A series of experiments was performed to test the viability of using immobilized-bed, biological reactors to remove trace organic contaminants from recycled water. Protoype reactors were designed and built to test this concept on three groups of target organics, aliphatics, aromatics, and chlorinated aliphatics.Three experiments have been performed using phenol as the target compound. Phenol was fed to the reactor in a 100 parts per million (ppm) phenol in water feed and 10 ppm phenol feed.The 10 ppm feed experiments were run with the reactors operating in recycle mode, which allows the reactor to operate as a continuously stirred tank reactor (CSTR), and in plug-flow mode.The 100 ppm experiments showed an average phenol removal efficiency of 99.98% over a seven day period, with an average retention time of 27.2 hours. The seven day 10 ppm experiment in recycle mode had a 97.08% removal efficiency with a retention time of 13.7 hours.The 10 ppm plug-flow experiments were able to remove 99.88% of the phenol with a retention time of 12.5 hours. The phenol levels in the reactor effluent averaged below 10 parts per billion over the seven days of the experiment.