Polc R., Peťková K., Lalinská-Voleková B., Jurkovič Ľ. & Milička J., 2016: Ashes from oily sewage sludge combustion: chemistry, mineralogy and leaching properties. Acta Geologica Slovaca, 8, 1, 119–130.

Ashes from oily sewage sludge combustion: chemistry, mineralogy and leaching properties

Róbert Polc¹, Katarína Peťková², Bronislava Lalinská-Voleková³, Ľubomír Jurkovič² & Ján Milička²

¹SLOVNAFT, a. s., SD & HSE, Environmental protection department, Vlčie hrdlo 1, 824 12 Bratislava 214; robert.polc@slovnaft.a.s.
²Comenius University in Bratislava, Faculty of Natural Sciences, Department of Geochemistry, Mlynská dolina, Ilkovičova 6, 842 15 Bratislava, Slovakia; katkapetkova@gmail.com, jurkovic@fns.uniba.sk, milicka@fns.uniba.sk
³SNM – Natural History Museum, Vajanského nábrežie 2, 810 06 Bratislava; bronislavalalinska@gmail.com

Abstract

In the current paper the chemical and mineralogical properties of bottom ash and fly ash from oily sewage sludge combustion are investigated. The mineralogical composition and the morphology of ashes were determined by X-ray powder diffraction (XRD) in combination with scanning electron microscopy with quantitative energy-dispersive X-ray microanalysis (SEM-EDX). In addition, a leaching test results are presented to shed light on the potential toxicity of studied materials and their impact on the environment is discussed. Both of the studied materials are final products of thermal oxidation at industrial sludge incinerator. This facility aims to sanitary disposal of mechanical and biological sludge from industrial wastewater treatment plant. Bottom ash and fly ash are relatively stable solid products with slightly different chemical and mineralogical composition that reflects their different origin – burning condition in furnace vs. flues gas cleaning technology. Leaching tests of both mentioned materials were implemented under laboratory conditions. The aim of the laboratory tests was to determine the possibility of the pollutants release into the environment. The data presented herein support the importance of detailed mineralogical and geochemical study for the better understanding of the leaching tests. The obtained results showed that both of the sewage sludge ash samples exceed the criteria for accepting waste in landfilles established for Slovakia.

Key words: bottom ash, fly ash, incineration, mineralogical analyses, leaching test, hazardous waste

Manuscript received: 2016-03-08

Revised version accepted: 2016-04-26