B604-96

American Water Works Association

ANSI/AWWA B604-96(Revision of ANSI/AWWA B604-90)

AWWA STANDARD

FOR

GRANULAR ACTIVATED CARBON

Effective date: Mar. 1, 1997.

First edition approved by AWWA Board of Directors Jan. 28, 1974.

This edition approved June 23, 1996.

Approved by American National Standards Institute Nov. 27, 1996.

AMERICAN WATER WORKS ASSOCIATION

6666 West Quincy Avenue, Denver, Colorado 80235

R

Copyright (C) 1998 American Water Works Association, All Rights Reserved.

AWWA StandardThis document is an American Water Works Association (AWWA) standard. It is not a specification.AWWA standards describe minimum requirements and do not contain all of the engineering andadministrative information normally contained in specifications. The AWWA standards usually con-tain options that must be evaluated by the user of the standard. Until each optional feature isspecified by the user, the product or service is not fully defined. AWWA publication of a standarddoes not constitute endorsement of any product or product type, nor does AWWA test, certify, orapprove any product. The use of AWWA standards is entirely voluntary. AWWA standards areintended to represent a consensus of the water supply industry that the product described willprovide satisfactory service. When AWWA revises or withdraws this standard, an official notice ofaction will be placed on the first page of the classified advertising section of Journal AWWA. Theaction becomes effective on the first day of the month following the month of Journal AWWA publi-cation of the official notice.

American National StandardAn American National Standard implies a consensus of those substantially concerned with its scopeand provisions. An American National Standard is intended as a guide to aid the manufacturer, theconsumer, and the general public. The existence of an American National Standard does not in anyrespect preclude anyone, whether that person has approved the standard or not, from manufactur-ing, marketing, purchasing, or using products, processes, or procedures not conforming to the stan-dard. American National Standards are subject to periodic review, and users are cautioned to obtainthe latest editions. Producers of goods made in conformity with an American National Standard areencouraged to state on their own responsibility in advertising and promotional materials or on tagsor labels that the goods are produced in conformity with particular American National Standards.

CAUTION NOTICE: The American National Standards Institute (ANSI) approval date on the frontcover of this standard indicates completion of the ANSI approval process. This American NationalStandard may be revised or withdrawn at any time. ANSI procedures require that action be takento reaffirm, revise, or withdraw this standard no later than five years from the date of publication.Purchasers of American National Standards may receive current information on all standards bycalling or writing the American National Standards Institute, 11 W. 42nd St., New York, NY 10036;(212) 642-4900.

Copyright © 1997 by American Water Works AssociationPrinted in USA

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Committee Personnel

The Subcommittee on Granular Activated Carbon as a Filter Medium, whichassisted in developing this revision, had the following personnel at the time:

B.H. Kornegay, Chair

Consumer MembersJ.A. Bella

D.J. Hartman

General Interest MembersS.L. BishopC.R. James

B.H. Kornegay

Producer MembersR.W. FarmerJ.R. HedgerBob Thomas

The Filtering Materials Subcommittee on Granular Activated Carbon, whichassisted in developing this revision, had the following personnel at the time:

S.L. Bishop, Chair

Consumer MembersR.H. MeyerF.W. Pogge

General Interest MembersS.L. BishopE.A. BryantP.H. Kraft

K.J. Roberts

Producer MembersR.P. Beverly

S.L. Butterworth

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The AWWA Standards Committee on Activated Carbon, Powdered and Granu-lar, which developed this standard, had the following personnel at the time of approval:

Joseph A. Bella, ChairBilly H. Kornegay, Vice-Chair

Consumer Members

D.G. Ballou, City Utilities of Springfield, Springfield, Mo. (AWWA)J.A. Bella, Passaic Valley Water Commission, Little Falls, N.J. (AWWA)D.J. Hartman, Cincinnati Water Works, Cincinnati, Ohio (AWWA)A.F. Hess, Regional Water Authority, New Haven, Conn. (AWWA)W.R. Inhoffer,* Passaic Valley Water Commission, Clifton, N.J. (AWWA)E.D. Mullen, Elizabethtown Water Company, Bound Brook, N.J. (AWWA)M.J. Pickel, Philadelphia Water Department, Philadelphia, Pa. (AWWA)H.L. Plowman Jr., Philadelphia Suburban Water Company, Media, Pa. (AWWA)C.E. Stringer, Dallas Water Utilities, Dallas, Texas (AWWA)

General Interest Members

F.S. Cannon, Pennsylvania State University, University Park, Pa. (AWWA)Phillipe Charles, Lyonnaise des Eaux, Le Pecq, France (AWWA)J.C. Crittenden, Michigan Technological University, Houghton, Mich. (AWWA)Laura Cummings, Montgomery Watson Americas Inc., Pasadena, Calif. (AWWA)J.E. Dyksen,† Council Liaison, Malcolm Pirnie Inc., Mahweh, N.J. (AWWA)L.L. Harms, Black & Veatch Engineers, Kansas City, Mo. (AWWA)C.R. James, Montgomery Watson Inc., Walnut Creek, Calif. (AWWA)B.H. Kornegay, Parsons Engineering-Science Inc., Fairfax, Va. (AWWA)Wolfgang Kuhn, Universitat Karlsruhe, Karlsruhe, Germany (AWWA)R.G. Lee, American Water Works Service Company Inc., Belleville, Ill. (AWWA)S.J. Medlar, Camp, Dresser & McKee Inc., Edison, N.J. (NEWWA)J.L. Oxenford, AWWA Research Foundation, Denver, Colo. (AWWA)R.G. Saterdal, Consultant, Denver, Colo. (AWWA)Paul Schorr, State of New Jersey, Trenton, N.J. (AWWA)T.F. Speth, US Environmental Protection Agency, Cincinnati, Ohio (AWWA)I.H. Suffet, UCLA School of Public Health, Los Angeles, Calif. (AWWA)R.S. Summers, University of Cincinnati, Cincinnati, Ohio (AWWA)W.J. Weber Jr., University of Michigan, Ann Arbor, Mich. (AWWA)J.H. Wilber,† Standards Engineer Liaison, AWWA, Denver, Colo. (AWWA)

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*Alternate

†Liaison, nonvoting


Producer Members

D.A. Ainsworth, Cameron Carbon Inc., Baltimore, Md. (AWWA)S.L. Butterworth,* Calgon Carbon Corporation, Pittsburgh, Pa. (AWWA)R.W. Farmer, Calgon Carbon Corporation, Pittsburgh, Pa. (AWWA)J.R. Graham, Westates Carbon Inc., Los Angeles, Calif. (AWWA)J.B. Hedger, Elf Atochem NA Inc., Pryor, Okla. (AWWA)D.C. Ivey,* Elf Atochem NA Inc., Pryor, Okla. (AWWA)W.B. Leedy, Westvaco Chemical Division, Covington, Va. (AWWA)T.N. McFerrin,* Consultant, Dunnellon, Fla. (AWWA)G.B. Parker, Acticarb, Tyrone, Pa. (AWWA)D.O. Rester, Norit Americas Inc., Marshall, Texas (AWWA)Bob Thomas,* Norit Americas Inc., Atlanta, Ga. (AWWA)Carl Tobias, Envirotrol Inc., Sewickley, Pa. (AWWA)

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*Alternate


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Contents

All AWWA standards follow the general format indicated subsequently. Some variations from this format maybe found in a particular standard.

