Accelerated leaching of heavy metals from Landfilled municipal solid waste incineration bottom ash

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Assisted leaching mechanisms of heavy metals from landfilled municipal solid waste incineration bottom ash was investigated. Citric acid co-existed with urea had the largest effect on the complexation with heavy metals and promoted the leaching of some elements, in particular chromium, copper, iron, and phosphorus. Although fulvic acid generated in landfill site had great complexation capacity with copper cation, it was two orders of magnitude smaller than that of natural fulvic acid. The combination of pH-dependent leaching tests and sequential extraction tests indicated great difference between geochemical simulation results and leaching test results. This suggested that leaching mechanisms were not controlled by some dominant minerals. In addition, it is also concluded that leaching of heavy metals from bottom ash are very complex mechanisms, which consisted of dissolution, precipitation, and conversions of heavy metals to other geochemical forms during leaching.