The aim of this work was to characterize and optimize the treatment process of water contaminated by VOCs in constructed wetlands (CWs). New CW variants—the floating plant root mat (FPRM) and plant root mat filter (PRMF)—were applied at pilot scale to the treatment of benzene, MTBE, and dissolved-phase chlorinated hydrocarbons. The FPRM showed similar treatment efficiencies as the planted CW for benzene but was more effective for MTBE. Volatilization played an important role in MTBE removal in a new established FPRM, but it decreased with the age of the root mat. Performance results for the no-soil PRMF and FPRM variants indicate strong potential for a cost-competitive alternative for wastewater treatment. http://digital.bibliothek.uni-halle.de/urn/urn:nbn:de:gbv:3:4-8744