SEC. PAGE SEC. PAGE

Foreword

I Introduction........................................ ixI.A Background ........................................ ixI.B History................................................ ixI.C Acceptance.......................................... ixII Special Issues...................................... xII.A Handling and Storage ........................ xII.B Filter Media ....................................... xiII.C GAC Size Distribution....................... xiII.D Adsorptive Capacity ......................... xiiII.E Abrasion Resistance ....................... xiiiII.F Reactivation .................................... xiiiIII Use of This Standard ..................... xiiiIII.A Purchaser Options

and Alternatives........................... xiiiIII.B Modification to Standard ................ xivIV Major Revisions ............................... xivV Comments ........................................ xiv

Standard

1 General1.1 Scope.................................................... 11.2 Purpose................................................ 11.3 Application .......................................... 1

2 References......................................... 1

3 Definitions ........................................ 2

4 Requirements ................................... 34.1 Physical Requirements....................... 34.2 Performance Criteria.......................... 34.3 Impurities............................................ 4

5 Verification5.1 Sampling ............................................. 45.2 Test Procedures................................... 55.3 Rejection ............................................ 14

6 Delivery6.1 Marking............................................. 156.2 Packaging and Shipping .................. 156.3 Affidavit of Compliance.................... 16

7 Placing GAC Filter Material7.1 Preparation ....................................... 167.2 Placement of Support Media ........... 167.3 Placement of GAC ............................ 177.4 Top Surface Elevation ...................... 187.5 Contamination .................................. 18

8 Preparation of Filter forService

8.1 Backwashing..................................... 188.2 Scraping ............................................ 198.3 Disinfection ....................................... 198.4 Cleaning ............................................ 198.5 Safety................................................. 20

Appendixes

A Bibliography................................... 21

B Adsorptive Capacity TestsB.1 Tannin Adsorption Test.................... 25B.2 Phenol Adsorption Test .................... 26

Figures

1 Apparent Density Apparatus............. 62 Stirring Abrasion Unit ....................... 93 Testing Pan Assembly for Ro-Tap

Abrasion Test ................................. 114 Abrasion Testing Pan for Ro-Tap

Abrasion Test ................................. 11

TablesF.1 Typical Characteristics for a Range

of GAC Products ............................ xii1 Sampling of Bagged Media................ 5

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2 US Standard Sieves and Opening Sizes .................................................. 7

3 Sieving Apparatus Required for Stirring Abrasion Test ..................... 9

4 Recommended Particle Sieve Sizes ................................................ 12

5 Di Values for Ro-Tap Abrasion Test.................................................. 14

B.1 Standard Curve of Tannin Dilution........................................... 27

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ForewordThis foreword is for information only and is not a part of AWWA B604.

I. IntroductionI.A. Background. Activated carbon is a form of carbon that is produced by a

carefully controlled oxidation process to develop a porous carbon structure with asurface area greater than 500 m2/g. This surface area gives the activated carbon thecapacity to adsorb dissolved organic materials, many of which are taste- and odor-causing substances in water.

The major raw materials used in the manufacture of granular activated car-bons (GAC) include, but are not limited to, peat, bituminous coal, coconut shells,wood, and lignite. During activation, the raw materials are either reacted at hightemperatures in the presence of steam or at more moderate temperatures in thepresence of certain activation chemicals. These activation processes carbonize theraw materials and develop the extensive internal pore structure required to obtainappreciable adsorption. Subsequent processing may include crushing, screening,grading, and packaging.

Water treatment with granular activated carbon is accomplished by percolatingthe water to be treated through fixed-adsorption beds of granular activated carbon.The granular activated carbon may be crushed and screened to any particle size, buttypical sizes used for water treatment range from No. 8 to No. 50 US standard sievesizes.

I.A.1 Source of supply. Activated carbon to be used in water treatment shouldbe obtained from manufacturers regularly engaged in the production of activatedcarbon found satisfactory for service in the water treatment field.

I.B. History. The first edition of ANSI/AWWA B604, Standard for GranularActivated Carbon, was approved by the AWWA Board of Directors on Jan. 28, 1974.The first revision of ANSI/AWWA B604 was approved on June 17, 1990. This is thesecond revision. This edition was approved by the AWWA Board of Directors onJune 23, 1996.

ANSI/AWWA B604 provides information on preparing specifications for granu-lar activated carbon used as an adsorption medium and filtration/adsorption me-dium for the treatment of municipal and industrial water supplies. Powderedactivated carbon is covered in ANSI/AWWA B600, and other filtering materials arecovered in ANSI/AWWA B100.

This standard does not cover the design of carbon-handling facilities or adsorp-tion processes. Design information may be found in Journal AWWA and in otherpublications, some of which are listed in the bibliography (appendix A) to this standard.

I.C. Acceptance. In May 1985, the US Environmental Protection Agency(USEPA) entered into a cooperative agreement with a consortium led by NSF Inter-national (NSF) to develop voluntary third-party consensus standards and a certifica-tion program for all direct and indirect drinking water additives. Other members ofthe original consortium included the American Water Works Association ResearchFoundation (AWWARF) and the Conference of State Health and EnvironmentalManagers (COSHEM). The American Water Works Association (AWWA) and the As-sociation of State Drinking Water Administrators (ASDWA) joined later.

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In the United States, authority to regulate products for use in, or in contactwith, drinking water rests with individual states.* Local agencies may choose toimpose requirements more stringent than those required by the state. To evaluatethe health effects of products and drinking water additives from such products, stateand local agencies may use various references, including

1. An advisory program formerly administered by USEPA, Office of DrinkingWater, discontinued on Apr. 7, 1990.

2. Specific policies of the state or local agency. 3. Two standards developed under the direction of NSF, ANSI†/NSF‡ 60,

Drinking Water Treatment Chemicals—Health Effects, and ANSI/NSF 61, DrinkingWater System Components—Health Effects.

4. Other references, including AWWA standards, Food Chemicals Codex,Water Chemicals Codex,§ and other standards considered appropriate by the state orlocal agency.

Various certification organizations may be involved in certifying products inaccordance with ANSI/NSF 60. Individual states or local agencies have authority toaccept or accredit certification organizations within their jurisdiction. Accreditationof certification organizations may vary from jurisdiction to jurisdiction.

Appendix A, “Toxicology Review and Evaluation Procedures,” to ANSI/NSF 60does not stipulate a maximum allowable level (MAL) of a contaminant for sub-stances not regulated by a USEPA final maximum contaminant level (MCL). TheMALs of an unspecified list of “unregulated contaminants” are based on toxicitytesting guidelines (noncarcinogens) and risk characterization methodology (carcino-gens). Use of appendix A procedures may not always be identical, depending on thecertifier.

