AREA A/B ENGINEERING REPORT - Waste Management

Table 6-1: Outline of Four Main Types of Managed Landfill
Type Key Features of Landfill Design and Operation
Design Type 1:
Engineered Liner
and Cover
Design Type 2:
Engineered Liner
and Natural
Analog Cover
Design Type 3:
Engineered Liner
and Natural
Analog Cover +
Enhanced
Degradation
Design Type 4:
Engineered
Natural Barrier
and Cover
Geosyntec Consultants
• Design prescribed under Subtitle D, relies on engineered systems that feature a leachate
management system (LMS) and a gas management system (GMS), which may be active or
passive depending on the size and age of the landfill.
• Operation, maintenance, and monitoring provide for waste containment and operational
control system performance.
• Waste treatment is not enhanced in this type of landfill since the objective is to minimize or
control (i.e., inhibit) infiltration of moisture for the very long term.
• While this type of landfill is very protective of groundwater and other environmental
media, it limits end use options after closure because of the need for the final cover to
remain undisturbed.
• Design is identical in component systems and performance to a Type 1 landfill, with the
exception that it features a natural analog cover system as an alternative to the
prescriptive Subtitle D cover design.
• These landfill cover designs can exceed many important cover system performance criteria
such as erosion control, methane oxidation, and slope stability. This landfill type controls
infiltration through the cover system at a rate that can sustain active waste treatment but
not result in leachate build-up and compromise of the engineered liner.
• A significant advantage of this landfill design is that it affords more flexibility in end use
because natural analog covers can be designed as low maintenance or even self
sustaining systems. Active maintenance of the cover may not be required in the longer
term for ongoing protection of human health and the environment.
• Design is identical in component systems and performance to Type 2, with the exception
that it features enhanced treatment systems in the form of controlled enhanced
biodegradation.
• Operationally, this landfill design may require more infrastructure (such as for liquids
distribution) and higher levels of operational management than other types, and is
generally more costly in terms of capital expenditure.
• A significant advantage of this landfill design is that it will require significantly less longterm
care due to the efficient and rapid degradation of waste. This, coupled with the
advantages of a natural analog cover system, affords much flexibility in end use options
because long term active maintenance of containment systems should not be required in
the longer term.
• Design is identical in component systems and performance to Type 1, with the exception
that it features an engineered natural barrier soil liner as an alternative to the
prescriptive Subtitle D liner design.
• This landfill is designed to be just as protective of groundwater and other environmental
media as the other types of modern landfills, but a greater focus is placed on its
management elements (particularly cover maintenance and environmental monitoring).
• These landfills are simpler to operate than other landfill types because they often do not
require a LMS as part of their permit. However, Type 4 Landfills will typically require
longer-term final cover system maintenance.
MD10186.doc 83 29 March 2009