Heavy metal immobilization in the mining-contaminated soils using various industrial wastes

Opportunities and challenges in the use of coal fly ash for soil improvements – A review

“…It can also help alleviate soil compaction and improve aggregate stability of sodic soils (Kumar and Singh, 2003); can supplement useful plant nutrients, e.g. P, Ca, S, and Mg, K, Fe, Mn, Zn, Cu, and B (Sajwan et al, 2003) and can help correct acidic pH conditions (Ciccu et al, 2003;Shaheen and Tsadilas, 2010). It is important to stress that soil and CFA properties need to be carefully considered as incorrect use of CFA may not prove beneficial and possibly may cause adverse effects including toxicity (e.g.…”

“…They concluded that CFA application increased soil pH (from 5.6 to 6.6 and 7.5, respectively for 5.5 and 11 t ha À1 CFA application rates), with significant enhancement in wheat biomass and grain yields compared to the untreated control soil. Therefore, CFA can ameliorate acidic and degraded soils for the following reasons: CFA increases the surface area available for element sorption, improves the physical properties of soil (Gorman et al, 2000), neutralizes the pH of acidic soils and renders most cationic metals less mobile (Ciccu et al, 2003). Also, CFA contains K and alkaline earth elements (Ca, Mg) that are essential plant nutrients.…”

“…Studies have indicated that land application of CFA improves the physical, chemical and biological qualities of such mining activities affected soils. The use of CFA as a soil amendment for contaminated mine sites would solve several problems by reducing the amounts of other soil ameliorants (fertilizers, lime) required and by decreasing the mobility and bioavailability of PTEs (Ciccu et al, 2003;Mittra et al, 2005). However, in view of the variability in the characteristics of CFAs that are associated with location, feed coal, combustion conditions and other CFA factors, the suitability of a particular CFA for a specific soil/mine spoil needs to be carefully evaluated before it is applied in order to maximize favourable results and to prevent unexpected consequences.…”

“…For example, a laboratory column leaching study demonstrated that relatively small additions of CFA to contaminated soils drastically reduced the toxic metal content in the effluent (Ciccu et al, 2003). Similarly, Dermatas and Meng (2003) found that addition of CFA to metal-contaminated soils effectively reduced metals leaching well below their nonhazardous regulatory limits.…”

Immobilization of Cd, Zn and Pb in sewage sludge using red mud

“…A large number of different amendments have been proposed and tested for immobilization of heavy metals in soils. Amendments investigated for immobilization of heavy metals in soils include limestone (Basta and McGowenb 2004), phosphate rock (Hettiarachchi et al 2000;Chen et al 2003;Cao et al 2003;Basta and McGowenb 2004;Scheckel and Ryan 2004;Cao et al 2009), sewage sludge (Basta et al 2001), natural zeolites (Gadepalle et al 2007), beringite (Lombi et al 2003), steel shot (Muller and Pluquet 1998) and fly ashes (Dimitris and Meng 2003;Querol et al 2006;Ciccu et al 2003;Kumpiene et al 2007). Chemical immobilization will provide an attractive technology if the amendment is cheap and ease of application.…”