http://dzumenvis.nic.in/microbes and metals interaction/pdf/metal bioremediation through growing cells.pdf

Metal bioremediation through growing cells.

This paper reviews the technology and biotechnology to remove heavy metals (such as copper, arsenic, lead and zinc) and cyanide from contaminated wastewater. The paper places special emphasis on gold mine wastewater and the use of low cost materials as sorbent. Various biological as well as physicochemical treatment processes are discussed and compared on the basis of costs, energy requirement, removal efficiency, limitations and advantages. Sorption using natural plant materials, industrial and agricultural waste has been demonstrated to have the potential to replace conventional methods for the removal of heavy metals because of its cost effectiveness, efficiency and the local availability of these materials as biosorbent. The parameters affecting sorption, such as initial ion concentration, pH, sorbent dosage, particle size and temperature, are discussed. The overall treatment cost of metal and cyanide contaminated wastewater depends on the process employed and the local conditions. In general, technical applicability, cost-effectiveness and plant simplicity are the key factors in selecting the most suitable treatment method.

Removal of heavy metals and cyanide from gold mine wastewater

Contamination of soil and groundwater by heavymetals is a widespread problem due to theformer activities of metal processing, sufracetreatment and mining industry and theuncontrolled dumping of waste in landfills.Several methods do exist to treat soil andgroundwater. This paper will pay attention tosome new developed methods based on removal ofthe metals from the soil (simultaneousextraction and binding to biomass) or thegorundwater (aboveground treatment by sulphatereducing bacteria). Due to the fact that veryoften large areas are affected by heavy metalcontamination a removal is difficult. Thereforesome methods are developed to keep the metalsin the soil but reduce the risks related tothis presence. This risk reduction is based ona decrease in bioavailability by in situimmobilisation processes. These in situimmobilisation processes allow the treatment oflarge diffusely contaminated areas. Twoapproaches are presented. The first approach isbased on the addition of soil additives toimmobilize the metals. In this case specialattention is paid to the the biologicalevaluation methods of the reduction in metalbioavailability. The second approach uses againSRBs for the in situ precipitation ofmetal sulphides.

New developments in treatment of heavy metal contaminated soils

Removal of hazardous metals through biological means has received considerable attention in the last few decades. Nevertheless, only a fraction of these studies employed growing microbial cells that harbor multiple mechanisms of metal sequestration and thus may hold greater metal uptake capacities. The authors summarize the studies concerning response of growing cells to metals toxicity in terms of growth rate, biomass production, and morphological/structural adaptations along with latest reports involving genomics and proteomics approach. The studies indicate bright potential of metal resistant strains or strains with hormesis phenomenon for field application. In the second part of the review they focuses on the effect of nutritional conditions and process parameters on metal removal capacities and the performance in simultaneous removal of multiple pollutants. Reports demonstrating effective treatment of actual industrial effluents using growing cells have been summarized. With ample evidence available ...

Recent Advances in Microbial Metal Bioaccumulation

Preface.- 1. Microbial Biosorption of Metals - General Introduction.- 2. Potential of Biosorption Technology.- 3. The Mechanism of Metal Cation and Anion Biosorption.- 4. Equilibrium, Kinetic and Dynamic Modelling of Biosorption Processes.- 5. Bacterial Biosorption and Biosorbents.- 6. Fungal Biosorption and Biosorbents.- 7. Algal Biosorption and Biosorbents.- 8. Removal of Rare Earth Elements and Precious Metal Species by Biosorption.- 9. Biosorption and Metal Removal through Living Cells.- 10. Yeast Biosorption and Recycling of Metal Ions by Cell Surface Engineering.- 11. Bacterial surface display of metal-binding sites.- 12. Immobilized Biosorbents for Bioreactors and Commercial Biosorbents.- 13. Magnetically responsive biocomposites for inorganic and organic xenobiotics removal.- Index.

A. Stankovic

Papers

Treatment of rinsing water from electroless nickel plating with a biologically active moving-bed sand filter