MUNICIPAL WASTEWATER IN EXPERIMENTS ON RECLAMATION OF LOPARITE ORE DRESSING TAILINGS

Abstract

Introduction. This paper discusses the effectiveness of using clarified municipal wastewater (CMW) and wastewater sludge (WS) to form stable phytocenoses at the waste storage facilities of the rare metal industry in Murmansk Region. The restoration of the vegetation cover at tailing dumps is limited by the low content of organic matter and associated nitrogen, and the low bioavailability of plant nutrients (K, Ca, Mg, P). The use of WS and other ameliorants of organic nature is a type of chemical amelioration aimed primarily at improving the edaphic properties of man-made soils. Methods. We examined the loparite ore dressing tailings sampled in the operating field of the tailing dump of a rare metal industry enterprise in the center of the Kola Peninsula. In the course of the study, we determined the suitability of the man-made soil for reclamation. To form seeded phytocenosis in a laboratory experiment, seeds of meadow fescue (Festuca pratensis Huds.) were used. The laboratory experiment involved the introduction of CMW, WS, a mixture of WS with silica clay into the soil, and a check. Analysis of the soil and plants was performed using inductively coupled plasma mass spectrometry. The quality of seeded cenosis was assessed according to the following parameters: green biomass, plant height, and projective cover. Results. The preliminary assessment of the man-made soil suitability for reclamation showed the following: the loparite ore dressing tailings have unfavorable characteristics both for the natural regeneration of the vegetation cover and biological reclamation. The introduction of ameliorants had a stimulating effect on the growth of terrestrial biomass during the formation of phytocenosis under laboratory conditions. The results of leaf analysis confirmed the effectiveness of the surface application of organic additives with regard to the loparite ore dressing tailings. Conclusion. In the laboratory experiment with the simulation of surface application, the stimulating effect of unconventional ameliorants (clarified municipal wastewater, wastewater sludge, and its mixture with silica clay) on the supply of nutrients to the reclaimed loparite ore dressing tailings was confirmed. The investigated ameliorants can be recognized as suitable for the biological reclamation of the dressing tailings of the rare metal industry, which does not require costly earthing and the application of protective polymer coatings.