AREA A/B ENGINEERING REPORT - Waste Management

Geosyntec Consultants
A review of the literature shows that the number of landfill failures that have occurred have been
extremely small compared to the number of landfills, and no significant failures are known to
have been reported at landfills that have been closed or that have exited PCC. Several
publications describe landfill failures and the causes of the failures, including Kavazanjian, et. al.
(2001), Merry, et al. (2000), Mitchell & Mitchell (1993), Bonaparte, et al. (2002), and Hendron
(2006). These references describe conditions in landfills that experienced liner or cover system
instability. The few significant landfill stability problems reported resulted from severely
inadequate operations or from poor construction practices. In contrast, the vast majority of the
referenced issues involved minor stability problems that were addressed in the normal course of
operations without resulting in any adverse environmental impact, demonstrating the fact that
most stability issues occur during construction or operations and are mitigated. None of the
referenced failures occurred at closed landfills or landfills that had been released from PCC.
Recently, Blight (2008) performed a global study of six large-scale failures of municipal solid
waste dumps and landfills that have been recorded in the technical literature between 1977 and
2005. Of the six failures studied, four – Sarajevo in the former Yugoslavia (1977), Istanbul,
Turkey (1993), Quezon City, Phillippines (2000), and Bandung, Indonesia (2005) – occurred in
largely unregulated dumps that, as far as is known, had not been subjected to any prior technical
investigation of their geotechnical stability. The remaining two failures occurred in engineerdesigned
landfills. In the first case (Doña Juana Landfill in Bogota, Colombia, 1997), leachate
recirculation was practiced at an aggressive rate, but the effects of elevated moisture conditions
and high injection pressures on landfill stability had not been the subject of rigourous engineering
analysis. The leachate management system was also inadequately designed and the landfill was
not operated in accordance with safe procedures for reinjection of leachate. In the second case
(Bulbul Landfill in Durban, South Africa, 1997), co-disposal of liquid waste along with solid waste
was permitted, but the engineer-designed drainage provisions had been omitted and the landfill
constructed without professional oversight involving the design engineer. This record supports the
conclusion that failures are the rare exception, not the rule, in landfill performance, and are
essentially unknown at modern managed MSW landfill facilities that are designed, constructed,
and operated in adherence with regulatory and professional oversight.
Studies on the performance of landfills during catastrophic events suggest that landfills are highly
resistant to damage from such events. Studies performed after recent disasters including
hurricanes (such as the Florida hurricanes of 2004; see for example Roberts, et al., 2005),
earthquakes (such as the Northridge and Loma Prieta earthquakes in California; see Matasovic &
Kavazanjian, 1998), and fires (such as the San Diego wildfires of 2003) show that the long-term
environmental protection systems of the landfills had not been compromised and that the only
damage that occurred was to surface features (e.g., vegetation and LFG vents) that were
repaired at reasonably small cost and level of effort. This documented information shows that
landfill contaminated systems have a high degree of resistance to damage from severe natural
events.
In conclusion, contention that major landfill failures will occur after PCC ends is unwarranted,
because the causes of failure are understood and the landfill is evaluated for those causes before
PCC is permitted to end. The literature cited above shows that the potential causes of failures are
MD10186.doc 149 29 March 2009