AWWA B604-96 does not address additives requirements. Thus, users of thisstandard should consult the appropriate state or local agency having jurisdiction inorder to

1. Determine additives requirements, including applicable standards. 2. Determine the status of certifications by all parties offering to certify prod-

ucts for contact with, or treatment of, drinking water. 3. Determine current information on product certification.II. Special IssuesII.A. Handling and Storage. Wet activated carbon will readily adsorb oxygen

from the air, creating an acute oxygen depletion hazard in confined areas. Appropri-ate safety measures for oxygen-deficient atmospheres should be strictly adhered towhen entering enclosed or partially enclosed areas containing activated carbon.

In storing activated carbon, precautions must be taken to avoid direct contactwith strong oxidizing agents, such as chlorine, hypochlorites, potassium permanga-nate, ozone, and peroxide.

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*Persons in Canada, Mexico, and non-North American countries should contact theappropriate authority having jurisdiction.

†American National Standards Institute, 11 W. 42nd St., New York, NY 10036.

‡NSF International, 3475 Plymouth Rd., Ann Arbor, MI 48106.

§Both publications available from National Academy of Sciences, 2102 Constitution Ave.N.W., Washington, DC 20418.


Mixing carbon with hydrocarbons (such as oils, gasoline, diesel fuel, grease,paint thinners, and so forth) may cause spontaneous combustion. Therefore, acti-vated carbon must be kept separated from hydrocarbon storage or spills.

Activated carbon dusts are classified as “nuisance particulates” and the appli-cable Threshold Limit Values (TLVs) should be followed.*

II.B. Filter Media. Filter media are those portions of the filter bed that re-move particulate matter from the water during the filtration process. This standardcovers granular activated carbon which serves as both an adsorbent and filter me-dium. Properties of other filter media such as sand, anthracite, and filter mediasupport such as gravel are contained in ANSI/AWWA B100.

II.C. GAC Size Distribution. The selection of the type, size, and bed depth ofGAC in any particular application is site specific and depends on the raw waterquality, pretreatment provided, and water quality objectives. These are site-specificdesign criteria and must be determined by the design engineer.

In general, for a given pretreatment of raw water and a given filtration rate,coarse media will permit longer filtration runs, but the rate of adsorption is slower.The organic removal and filtration efficiency will normally decrease as the particlesize is increased. However, the head loss will also increase with decreasing particlesize, and, as a result, the filter runs may be shorter. The uniformity coefficient (UC)of GAC used as a filter medium may be less than the UC of GAC used as an adsorb-ent. Experience indicates that a more uniform media results in greater filtrationefficiency.

Dual- or multi-media GAC filters have been used in lieu of a single medium instandard filter-adsorbers for water treatment. The dual or multi-media are selectedto provide a coarse layer of GAC in the upper filter with the smaller and more densesand in the lower layers. This coarse-to-fine grading combines longer filter runs withthe superior filtration characteristics of finer media. Obviously, the larger mediamust be lighter than the smaller media to provide the desired gradation, and therelative sizes of the various media should be selected on the basis of the desiredbackwash properties. Therefore, the relative size depends on the density and shapeof the media, as well as particle size. It should also be noted that intermixing sandwith GAC may introduce reactivation problems.

Since granular activated carbon is normally used as a filter medium due to theadsorption characteristics, the adsorption properties of the material must be consid-ered. Efficient adsorption requires that the adsorption wave front of the GAC bemaintained during the backwash/filtration cycle. Excessive intermixing of the GACwill reduce the adsorption capacity of the filter bed material and increase the cost ofoperation. Maintaining a stratified bed is more difficult with GAC than with othermedia such as sand or anthracite. As the activated carbon granules in the upperportion of the bed adsorb organic materials, the density increases and the particlessettle to a lower portion of the bed. To assist in the maintenance of bed stratifica-tion, the adsorption wave front, and efficient adsorption, GAC is typically producedto be as nonuniform as possible. That is, the GAC is produced as non-uniform aspossible without reaching the transport velocity of the smallest particles prior toachieving expansion of the largest fraction. This normally occurs at a uniformitycoefficient of approximately 2.1. Where filtration is the primary function of the GAC,

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*American Conference of Governmental Industrial Hygienists, 6500 Glenway Ave., Bldg.D-7, Cincinnati, OH 45211-4438.


more uniform carbons may be warranted. The design engineer must balance theadsorption performance with the filtration requirements.

In specifying the size of granular activated carbon, it is normal to express theeffective size of the particle and maximum allowable uniformity coefficient, or theaverage particle size and maximum uniformity coefficient. An oversize and undersizeallowance may also be specified on the mesh sizes that incorporate the desired car-bon gradation. For example, when specifying an 8 × 30 mesh size, the maximumamount that is retained on the 8 mesh (oversize) and the maximum percent thatpasses the 30-mesh screen (undersize) may also be specified. Commonly manufac-tured size ranges for granular activated carbon are expressed in US standard sievesizes that include, but are not limited to, 8 × 16, 8 × 20, 8 × 30, 10 × 30, 12 × 40, 14× 40, 20 × 40, and 20 × 50, with effective size ranges from 0.35 mm to 2.0 mm.Extruded carbons are also produced in various size ranges. The typical properties ofthe more standard GAC products are shown in Table F.1.

II.D. Adsorptive Capacity. The optimum method for determining the effective-ness of a granular activated carbon is by using water from the particular plant inquestion for the test. These methods may include testing for removal of a specificchallenge compound. Various surrogate tests have been developed that give an indi-cation of a granular activated carbon’s performance under specific conditions. These

Table F.1 Typical characteristics for a range of GAC products*

Standard US Mesh Size UniformityCoefficient

Effective Size(mm)

Apparent Densitylb/ft3

Bituminous Coal-Based GAC

12 × 40 ≤1.9 0.55–0.75 27–4110 × 20 ≤1.6 0.8–1.1 28–39

8 × 30 ≤2.1 0.7–1.0 28–418 × 20 ≤1.5 1.0–1.2 29–398 × 16 ≤1.5 1.2–1.5 29–396 × 14 ≤1.5 1.7–1.9 31–39

Lignite Coal-Based Carbons

20 × 50 ≤1.6 0.3–0.5 22–2620 × 40 ≤1.5 0.45–0.65 22–2612 × 40 ≤1.8 0.55–0.8 22–2610 × 30 ≤1.6 0.7–0.9 22–2612 × 20 ≤1.7 0.7–1.0 22–26 8 × 30 ≤1.8 0.7–1.0 22–26 8 × 16 ≤1.5 1.2–1.5 22–26

Wood-Based Granular Activated Carbons

14 × 35 ≤1.5 0.6–0.8 16–1910 × 25 ≤1.5 1.0–1.3 15–18 4 × 14 ≤1.5 1.6–2.0 14–17

*The characteristics shown above represent a range of GAC products and not a specific grade and meshsize. Manufacturer’s product data bulletins should be consulted for information on specific grades andparticle sizes.

