Advantages and Limitations

Carbon adsorption is an effective and simple treatment technology for volatile organic compounds. In addition, GAC can be used in conjunction with other treatment technologies.

However, GAC is not recommended for low-molecular-weight and high-polarity compounds. In addition, high-suspended solids, oil and grease, and a high concentration of iron and manganese can foul the carbon and require frequent backwashing. GAC showed poor adsorption capacity for wastewaters with high fatty acids (i.e., leachate from young landfills) or wastewaters with high BOD/COD and COD/TOC ratios (U.S. EPA 1977). Furthermore, the amount of carbon required, the frequency of regeneration and reactivation, and the potential need to handle the dis-

Moving Bed Downflow in Series out

Downflow in Parallel

Upflow Expanded in Series

Downflow in Parallel

Upflow Expanded in Series

FIG. 9.17.13 Single-stage and multiple-stage contactors. (Reprinted from U.S. Environmental Protection Agency, 1985, Handbook, remedial action at waste disposal sites, EPA/625/6-85/006, Washington, D.C.: U.S. EPA.)

out in

FIG. 9.17.13 Single-stage and multiple-stage contactors. (Reprinted from U.S. Environmental Protection Agency, 1985, Handbook, remedial action at waste disposal sites, EPA/625/6-85/006, Washington, D.C.: U.S. EPA.)

out in carded carbon as a hazardous waste make GAC a relatively expensive technology.

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