Imagine you're walking around in a grove full of newly planted trees. What do you think you might see? Perhaps willowy new trunks with promising foliage, signaling nature's eruption into spring? Or maybe you'll see birds and insects returning to an area once marred by landfill waste? Scientist working at the Environmental Assessment Division at Argonne National Laboratory outside Chicago, however, see an enormous network of solar-driven pumps, hard at work extracting groundwater pollutants.


What? Solar-driven pumps? You can't see any network of pumps here—this is just a grove of trees. But can you really see the forest for the trees? Well, look a little closer, and you may find there's more going right underfoot than you ever could have imagined.

For many years, large amounts of waste were disposed at Argonne. The materials included anything from nonhazardous solid waste deposited in Argonne's sanitary landfill to chemicals now recognized as harmful that were dumped in a drain in the ground. Eventually, much of that waste permeated the soil and polluted the groundwater.

Recently, Argonne has taken on the cleanup of wastes and contaminated soils at the site, as well as actively containing and getting rid of groundwater pollutants. In addition to a traditional pump-and-treat system, in which contaminated water is pumped out with mechanical wells and treated above ground, workers implemented a more innovative approach to cleanup. In 1999, they planted 800 hybrid poplar and willow trees in deep, plastic-lined boreholes called caissons. The shapes of the plastic caissons were designed to force the tree roots to grow very straight and deep into the ground.


Access Online | Posted 3-11-2003