EFFECT OF INFLUENT OXYGEN CONCENTRATION ON THE GAC ADSORPTION OF VOCSIN THE PRESENCE OF BOM

Two rapid small-scale column tests (RSSCTs) were conducted in combinat ion with a large column adsorber to determine if the small columns cou ld predict the performance of a large column. The adsorbate solution c onsisted of three volatile organic chemicals (VOCs) in the presence of background organic matter (BOM). Landfill leachate was used as the BO M source. Dissolved molecular oxygen was used as a parametric viriable in the column studies to determine its influence on the breakthrough behavior of the adsorbate solution. The RSSCT, designed according to t he assumption of no dependency of the intraparticle surface diffusion coefficient on the activated carbon particle size, accurately predicte d the performance of the large column under anoxic conditions (absence of molecular oxygen), but failed to predict its performance under amb ient (8 mg l(-1) dissolved oxygen) or oxic conditions (30 mg l(-1) dis solved oxygen). The RSSCT, designed according to the assumption of a l inear dependency of the intraparticle surface diffusion coefficient on the activated carbon particle size, accurately predicted the performa nce of the large column under oxic and ambient conditions, but failed to predict its performance under anoxic conditions. The presence of mo lecular oxygen in the test environment resulted in an increased adsorp tion of the BOM on the GAC surface, which in turn, decreased the capac ity of the VOCs due to competitive effects.