Page 334 - Materials Chemistry, Second Edition

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The Sanitary Landfill 305
10.4.13 CONSTRUCTION QUALITY ASSURANCE
To minimize holes in a geomembrane liner (whether caused by product defects, transportation,
installation, or seaming) and to meet required standards, a construction quality assurance (CQA)
program should be established for liner installation (U.S. EPA, 1994, 1992a). The CQA program is
a planned system of activities performed by landfill owners to ensure that the cells and associated
facilities are constructed as specified in the design. The program should be developed during the
design stage, and the state regulatory agency should review a facility CQA program before a per-
mit is issued for construction.

10.4.14 DAILY OPERATIONS AND ISSUES
10.4.14.1 Filling Sequences
After weighing the truck at the weigh station, the waste is brought to the so-called ‘working face’
of the landfill. Waste is deposited into daily cells, i.e., small units of land that are filled with MSW
and then covered at the end of the day by a layer of soil or similar material (e.g., compost and shred-
ded tires). At the base of a new landfill cell, waste must be placed in order to prevent compactor
wheels from contacting the leachate collection systems, liner, and other sensitive layers installed
below. Filling continues with the placement of successive lifts, typically starting in a corner and
moving outward. The filling sequence is established at the time of landfill design and permitting.
The working face must be large enough to accommodate several vehicles unloading simultaneously,
approximately 4 to 6 m (12 to 20 ft) per vehicle (Vesilind et al., 2002).
The maximum working area for a landfill can be calculated by (Kiely, 1997)

A (0.1 W)/R (10.4)
max
where A is the maximum working area, R the average annual rainfall (m), and W the average
max
annual waste input (metric tons).
3
The above equation assumes an absorption capacity of the waste of 0.1 m /metric ton.
EXAMPLE 10.2

Compute the maximum working area of a landfill cell if W is 12,000 MT/year and R is 1.1 m/year
(approx. 43 in./year). Comment on the result.

SOLUTION
A (0.1 12,000)/1.1 1090 m 2
max
If the cell measures 75 m in length, then the average width of the working area would be 14.5 m.
As waste is placed in the landfill, heavy equipment drives over and compacts the waste
(Figure 10.7). The degree of compaction is related to several factors including thickness of the
waste layer (see Figure 10.8), the number of passes made over the waste (see Figure 10.9), slope
(flatter slopes and steeper slopes compact better by landfill compactors and track-type tractors,
respectively and moisture content (wetter waste compacts more effectively than dry waste)
(Vesilind et al., 2002).

EXAMPLE 10.3
Determine the area required for a new sanitary landfill with a projected lifetime of 25 years. The
landfill will serve a population of 250,000 persons, generating 28 kg (62 lb) per household per
3
week. Waste density in the landfill averages 550 kg/m . Landfill height is not to exceed 25 meters.
Assume four persons per household.