Promising technologies for bioremediation of wastewater from gold mining enterprises in Uzbekistan

Abstract

The ever-increasing volumes of gold mining in the Republic of Uzbekistan requires an increase in the cost of water resources. However, the subdivisions of the Navoi MMC are located in the arid, lowwater areas with high (40–80 %) and extreme (more than 80 %) water shortages. Therefore, the problem of water supply, water disposal and improvement of the closed water circulation system with the use of innovative biotechnological solutions is acute for the enterprise. The purpose of this work is to summarize current data on the use of wastewater bioremediation technologies at mining enterprises and to assess the prospects for using this technology by Navoi Mining and Metallurgical Company. The article summarizes the data on the use of bioremediation at mining enterprises in Russia and other countries and data obtained from our own experimental studies of the cleansing functions of plants in Uzbekistan. These studies were carried out under the laboratory modeling conditions using wastewater from tailing ponds GMZ-2 and GMZ-3 NMMC. The cleansing functions of the plants of the Zarafshan river valley were studied: eichornia, pistia, azoles and duckweed. It was found that eichornia has the highest cleansing potential: due to the high activity of the cyanidutilizing enzyme beta-cyanoalanine synthase, it accumulates metals and metabolizes cyanides. Pistia and azola have proven to be tolerant to high salinity levels and need to be adapted by adding organic matter, including sheep manure. The next stage is semi-industrial testing in a tailing dump and development of technical regulations.