Humans And The Environment Exam 3 Long Questions

Front 1

Draw and label the hydrologic cycle, discuss what happens at each step

Back 1

See image; Evaporation: The sun heats water in rivers, lakes, and the ocean and turns it into vapor or steam, which then rises into the air. Condensation: The vapor cools and turns into tiny water droplets that attach to each other and form clouds. Precipitation: Water falls from the clouds as rain, snow, sleet, or hail. Runoff: Some water stays on the earth’s surface and flows into rivers, lakes, reservoirs, etc. Percolation: Other water seeps down into the earth’s natural underground reservoirs called aquifers. Then the cycle begins again, as water from the earth’s surface evaporates into the air.

Front 2

Discuss both point-source and non-point-source water pollution, types and sources. How do they affect people, DO, BOD, other organisms?

Back 2

Nonpoint source pollution - comes from a a wide variety of sources. It is the surface water runoff. (ex) fertilizers, lawn chemicals. (ex) Red tide ---- Point Source pollution come from a single source. (ex) Factories (pipes), sewage treatment. (ex) Minamata; humans that ate contaminated fish and shellfish that were contaimanted from the waste water of a chemical plant. Dissolved Oxygen (DO): refers to microscopic bubbles of gaseous oxygen (O2) that are mixed in water and available to aquatic organisms for respiration—a critical process for almost all organisms. Primary sources of “BLANK” include the atmosphere and aquatic plants. Biochemical Oxygen Demand (BOD) :The index of organic pollution (ex) carbon based materials, the higher the BOD the more pollution there is.

Front 3

What causes acid rain? What effects might it have on the enviroment?

Back 3

Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain. Sulfur dioxide and nitrogen oxides dissolve very easily in water and can be carried very far by the wind. Human activities are the main cause of acid rain. Over the past few decades, humans have released so many different chemicals into the air that they have changed the mix of gases in the atmosphere. Power plants release the majority of sulfur dioxide and much of the nitrogen oxides when they burn fossil fuels, such as coal, to produce electricity. In addition, the exhaust from cars, trucks, and buses releases nitrogen oxides and sulfur dioxide into the air. These pollutants cause acid rain. Excess nitrogen may cause eutrophication (over nourishment) in areas where rivers enter the ocean. This may lead to unwanted growth of algae and other nuisance plants.

Front 4

What are the main sources of Greenhouse Gases, what are they, and how do they contribute to global warming? What are the major sources of Carbon Dioxide?

Back 4

Carbond dioxide (CO2 ), Methane (CH4), Nitrous oxide (N2O) and fluorinated gases are the major Greenhouse Gases. Carbon Dioxide (CO2): Carbon dioxide enters the atmosphere through the burning of fossil fuels (oil, natural gas, and coal), solid waste, trees and wood products, and also as a result of other chemical reactions (e.g. cement production). Carbon dioxide is also removed from the atmosphere (or "sequestered") when it is absorbed by plants as part of the biological carbon cycle. Methane (CH4): Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from livestock, certain agricultural practices and by the decay of organic waste in municipal solid waste landfills. Nitrous Oxide (N2O): Nitrous oxide is emitted during agricultural and industrial activities, as well as during the combustion of fossil fuels and solid wastes. Fluorinated Gases or High GWP gases: Hydrofluorocarbons(HFCs), perfluorocarbons(PFCs), and sulfur hexafluoride(SF6) are synthetic, powerful greenhouse gases that are mostly emitted from the creation and/or use of refrigerators, air conditioning systems, foams and aerosols. These gases are typically emitted in smaller quantities, but because they are potent greenhouse gases, they are referred to as High Global Warming Potential gases. Greenhouse gases let the sun’s short wave radiation (visible light) reach the earth, but trap some of the long wave (infared or heat) radiation coming from the warm earth. Electricity, transportation, and industry are the major sources of CO2. Electricity is a significant source of energy in the United States and is used to power homes, business, and industry. The combustion of fossil fuels to generate electricity is the largest single source of CO2 emissions in the nation, accounting for about 38% of total U.S. CO2 emissions and 32% of total U.S. greenhouse gas emissions in 2011. The type of fossil fuel used to generate electricity will emit different amounts of CO2. To produce a given amount of electricity, burning coal will produce more CO2 than oil or natural gas. Transportation. The combustion of fossil fuels such as gasoline and diesel to transport people and goods is the second largest source of CO2 emissions, accounting for about 31% of total U.S. CO2 emissions and 26% of total U.S. greenhouse gas emissions in 2011. This category includes transportation sources such as highway vehicles, air travel, marine transportation, and rail. Industry. Many industrial processes emit CO2 through fossil fuel combustion. Several processes also produce CO2 emissions through chemical reactions that do not involve combustion, for example, the production and consumption of mineral products such as cement, the production of metals such as iron and steel, and the production of chemicals. Fossil fuel combustion from various industrial processes accounted for about 14% of total U.S. CO2 emissions and 12% of total U.S. greenhouse gas emissions in 2011. Note that many industrial processes also use electricity and therefore indirectly cause the emissions from the electricity production.

