Behaviour of heavy metals immobilized by co-melting treatment of sewage sludge ash and municipal solid waste incinerator fly ash

Abstract

This study elucidates the behaviour of heavy metals in slag produced from four different sewage sludge ashes mixed with municipal solid waste incinerator fly ash and then co-melted. Experimental results indicate that sewage sludge ashes consisted of SiO(2), CaO, and Al(2)O(3). Fly ash consisted of CaO, Na(2)O and SO(3). The speciation of sewage sludge ashes indicates that the ashes contained quartz and AlPO(4). The speciation in fly ash consisted of anhydrite, microcline, calcium chloride, sylvite and halite. The leaching behaviours of sewage sludge ashes met the Taiwan Environmental Protection Administration's regulatory standards. The fly ash had high concentrations of Zn and Pb; however, the leaching of these metals was low. The major components of synthetic slags were SiO(2) (33.5-54.0%), CaO (21.4-36.7%), and Al(2)O(3) (8.1-15.7%). The X-ray diffraction patterns of co-melted slags demonstrate that the slags contained significant amounts of glass. Most heavy metals can be fixed in a net-like structure; thus, they can not be extracted easily. The toxicity characteristic leaching procedure (TCLP) leaching concentrations for target metals in all slags met the Taiwan Environmental Protection Administration's regulatory standards.

Sewage sludge ash characteristics and potential for use in concrete

“…Quartz and hematite have been identified as the most abundant minerals in SSA, whilst many other iron oxides, iron phosphates, calcium phosphates and aluminium phosphates have been reported to a lesser degree [3][4][5][11][12][13]16,21,24,[29][30][31][32][43][44][45]51,58,59,64,68,74,76,77,79,94,95,99,102,[105][106][107][108][109][110]. The amorphous content of SSA ranged from 35-75%, which suggests that the material is somewhat reactive and, when ground sufficiently fine, may have potential as a cement component.…”

“…The amorphous content of SSA ranged from 35-75%, which suggests that the material is somewhat reactive and, when ground sufficiently fine, may have potential as a cement component. Table 1 has been prepared to provide analysis of the extensively reported toxic and non-toxic element concentrations of SSA [2,4,12,13,17,28,30,32,34,35,42,44,45,49,55,56,58,[70][71][72][73][74]76,82,83,85,87,97,[100][101][102][103][104]107,108,.…”

Vitrified forts as anthropogenic analogues for assessment of long-term stability of vitrified waste in natural environments

“…3). Also the origin of the fuel may vary, for example, municipal solid waste (most common), sewage sludge [41,42], galvanic sludge [42], chromium electroplating sludge [43], copper fl otation waste [44], hospital waste [45][46][47], chromium-rich tannery waste [48] or any mixtures of these [41].…”

On the possibility of using vitrified forts as anthropogenic analogues for assessment of long-term behaviour of vitrified waste

“…In this way, trace elements are immobilized so that they cannot influence health and the environment. See also References [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36].…”