Page 385 - Materials Chemistry, Second Edition

CAT3525_C10.qxd 1/31/2005 12:00 PM Page 356
356 Waste Management Practices: Municipal, Hazardous, and Industrial
24. The ‘Second Law of Thermodynamics’states, in essence, that all systems proceed toward
maximum disorder (chaos, entropy). How can a landfill be affected over time in the con-
text of the Second Law? In other words, discuss how landfill liners, LCR systems, and
caps can be transformed 100 years after landfill closure. Will the landfill remain imper-
vious ad infinitum?
25. Soil material is being assessed as a possible liner for a sanitary landfill. A soil core was
collected and brought to the laboratory. A 10-cm-tall section of soil has 2 cm of water
2
continuously ponded on it. The area of the core surface is 78 cm . A total of 62 mL water
is collected per hour. Calculate the K . The upper limit for K for liners is 1 x 10 7 cm/sec.
s
s
Is this soil suitable for a landfill liner?
26. Determine the area required for a new sanitary landfill with a projected lifetime of 20
years. The landfill will serve a population of 175,000 people. It is estimated that per
capita waste generation is 1.9 kg/day (4.1 lb/day). Waste density in the landfill averages
3
625 kg/m . Landfill height is not to exceed 20 m.
27. Calculate the annual volume of leachate generated per hectare for a sanitary landfill
located along the east coast of the United States. The climate is temperate, average
annual rainfall is 122 cm/yr (48 in./yr), and evapotranspiration is estimated at 48%. The
wastes are covered with soil and runoff from the site is 10%. There is no run-on of sur-
face water; Similarly, there is no underflow of groundwater into the cell.

A.10.1 APPENDIX: LANDFILL GAS EMISSIONS MODEL
A.10.1.1 OVERVIEW

The Landfill Gas Emissions Model (LandGEM) estimates the emissions of a number of gases from
landfills. Due to differences in waste types, disposal rates, climate, and operating conditions, the
rate of generation of emissions is highly variable from landfill to landfill; mathematical models may
account for the variability of factors such as waste types, pH, temperature, and availability of nutri-
ents for methanogenic microorganisms (U.S. EPA, 1998). In this exercise, you will apply the
LandGEM model for estimation of generation of selected landfill gases. The model, as zipped files,
can be downloaded from: http://www.weblakes.com/lakeepa7.html.

A.10.1.2 HOW TO USE THE MODEL
A.10.1.2.1 Entering MSW Data for a Site
To estimate landfill emissions for a given year, the software model must be provided with the mass
of MSW (‘refuse’) in the landfill for that year and the age of the MSW. This information is pro-
vided when you enter MSW data into the model on an annual basis, thus indicating the mass of
MSW in the landfill and the age. Because MSW data are entered on an annual basis, MSW must be
assigned an age in years based on an instantaneous disposal. The model assumes that MSW is
accepted at the last moment of the year and that MSW accumulates into a landfill at the first instant
of the year after it is accepted. Therefore, MSW accepted into the landfill one year (e.g., 2003) will
appear as MSW in place the next year (e.g., 2004). Rounding the age of the accumulated MSW to
the nearest whole number results in an age of zero years to MSW accepted (e.g., MSW accepted
during 2003 will be zero years old in 2004). The following year (e.g., 2005), this MSW would then
be assigned an age of 1 year, and so on.
The following data entry pattern to the model is recommended:

● Select the Year Opened
● Select the final year for which information is available (Current Year)