tailieunhanh - Environmental Fluid Mechanics - Chapter 16 (end)

Khi nhận thức của các vấn đề môi trường đã phát triển trong những năm qua, đã có một sự tập trung không chỉ vào việc giảm các nguồn ô nhiễm đang diễn ra mà còn khắc phục hậu quả của các trang web đã bị nhiễm ngày càng tăng. Một ví dụ rõ ràng của việc này là với chương trình Superfund cái gọi là thiết lập tại Hoa Kỳ trong những năm 1980 để làm sạch lớn các trang web chất thải nguy hại gây ô nhiễm nghiêm trọng các nguồn tài nguyên nước ngầm. Một ví dụ. | 16 Remediation Issues INTRODUCTION As awareness of environmental problems has evolved over the years there has been an increasing focus not only on reducing ongoing sources of pollution but also on remediation of sites that are already contaminated. A clear example of this is with the so-called Superfund program set up in the United States during the 1980s to clean up large hazardous waste sites causing serious contamination of groundwater resources. Another example is with efforts in the Great Lakes basin of North America to reverse the trend of eutrophication that had been growing steadily in the middle part of the last century. Reduction of nutrient loadings such as phosphorus and nitrogen have reduced drastically the productivity in the lakes and now the concern is with cleaning residual sites of contamination in large part associated with contaminated sediments. In general the initial phase of remediation involves controlling contaminant disposal into the particular environment under consideration. This may mean complete cessation of all source loadings or at least reduction of loads to a suitable level to allow recovery of the system either by natural or by engineered processes. According to the type of environment and the time and length scales of the problem the remediation may include containment and treatment. Most phases of environmental remediation require an understanding of fluid flow and transport phenomena by advection and diffusion as discussed in previous chapters of this text. Remediation strategies also may incorporate the use of chemical agents and biodegradation of contaminants. Methodologies that have been developed and used for many decades for water and wastewater treatment can often be adapted for environmental remediation. Copyright 2001 by Marcel Dekker Inc. All Rights Reserved. SOIL AND AQUIFER REMEDIATION General Aspects In cases of soil and aquifer contamination the source of contaminant is usually located above .