Food Advantages And Disadvantages

1000 Words4 Pages
incineration, chemical reactions occurring within the effluents and also the quantities of the chemicals required to treat the effluent was massive. The chemical processes were not cost effective and along with removing these heavy metals, new chemical wastes were equally produced. Chemical precipitation is one such conventional method which produces toxic sludge which is further incinerated and thus energy expenditure to carry out this whole process is not economical. Another disadvantage of using chemical methods is that there is no complete removal of the heavy metal. Thus, the need for a cost effective and environment safe alternative aroused. It was later realized that using microorganisms to reduce the amounts of heavy metals in the effluents was a better and a more cost effective option. 1.4 MECHANISMS FOLLOWED BY MICROORGANISMS FOR HEAVY METAL REMOVAL Microorganisms follow different mechanisms to take up the heavy metals. Some of these methods involve the metabolic pathways while some others do not depend on these pathways. Apart from whether it is metabolism dependent or independent; the mechanisms also are classified based on whether it is extracellular accumulation, precipitation, cellular sorption or intracellular accumulation. Intracellular transport and metabolism dependant biosorption requires the cell to be active; hence, this process is possible only with viable cells. Non-metabolism dependant uptake mostly involves physico-chemical processes where the metal
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