reduction of surface water runoff and backwater effect from the Matyrskoe reservoir. All of that led to increasing of groundwater levels in the aquifers at the industrial site and to underflooding of the buried structures of industrial facilities. The main elements of protection of buried buildings and structures from underflooding with groundwater of the Neogene–Quaternary aquifer are the permanent drainage sites and injectable plugging for fixing of aquifers rocks. Protection of buried structures from underflooding with groundwater is carried out using 30 dewatering wells located on four sites of permanent drainage. It was found that operation of the permanent drainage sites led to the formation of a depression funnel in the Neogene–Quaternary aquifer, to the flow of groundwater from the Devonian aquifers into the Neogene–Quaternary aquifer and to the change in the groundwater chemistry. The sources of groundwater pollution are the process water leaks from production workshops and settling tanks, chemical water treatment facilities, sewerage networks, and raw material storage sites. The main pollutants of groundwater are iron, manganese, cyanides, rhodanides, phenols, petroleum products and organic nitrogen-containing substances. It is shown that the localization of polluted waters occurs within the depression funnel, the center of which is in the location of sites of permanent drainage. The spread of polluted waters through the Neogene–Quaternary aquifer beyond the depression funnel and the Devonian aquifer contamination with seepage waters from the industrial site are eliminated.