Utilization of municipal solid waste incineration bottom ash as road construction materials

Abstract

The possibilities of reutilizing municipal solid waste incineration (MSWI) bottom ash have been increasingly concerned in China. Major interests in this sense are to use the ash as construction materials in road building elements. Bottom ash from a MSWI plant of China was characterized to investigate the feasibility of recycling its fine and coarse fractions in road construction and assess their environmental impacts. The present work mainly focused on measuring the detailed physical and mineralogical parameters, and full chemical properties and the study of leaching of heavy metals and salts as a function of the ratio of liquid and solid. According to Chinese specification for road construction materials, the results obtained indicate that bottom ash basically complies with the technical requirements for road base and sub-base materials with exception of the low compataclity and high organic content of the fine fraction. Therefore, for use the ash in road base, it should be mixed with other materials to improve the compataclity. And pretreatment of fine fraction of bottom ash to remove organic matter is necessary. Data obtained from the toxicity test satisfy the limit values established by Chinese specification for hazard solid residues landfill.