How a Landfill Works: Storm Water Drainage

Critical to any landfill is keeping it as dry as possible to reduce the amount of leachate. This can be
done in two ways:

• Exclude liquids from the solid waste. Solid waste must be tested for liquids before entering
the landfill. This is done by passing samples of the waste through standard paint filters. If no
liquid comes through the sample after 10 minutes, then the trash is accepted into the landfill.

• Keep rainwater out of the landfill. To exclude rainwater, the landfill has a storm drainage
system. Plastic drainage pipes and storm liners collect water from areas of the landfill and
channel it to drainage ditches surrounding the landfill’s base.

The ditches are either concrete or gravel-lined and carry water to collection ponds to the side of
the landfill. In the collection ponds, suspended soil particles are allowed to settle, and the water is
tested for leachate chemicals. Once settling has occurred and the water has passed tests, it is then
pumped or allowed to flow off-site.