Typically, 2–5% flyash collected
by the filters will be generated from MSW incineration,
and different kind of heavy metals, such as zinc, copper,
lead, chromium and cadmium may contain in flyash. There
is much concern over the emission of heavy metals to the
environment due to their associated health hazard, espe-
cially, heavy metals can exert a range of toxic health effects
including carcinogenic, neurological, hepatic, renal and
haematological [2,3,8]. With regard to toxicity, flyash is
most harmful because of its high content of leachable heavy
metals. Therefore, a good way must be found to treat flyash
from incineration before its disposal to avoid secondary
pollution [9].