1、环境概论重点一Classifying environmental problems环境问题分类1.Overpopulation 人口过剩2.Pollution污染3.Depletion of resources 资源消耗殆尽4.Changes in the global condition 全球环境的改变二Pollution污染1.Matter or energy 物质或能量2.Negatively affects environment or human well being 三Basic principle1.Matter and energy are indestructible 不能破
2、坏的2.Therefore pollution is indestructible! 四Pollution control methods1. Recovery 恢复2.Waste minimization最小化 3.Conversion 转变4.StorageRecoveryRecycle: use wastes as source of raw materials原材料Reuse: use materials原料 more than onceWaste minimizationChange product 改变产物Alter process Conversion转变Transform po
3、llutants to harmless or useful materials: 把污染物变成轻污染或无污染的原料Oxidize CO to CO2Convert wastes to compost StorageEnsure that the pollutants will not migrate out 迁移Ensure that pollutants will not react with each other A sustainable长期的 development1Environmental Scientists and 2Engineers1.Evaluate source an
4、d nature of pollution problem 对资源和污染物的性质进行评价Evaluate environmental impact评估环境污染的影响2.Evaluate possible solutionsDesign, build and operate pollution control systems.评估可行的解决方法，建造并实行污染控制系统OutlineProblemsUneven water resourcesWater shortageFloodingWater pollution EutrophicationRiver RehabilitantWater and
5、 Wastewater Treatment3333333333333333333333333333Steps for the study of water and wastewater treatmentWater property特性Treatment methodsWater treatmentWastewater treatment1Primary treatment初级处理2Secondary treatment第二步处理3Tertiary treatment第三步处理4Sludge treatment污泥处理Physicalwater-quatyparameters:define t
6、hose characteristics of water that respond to the senses of sight, touch or smellSuspended solids固体悬浮物Turbidity浑浊TemperatureConductivity导电性ColorTaste and odorSuspended solids are typically主要 comprised组成 of clay粘土, silt淤泥, fine particulate organic细小的有机物质 and inorganic matter无机物质 and microscopic organ
7、isms.微生物的有机体 The suspended solids parameter参数 is used to measure the quality of the wastewater influent, to monitor检测 several treatment processes, and to measure the quality of the effluent.In suspension在悬浮液中, solids increase turbidity, and the reduced light penetration减少光的穿透性 may restrict the photo
8、 synthetic activity of plants,会限制植物的光合作用 inhibit the vision of aquatic animals阻碍了水生动物的视力, interfere干扰 with feeding of aquatic animals that obtain food by filtration干扰水生动物通过过滤进食, and be abrasive to respiratory structures such as gills鱼鳃 of fish.For most treated wastewater, a maximum suspended solids
9、standard of 30 mg/Lwas 最大固体悬浊物指标为30mg每升set by EPA.TurbidityTurbidity is a measure of the relative clarity of water水的相对清晰度: the greater the turbidity, the murkier the water.浊度越大水越黑 Turbidity increases as a result of suspended solids in the water that reduce the transmission of light浊度的提高是由水中的悬浊物引起的.
10、So the water is dirty, whats the big deal?With higher levels of turbidity, water loses its ability to support a diversity of aquatic organisms.水失去了自身的对有机物的控制力Water becomes warmer as suspended particles absorb heat from the sunlight and cause oxygen levels to fall. 水温升高是由于固体物质吸收阳光引起的Remember-warm wat
11、er holds less oxygen than cooler water!热的水含氧量比水底Photo synthesis decreases because less light penetrates the water, resulting in even further drops in oxygen levels.The combination of warmer water, less light and oxygen depletionmakes it impossible for some forms of aquatic life to survive.Temperatur
12、eThe rates of biological and chemical processes depend on temperature化学反应的速率靠温度.Temperature affects the oxygen content of water (oxygen levels become lower as temperature increases)温度升高影响氧在水中的含量，温度越高水含量越低; the rate of photo synthesis by aquatic水生的 plants影响水生植物的光合作用速率; the metabolism新陈代谢 rates of aqu
13、atic organisms生物;影响水生生物的新陈代谢 and the sensitivity of organisms to toxic有毒的 wastes, parasites寄生物, and diseases.和对有毒污染物、寄生虫、和疾病的敏感度Thermal pollution is a way that the temperature of water can increase. Thermal pollution is an increase in water temperature caused by adding relatively warm water to a bod
14、y of water. 热污染是一种水的温度提升的污染，由于往水中排放温暖的水Thermal pollution can come from storm water running off warmed urban surfaces(streets, sidewalks, parking lots) and industries that discharge warm water from their facilities that was used to cool machinery.热污染来是自城市流出的水或是工厂由于用于冷却设备后而排除的水Chemical water-quality p
15、arameters因素pHAlkalinity碱度DO需氧量Total dissolved solids总共溶解的固体Metals重金属Hardness硬度Organics (BOD,COD)有机物含量，化学需氧量和生物需氧量Nutrients营养物质pHpH is the percentage of hydrogen ions(H+) in a solution.氢离子的百分率在溶液中的 A solution is more acidic when it contains more hydrogen ions. 溶液呈酸性当含有更多的氢离子时The level of acidity can
16、be changed by humans actions. 酸性可以被人类的行为改变Acid rain, a result of air pollution酸雨是空气污染的结果 and matter emitted from tail pipes 废气从排气尾管中排除and smokes tacks affect the pH烟的航向影响ph值. A pH of 7 is considered to be neutral 。ph为7认为是中型的. When the pH is less than 7, it is acidic; a pH greater than 7 is basic. A