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tests use a very high concentration of adsorbate to reduce the amount of time re-quired to run the test. Sampling tubes may be added to the GAC vessel to aid indetermining the adsorptive wavefront. Various producers of activated carbon suggestdifferent adsorbates to give an index of a carbon’s performance. Examples are phe-nol, tannin, iodine, and molasses. Phenol adsorption is an index of a carbon’s abilityto remove some types of chemical taste and odor; tannin is representative of organiccompounds added to water by decayed vegetation; and iodine adsorption is an indexof the total surface area of a carbon. Iodine and molasses adsorption are often usedto show the degree of carbon activation. An iodine adsorption test is included in thisstandard. Information on tannin and phenol adsorptive capacity tests may be foundin appendix B to this standard for those purchasers who want to include these re-quirements in their specifications. An American Water Works Association ResearchFoundation (AWWARF) protocol has also been developed for the evaluation of granu-lar activated carbons. (See appendix A.)

II.E. Abrasion Resistance. Granular activated carbons used for municipalwater treatment are exposed to a variety of external forces during shipping, loadinginto adsorption beds, backwashing, and reactivation. These forces can cause acti-vated carbon granule crushing on impact, granule-to-granule abrasion, and the gen-eration of undesirable fines. Because of the difficulty in devising a test thatsimulates the various handling conditions that may be encountered, the industryhas not yet agreed on any one standard test for predicting activated carbon durability.

Two tests, the stirring abrasion test and the Ro-Tap abrasion test, have beenincluded in this standard for measuring granular activated carbon durability. It isrecognized that differences in bulk density and other physical properties of the vari-ous manufactured activated carbons, which might not be related to durability, influ-ence the results obtained in using these tests. For this reason, it is current practiceto use the stirring abrasion test for lignite-based granular activated carbons and theRo-Tap abrasion test for bituminous-based granular activated carbons.

II.F. Reactivation. The characteristics of granular activated carbon have animpact on the physical and adsorptive losses during reactivation and must, there-fore, be considered. Resistance to abrasion and the operating conditions required torestore the adsorptive capacity are significant factors in carbon losses and cost. Aseparate standard is being developed for reactivated GAC.

III. Use of This Standard. AWWA has no responsibility for the suitability orcompatibility of the provisions of this standard to any intended application by anyuser. Accordingly, each user of this standard is responsible for determining that thestandard’s provisions are suitable for and compatible with that user’s intendedapplication.

III.A. Purchaser Options and Alternatives. The following items should be cov-ered in the purchaser’s specifications:

1. Standard used—that is, ANSI/AWWA B604, Standard for GranularActivated Carbon, of latest revision.

2. Quantity of granular activated carbon to be purchased. Activated carbonintended for immediate placement in an adsorption bed is typically purchased byvolume, and is backwashed, drained, and in place. Makeup activated carbon or acti-vated carbon intended for subsequent placement is purchased on a volume or weightbasis.

3. Whether an affidavit of compliance is required (Sec. 6.3). 4. Whether this is a supply contract or a supply and installation contract

(Sec. 7).

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5. Whether the purchaser requires additional adsorptive capacity tests(Sec. 4.2.2).

6. When requested, a representative sample of the granular activated carbonshall be submitted to the purchaser for acceptance before shipment. The samplemust be submitted in clean, vaporproof containers, clearly marked with the addressof the supplier, and identified with the lot number of the contents. A duplicate sam-ple shall be tested by the supplier and a certified test report shall be submitted tothe purchaser with the purchaser’s sample, showing compliance with the require-ments of the purchaser’s specifications, along with a statement certifying that thematerial for shipment is equal in quality to the sample submitted.

7. The purchaser may elect to accept the granular activated carbon on thebasis of (1) the supplier’s certified test report and an accompanying affidavit of com-pliance indicating the product proposed for use complies with this standard and withthe purchaser’s specifications with no exceptions; (2) the supplier’s certified test re-port completed by a qualified third-party testing laboratory approved by the pur-chaser and an accompanying affidavit of compliance; (3) the purchaser’s own testingof the reference sample submitted by the supplier and the required affidavit of com-pliance; or (4) the purchaser’s own testing of the representative sample, collectedaccording to Sec. 5.1 after receipt of shipment, showing compliance with this stand-ard and the purchaser’s specifications. (See note in Sec. 4.1.1.)

8. Particle-size range, effective size, and uniformity coefficient, if other thanthat specified (Sec. 4.1).

9. Special adsorptive capacity tests (Sec. 4.2.1 and Sec. 4.2.2).10. Provisions for reaching agreement on sampling technique (Sec. 5.1.1).11. Method of packaging and shipping (Sec. 6.2).12. If shipment is to be in bulk: type of railcar or hopper truck (Sec. 6.2.4);

and whether bulk shipments are to be accompanied by weight certificates of certifiedweighers (Sec. 6.2.5).

13. The purchaser may authorize shipment on the basis of the supplier’s certi-fication of quality, or may test the reference sample submitted by the supplier toconfirm compliance before shipment is authorized.

14. The purchaser may elect to collect a representative sample of the materialafter delivery. The procedure used shall be in accordance with Sec. 5.1. One of thethree sample portions taken may be tested to determine compliance with the pur-chaser’s specifications.

III.B. Modification to Standard. Any modification to the provisions, definitions,or terminology in this standard must be provided in the purchaser’s specifications.

IV. Major Revisions. Major changes made to the standard in this revisioninclude the following:

1. The format has been changed to AWWA standard style. 2. Parameters required to specify GAC as a filter/adsorber, as well as an ad-

sorbent, have been included.V. Comments. If you have any comments or questions about this standard,

please call the AWWA Standards and Materials Development Department, (303) 794-7711 ext. 6283, FAX (303) 795-1440, or write to the department at 6666 W. QuincyAve., Denver, CO 80235.

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American Water Works Association

ANSI/AWWA B604-96(Revision of ANSI/AWWA B604-90)

AWWA STANDARD FOR



SECTION 1: GENERAL

Sec. 1.1 Scope

This standard covers the use of granular and extruded activated carbons as afilter medium and adsorbent in water treatment. It involves the selection, place-ment, and use of granular activated carbon (GAC) in filter-adsorbers where the GACmust function as both a filter medium and adsorbent, as well as those systemswhere the primary function is adsorption.

Sec. 1.2 Purpose

The main purpose of this standard is to provide the minimum requirements forgranular activated carbon, including physical, testing, packing, and shippingrequirements.

Sec. 1.3 Application

This standard can be referenced in specifications for purchasing and receivinggranular activated carbon and can be used as a guide for testing the physical prop-erties of granular activated carbon samples. The stipulations of this standard applywhen this document has been referenced and then only to granular activated carbonused in water supply service applications.

SECTION 2: REFERENCES

This standard references the following documents. In their latest editions,these documents form a part of this standard to the extent specified in this stand-ard. In any case of conflict, the requirements of this standard shall prevail.

R

1


ANSI*/AWWA B100—Standard for Filtering Materials.ANSI/AWWA B600—Standard for Powdered Activated Carbon.ANSI/AWWA C653—Standard for Disinfection of Water Treatment Plants.ASTM D4607—Standard Test Method for Determination of Iodine Number of

Activated Carbon.Standard Methods for the Examination of Water and Wastewater. APHA,†

AWWA, WEF.‡ Washington, D.C. (19th ed., 1995).

