1 Chapter 13 Solid Waste Management 13 1 Design and safely perform a waste characterization on the solid waste at your residence and at an office at your university or college a How does your waste characterization compare with the data in Figure 13 2 b Which of the three R s reuse reuse recycle would you implement to reduce the discard rate Solution Students responses will vary Solutions Manual prepared by Ziad Katirji and Heather E Wright Wendel Environmental Engineering Fundamentals Sustainability Design James R Mihelcic and Julie Beth Zimmerman John Wiley Sons New York 2009 2 13 2 Identify one source of solid waste on your campus that could readily be reduced one source that could be reused and one that could be recycled What social economic and environmental benefits would come from implementing a plan to deal with the three items you identified Solution Students responses will vary Solutions Manual prepared by Ziad Katirji and Heather E Wright Wendel Environmental Engineering Fundamentals Sustainability Design James R Mihelcic and Julie Beth Zimmerman John Wiley Sons New York 2009 3 13 3 Research the energy and water savings associated with recycling 1 000 kg of office paper Which value do you consider the most reliable of the ones you found Justify your choice and provide a reference for your preferred source of information Solution Students responses will vary Solutions Manual prepared by Ziad Katirji and Heather E Wright Wendel Environmental Engineering Fundamentals Sustainability Design James R Mihelcic and Julie Beth Zimmerman John Wiley Sons New York 2009 4 13 4 Using the e values provided in Example 13 2 estimate the low moisture content and typical moisture content for the waste as a whole Solution dry mass 100 moisture content total mass 100 578 9 100 low moisture content low moisture content 17 3 700 100 578 9 100 typical moisture content typical moisture content 43 5 1 024 1 100 Solutions Manual prepared by Ziad Katirji and Heather E Wright Wendel Environmental Engineering Fundamentals Sustainability Design James R Mihelcic and Julie Beth Zimmerman John Wiley Sons New York 2009 5 13 5 Waste composition has been measured for two cities The results are summarized in Table 13 19 City 1 City 2 Wet Weight Generation Rate kg person day 2 0 1 8 Wet Weight Composition Food 15 10 Paper 30 40 Yard 20 15 Other 35 35 Moisture Content of Fractions on wet weight basis Food 80 50 Paper 10 4 Yard 80 30 Other 5 4 a Which city generates more paper on a dry weight basis b Find the percent moisture wet weight basis for city 1 c A nearby disposal site receives all of its MSW from cities 1 and 2 The average moisture content for MSW disposed of at the site is 20percent What fraction of the dry weight refuse comes from city 1 Solution a dry paper mass for city 1 2 kg person day dry paper mass for city 2 1 8 kg 100 10 of dry paper from city 1 0 54 person day 100 30 kg person day kg 100 4 of dry paper from city 2 0 69 person day 100 40 Solutions Manual prepared by Ziad Katirji and Heather E Wright Wendel Environmental Engineering Fundamentals Sustainability Design James R Mihelcic and Julie Beth Zimmerman John Wiley Sons New York 2009 6 City 2 produce more paper on dry basis per person b Determine the dry weight production Type of Wet weight Moisture waste city 1 content composition Food 0 15 80 Paper 0 3 10 Yard 0 2 80 Other 0 35 5 Total 100 Moisture Wet weight city 2 composition 12 0 1 3 0 4 16 0 15 1 8 0 35 100 32 8 Moisture content Moisture 50 4 30 4 5 1 6 4 5 1 4 12 5 c Let X be fraction of dry weight from city 1 moisture content of city 2 refuse MC2 12 5 Fraction of total weight of city 2 1 X moisture of city 1 moisture of city 2 Total fraction of city 1 Total fraction of city 2 MC1 MC2 1 X 0 2 1 0 2 0 328 X 0 125 1 X X 0 37 Moisture of mix Determine the dry waste from each city Dry waste 1 Fraction of city 1 1 MC1 0 37 1 0 328 0 249 Dry waste 2 0 63 1 0 125 0 551 Fraction of dry weight 0 249 100 31 1 0 249 0 551 Solutions Manual prepared by Ziad Katirji and Heather E Wright Wendel Environmental Engineering Fundamentals Sustainability Design James R Mihelcic and Julie Beth Zimmerman John Wiley Sons New York 2009 7 13 6 What is the dry weight percent composition for the following combined waste Component Paper Yard Food Other Composition 40 30 30 Moisture wet weight 6 60 3 Solution Dry weight of total weight composition x moisture x 100 Dry weight of total weight Dry weight 100 Total Component Composition Moisture wet weight Paper Yard Food Other Total 40 30 30 100 6 60 3 Dry weight of total weight 2 4 18 9 29 4 Dry weight percent 8 2 61 2 30 6 100 Solutions Manual prepared by Ziad Katirji and Heather E Wright Wendel Environmental Engineering Fundamentals Sustainability Design James R Mihelcic and Julie Beth Zimmerman John Wiley Sons New York 2009 8 13 7 The mass composition of dry paper is 43 percent carbon 6 percent hydrogen 44 percent oxygen and 7 percent other Estimate the liters of air required to burn 1 kg dry paper Assume carbon dioxide and water are the only products of combustion of carbon hydrogen and oxygen Assume a temperature of 20 C and pressure of 1 atm Solution Assume that all 7 of other is ash therefore no air or O2 is required for that MW No of Element Mass g kg of paper g mole moles kg of paper Carbon 430 12 35 8 Hydrogen 60 1 60 Oxygen 440 16 27 5 1 mole O2 mole O2 4 35 8 moles C mole C 60 moles H mole H PV nRT V 37 moles O2 0 082 889 L O2 1 mole O2 2 27 5 moles O mole O 37 moles O2 L atm 293 K 889 L O2 mole K 1 atm 1 L air 4 295 L air 0 207 L O2 Solutions Manual prepared by Ziad Katirji and Heather E Wright Wendel Environmental Engineering Fundamentals Sustainability Design James R Mihelcic and Julie Beth Zimmerman John Wiley Sons New York 2009 9 13 8 Estimate the oxygen demand for composting mixed garden waste units of kg of O2 required per kg of dry raw waste Assume 1 000 dry kg mixed garden waste has a composition of 513 g C 60 g H 405 g O and 22 g N Assume 25 percent of the nitrogen is lost to NH3 g during composting The final C N ratio is 9 43 The final molecular composition is C11H14O4N Solution First determine the final amount Nitrogen available for composting 22 g N x 100 25 …