Phytoremediation of petroleum-contaminated soils

This chapter shows that the primary consideration is the conduit material for subsurface drains, which are installed to lower the water table in the soil matrix. Plastic tubing, both smooth thin-wall or corrugated, is classified and designed as flexible pipe. Heavy-wall plastic pipe, clay and concrete tile, and steel pipe are rigid pipe. Polypropylene, high-density polyethylene, and polyvinyl chloride, plastics are the primary materials for making drain tubing. The overburden soil load for most agricultural subsurface drain conduits can be approximated by use of classical procedures which are described in many texts and publications. The three-edged bearing test for clay and concrete tile is the basis for determining the strength of the rigid pipe. Subsurface pipe drainage systems require many accessories or structures, such as pipe outlets, couplers, reducers, junctions, special fittings, inlets, manholes, subirrigation or controlled-drainage facilities, blind inlets over drains, and pump sumps and related structures.