دانلود کتاب رویکردهای بیولوژیکی برای کنترل آلاینده ها – پیشرفت در تحقیقات آلودگی

Environmental biotechnology is an old field; composting and wastewater treatments are common examples of older environmental biotechnologies. Current studies in ecology and molecular biology present opportunities for extra-efficient biological processes. Notable accomplishments of these studies include the cleanup of polluted water and land areas. Bioremediation is a process in which organic wastes are biologically degraded under controlled conditions to levels below the concentration limits established by regulatory authorities or to innocuous states (Mueller et al., 1996). In other words, bioremediation is the use of living organisms, mainlymicroorganisms, to degrade environmental pollutants into less toxic forms. It mainly uses bacteria and fungi or plants to degrade or detoxify substances harmful to human health and the environment. The microorganisms and plants may be native to a contaminated area or collected from elsewhere and brought to the contaminated site. Pollutants are transformed by living organisms by biochemical reactions that occur as a part of their metabolic processes. Biodegradation of pollutants is a consequence of the actions of multiple organisms. When microorganisms are added to a contaminated site to supplement and improve degradation, the process is known as bioaugmentation. In the bioremediation process, microorganisms enzymatically attack pollutants and convert them to harmless products. Bioremediation can be effective only when environmental conditions allow microbial growth and activity; its application often involves the manipulation of environmental parameters to allow microbial growth and degradation to proceed at a faster rate. Bioremediation techniques are typically more economically feasible than traditional methods such as incineration because some pollutants can be treated on site, thus minimizing exposure risks for cleanup personnel or potentially wider exposure as a result of transportation accidents. Because bioremediation is based on natural attenuation of pollutants, it is considered more acceptable than other technologies. Most bioremediation systems are run under aerobic conditions, but running a system under anaerobic conditions may permit microbial organisms to degrade otherwise recalcitrant molecules (Colberg and Young, 1995). As with other technologies, bioremediation has its limitations.