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Wetlands for Acid Mine and Livestock Drainage Treatment By: Gabe Jenkins April 18 th 2005
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Why is this Important? Most everyone in class comes from a coal mining or a farming history. Effects stream pH and water quality. Acidic streams and eutrophication do not allow for aquatic life. Runoff affects local streams, waterways, and groundwater thus contaminating drinking water.
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Wetlands for Acid Mine Drainage (AMD) Treatment
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What is Acid Mine Drainage and where does it come from? Comes from a reaction with water, air, and pyrite and produces sulfuric acid. Pyretic rock is found below the coal seam and is exposed during coal removal. Sulfuric acid in water lowers the pH to a very acidic condition. The acidic runoff also dissolves other heavy metals such as copper, lead, mercury, and iron.
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Common Signs of Acid Mine Drainage (AMD) Land that has had strip mining or surface mining. Red or orange colored water from dissolved heavy metals. No fish and very little or no aquatic life Very little or no aquatic vegetation.
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Ways for treatment Aerobic Wetlands Water treatment plants Limestone Drainage Diversion Wells
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Wetland Treatment Wetlands have the ability to remove metals from mine drainage and to neutralize AMD. Wetlands contain microbes that have the ability to convert sulfates into sulfides this process, makes the water significantly less acidic.
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Wetland Construction Factors pH Wetland Size Water level Water flow Destruction
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pH A acidic pH will not allow for plant survival in a wetlands Lime can be added to the water to help raise the pH. Anoxic Limestone Drain.
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pH Cont. A neutral pH is best Optimal range would be 6.0-8.0 Inorganic oxidation reaction rates decrease a hundred-fold with each unit drop in pH.
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Wetland Size Varies from a few hectares to more than 300 hectares Larger size the more plant life and nutrient cycling. Large surface area available to let the metals settle out of the water.
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Water Level Water level should be 6-18 inches. Shallow water zones enhance oxygenation and oxidizing reactions and precipitation. Deeper water zones provide storage areas for precipitates but decrease vegetative diversity.
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Water Flow Riffles and falls above the wetlands in the limestone ditch help to increase oxygen levels before entering the wetland. This increases the efficiency of the oxidation process and therefore the precipitation process This is important for iron precipitation. Flow should be extremely slow inside the wetland. The slower the flow the better the heavy metals can settle out of the water and into the soil. Flow can be altered by the amount of plant composition.
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Destruction The biggest problem for the destruction of a wetland for AMD is the beaver. Plugs drains and diverts the water flow into unwanted areas.
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Water Quality after Wetland Treatment A more neutral pH Loss of heavy metals Cleaner water Healthier streams with fish and aquatic life
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Livestock Drainage Treatment Am I the problem? Or am I ?
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What’s all this crap about? Eutrophication in streams Rise in water temperature Baby Blue Syndrome Affects water quality in streams, ground water, and drinking water Caused by water that runs off animal manure
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What causes all this crap?
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What causes the problem? Nitrates are formed from the animal organic matter Nitrates then enter the water. Water is either leached into ground or runs off into streams and lakes
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Eutrophication Graph Defined- the process that takes place when freshwater is 'enriched' by nutrients, especially nitrates and phosphates.
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What can fix this problem? Wetlands Consider kidney’s of the world
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Benefits from wetlands Provides a high level of treatment Is inexpensive to operate Inexpensive to construct Reduces, if not completely eliminates odor Can handle variable wastewater loadings Reduces the land area needed for application of wastewater Can be ascetically pleasing Provides wildlife habitat
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Factors to consider when constructing a wetland Number and size of animals Type of feed animals are fed Amounts, timing, and intensity of rainfall Frequency of solids removal from feedlots Relationship of removal to timing of rainfall
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Most importantly This can only be done for waste water Solids must be removed from the waste water before they enter the wetland Solid waste intrusion will kill a wetland extremely fast
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How it works Water must flow through a lagoon or settling tank before entering the wetland to remove any solid waste. Next the waste water enters the wetland Here plants and organisms in the wetland treat organic waste and reduce levels of contamination. Potential pollutants are trapped in the wetland and transformed into basic elements and plant biomass. The water then exits the wetland clean of nitrates and other pollutants and enters into the water cycle.
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Summary Water is a limited source and it must be taken care of. Wetlands are the kidney’s of the world and they can help to clean up our environment We are only just beginning to understand the benefits of wetlands.
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I’m outta here!!
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