Effect of Ca-Rich Granulated Oil Shale Ash Amendment on Leaching Properties of Peat Soil: Experimental and Field Study

The combustion of low-grade solid fuels such as oil shale generates huge amounts of solid wastes such as fly ash. Use of oil shale combustion ash in granulated form for liming and amending peat soil has been suggested as a feasible recycling opportunity. However, the effect of granulated oil shale ash application on the characteristics of soil moisture and mobility of potentially toxic elements has not been thoroughly studied. The aim of the work was to study the environmental safety of the granulated oil shale fly ash when applied at peat soil in post-harvested peatlands. The oil shale ash was granulated using Na-alginate gel. The pH, EC and mobility of selected elements such as Al, As, Ba, Ca, Cd, Cr, Cu, Hg, K, Mo, Ni, Pb and Zn in amended peat soil was followed by analyzing soil water samples from the field. During vegetation period from April 2016 to September 2016 the pH value of the soil water samples in areas amended with granulated oil shale ash increased from 3 up to 6. The concentration of essential nutrients as well as other beneficial trace elements increased in soil water samples. The concentrations of potentially toxic microelements Cd, Hg and Pb were below detection limits in all collected soil water leachates. Granulated oil shale ash did not increased the mobility of other potentially hazard elements in amended peat soil during the study.