tailieunhanh - Environmental Pollution Control Microbiology - Chapter 14 (end)

Chất thải nguy hại là một thuật ngữ được giới thiệu vào những năm 1970 để thay thế hạn, chất thải độc hại. Trong nhiều năm các kỹ sư và nhà khoa học nhận ra rằng các hợp chất cụ thể ở dạng khí, lỏng, rắn độc hại đối với đời sống sinh học. Cũng công nhận rằng chất thải độc hại yêu cầu xử lý đặc biệt và điều trị trước khi các vật liệu phế thải có thể được trả lại cho môi trường. Trong thực tế, chất thải độc hại cần được chuyển đổi sang các hợp. | Chapter 14 HAZARDOUS WASTES Hazardous wastes is a term that was introduced in the 1970s to replace the term toxic wastes. For years engineers and scientists recognized that specific compounds in gaseous liquid and solid wastes were toxic to biological life. It was also recognized that toxic wastes required special handling and treatment before the waste materials could be returned to the environment. In effect the toxic wastes needed to be converted to non-toxic compounds. Concentrated inorganic acid wastes primarily sulfuric acid nitric acid hydrochloric acid and hydrofluoric acid had to be neutralized and diluted prior to discharge in the environment. Concentrated inorganic alkaline wastes containing sodium hydroxide calcium hydroxide and magnesium hydroxide also needed to be neutralized and diluted prior to discharge. The same was true of strong oxidizing compounds such as chlorine and ozone. Strongly reduced compounds such as hydrogen sulfide requữed oxidation and dilution. One of the major problems with toxic wastes lay with the multitude of organic compounds that had varying degrees of toxicity. There were no simple methods to treat the toxic organic wastes. Unfortunately too many industrial plants ignored their toxic wastes and created serious pollution problems. Rachel Carson s book Silent Spring focused on the potential dangers of organic pesticides such as DDT methoxychlor chlordane heptachlor and benzene hexachloride. Rachel Carson s concerns with the dangers of pesticides struck a special chord with the rising envứonmental movement in the late 1960s. Widespread use of the herbicides 2 4-D and 2 4 5-T during the unpopular war in Vietnam became a focal point of opposition to the organic chemical industry as a whole. As public opinion against toxic organic Copyright 2004 by Marcel Dekker Inc. All Rights Reserved. chemicals increased efforts were soon directed towards federal legislation to prohibit their manufacture and use. Part of the public relations .