The distribution of heavy metals: Cd (A), Cu (B), Fe (C), Ni (D), Zn (E) in the compacted sludge specimens, with the deionized water (DW), pH 2.1 sulfuric acid water (SA), or the synthetic AMD as the permeant liquid at start point (SP), time1(T1) and time2(T2).

<p>The distribution of heavy metals: Cd (A), Cu (B), Fe (C), Ni (D), Zn (E) in the compacted sludge specimens, with the deionized water (DW), pH 2.1 sulfuric acid water (SA), or the synthetic AMD as the permeant liquid at start point (SP), time1(T1) and time2(T2).