SANITARY LANDFILL OPERATIONS - Environmentally Conscious Materials Handling - page 200

from each category was recycled or composted in 2006. The highest recov-
ery rates were achieved in yard trimmings, paper and paperboard products, and
metal products. Recycling of organic materials alone (i.e., paper and paper prod-
ucts) reduced the quantity of MSW disposed of in landfills and incinerated at
combustion facilities by 25 percent.

5 LANDFILL PLANNING AND DESIGN

The volume of waste to be placed in a landfill can be estimated based on two
factors:
1. Per capita solid waste generation rates per year
2. Projected increase in waste generation rate based on the historical records
and population growth rate
The required landfill capacity for fill and development (also called air space)
is significantly greater than the waste volume due to specific site development
needs. The actual capacity of the landfill depends on the volume occupied by the
liner system, cover material (daily, intermediate and final cover), cap system, gas
collection wells, amount of waste to be deposited, in-place density of the waste,
anticipated settling that the waste will undergo due to overburden stress, and
biodegradation potential of the waste. The life of a landfill extends over many
years and involves several phases, as follows (O'Leary and Walsh 2002):
1. Site selection and investigation . Potential sites for a proposed landfill are
evaluated, and a public participation program is initiated to communicate
with the public and minimize potential opposition to the siting process.
2. Design and regulatory approval . Detailed plans and specifications are
prepared, regulatory approvals and financial commitments are received,
and construction is initiated.
3. Site construction . Support facilities are constructed and first cells for solid
waste deposition are developed.
4. Operation . The active period of the landfill during which the landfill
accepts waste. The landfill typically operates 10 to 30 years, depending
on the capacity of the landfill.
5. Site closure . The cells are filled to capacity and are closed. At the com-
pletion of waste deposition period, the landfill is capped.
6. Long-term care . Regulatory standards require an owner to monitor the
landfill and provide facility maintenance for 30 years after closure. The
postclosure care period can be longer if the site presents a risk for the
community.

5.1 Site Selection

Proper planning and site selection can prevent many future design, operational,
and environmental problems during the operation and postclosure periods of a