tailieunhanh - Applications of Environmental Aquatic Chemistry: A Practical Guide - Chapter 8

Các phân hủy sinh học là sự cố hóa học của chất ô nhiễm hữu cơ vào nhỏ hơn, thông qua các hợp chất enzyme chuyển hóa hoặc các quá trình của sinh vật sống trong môi trường, chủ yếu vi khuẩn, nấm men, và nấm. Nó khác với hóa chất và các quá trình suy thoái vật lý (ví dụ, clo quá trình oxy hóa, giảm bởi các hạt sắt kim loại, thủy phân, photolysis, xúc tác là phản ứng bề mặt, vv). Trong khi gây ra bởi hoạt động của các sinh vật sống. . | 8 Biodegradation and Bioremediation of LNAPLs and DNAPLs BIODEGRADATION AND BIOREMEDIATION Biodegradation is the chemical breakdown of organic contaminants into smaller compounds through metabolic or enzymatic processes of living organisms in the environment primarily bacteria yeast and fungi. It differs from chemical and physical degradation processes . chlorine oxidation reduction by metallic iron particles hydrolysis photolysis catalysis on reactive surfaces etc. in being caused by the action of living organisms. Some chemical structures are more susceptible to microbial breakdown than are others vegetable oils for example will biodegrade more readily than petroleum oils which in turn biodegrade more readily than polycyclic aromatic hydrocarbons PAHs . Bioremediation of soil and groundwater at sites contaminated with total petroleum hydrocarbons TPH and benzene toluene ethylbenzene and xylenes BTEX is a well-established technology compared to sites contaminated with PAHs chlorinated volatile organic compounds VOCs pesticides and herbicides and explosives which are more difficult to biodegrade. When biodegradation converts hazardous contaminants into less hazardous or benign substances not always it is called bioremediation. Microbial metabolism is a series of biological reactions predominantly oxidation-reduction also called redox reactions which convert organic compounds into energy and carbon to sustain microbial growth. In a typical metabolic redox reaction an organic carbon compound serves as an electron donor that microbes use as a food source. The transfer of an electron from the donor to an electron acceptor proceeds through multiple reaction steps that generate energy and materials carbon and other elements for microbial cell growth. Bioremediation is one of several approaches for the remediation of sites contaminated with nonaqueous phase liquids. It is however the only remediation method treated with some depth in this book. Other methods such .