exposure to airborne respirable dust. ii.Make a claim that proposes a solution to reduce the environmental impacts of mining, other than a ban on mining. A possible solution to reduce the negative impact on the environment can be proper disposal of waste from mining. iii.Use data and evidence from the graph to support a potential solution to reduce the impacts of mining on stream quality. Increased vegetation in mining areas will keep soil from eroding, sedimenting and ending up in a stream. FRQ#2 Eutrophication and Landfill Gas Human and other animal waste can result in water and air pollution. a.Eutrophication of waterways is a potential environmental problem that can result from concentrated animal feeding operations ( CAFOs ). i.Describe how eutrophication negatively affects waterways. Eutrophication is a natural process that results from accumulation of nutrients in lakes or other bodies of water. Algae that feed on nutrients grow into unsightly scum on the water surface, decreasing recreational value and clogging water-intake pipes. ii.Propose a realistic solution to prevent eutrophication of waterways near CAFOs trees and shrubs are planted in zones to filter nutrients from runoff before it enters waterways. iii.Justify the solution you described in (a)(ii) with an additional environmental benefit. b.Organic materials (such as food scraps and yard waste) in landfills can decompose and produce landfill gas ( LFG ) over time. About50%ofLFGis methane, a greenhouse gas with a global warming potential25times higher than that of carbon dioxide over a100 -year period.LFGcan be collected and burned to produce electricity. i.Explain a process during whichLFGis burned to produce electricity. Process during which LFG is burned to produce electricity Cogeneration, also known as combined heat and power (CHP), projects use LFG to generate both electricity and thermal energy, usually in the form of steam or hot water. ii.The Puente Hills Landfill in California contains about123million tons of landfill waste and burnsLFGto produce electricity. In a typical landfill, one million tons of landfill waste emits approximately432,000cubic feet ofLFGper day. Calculate how muchLFGis emitted at the Puente Hills Landfill per year The amount of landfill gas (lfg) which is emitted at the puente hills landfill in California per year is 53,136,000 cubic feet of lfg. iii.BurningLFGfor electricity produces the additional benefit of preventing methane from entering the atmosphere. Calculate how much methane is prevented from entering the atmosphere by burningLFGto produce electricity at the Puente Hills Landfill over a10 -year period. Therefore, 9.7 * 10¹ cubic feet of methane is prevented from entering the atmosphere.⁰ iv.All of the landfills in the United States that burnLFGto produce electricity produce a total of about15billion kilowatt-hours ( kWh ) of electricity per year. The average house in the United States uses about30.3 kWhof electricity per day. Calculate how many households can have their total electricity needs provided by these landfills. Therefore, the number of households that can have their total electricity needs provided by these landfills is 1,368,925 households.
