To obtain the material, the researchers added a reagent with calcium to the mine water, which led to settling of soluble metals. As a result, the water changed from acidic to highly alkaline, and the formed sediment precipitated as a fine powder composed of water-insoluble metal compounds, as well as calcium salts and binders. Then the scientists isolated the powder from water and dried it at 140 degrees Celsius. This produced the material preventing oxygen and atmospheric water from entering, as well as suppressing the decay of waste and formation of stinky odours.
Finally, at the final stage, the scientists conducted a landfill experiment, mixing the material with municipal solid waste in a ratio of 1:4. Observations have shown that when precipitation falls, this mixture forms a hard stone preventing penetration of water and air, also due to a rapid “setting” of the binding material.
“When moisture hits a landfill, garbage together with the sludge absorbs it and forms a hard stone. The experiments have unexpectedly revealed that iron hydroxide, hydroxoferrite, hydroxoferrate and manganese in the landfill body are firmly bound in the insoluble complex compounds of nickel, cobalt, magnesium, copper, chromium and vanadium, which means that the sludge from the mine water treatment not only isolates but also disinfects the waste entering the landfill containing these pollutants,” Tomsk Polytechnic quotes Olga Ruchkinova, one of the authors of the study.
In general, the development makes it possible to reliably bury municipal solid waste. Therefore, commercialisation of the research results is going not only to increase the safety of landfills, but also make possible construction of non-residential premises in their territory.
