Записки Горного института (Jul 2024)
Potential use of water treatment sludge for the reclamation of small-capacity sludge collectors
Abstract
In small settlements, collectors for the sludge produced during water treatment processes are small-sized and located in the vicinity of drinking water storage reservoirs or in coastal areas. Sludge removal is not economical. Besides, the relief depressions formed after sludge disposal are required to be reclaimed. In ore mining regions, where the main settlements of the Urals are located, sludge produced in water treatment has high contents of heavy metals typical of ore mining provinces. Consequently, places of sludge accumulation are potential sources of water pollution. The article discusses the possibility to mix sludge with slaked lime and local overburden with the help of special equipment. So far water treatment sludge in the region has been used to reclaim the surface of solid waste landfills by creating anaerobic conditions for waste decomposition. When placed inside the embankment dams as an independent object, sludge needs to be improved for the increase of its bearing capacity and the ability to bind heavy metals. The article aims at the substantiation of the composition and properties of the reclamation material made of the water treatment sludge mixed with local overburden and slaked lime (technosoil). For this reason the paper describes the composition of the sludge in a sludge collector, the composition and properties of the overburden rocks as a component of the mixtures with water treatment sludge, the composition and properties of the mixtures of water treatment sludge with overburden rocks and Ca(OH)2 as a component dewatering sludge and neutralizing toxicants. Furthermore, the research work provides the technology created for the optimal processing of the water treatment sludge in the process of the reclamation of a sludge collector. The research results and the experience obtained in reclamation of disturbed lands in the region have confirmed the possible use of technosoil for the reclamation of small-capacity sludge collectors. The analysis of the chemical composition and physical and mechanical properties of the mixtures under study has shown that the most economical and environmentally sound reclamation material is a mixture of water treatment sludge, loose overburden dump soils and Ca(OH)2 in a ratio of 60 : 30 : 10 %.
