But already there are signs that some wastes are seeping beyond the original confines.
Toxic waste sites are often difficult to clean up, particularly when the wastes have seeped deep into the ground.
Old sinks (latrines) were not sealed properly and waste was seeping to the surface.
Before construction reforms were introduced in the early 19th century, liquid waste would seep away through the ground, leaving solid waste behind in the cesspit.
But the state never enforced the order, and in May 1983 the waste from the plant seeped into the town's drinking water.
Radioactive waste is slowly seeping into the surrounding water and air.
Now, years later, the highly toxic wastes have seeped through some building walls and leached up to ground level.
The raw waste seeps into the ground, contaminating the water.
The company promises that poisonous wastes from the mine will not seep into the surrounding streams and the park.
Chloera starts when infected human waste seeps into the water supply of a community.