Granular activated carbons

Removal of Refractory Organics. Ozone reacts slowly or insignificantly with certain micropoUutants in some source waters such as carbon tetrachloride, trichlorethylene (TCE), and perchlorethylene (PCE), as well as in chlorinated waters, ie, ttihalomethanes, THMs (eg, chloroform and bromoform), and haloacetic acids (HAAs) (eg, trichloroacetic acid). Some removal of these compounds occurs in the ozone contactor as a result of volatilization (115). Air-stripping in a packed column is effective for removing some THMs, but not CHBr. THMs can be adsorbed on granular activated carbon (GAG) but the adsorption efficiency is low. 

DecoloriZation. Filtration, often a refinery botdeneck, especially with poor-quaHty raw sugar, is foUowed by decolorization with bone char (traditional), granular activated carbon (now most common), ion-exchange resias, or any combination of these. Comparative merits and regeneration of these decolorizing systems are a frequent topic ia the Hterature (r6—r8,rll). 

Most carbon adsorption units use granular activated carbon (GAC). The powdered form of activated carbon (PAC) typically is less than 100 microns in diameter and may be used to reduce dioxins in incinerator emissions (2) and in the treatment of drinking water and wastewater treatment (see the section on "Activated Sludge"). 

Fig. 1. Alternative wastewater treatment technologies, where GAC = granular activated carbon, PAC = powdered activated carbon, POTW = publicly owned treatment works, and RBC = rotating biological contactor (— ), wastewater return flows (—— ), sludge.

Table 15. Granular Activated Carbon (GAG) Adsorption Effectively Removes Organics From a Variety of Industrial Wastewaters...

Particle Size Distribution of Granular Activated Carbon... 

Ignition Temperature of Granular Activated Carbon Carbon Tetrachloride Activity of Activated Carbon Ball-Pan Hardness of Activated Carbon... 

Determination of Adsorptive Capacity of Carbon by Isotherm Technique Determining Operating Performance of Granular Activated Carbon... 

AWWA Standardfor Granular Activated Carbon, ANSI/AWWA B604, American Water Works Association, Denver, Colo., 1991, 32 pp. 

R. M. Clark and B. W. Lykins, Jr., Granular Activated Carbon—Design, Operation, and Cost, Lewis PubHshers, Inc., Chelsea, Mich., 1989, pp. 295—338. 

B. W. Lykins and M. Giiese, Chlorine Dioxide Disinfection and Granular Activated Carbon Absorption, EPA Project Summaiy, EPA-600/S2-82-051, Washington, D.C., May 1983. 

W. G. Schwer, "Purification of Industrial Liquids with Granular Activated Carbon Techniques for Obtaining and Interpreting Data and Selecting the Type of Commercial System," Carbon Ahsoption Handbook, Ann Arbor Science, Ann Arbor, Mich., 1978. 

GAX Granular activated carbon TCP Traditional costing procedures... 

Fig. 6. Breakthrough curves for aqueous acetone (10 mg 1" in feed) flowing through exnutshell granular active carbon, GAC, and PAN-based active carbon fibers, ACF, in a continuous flow reactor (see Fig. 5) at 10 ml min" and 293 K [64]. C/Cq is the outlet concentration relative to the feed concentration. Reprinted from Ind. Eng. Chem. Res., Volume 34, Lin, S. H. and Hsu, F. M., Liquid phase adsorption of organic compounds by granular activated carbon and activated carbon fibers, pp. 2110-2116, Copyright 1995, with permission from the American Chemical Society.

Lin, S. H. and Chen, Y. V., Adsorption and desorption characteristics of 1,1-dichloro-1-fluoroethane by granular activated carbon and activated carbon fiber, J. Environ. Sci. Health, Part A Toxic / Hazard Subst. Environ. Eng., 1996,31(6), 1279 1292. 

Critoph, R.E. and Thorpe, R.N., Momentum and heat transfer by forced convection in fixed beds of granular active carbon. Applied Thermal Engineering, 1996, 16,419 427. 

Fluidized-bed powdered activated carbon systems represent another important process. The use of activated carbon for the tertiary treatment of secondary sewage effluents has been used extensively. Powdered carbon is as effective as granular activated carbon for removing the organic impurities from the wastewater. 

Subsequently, biological/physical treatment of leachate with an activated carbon-enhanced sequencing batch bioreactor (PAC-SBR) was analyzed to determine whether the improved treatment by simultaneous adsorption and biodegradation in the SBR would produce an acceptable effluent without post-treatment in the existing granular activated carbon adsorber (Ying et al., 1986). 

For organic contaminant removal from surface water packed-tower aeration, granular activated carbon (GAC), powdered activated carbon (PAC), diffused aeration, advanced oxidation processes, and reverse osmosis (RO). 

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