17、pH value between 7.0 and 8.0 are optimal for supporting a divers aquatic ecosystem.ph值在7-8是水生系统的最佳状态Alkalinity什么是碱度？ Alkalinity is a total measure of the capacity of water to neutralize acids碱度是对水体酸性进行中和的总体测量.Alkalinity is not a pollutant and is different from pH. pH measures the strength of an acid
18、 or base. ph测量一个酸性物质的酸度 Alkalinity indicates a solutions power to react with acid and buffer its pH碱度指示一个中和酸性和缓冲溶液ph的解决能力, the power to keep its pH from changing.一种阻止ph改变的能力Alkalinity is important for fish and aquatic life because it protects or buffers against pH changes 碱度对水生生物非常重要，因为他可以保护或缓冲溶液的ph
19、不发生改变(keeps the pH fairly constant不变的) and makes water less vulnerable to acid rain.使得水体对酸雨不是很敏感 The main sources of natural alkalinity are rocks碱的主要来源是岩石, which contain carbonate, bicarbonate and hydroxide compounds.钙盐、重碳酸盐，和氢氧化物Alkaline compounds in the water such as bicarbonates (baking soda is o
20、ne type), carbonates, and hydroxides remove H+ ions and lower the acidity of the water (which means increased pH).这些东西都和H离子反应Dissolved Oxygen (DO)Aquatic life uses oxygen that is dissolved in the water and is in much smaller quantities than in the air. Oxygen, in water, is measured as dissolved oxyg
21、en (DO). If more oxygen is consumed than is produced, dissolved oxygen levels decline and some sensitive animals may move away, weaken, or die.Weather, temperature and salinity 盐分affect amounts of dissolved oxygen (DO). Cold, fresh water holds more oxygen than warm or salty water冷水淡水含有氧的量比热的咸的水高. If
22、 DO levels are severely严重缺乏 low, large quantities of fish may die. The stream system gains oxygen from the atmosphere and from aquatic plants as a result of photo synthesis河流从大气或进行光合作用的水生植物那里获得氧气. Running water, because of its churning, dissolves more oxygen than still water流动的水由于搅拌比净水获得的氧更多. Respir
23、ation by aquatic animals, decomposition, and various other chemical reactions consume oxygen. 水生动物，微生物的分解作用和其他的一些化学反应都需要消耗氧气Total dissolved solids is the amount of particles that are dissolved in the water.溶解的颗粒物 Dissolved solids may come from organic sources such as leaves, silt, plankton, and indu
24、strial waste and sewage. 可能的来源为树叶、於泥、浮游生物，工业废物和废水Changes in the amounts of dissolved solids can be harmful because the density of total dissolved solids determines the flow of water in and out of an organisms cells溶解物的浓度的变化是有害的，因为溶解物的浓度决定水在有机体内的进出. Many of these dissolved solids contain chemicals, s
25、uch as nitrogen, phosphorous, and sulfur, which are the building blocks of molecules for life溶解物中含有生物必须的化学成份N、p、s等. Drinking water may have a TDS reading of 25-250 mg/L. Distilled water will have a TDS reading that will range from 0.5-1.5 mg/L. The amount of TDS ranges from 100-20,000 mg/L in rivers
26、 and may be higher in groundwater. Seawater may contain 35,00 mg/L of TDS. Lakes and streams may have a TDS reading of 50-250 mg/L. 不同的水体好友tds的量不同Heavy metal pollution is typically 典型的，特有的associated with mining activities or discharges from some industries.重金属污染和采矿活动相联系的一种特有的污染，或者由工业生产而排放Persistent
27、toxicants (heavy metals) in water and sediments沉淀物 affected by heavy metal pollution can have serious affects on the aquatic ecosystem and can make water unsuitable for human consumption.不断的有水和沉淀物被重金属所影响并造成很严重的后果对水生生态系统而且使得水体不适合人类使用Cumulative toxins积累的毒素: Arsenic砷, Cadmium镉, Chromium铬, Lead铅, Mercur
28、y.汞Some animals can also bioaccumulate 生物富集metals, making them unsafe to eat.使得他们不能被人类食用 They are concentrated by the food chain他们通过食物链被富集, thereby posing the greatest danger to organisms near the top of the chain.因此受到最大危害的是最靠近链中最高级的生物HardnessHardness is defined as the concentration of multivalent m
29、etallic cationsin solution. At supersaturated 4 conditions, the hardness cationswill react with anions in the water to form a solid precipitate. The multivalent metallic ions most abundant in natural waters are calcium (Ca2+)and magnesium (Mg2+).Others may include iron and manganese in their reduced
30、 states (Fe2+, Mn2+).A generally accepted classification is as follows:Soft300 mg/l as CaCO3The Public Heath Service standards recommend a maximum of 500 mg/l of hardness in drinking water.Biochemical Oxygen Demand生物需氧量When organic matter decomposes, microorganisms (such as bacteria and fungi) feed
31、upon this decaying material and eventually it becomes oxidized.有机物腐败后被微生物氧化分解成气体 Biochemical oxygen demand, or BOD, measures the amount of oxygen consumed by microorganisms in the process of decomposing organic matter in stream water.BOD directly affects the amount of dissolved oxygen in rivers and
32、streams. bod直接反应水体中的溶解氧的量 The more rapidly oxygen is depleted in the stream, the greater the BOD. This means less oxygen is available. Sources of BOD include leaves and woody debris残骸; dead plants and animals; animal manure粪便; effluents from pulp and paper mills工厂, wastewater treatment plants, feedlots, and food-processing plants; falling septic syste
