第七章 有害废物及放射性固体废物.ppt

1、有害固体废物及放射性固体废物,一、固体废物及分类,固体废物的特点,时空性（资源和废物的相对性）,成分的多样性和复杂性,危害的潜在性、长期性和灾难性,污染“源头”和富集“终态”的双重性,Love Canal 污染事件,一些有害气体或飘尘，通过治理，最终富集成废渣；一些有害溶质和悬浮物，通过治理最终被分离出来成为污泥或残渣，一些含重金属的可燃固体废物，通过焚烧处理，有害金属浓集于灰烬中。但是，这些“终态”物质中的有害成分，在长期的自然因素作用下，又会转人大气、水体和土壤，又成为大气、水体和土壤环境污染的“源头”。,分类,按来源分类,按有害成分分类,矿业固体废物,工业固体废物,城市垃圾,农业固体废物

2、,放射性固体废物,一般废物,有害废物,从时间方面讲，废物仅仅相对于当前科技水平和经济条件下尚难以利用而被丢弃的物质，随着科学技术和社会经济的发展，今天的废物可能是明天的宝藏。 从空间方面讲，废物仅仅相对于某一过程或某一方面没有使用价值，然而往往可以成为另一个过程或方面的原料。,The name Love Canal came from the last name of William T. Love, who in the early 1890s envisioned a canal connecting the two levels of the Niagara River separate

3、d by Niagara Falls. He believed it would serve the areas burgeoning industries with much needed hydroelectricity; however, the power scheme was never completed due to limitations of direct current (DC) power transmission, and Teslas introduction of alternating current (AC). Furthermore, the Panic of

4、 1893 caused investors to no longer sponsor the project. Congress also passed a regulation in which water was not to be removed from the Niagara river because Congress wanted to preserve the Niagara Falls.,Loves plan changed to incorporate a shipping lane that would bypass the Niagara Falls in order

5、 to reach Lake Ontario. He began to envision a perfect urban area called Model City and prepared a plan that called for the construction of a vast community of beautiful parks and homes along Lake Ontario. Unfortunately for Love, his plan was never realized. He was barely able to start digging the c

6、anal and build a few streets and homes before his money ran out.2 Only one mile (1.6km) of the canal, about 50 feet (15 m) wide and 10 to 40 feet (3 m to 12 m) deep, stretching northward from the Niagara River, was ever dug.,With the project abandoned, the canal gradually filled with water. At some

7、time in the 1920s, the canal became a dumping site for the municipality of Niagara Falls.,By the 1940s, Hooker Chemical Company founded by Elon Hooker began a search for a dump to store the increasing amount of chemical waste it was producing. Hooker was granted permission in 1942 to dump its wastes

8、 in the Love Canal. The canal was drained and lined with thick clay. Into this site, Hooker began placing fifty-five gallon metal or fibre barrels. This dumpsite was in operation until 1952 in which 21,000 tons of chemicals such as “caustics, alkalines, fatty acids and chlorinated hydrocarbons from

9、the manufacturing of dyes, perfumes, solvents for rubber and synthetic resins” were added. These chemicals were buried at a depth of between twenty to twenty-five feet. In 1947, Hooker bought the canal and the seventy foot wide banks on either side of the canal. After 1952, the canal was covered wit

10、h dirt and vegetation such as grass began to grow on top of the dumpsite.,At the time of the dumps closure, Niagara Falls population began to expand drastically. The local school board was desperate for land, and attempted to purchase an area of expensive property from Hooker Chemical that had not y

11、et been used to bury toxic waste. The corporation refused to sell, citing safety concerns, and even took members of the school board to the canal and drilled several bore holes through the clay, to demonstrate that there were toxic chemicals below the surface. However, the board refused to capitulat

12、e. Eventually, faced with the property being condemned and/or expropriated, Hooker Chemical agreed to sell on the condition that the board buy the entire property for one dollar. In the agreement signed on April 28, 1953, Hooker included a seventeen line caveat that explained the dangers of building

13、 on the site. Hooker was thus released from all legal obligations should lawsuits arise in the future .,Upon completion of the school in 1955, 400 children attended the academic institution. That same year, a twenty-five foot area crumbled exposing toxic chemical drums, which then filled with water

14、during rainstorms. This created large puddles that children enjoyed playing in.,In 1957, the City of Niagara Falls constructed sewers for a mixture of low-income and single family residences to be built on lands adjacent to the landfill site.,The subsequent construction of the LaSalle Expressway res

15、tricted groundwater from flowing to the Niagara River. Following the exceptionally wet winter and spring of 1977, the elevated expressway turned the breached canal into an overflowing pool. People reported having puddles of oil or colored liquid in yards or basements.,In 1978, residents became conce

16、rned about unusual health issues in the Love Canal region, including high rates of cancer and birth defects. They subsequently became a national news, and in 1980, president Jimmy Carter declared a federal emergency in the area. Residents were eventually relocated, and Occidental paid $129 million i

17、n restitution. (In 1968, Hooker Chemical was purchased by Occidental Petroleum. ),返回,有害废物的鉴别标准（GB5085.1-7-2007),易燃性,浸出毒性,反应性,腐蚀性,急性毒性,放射性（GB9133-1995）,闪点低于60;13%;,自身不稳、与水猛烈反应等物质、爆炸物,浸出液的pH2或pH12.5或腐蚀钢的速率6.35mm/a,如重金属、氟等有具体的规定值,口摄入：固体LD50200mg/kg，液体500mg/kg； 皮肤： LD501000mg/kg；呼吸： LC5010mg/L,按半衰期长短、发射

18、类型等分为五种 在按放射性比活度水平划分等级,二、放射性固体废物,1、核素：核素是具有特定的原子质量数、原子序数和核能态的一类原子,2、核素的分类,稳定核素：质子和中子保持不变的,放射性核素：具有自发地放出带电或不带电粒子的性质,3、放射性衰变及类型,放射性核素自发地改变结构形成另一种核素的过程，称为核衰变,分类,衰变,衰变,+衰变,衰变,电子俘获,衰变是放射性核素内一个中子转变成质子并放出粒子和中微子v的核衰变。,放射性核素俘获核外绕行的一个电子，使核内一个质子转变成中子并放出中微子的过程。,吴健雄 1912-1997,放射性核素从较高能级跃迁至较低能级时放出一种波长很短的电磁辐射（高能光子）的光程。, +衰变是放射性核素内一个质子转变成中子并放出+粒子和中微子v的核衰变。,4、放射性衰变速率方程及放射性活度,Nt瞬间未衰变的核数,放射性活度随时间的变化服从指数