SECTION 3: DEFINITIONS

The following definitions shall apply in this standard: 1. Activated carbon: A family of carbonaceous substances manufactured by

processes that develop internal porosity, thereby creating adsorptive properties. 2. Adsorption: A process in which fluid molecules are concentrated on a sur-

face by chemical forces, physical forces, or both. 3. Bag: A plastic, paper, or woven container that may contain approximately

2.0 ft3 of GAC. 4. Bulk containers: These are typically specially constructed trucks that may

contain 20,000 lb to 40,000 lb of GAC. 5. Effective size: That size opening that will just pass 10 percent of a repre-

sentative sample of a filter material; that is, if the size distribution of the particlesis such that 10 percent of a sample is finer than 0.45 mm, the filter material has aneffective size of 0.45 mm.

6. Extruded activated carbon: A form of granular activated carbon in whichthe particles are uniform cylinders or cylindrical pellets. Effective size and uniform-ity coefficient are not applicable for extruded carbons. The diameter is normallyspecified.

7. Manufacturer: The party that manufactures, fabricates, or produces mate-rials or products.

8. Purchaser: The person, company, or organization that purchases any mate-rials or work to be performed.

9. Supplier: The party that supplies materials or services. A supplier may ormay not be the manufacturer.

10. Uniformity coefficient: A ratio of the size opening that will just pass 60 per-cent of a representative sample of the filter material divided by that opening thatwill just pass 10 percent of the same sample.

11. Semibulk container: A large plastic or woven bulk container that may con-tain 800 lb to 2,000 lb of GAC.

12. Support media: For the definitions and shipment requirements of gravel,sand, and associated support media, see ANSI/AWWA B100.

2 AWWA B604-96

*American National Standards Institute, 11 W. 42nd St., New York, NY 10036.

†American Public Health Association, 1015 15th St. N.W., Washington, DC 20005.

‡Water Environment Federation, 601 Wythe St., Alexandria, VA 22314-1994.


SECTION 4: REQUIREMENTS

Sec. 4.1 Physical Requirements

4.1.1 Moisture. The moisture content of granular activated carbon shall notexceed 8 percent, by weight, of the listed container contents as packaged or at thetime of shipment by the supplier in the case of a bulk shipment. The moisturecontent shall be determined according to Sec. 5.2.3.

NOTE: Because ambient conditions may be beyond the control of the supplier,the moisture content of activated carbon may increase during bulk shipment. Amoisture content exceeding 8 percent is permitted in the reference sample that iscollected after receipt of shipment (Sec. III.A(5) and Sec. 5.3.1).

4.1.2 Apparent density. The apparent density of the activated carbon shall benot less than 0.25 g/cc as determined according to Sec. 5.2.4.

4.1.3 Particle-size distribution. Particle-size distribution shall be determinedin accordance with Sec. 5.2.5. The particle-size range of the granular activated car-bon shall be as specified by the purchaser. Not more than 15 percent of the activatedcarbon shall be retained on the maximum-size sieve,* and not more than 5 percentof the activated carbon shall pass the minimum-size sieve.

4.1.4 Effective size. The effective size of the granular activated carbon shall bewithin the limits specified by the purchaser. A range from 0.30 mm to 2.0 mm isavailable. This parameter does not apply to extruded carbons where the cylindricaldiameter is typically specified.

4.1.5 Uniformity coefficient. Unless otherwise specified by the purchaser,granular activated carbon shall have a uniformity coefficient not greater than 2.1.This parameter does not apply to extruded carbons. More uniform carbons may bespecified where desirable for filtration performance.

4.1.6 Abrasion resistance. The retention of average particle size of granularactivated carbon shall not be less than 70 percent as determined by either the stir-ring abrasion test or the Ro-Tap abrasion test, according to Sec. 5.2.6.

4.1.7 Water-soluble ash. The water-soluble ash shall not exceed 4 percent asdetermined according to Sec. 5.2.8, Water Extractables Test.

Sec. 4.2 Performance Criteria

4.2.1 Adsorptive capacity—iodine number. The iodine number of the granularactivated carbon shall not be less than 500 mg/g carbon as determined according toSec. 5.2.7. If desired, a higher iodine number may be specified. (See foreword,Sec. II.D, for discussion of other tests to determine special adsorptive characteristicsfor color, taste, and odor and specific organics removal. These special test proceduresshould be specified, if deemed advisable, and the purchaser’s specifications shouldallow adequate time to complete testing and confirmation analysis.)

4.2.2 Additional adsorptive capacity tests. If the purchaser desires to use ad-ditional adsorptive capacity tests to measure adsorptive capacity, the purchaser shall

GRANULAR ACTIVATED CARBON 3

*All sieve numbers referred to in this standard are US Standard Sieve Series numbers, asspecified in the American Society for Testing and Materials (ASTM) Standard DesignationE11, Specification for Wire-Cloth Sieves for Testing Purposes, available from ASTM, 100 BarrHarbor Dr., West Conshohocken, PA 19428-2959.


notify the supplier of which type of shipment sampling will be required(Sec. III.A(5)).

Sec. 4.3 Impurities*

4.3.1 General impurities. The granular activated carbon supplied according tothis standard shall contain no substances in quantities capable of producing delete-rious or injurious effects on the health of those consuming water that has beenproperly treated with granular activated carbon.

4.3.2 Specific impurity limits. The granular activated carbon shall not containspecific impurities in excess of the limits listed in the Food Chemicals Codex.† andshould comply with ANSI/NSF‡ Standard 61, Drinking Water System Components—Health Effects.

SECTION 5: VERIFICATION

Sec. 5.1 Sampling

5.1.1 Sampling location. If the purchaser elects to accept the material on thebasis as required in Sec. III.A(5), samples shall be taken at the point of destination.The technique of sample collection shall be agreed on by both the supplier and thepurchaser before shipment.

5.1.2 Mechanical sampling. If the granular activated carbon is handled byconveyor or elevator or shipped in bulk, a mechanical sampling arrangement may beused.

5.1.3 Package sampling. When material is shipped to the jobsite in bags, rep-resentative samples shall be collected using a core sampler. The representative sam-ples from each bag shall be combined to produce the required composite sample. Theminimum size sample shall be 10 lb (4.5 kg) and the number of bags to be sampledis indicated in Table 1.

5.1.4 Sampling tube. Carbon may be sampled, by the use of a sampling tubeof at least 3⁄4 in. (19 mm)§ diameter, from bulk carload shipments or from packages.When taking samples from packages, the sampling tube shall be extended the fulllength of the package to obtain a representative sample. It should be noted that it isvirtually impossible to avoid particle fracture when using a sampling tube. Extremecare should be taken to minimize the effect of this on particle-size distribution. Sam-pling bulk shipping containers after shipment from the manufacturer will be subjectto error caused by stratification and compaction during shipment. Extreme careshould be exercised in sampling bulk shipping containers after shipment.

4 AWWA B604-96

*See Sec. I.C of the foreword.

