Three-dimensional vertical circulation flows around wells with two screen sections in one aquifer. so called ″groundwater circulation wells″ (GZB), are an important subject of numerical investigation. Normally, the two screen sections are placed at the bottom and top of an aquifer. When on-site remediation techniques should be used, e.g. for the elimination of dissolved heavy metals from the groundwater, the same techique of a GZB can be utilizerd: The groundwater entering the well is pumped above ground, treated, and infiltrated into the same well using the other well screen.