Bioremediation of tailings and waste dumps

Mining processes of mineral extraction are neither completely efficient nor able to recover all expended and reusable reagents and chemicals from them. The process effluents known as tailings are generally stored in surface reservoirs; in recent times of high volume related to the current extensive exploitation of low grade ores. Environmental regulations become harder due to the present and long-term risks involved in the storage of high quantities of heavy metals and chemicals. It is also important to consider that tailings do not provide any financial gain to the mining company, representing an external cost for the operation.

Naturally many bioprocesses take place on tailings; however the bioreaction rates are not enough to fulfill an extensive natural remediation schema within a reasonable time frame. The current level in the environmental biotechnology field brings alternatives to explore and develop a sustainable bioremediation technology with the production of value added products from the tailings turning them renewable materials.

Microorganisms and enzymes make possible chemical transformation reactions. The application of these biotransformation products is from the interest of degrading heavy metals as well as toxic compounds into smaller particles and less toxic compounds.

 

Objectives

The investigation proposed by Gidahatari is focused on developing a feasible bioremediation process for mining tailing reservoirs and their potential use on industrial level. The investigation deals initially with the identification of the most significant bioprocesses which take place on a tailing reservoir. Relevant microorganisms related to the degradation of heavy metals and toxic compounds will be studied and used as a base for the bioremediation process development. Biotechnological conditions for the remediation process should be characterized through analytical physicochemical processes.

Products from the biological remediation will be evaluated to determine their commercial value.

 

Work Plan

The investigation proposed by Gidahatari will be carried in the fields of metabolic engineering which deals with the genetic and regulatory optimization processes to increase the cell production of a certain substance. After a complete bacteriological mapping of tailings and neighboring areas, all relevant bacteria involved in the degradation of heavy metals and toxic compounds will be identified. From the selected bacteria, the reaction schema of their metabolism has to be documented as well as the limitations for the bioproduction activity with a Metabolic Control Analysis (MCA).

An essential optimization step is based on the aggregation of enzymatic catalyzing reactions in the metabolic network. Research will take place on in-vivo conditions with the aim of understanding the metabolic pathways and collecting enough data of the reaction kinetics to perform a mathematical model of the processes. Once the bioreaction is optimized, it has to be up-scaled for a commercial use. The design of large scale bioreactors with different measuring and inspection techniques is essential. There is a particular interest in reaching a full automation of the bioreactor together with on-line measurements.

 

Bioremediation Application

The results from the investigation on tailing bioremediation should be a starting point for Gidahatari in biotechnology up-scaling into mining application. Potential commercial products from bioremediation will be analyzed as well.

Saul Montoya

Saul Montoya es Ingeniero Civil graduado de la Pontificia Universidad Católica del Perú en Lima con estudios de postgrado en Manejo e Ingeniería de Recursos Hídricos (Programa WAREM) de la Universidad de Stuttgart con mención en Ingeniería de Aguas Subterráneas y Hidroinformática.

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