Determination of the Hazard Class of Ash After Coal Combustion by the Method of Biotesting

Abstract

Ash and slag wastes after coal combustion at power plants are usually considered as environmentally non-hazardous. The term "toxic" is not applied to ash and slag. This article discusses the results by researchers of several countries concerning the aspect of determination of hazard class of ash and slag wastes after coal combustion at power plants. Toxicity of ash and slag mixture has been determined experimentally using test organisms, contrary result has been obtained. Biotesting has been performed according to testing procedures (the Russian Federation) specified by the Federal Register, FR 1.39.2007.03222 and FR 1.39.2007.03223. While analyzing toxicity of ash and slag mixture after combustion of culm of Donetsk deposit (Russia), acute toxic impact water extract from waste on test organisms, Daphnia magna Straus and weeds Scenedesmus guadricauda, was revealed. Non-hazardous dilution factor water extract from waste has been detected, causing lethality of not more than 10% of daphnia in 96 h and deviation of quantity of weeds not higher than by 20% in 72 h in comparison with reference. Ash and slag wastes are classified as hazard class III-IV for environment which agrees with the results by other researchers.