†Available from National Academy of Sciences, 2102 Constitution Ave. N.W., Washington,DC 20418.

‡NSF International, 3475 Plymouth Rd., Ann Arbor, MI 48106.

§Metric conversions given in this standard are direct conversions of US customary unitsand are not those specified in International Organization for Standardization (ISO)standards.


5.1.5 Sample size. The gross sample of approximately 10 lb shall be sealed invaporproof containers. Each sample container shall be labeled to identify it, and thelabel shall be signed by the sampler. The gross sample shall be divided using one ofthe following methods:

1. Mix thoroughly and divide the sample to provide three 1-lb (0.45-kg) samples. 2. Pour through a sample riffler. Repeat as necessary using the split portions

to provide three 1-lb (0.45-kg) samples.

Sec. 5.2 Test Procedures

5.2.1 Samples. If the purchaser elects to accept the material on the basisspecified in Sec. III.A(5), samples shall be taken from each shipment of granularactivated carbon according to Sec. 5.1. The sample delivered to the laboratory shallbe divided to provide approximately 1 lb (454 g). After thorough mixing, this sampleshould be stored in a vaporproof container and weighed out of it rapidly to avoidchange in moisture content.

5.2.2 Testing period. The laboratory examination of a sample shall be com-plete in time to meet the requirements of Sec. 5.3.1 for notification of the supplier inthe event that tests reveal that the material does not comply with this standard orthe purchaser’s specifications.

5.2.3 Moisture.5.2.3.1 Procedure. In a tared weighing bottle, accurately weigh approximately

2 g of the sample. Dry in a drying oven at 140°C for 2 h or 110°C for 3 h; then coolin a desiccator and weigh rapidly.

5.2.3.2 Calculation.

loss of weightweight of sample

× 100 = % moisture

Table 1 Sampling of bagged media*

Lot Size(number of bags shipped)

Minimum Sample Size(number of bags sampled)

2–8 2 9–15 316–25 526–50 851–90 13

91–150 20151–280 32281–500 50

501–1,200 801,201–3,200 125 3,201–10,000 200

10,001–35,000 315 35,001–150,000 500

*Refer to Military Standard MIL-STD-105D (1963), Sampling Procedures for Inspection by Attributes.



5.2.4 Apparent density.5.2.4.1 General. The apparent density of a carbon is the weight in grams per

cubic centimeters (g/cc) of the carbon in air. Carbons should have the density deter-mined on an “as-received” basis with corrections made for moisture content.

5.2.4.2 Apparatus. The testing apparatus shall be as shown in Figure 1. Res-ervoir and feed funnels are glass or metal. The metal vibrator is 26-gauge galva-nized sheet metal. A balance with a sensitivity of 0.1 g is required.

5.2.4.3 Procedure. 1. Carefully place a representative sample of the carbon into the reservoir

funnel. If the material prematurely flows into the graduated cylinder, return thematerial to the reservoir funnel.

2. Add the sample to the cylinder by the vibrator feeder at a uniform rate ofnot less than 0.75 mL/s nor greater than 1.0 mL/s up to the 100-mL mark. Adjustthe rate by changing the slope of the metal vibrator or raising or lowering the reser-voir funnel, or both, or by using a variable autotransformer to vary the current tothe buzzer transformer.

3. Transfer the contents from the cylinder to a balance pan and weigh to thenearest 0.1 g.

5.2.4.4 Calculation. Calculate the apparent density in grams/millilitre on thedry basis:

apparent density = (weight of carbon) × (100 − % moisture)

10,000

Ring StandReservoir FunnelClamped to Ring Stand

Metal Vibrator

Door Bell "Buzzer"(For 10-V, 60-Hz Service)

Feed FunnelClamped to Ring Stand

Switch([SPST] Bat-Handle Toggle)

100-mL ASTM GraduatedCylinder

TransformerPrimary Volts 115Volt Ampere 10Secondary Volts 6/12/18Frequency 50–60 Hz

(Not to Scale)

Assembly of Apparatus

12.7-mm Diameter Rod19.1 mm

Metal Vibrator

Reservoir Funnel Feed Funnel

88.9 mm

44.5 mm

76.2 mm

41.3 mm

120.7 mm82.6 mm

68.9 mm

101.6 mm

38.1 mm

23.8 mm

Figure 1 Apparent density apparatus

6 AWWA B604-96


5.2.5 Particle-size distribution.5.2.5.1 General. Determine the particle-size distribution of granular activated

carbon by mechanically shaking a weighed amount of material through a series ofUS standard sieves and then determining the quantity retained on or passingthrough each sieve.

5.2.5.2 Apparatus.• Sample splitter—similar to Jones riffler• Sieve shaker, electrically driven, equipped with automatic timer similar to

Ro-Tap• Sieves—US standard sieves, 8 in. diameter and 2 in. high• Bottom receiver pan—8 in. diameter and 2 in. high• Top sieve cover—8 in. diameter• Balance—top loader with sensitivity of 0.1 g• Brush—soft brass-wire brush5.2.5.3 Procedure. 1. Assemble the sieves to be used on the bottom receiver pan in order of

increasing sieve opening size from bottom to top. The smallest and largest openingsize sieves should correspond to the limiting sizes for the grade of carbon specified;for example, for 12 × 40 carbon, use sieve numbers 12, 14, 16, 20, 30, and 40. USstandard sieves and opening sizes are tabulated in Table 2.

2. Mix the sample by passing the material through the riffle and recombiningtwice.

3. Carefully reduce the mixed sample by repeated passes through the riffle toobtain a test sample of 100 ± 5 g. No more than 5.0 g of activated carbon may beadded or taken from the test sample without additional riffling.

4. Transfer the weighed sample to the top sieve. Install the sieve cover andsieve shaker cover and place the assembly on the sieve shaker.

5. Allow the sieve assembly to shake for 3 min ± 3 s with the hammeroperating.

Table 2 US standard sieves and opening sizes

US StandardSieve Number

Sieve Openingmm

8 2.3610 2.0012 1.7014 1.4016 1.1818 1.0020 0.85025 0.71030 0.60035 0.50040 0.42545 0.35550 0.300



6. Remove the sieve assembly from the sieve shaker and quantitativelytransfer the activated carbon retained on the top sieve to a tared balance pan andweigh to the nearest 0.1 g. Repeat this procedure for material retained on each sub-sequent sieve and the bottom receiver pan. Lightly brush the material from eachsieve to free particles held in the screen.

7. Add the weights of each sieve fraction; if the sum deviates more than 2.0 gfrom the test sample weight, repeat the analyses.

5.2.5.4 Percentage retained on each sieve.

(sieve fraction weight) (100)(sum of sieve fraction weights)

= % retained on each sieve

5.2.5.5 Effective size and uniformity coefficient. a. From the percentage retained on each sieve, calculate the cumulative per-

centage passing each sieve. The cumulative percentage passing a sieve is the sum ofall the percentages retained on subsequent (smaller) sieves plus the percentage re-tained on the pan.

b. Using probability × logarithmic paper, plot the sieve opening in millime-tres on the ordinate or vertical scale versus the cumulative percentage passing eachsieve on the abscissa or horizontal scale.

c. The effective size is the sieve opening in millimetres at which 10 percent ofthe material passes on the cumulative percentage passing scale.

d. The uniformity coefficient is determined by dividing the millimetre open-ing at which 60 percent passes by the millimetre opening at which 10 percent passes.