Front 5

We want to have ozone in the stratosphere but not so much as sea level. Why? What causes depletion of stratospheric ozone? What causes increases of sea level ozone?

Back 5

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Front 6

What problems are caused by the different sorts of smog which exist? Where do thermal (temperature) inversion usually occur? What sorts of problems do they cause?

Back 6

Smog is impacted by the inversion layer because it is in essence, capped, when the warm air mass moves over an area. This happens because the warmer air layer sits over a city and prevents the normal mixing of cooler, denser air. The air instead becomes still and over time the lack of mixing causes pollutants to become trapped under the inversion, developing significant amounts of smog. During severe inversions that last over long periods smog can cover entire metropolitan areas and cause respiratory problems for the inhabitants of those areas. In December 1952, for example, such an inversion occurred in London. Because of the cold December weather at the time, Londoners began to burn more coal, which increased air pollution in the city. Since the inversion was present over the city at the same time, these pollutants became trapped and increased London’s air pollution. The result was the Great Smog of 1952 that was blamed for thousands of deaths. Inversion occurs in the lower atmosphere. (troposphere and lower stratosphere.) Some of the most significant consequences of temperature inversions are the extreme weather conditions they can sometimes create. Intense thunderstorms and tornadoes are also associated with inversions because of the intense energy that is released after an inversion blocks an area’s normal convection patterns.

Front 7

How has the human population changed over the past million or so years? What have been some of the forces and transitions that have caused these changes?

Back 7

Neolithic Revolution: was a fundamental change in the way people lived. The shift from hunting & gathering to agriculture led to permanent settlements, the establishment of social classes, and the eventual rise of civilizations. Industrial Revolution: was the transition to new manufacturing processes in the period from about 1760 to sometime between 1820 and 1840. By domesticating it allows you to have your animals and plants close to you. (Population started to go up) There was more suitable and reliable source of calories and nutrition. It's creating a circumstance of not just food reliability but place reliability. It allows you to stay where you are. People have a better rate of fertility. The unique system is we have a hidden ovulation. Birthrate has increased due to man and women being closer together.

Front 8

Describe and discuss the typical stages of wastewater treatment and what happens at each stage. Why is such treatment rarely 100% efficient?

Back 8

(1)Preliminary treatment, or screening, is the first step in cleaning wastewater. Before the raw sewage is introduced into our plants, large contaminants such as rocks, rags, toys, and golf balls must be removed. Mechanically cleaned barscreens accomplish this task, removing the offensive material, and depositing it into dumpsters for disposal at a landfill. (2) In primary treatment, the incoming flow is slowed in large tanks which allow the dirt, gravel, and other heavier-than-water components of the waste stream to settle out. Grease, oil, and other floatables are also removed here. Rotating arms simultaneously remove the settled solids from the bottom and the separated floatables from the top. Both pollutants are pumped into large heated holding silos, called digesters. Odor, resulting mainly from the formation of Hydrogen Sulfide in the incoming sewage lines, escapes the solution at all points of turbulence. These first tanks, or primary clarifiers as they are called, are covered and kept under a constant vacuum, with the gases removed routed through odor reduction equipment. The flow leaving this process is markedly cleaner than the contaminated flow that first appeared at the head of the plant. It is as clean as much of our nation's wastewater was upon discharge to rivers, bays, and oceans, not so long ago. There is still however, about 30 percent of the original suspended solids that were in the plant's influent, and about 70 percent of the original Biochemical Oxygen Demand or BOD, (a measurement of the strength of the pollution). (3) Secondary (biological) treatment removes the dissolved organic matter that escapes primary treatment. This is achieved by microbes consuming the organic matter as food, and converting it to carbon dioxide, water, and energy for their own growth and reproduction. The biological process is then followed by additional settling tanks (“secondary sedimentation", see photo) to remove more of the suspended solids. About 85% of the suspended solids and BOD can be removed by a well running plant with secondary treatment. Secondary treatment technologies include the basic activated sludge process, the variants of pond and constructed wetland systems, trickling filters and other forms of treatment which use biological activity to break down organic matter. (4) Tertiary treatment is simply additional treatment beyond secondary! Tertiary treatment can remove more than 99 percent of all the impurities from sewage, producing an effluent of almost drinking-water quality. The related technology can be very expensive, requiring a high level of technical know-how and well trained treatment plant operators, a steady energy supply, and chemicals and specific equipment which may not be readily available. An example of a typical tertiary treatment process is the modification of a conventional secondary treatment plant to remove additional phosphorus and nitrogen.(5) Disinfection, typically with chlorine, can be the final step before discharge of the effluent. However, some environmental authorities are concerned that chlorine residuals in the effluent can be a problem in their own right, and have moved away from this process. Disinfection is frequently built into treatment plant design, but not effectively practiced, because of the high cost of chlorine, or the reduced effectiveness of ultraviolet radiation where the water is not sufficiently clear or free of particles.