Reclamation of disturbed lands by means of technogenic water treatment sludge

Abstract

An effective option of disturbed land reclamation by stowing the goaf with overburden rocks of mineral deposits is considered. Outside the settlements, under favorable geological conditions, a goaf may be stowed with solid household waste. It is noted that to prevent migration of waste degradation products, their intermediate layer-by-layer isolation is required. The purpose of this work is to study the possibility of using man-made sediments of water treatment plants to form an insulating layer during the reclamation of disturbed land. Method of research. The main physical and chemical parameters of the water treatment sediment were determined by generally accepted methods in accordance with the standards for soil samples. The fractional composition was studied by the method of Rutkovski. Humidity was determined by evaporation of water from a sample of sediment followed by drying to a constant mass. The mineral composition was studied by semi-quantitative spectral analysis. The relative deformation of the swelling was determined using the swell meter. The filtration coefficient was determined by filling the pits. A representative gross sample of sediment was placed in a ground recess to conduct research in natural conditions. Outcomes and discussion. Water treatment sediment by its physical and chemical properties is a colloidal system consisting mainly of humus substances and clay minerals, as well as hardly soluble iron and aluminum hydroxides and manganese oxide. The results of the research indicate the stability in atmospheric conditions of the bearing properties of man-made soil formed when the sediment dries. The chemical composition of the sediment is characterized by the presence of heavy metals. Toxic elements such as lead and arsenic are bound by clay and organic particles, metal hydroxides and oxides that form sediment. As a result, the mobility of the elements is noticeably reduced. On the other hand, water treatment sediment can serve for plants as a source of trace elements such as copper, zinc, and nickel, contributing to the biological stage of reclamation. Conclusion. Sediment of water treatment of filter plants is a promising material for use as a man-made insulating soil. The main advantages of this application of water treatment sediment are associated with the possibility of using it on the surface of steep slopes, good sorption capacity in regard to polluting chemical elements and reduced filtration properties that prevent precipitation from entering the waste depth. The use of water treatment sludge as a technogenic secondary raw material makes it possible to solve the problems of environment-friendly waste management and recultivation of disturbed lands.