5.2.6 Abrasion resistance.5.2.6.1 General. Determine abrasion resistance either by the stirring abrasion

test or by the Ro-Tap abrasion test as follows.5.2.6.2 Stirring abrasion test. The stirring abrasion test measures percentage

retention of the average particle size in the carbon after abrading the carbon by theaction of a T-shaped stirrer in a specially fabricated abrasion unit. This test is usedto measure abrasion resistance of lignite- and petroleum-coke-based granular activatedcarbons.

5.2.6.2.1 Sieving apparatus—stirring abrasion test.• Sieve shaker, electrically driven, equipped with automatic timer—similar to

Ro-Tap• Sieves—US standard sieves, 8-in. diameter and 2-in. high; Table 3 indi-

cates sieves that are required• Bottom receiver pan—8-in. diameter, full height• Top sieve cover—8-in. diameter• Balance—top loader with sensitivity of 0.1 g• Brush—soft brass-wire brush5.2.6.2.2 Stirring abrasion unit. The abrasion unit is detailed in Figure 2. The

apparatus includes a T-shaped stirrer made from 1⁄2-in. metal rod that is driven at855 ± 15 rpm. The stirrer and cylinder may be made of any suitable material; forexample, steel, stainless steel, or brass. The absence of burrs and rough welds isabsolutely necessary. The T-bar stirrer should be replaced when the length of thecross bar is 0.02 in. less than the designed size or when the hemispherical endsshow signs of serious wear; that is, when the length of the cross bar is more than0.025 in. from the designed size. Such wear will show on the leading edge of theT-bar stirrer.

8 AWWA B604-96


5.2.6.2.3 Procedure—stirring abrasion test. 1. Place a No. 8 sieve on top of a No. 70 sieve on the sieve shaker. Screen

sufficient granular activated carbon sample to obtain 250 mL–300 mL of 8 × 70mesh carbon by shaking portions of the activated carbon on the sieve shaker forexactly 3 min ±2 s with the hammer operating. Discard the material retained on theNo. 8 sieve and the material passing the No. 70 sieve.

2. Place the 250-mL–300-mL portion of granular activated carbon on the topscreen of a nest of US standard sieves, numbers 12, 16, 20, 40, 50, and 70; andshake on the sieve shaker for 15 min ±10 s with the hammer operating.

3. Remove the sieve assembly from the sieve shaker and quantitativelytransfer the carbon retained on the top sieve to a tared balance pan and weigh tothe nearest 0.1 g. Repeat this procedure for material retained on each subsequent

Table 3 Sieving apparatus required for stirring abrasion test

US StandardSieve Number

Sieve Openingmm

Average Openingmm (Di)

8 2.36 —12 1.70 2.0316 1.18 1.4420 0.850 1.0240 0.425 0.6450 0.300 0.3670 0.212 0.26

pan — 0.15

4-in. V-Pulley

Thick-Walled Brass Tubing1 1/2-in. OD × 1/4 in. Wall

Silver Soldered

Supporting FrameSlotted for Belt-Tension Adjustment

1/2-in. Brass Plate

Brass Tubing4-in. ID

Clearance,Bottom and Ends0.500 ± 0.010 in.

Ball Bearings(New Departure

77R8)

1/2-in.Shaft

EndsTurned

True

Abo

ut 4

in.

Abo

ut 6

in.

Silver Solder

Figure 2 Stirring abrasion unit



sieve and the bottom receiver pan. The material should be lightly brushed from eachsieve to free particles held in the screen. Record the weight of each sieve fractionand the total weight of carbon recovered.

4. Recombine and blend by tumbling the sieve fractions very gently in aquart fruit jar or similar container and place the carbon in the abrasion unit.Operate the abrasion unit for 1 h ± 1 min.

5. Remove the carbon from the abrasion unit and repeat the screening on anest of US standard sieves, numbers 12, 16, 20, 40, 50, and 70, as in step 2. Use thesame sieve shaker as was used for the initial sieve analysis. Record the weight ofeach sieve fraction and the total weight of carbon recovered.

5.2.6.2.4 Calculations—stirring abrasion test. Calculate the average particlesize before and after stirring by using the following equation:

Davg = summation of (Wi × Di)

summation of (Wi)

Where:

Davg = the average particle size, in millimetresWi = the weight of a sieve fraction, in gramsDi = the opening in millimetres that corresponds to the average of the

openings in the two sieves that enclose that mesh fraction (see Table 3)

Calculate the percentage retention of average particle size; adjust to 1 mmoriginal particle size by using the following equation:

% retention / millimetre = (100) 1 −

(original Davg − final Davg)

(original Davg)2

Report the value obtained as the percentage retention of particle size from thestirring abrasion test.

5.2.6.3 Ro-Tap abrasion test. The Ro-Tap abrasion test measures the percent-age retention of original average particle size by the resistance of the particles tothe action of steel balls in the Ro-Tap machine. This test is used to measure abra-sion resistance of bituminous coal and petroleum-coke-based granular activatedcarbons.

5.2.6.3.1 Sieving apparatus—Ro-Tap abrasion test.• Sample splitter—similar to Jones riffler• Ro-Tap—sieve shaker, electrically driven, equipped with automatic timer• Sieves—US standard sieves, 8-in. diameter and 2-in. high• Bottom receiver pan—8-in. diameter, full height• Top sieve cover—8-in. diameter• Balance—top loader with sensitivity of 0.1 g• Brush—soft brass-wire brush5.2.6.3.2 Testing pan assembly. The abrasion pan assembly is detailed in Fig-

ure 3. The assembly consists of a Ro-Tap lid with cork insert, a half-height blankpan, a specially fabricated abrasion testing pan, and a bottom receiver pan. Theabrasion testing pan is detailed in Figure 4. Ten 1⁄2-in. (12.7-mm) diameter and ten3⁄4-in. (19-mm) diameter smooth steel balls will also be required. The steel balls willbe placed in the testing pan together with the carbon sample to be tested for theabrasion test.

10 AWWA B604-96


Cork

Lid

Half-Height Blank Pan

Abrasion Testing Pan

Bottom Receiver Pan

Figure 3 Testing pan assembly for Ro-Tap abrasion test (not to scale)

8 in.

43-in. Radius

Solder1/2 in.

8 in.

14-Gauge Sheet BrassBrown and Sharp Standard

111/16 in.2 in.

3/16 in.5/16 in.

Figure 4 Abrasion testing pan for Ro-Tap abrasion test (not to scale)



5.2.6.3.3 Procedure—Ro-Tap abrasion test. 1. Assemble the sieves to be used on the bottom receiver pan in order of

increasing sieve opening from bottom to top. Suggested sieve sizes to be used withvarious particle-size ranges are given in Table 4.

