Bioleaching of metals from soils or sediments

Abstract

Bioleaching can be one of few techniques applicable for the removal of toxic metals from polluted soils or sediments. Its principle is a microbial production of sulphuric acid and leaching of metals with it. The use of bioleaching can benefit from the use of low-cost substrates and from a possible coupling to other processes of microbial sulphur cycle, like sulphate reduction to treat spent bioleaching liquor, or partial sulphide oxidation to recycle sulphur. For the evaluation of bioleaching, the existence of different leaching strategies is considered, i.e. intensive or extensive extraction. The intensive extraction uses high concentrations of acid at short extraction times, whereas low acid additions and long treatment times are used in extensive processes. On a reference study with wetland sediment receiving mine drainage we demonstrated that the bioleaching is a typical extensive process. The bioleaching experiments involved the use of the different sulphur substrates, i.e. orthorhombic sulphur flower and microbially produced, recycled sulphur from partial sulphide oxidation process. The latter type of sulphur substrate performed considerably better.

Developments in Bioremediation of Soils and Sediments Polluted with Metals and Radionuclides: 2. Field Research on Bioremediation of Metals and Radionuclides

“…However, only 9% was removed when the sediment were freshly dredged and anoxic. Similar processes have been reported in the Netherlands and Switzerland (TICHY et al 1998). …”

In situ proteo-metabolomics reveals metabolite secretion by the acid mine drainage bio-indicator, Euglena mutabilis

“…Nevertheless, it is now well established that the microbial communities they harbor are well adapted and can have a decisive impact on the evolution of such ecosystems (Tichy et al, 1998;Das et al, 2009). For instance, the bacterial community of the Carnoulès AMD (Gard, France) has been extensively studied and appears to have an active role in bio-attenuation processes.…”

Developments in Bioremediation of Soils and Sediments Polluted with Metals and Radionuclides – 1. Microbial Processes and Mechanisms Affecting Bioremediation of Metal Contamination and Influencing Metal Toxicity and Transport

“…In the past decade, the ability of Thiobacilli to remove trace metals from soils and sediments has been studied (Tichy et al 1998). Operational conditions studied include soil sediment characteristics (Loser et al 2004), initial pH (Chen & Lin 2001a), percentage of inoculum, retention time, initial solid content (Chen & Lin 2000) and nutrition (Chen & Lin 2001b).…”