Insolubilization of Heavy Metals in Municipal Solid Waste Incineration Fly Ash by Water Repellent Treatments using Fatty Acid

Abstract

Controlling the elution of heavy metals from municipal solid waste incineration (MSWI) fly ash using water repellent treatments was studied. Water repellent durability and adaptability to the environment in the final disposal site are required for landfilling water repellent MSWI fly ash. Three types of elution tests, including Ministry of the Environment Notification Test No. 13, were carried out to evaluate the elution suppression effect of water repellent treatments with six fatty acids (oleic acid, linoleic acid, α-linolenic acid, isostearic acid, ricinoleic acid, and erucic acid). All six water repellents could suppress the elution of heavy metals from MSWI fly ash. The elution suppression effects on heavy metals differed depending on the physical and chemical properties of the fatty acids. Water repellent treatments with fatty acids demonstrated effectiveness in the suppression of heavy metal elution in two types of fly ash with different incineration methods and indicated adaptability to the environments of final disposal sites. Based on the results of three types of elution tests, water repellent treatments with fatty acids have the potential to replace conventional methods as new treatments for suppressing the elution of heavy metals from MSWI fly ash.