ANAEROBIC TREATMENT OF VOLATILE AND SEMIVOLATILE ORGANIC-COMPOUNDS INMUNICIPAL WASTE-WATER

The potential of the expanded bed Granular Activated Carbon (GAC) anae robic reactor in treating a municipal wastewater containing Resource C onservation and Recovery Act (RCRA) volatile (VOC) and semivolatile or ganic compounds was studied. The GAC anaerobic reactor was followed by an aerobic nitrification tank. The GAC anaerobic reactor was operated at an empty bed residence time of 3.35 hours, whereas the nitrificati on tank was operated as a chemostat at a hydraulic residence time of 1 0 hours. A total of six VOCs (methylene chloride, chlorobenzene, carbo n tetrachloride, chloroform, toluene, and tetrachloroethylene) and six semivolatiles (o-chlorophenol, naphthalene, nitrobenzene, p-nitrophen ol, di-n-butyl phthalate, and lindane) were fed to the GAC anaerobic r eactor each at a concentration of 1 mg/L. The VOCs and semivolatiles w ere fed to the reactor as a mixture along with primary effluent from a local sewage treatment plant. The GAC anaerobic reactor was found to achieve greater than 94% removal of all VOCs except chloroform, which was removed to an extent of 75%. The semi-volatiles were removed in ex cess of 95%. The combined GAC anaerobic reactor-aerobic nitrification system was able to achieve removal efficiencies for chemical oxygen de mand and ammonia-nitrogen in excess of 97%.