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Emily Miglis, Melissa Castrogiovanni, Jackie Innella.

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Presentation on theme: "Emily Miglis, Melissa Castrogiovanni, Jackie Innella."— Presentation transcript:

1 Emily Miglis, Melissa Castrogiovanni, Jackie Innella

2  Degradation of water quality  Pollutants include heavy metals, sediment, certain radioactive isotopes, heat, fecal coli- form bacteria, phosphorus, nitrogen, sodium, certain pathogenic bacteria and viruses

3 Primary problem: lack of clean, disease-free drinking water  United States ◦ Epidemics of waterborne diseases have killed thousands of people in the past ◦ Now water is treated prior to consumption (less disease)  Worldwide ◦ Every year, several billion people are exposed to water borne diseases

4 Major uses for water: domestic, industrial, agriculture  Domestic Supply ◦ Cannot be harmful to health, taste good, odorless, should not damage plumbing/household appliances  Industrial Purposes ◦ May require distilled water ◦ May require noncorrosive water or water free of particles that could damage equipment  Agriculture ◦ Vegetation tolerates wide range or water quality ◦ Can vary widely in physical, chemical, and biological, properties

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6  Increasing population leads to introduction of more pollutants into the environment  Over ¼ of US drinking water systems reported a violation of federal health standards  US Environmental Protection Agency has set limits on water pollution levels for some pollutants  Pollutant maximum concentration standards have been set for only some of the more then 700 possible water contaminants

7  Bacteria decays dead organic matter in streams  Bacteria uses oxygen  A lot of bacterial activity decreases oxygen levels in water  A stream with low oxygen content is a poor environment for fish and most other organisms and is considered polluted.

8  The amount of oxygen required for biochemical decomposition processes is called the biochemical oxygen demand (BOD).  Measures the amount of oxygen consumed by microorganisms as they break down organic matter  Approximately 33% of all BOD in streams results from agricultural activities.

9  When the BOD is high, the dissolved oxygen content of the water may become too low to support the life in the water.  US Environmental Protection Agency ◦ Water pollution alert is when the dissolved oxygen content is less than 5mg/liter of water

10  Example of high BOD from an accidental spill  3 zones: pollution zone, active decomposition zone, recovery zone

11  All streams have some capability to degrade organic waste.  Problems occur when the stream is overloaded with biochemical oxygen- demanding waste.  This overpowers the stream’s natural cleansing function.

12  About half of US people depend on groundwater  Can be easily polluted  Difficult to recognize pollutants  75% of the 175,000 known waste disposal sites in the US may be producing plumes of hazardous chemicals that are migrating into groundwater resources.

13 Principles of Groundwater Pollution: An Example  Leaking buried gasoline tanks caused much pollution  Underground tanks now strictly regulated  Many thousands have been removed  Vapor extraction: removal and disposal of soil and treatment of water (expensive)  Bioremediation: microorganisms consume gasoline (much less expensive)

14 Leaking buried gasoline tanks led to important points about groundwater pollution:  Some pollutants are lighter then water (float on groundwater)  Some pollutants have multiple phases: liquid, vapor, and dissolved  Some pollutants are heavy than water (sink through groundwater)  Water treatment depends on physical and chemical properties of pollutant  Prevent pollutants from entering groundwater in the first place

15  Groundwater pollution differs from surface water pollution.  Groundwater kills aerobic types of microorganisms and is home for anaerobic varieties.  Groundwater channels are small and variable, therefore dispersion and dilution of pollutants is limited.

16 Long Island, New York  Nassau County and Suffolk County (population of several million people) depend entirely on groundwater  Two major problems: intrusion of salt water and shallow-aquifer contamination

17  Saltwater intrusion ◦ Salty groundwater cannot migrate inland due to the large wedge of fresh water moving beneath the island ◦ Intensive pumping has caused water levels to decline as much as 50 feet in some areas  Shallow-aquifer pollution ◦ Associated with urbanization ◦ Pollutants enter surface waters and then migrate downward ◦ Sources of pollution: urban runoff, household sewage, salt, industrial waste, and solid waste

18  Wastewater treatment, or sewage treatment costs over $15 billion per year in the United States and the cost continues to increase.  Conventional methods of wastewater treatment include septic tank disposal systems in rural areas and centralized wastewater treatment plants in cities.

19  Septic Tank Disposal Systems ◦ No central sewage systems or wastewater treatment facilities are available in many rural areas.  Basic parts of a septic-tank disposal system ◦ Sewer line from the house leads to an underground septic tank in yard. ◦ Tank is designed to separate solids from liquid, digest, and store organic matter through a period of detention, and allow the clarified liquid to discharge into the drain field from a system of piping through which the treated sewage seeps into the surrounding soil. ◦ It’s then treated by the natural processes of oxidation and filtering.

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21  Wastewater treatment methods are usually divided into 3 categories: ◦ Primary Treatment – Removal of large particles and organic materials from wastewater through screening. Removes 30% to 40% of the BOD by volume from the wastewater. ◦ Secondary Treatment – Use of biological processes to degrade wastewater in a treatment facility. The most common treatment is know as activated sludge. ◦ Advanced Water Treatment – Some additional pollutants can be removed by adding more steps of treatment. Advanced Water Treatment is used when it’s particularly important to maintain good water quality.

