1. University of Palestine Faculty of Engineering Environmental Sciences Course

2. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda 2 The Earth is the water planet; more than two-thirds of its surface is covered by water. Most of life on Earth is primarily composed of water; our cells, and those of plants and animals, are composed of about 70 percent water. Vast quantities of water cycle through the Earth's atmosphere, oceans, land, and biosphere over short and long time scales. This grand cycling of water is called the hydrologic cycle; the cycling of water shapes our weather and climate, supports plant growth, and makes life itself possible. The water cycle is dominated by the oceans, where 96 percent of the water on Earth is found and where 86 percent of global evaporation occurs. Water Cycle

3. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda 3 We can begin to follow the path of water with precipitation, or rain. When rain and other precipitation falls on land, some of it runs off into surface waters such as streams and lakes. Much of it, however, seeps into the ground. This process, the movement of water into and through the soil and rocks, is called infiltration. How water behaves in the ground, the speed and character of infiltration, is determined by the type of soil or rock through which the water moves. Water Cycle

4. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda 4 The water that is not absorbed into the soil flows from across the landscape to rivers, lakes, and streams, and eventually to the oceans, in a process called runoff. While some runoff waters originate from precipitation, others originate from melting snow or ice. This is called meltwater runoff. Rather than seeping into the soil or running off into surface waters, some water returns to the air in gaseous form (water vapor) through evaporation. However, of the water returned to the atmosphere through evaporation, land-based evaporation is much less important that ocean evaporation Water Cycle

5. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda 5 About 80 percent of global evaporation occurs over the oceans. Of land-based evaporation, roughly half occurs on the surface of plants. This movement of water from plants to air is called transpiration. The processes of evaporation and transpiration are sometimes given a single term: evapotranspiration. The process in which water vapor is converted back into liquid is called condensation. A familiar type of condensation is the formation of dew drops on blades of grass or on the outside of a cold glass. A more important type of condensation within the hydrologic cycle takes place in the atmosphere Water Cycle

6. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda 6 As water vapor moves upward in the atmosphere it cools. This process - the loss of heat through vertical movement - is called convection. The droplets formed from atmospheric condensation gather together as a result of their gravitation pull to form clouds. Depending on the temperature of the surrounding air, this cloud moisture will take either frozen or liquid form. Water in the atmosphere, after condensing and forming into clouds, returns to earth through precipitation, which can take the form of rain, ice, or snow. Although some water is transmitted directly to earth through condensation of ambient water vapor, Water Cycle

7. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda 7 it is mainly through precipitation that water moves from atmosphere to earth. Water is stored for periods of time in various reservoirs. The primary reservoirs are (in order of size) the oceans, polar ice and glaciers, the atmosphere, groundwater, lakes, soils, atmosphere, rivers and streams, and the biosphere (plants and animals). The largest reservoir is, of course the oceans. There is about 50 times as much water stored in the oceans than in the next largest water reservoir, polar ice and glaciers. Water Cycle

8. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda 8 Percentage of All Water in Hydrologic Cycle Size (volume of water (cubic km x 10,000,000) Reservoir 971370Oceans 229 Polar Ice and Glaciers 0.79.5Groundwater 0.010.125Lakes 0.0050.065Soils 0.0010.013Atmosphere 0.00010.0017Rivers and Streams 0.000040.0006Biosphere Reservoirs

9. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda 9 Approximate Residence Time Reservoir 40 yearsGlaciers 0.4 yearsSeasonal Snow Cover 0.2 yearsSoil Moisture 200 yearsGroundwater: Shallow 10,000 yearsGroundwater: Deep 100 yearsLakes 0.04 yearsRivers Storage Time in Reservoirs

10. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda 10 Sulfur Cycle Sulfur is mainly found on Earth as sulfates in rocks or as free sulfur. The largest deposits of sulfur in the World is in USA (Louisiana &Texas). Sulfur also occurs in combination with several metals such as lead & mercury, as PbS and HgS. Sulfur appears as the yellow aspects of soil in many regions.

11. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda 11 Sulfur Cycle Sulfur was mined early in the form of the yellow element and used for gunpowder and fireworks. While bacteria digest plant matter, they emit H 2 S, hydrogen sulfide, a gas that has the "rotten egg" smell characteristic of swamps and sewage. Sulfur is an essential element of biological molecules in small quantities.

12. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda 12 Sulfur Cycle Sulfur and its compounds are important elements of industrial processes. Sulfur dioxide (SO 2 ) is a bleaching agent and is used to bleach wood pulp for paper and fiber for various textiles such as wool, silk, or linen. SO 2 is a colorless gas that creates a choking sensation when breathed. It kills molds and bacteria. It is also used to preserve dry fruits, like apples, apricots, and figs, and to clean out vats used for preparing fermented foods such as cheese and wine. Sulfuric acid, H 2 SO 4, is a very widely used chemical

13. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda 13 Over 30 million tones of sulfuric acid are produced every year in the U.S. alone. The acid has a very strong affinity for water. It absorbs water and is used in various industrial processes as a dehydrating agent. The acid in the automobile battery is H 2 SO 4. It is used for "pickling" steel, that is, to remove the oxide coating from the steel surface before it is coated with tin or electroplated with zinc. Sulfur is also a biologically important atom. Although only small amounts of sulfur are necessary for biological systems, disulfide bridges form a critical function in giving biological important molecules specific shapes and properties Sulfur Cycle

14. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda 14 Sulfur is released into the atmosphere through the burning of fossil fuels-especially high sulfur coal--and is a primary constituent of acid rain. Sulfuric acid (H 2 SO 4 ) is the primary constituent of acid rain in about all regions other than California. Sulfur dioxide and carbonyl sulfide (COS) occur in small quantities in the atmosphere; but due to its high reactivity, sulfur is quickly deposited as compound (sulfates) on land and other surfaces. Sulfur Cycle