Page 384 - Materials Chemistry, Second Edition

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The Sanitary Landfill 355
3. Under RCRA, new landfills cannot be located in seismic zones unless the operator can
demonstrate that all containment structures (e.g. liners) are designed to resist the maxi-
mum horizontal shifting (true or false).
4. Landfill bird hazards to airports can be limited to a certain extent by shredding and bal-
ing MSW prior to disposal. Explain.
5. Landfill sizing is affected by the desired landfill lifetime, the population served, and the
shape and height of the landfill, among other factors. Explain.
6. What chemical changes occur during earliest anaerobic stage of decomposition in a san-
itary landfill? Discuss in terms of pH, BOD, and reactions of metals.
7. Methanogenic (methane producing) microorganisms prefer what type(s) of environmen-
tal conditions? How do they respond to pH?
8. What are the factors that influence methane gas migration below the land surface.
Consider soil texture, soil temperature, soil moisture, and barometric pressure.
9. What waste types are restricted from sanitary landfills under current federal regulations?
Be specific.
10. What is the significance of saturated hydraulic conductivity (K ) in assessing soils for
s
landfill liners, caps, and as a soil base? How is K influenced by soil texture and engi-
s
neering practices (e.g., compaction)? What is the RCRA limit for liner K ?
s
11. RCRA calls for stringent controls in MSWLF operation for air quality, explosive gases,
storm water runoff, wetlands protection, cover material, and vectors. Discuss the specific
requirements for each.
12. Geomembrane installation practices significantly influence possible leachate losses from
a landfill. List and discuss the factors that must be considered for successful geomem-
brane design and installation.
13. Explain the various phases of MSW decomposition in a closed landfill cell. How do
leachates and gases differ between each phase?
14. Under what conditions is passive landfill gas control acceptable? When is active gas
control a requirement?
15. How does landfill gas differ from utility-strength natural gas? How is the landfill gas
treated to render it suitable for possible sale to an energy utility?
16. If stormwater enters the landfill unit and contacts waste, what is the stormwater consid-
ered to be, according to the regulations (i.e., nonhazardous, hazardous, special waste)?
How is it to be managed?
17. RCRA regulations require that bulk or noncontainerized liquid wastes are not to be
placed in MSWLFs, with two exceptions. What are they?
18. Leachates vary in terms of physical characteristics, inorganic composition, organic com-
position, microbial composition, and toxicity. How are the above variables affected by
waste type and by age in the landfill cell?
19. What are the major purposes of layered sanitary landfill covers (caps)? How do they
function?
20. Subtitle D requires, at the time of landfill closure, the installation of a final cover (cap)
system. What are the primary purposes of the cover? Consider erosion, subsidence, and
limiting leachate production.
21. What are the Subtitle D requirements for proper landfill cover design and construction?
22. How does landfill reclamation occur, i.e., what mechanical steps are required for suc-
cessful reclamation? How is it beneficial in terms of extending landfill lifetime and
encouraging resource recovery?
23. How does sanitary landfill operation differ when ownership is private vs. public? Discuss
the advantages and pitfalls of each, in terms of economics, efficiency, and environmental
concerns.