22  Chlorine Treatment ◦ Frequently used to disinfect water as part of wastewater treatment. ◦ Chlorine Treatment is very effective in killing the pathogens that historically caused outbreaks of serious waterborne diseases. ◦ Recently discovered potential is that chlorine treatment produces minute quantities of chemical byproducts, some of which have been identified as potentially hazardous to humans and other animals. ◦ The degree of risks is controversial and is currently being debated.

23  Wastewater renovation and conservation cycle: Practice of applying wastewater to the land.  Steps: ◦ 1. Return of treated wastewater to crops by irrigation system ◦ 2. Natural purification (renovation) by slow leaking of the wastewater into the soil to eventually recharge the groundwater resource with clean water ◦ 3. Treated water reused and pumped out of ground for municipal, industrial, institutional and agricultural purposes  Sewage is transported by sewers to treatment plant. Wastewater is chlorinated and pumped into a network that transports effluent to a series of spray irrigation rigs. Wastewater trickles down through soil and collected into a network of tile drains. Indirect advanced treatment uses natural, physical, and biological environment as filter.

24  Resource recovery: the production of resources, including methane gas as well as ornamental plants and flowers that have commercial value.  Steps ◦ 1. Wastewater run through filters that remove large objects ◦ 2. Water undergoes anaerobic processing (produces methane gas) ◦ 3. Nutrient-rich water flows over an incline surface with plants  Plants use nutrients and purify water  Experimental technique  Problems: ◦ Huge investment in traditional wastewater treatments ◦ Economic incentives to provide for new technologies are not sufficient ◦ There are not sufficient amounts of people trained to design and operate new types of wastewater treatment plants

25  Wetlands are very effective in treating water quality problems ◦ Municipal wastewater from primary or secondary treatment plants (pathogens, phosphorus, nitrate, suspended solids, metals) ◦ Stormwater runoff (metals, nitrate, pesticides, oils) ◦ Industrial wastewater (metals, acids, oils, solvents) ◦ Agricultural wastewater and runoff (nitrate, pesticides, suspended solids) ◦ Mining waters (metals, acidic water, sulfates) ◦ Groundwater seeping from landfills (metals, oils, pesticides)  Wetland systems a lot less expensive ◦ Over 25 year period, $40,000 savings is expected  Louisiana: coastal wetlands ◦ Wastewater filled with nitrogen and phosphorus ◦ When put into wetlands, increases production of wetland plants, which in return improves water quality ◦ When plants die their organic material partially lets wetland loose, causing wetlands to grow vertically  Wetlands becoming more and more popular as water quality standards are tightened, and cost is very important

26  Phoenix, Arizona: Constructed wetlands ◦ Wetlands can be created in arid regions as well ◦ Wetland treatment for agricultural waste is sited in residential community ◦ 4.5 million gallons per day ◦ Incoming water has lots of nitrate  20 mg/l ◦ Naturally occurring bacteria reduce nitrate to below maximum contaminant level  10 mg/l ◦ Water flows by pipe to recharge basin ◦ Seeps into ground for groundwater resource

27  Water reuse can be inadvertent, indirect, or direct.  Inadvertent water reuse results when water is withdrawn, treated, used, treated, and returned to the environment, followed by further withdrawals and use. ◦ Very common ◦ Fact of life for millions of people who live along large rivers.

28  Several risks are associated with inadvertent reuse: ◦ Inadequate treatment facilities may deliver contaminated or poor quality water to downstream users. ◦ Because the fate of all disease causing viruses during and after treatment is not completely known, the environmental health hazards of treated water remain uncertain. ◦ New potentially hazardous chemicals are introduced into the environment every year. Harmful chemicals are often difficult to detect in the water.

29  Indirect water reuse ◦ Planned endeavor ◦ Treated water eventually enters groundwater storage to be reused for agricultural and municipal purposes.  Direct water reuse ◦ Refers to the use of treated wastewater that is piped directly from a treatment plant to the next user. ◦ Used in industry in most cases. ◦ Very little direct reuse of water is planned for human consumption due to perceived risks and negative cultural attitudes toward using treated wastewater.

30  Environmental law: the branch of law dealing with conservation and use of natural resources and control of pollution ◦ Done on federal, state, and local levels  Mid 1990s, water pollution big controversy  congress attempted to rewrite major environmental laws ◦ Clean water act of 1977  Congress wanted to give industry greater felxibilty in choosing how to comply with environmental regulations ◦ Industry interestes preferred proposed new regulations because more cost effective ◦ Environmentalists viewed this as a giant step backward in trying to clean up the earth ◦ Publics views were incorrectly read, most cared more about money ◦ Congress saw strong support for clean environement and thought people will pay for clean air and water

31  July 2000, president imposed new water pollution regulations  Purpose was to protect rivers and lakes from nonpoint sources to agricultural, industrial, and urban population sources.  EPA would work with local communities and states to develop detailed plans to reduce pollution.  Plan would take 15 years to implement  Been opposed for years by Congress, agricultural groups, utility industry, and U.S. Chamber of Commerce ◦ Requirements would be costly, spending billions ◦ Local and state governments better suited to implement own water pollution regulations


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