2. Mix the sample by passing the material through the riffle and recombiningtwice.

3. Carefully reduce the mixed sample by repeated passes through the riffle soas to obtain a test sample of 100 ± 5 g. Do not add to or take from the sample morethan 5.0 g of carbon without additional riffling.

4. Transfer the weighed sample to the top sieve. 5. Install the sieve cover and Ro-Tap cover and place the assembly on the

Ro-Tap sieve shaker. 6. Allow the sieve assembly to shake for 10 min ± 10 s with the hammer

operating. 7. Prepare the abrasion testing pan and count the steel balls to ensure that

ten 1⁄2-in. (12.7-mm) and ten 3⁄4-in. (19-mm) diameter smooth steel balls are con-tained in the pan.

8. Remove the sieve assembly from the Ro-Tap and quantitatively transferthe carbon retained on the top sieve to a tared balance pan. Weigh the carbon to thenearest 0.1 g, then transfer it to the abrasion testing pan. Repeat this procedure formaterial retained on each subsequent sieve and the bottom receiver pan. The mate-rial should be lightly brushed from each sieve to free particles held in the screen.Record the weight of each sieve fraction and the total weight of carbon recovered.

9. After the sieve fractions have been weighed and recombined in the abra-sion testing pan, place the testing pan assembly on the Ro-Tap sieve shaker. Thetesting pan assembly must be level and fit snugly on the Ro-Tap.

10. Allow the testing pan assembly to shake for 20 min ± 2 s with the hammeroperating. The time is critical; if the automatic timer is not capable of the specifiedaccuracy, the sieve shaker should be manually controlled and timed with astopwatch.

11. Remove the abrasion pan from the Ro-Tap and quantitatively transfer thecontents to the original set of sieves. A large-opening sieve may be temporarilynested into the top sieve to remove the steel balls from the carbon, or the balls maybe removed by hand.

12. Repeat steps 5, 6, and 8 using the same Ro-Tap as was used for the initialsieve analysis. However, after this second sieve analysis, discard the individual

Table 4 Recommended particle sieve sizes

Particle-Size Range US Standard Sieve Sizes

8 × 16 8, 12, 16, pan8 × 20 8, 12, 16, 20, pan8 × 30 8, 12, 16, 20, 30, pan

10 × 30 10, 12, 16, 20, 30, pan12 × 40 12, 16, 20, 30, 40, pan14 × 40 14, 16, 20, 30, 40, pan20 × 40 20, 30, 40, pan20 × 50 20, 30, 40, 50, pan

12 AWWA B604-96


screen fractions after weighing. Repeat the analysis if the sum of either sieve analy-sis deviates by more than 2.0 g from the test sample weight.

5.2.6.3.4 Calculations—Ro-Tap abrasion test. (a) Calculate the original and final average particle size by using the follow-

ing equation:

Davg = summation of (Wi × Di)

summation of (Wi)

Where:

Davg = the average particle size, in millimetresWi = the weight of a sieve fraction, in gramsDi = the opening in millimetres that corresponds to the average of the

openings in the two sieves that enclose that mesh fraction

Material caught on the pan is not considered in calculating the average particlediameter. Values for Di are given in Table 5.

(b) Calculate average particle size; example calculation using a 12 × 30 meshmaterial.

US Standard Sieve No. Retainedpercent

Average OpeningDi

mm

Average*

+12 1.5 2.03† 3.012 × 16 25.0 1.44 36.016 × 20 50.0 1.02 51.020 × 30 22.5 0.725 16.3

+30 1.0 0.00 0.0

100.0 106.3 *Weighted.†The 2.03 factor was used for material remaining on the No. 12 sieve because it was assumed that this material would pass

through a No. 8 sieve (generally the next larger sieve in the square root of two series).

Davg = 106.3100.0

= 1.063

(c) Calculate the percentage retention of average particle size by using thefollowing equation:

retention, percentage = final Davg

original Davg × 100

Report the value obtained as the percentage retention of average particle sizefrom the Ro-Tap abrasion test.

5.2.7 Test method for iodine number. The procedure for determining the iodinenumber of activated carbon is ASTM D4607, Standard Test Method for Determina-tion of Iodine Number of Activated Carbon.



5.2.8 Water extractables test. The method used for determining the water ex-tractable content of activated carbon is found in the Food Chemicals Codex proce-dures, under the category of Carbon, Activated.

Sec. 5.3 Rejection

5.3.1 Notice of nonconformance. If the granular activated carbon delivereddoes not meet the requirements of this standard or the purchaser’s specifications, anotice of nonconformance must be provided by the purchaser to the supplier within15 working days* after receipt of the shipment at the point of destination. Theresults of the purchaser’s test shall prevail unless the supplier notifies the pur-chaser within five working days of the notice of nonconformance that a retest isdesired. On receipt of the request for a retest, the purchaser shall forward to thesupplier one of the sealed samples taken according to Sec. 5.1. In the event that theresults obtained by the supplier on retesting do not agree with the test resultsobtained by the purchaser, the other sealed sample shall be forwarded, unopened,for analysis to a referee laboratory agreed upon by both parties. The results of thereferee’s analysis shall be accepted as final.

Table 5 Di values for Ro-Tap abrasion test

US Standard Sieve Numbers Average Opening(Di)mm

6 × 8 2.86 8 × 10 2.18 8 × 12 2.0310 × 12 1.8512 × 14 1.5512 × 16 1.4414 × 16 1.2916 × 20 1.0220 × 30 0.72530 × 40 0.51340 × 50 0.360

14 AWWA B604-96

*If testing for the removal of a specific challenge compound is required by the purchaser’sspecifications, adequate time must be allowed for conformance testing.


SECTION 6: DELIVERY*

Sec. 6.1 Marking

Each shipment of the material shall carry with it some means of identification.6.1.1 Packaged material. Each container of granular activated carbon shall

have marked legibly on it the net weight of the contents, the name of the manufac-turer, the lot number, a brand name, if any, and shall bear other markings as re-quired by applicable regulations and laws.†

6.1.2 Bulk material. When shipped in bulk, the information required inSec. 6.1.1 for packaged material shall accompany the bill of lading.

6.1.3 Conformance with standard (optional). Containers may bear the state-ment: “This material meets the requirements of AWWA B604, Standard for GranularActivated Carbon,” provided that the requirements of this standard are met, and thematerial is not of a different quality in separate agreement between the supplierand the purchaser.

Sec. 6.2 Packaging and Shipping

6.2.1 Containers. Granular activated carbon shall be shipped in packages ac-ceptable to the US Department of Transportation (USDOT). Individual paper bagsshall contain from 35 lb (16 kg) to 150 lb (68 kg) each and semibulk containers shallcontain 800 lb (363 kg) to 2,000 lb (908 kg), or other quantity as agreed upon by thepurchaser and supplier.

6.2.2 Package shipments. Paper bag packages used in shipments of activatedcarbon in less than carload lots shall be protected by an outer package of a resistantnature, to avoid tearing the bags. Complete protection from weather shall be pro-vided for the individual packages or by the conveyance.

6.2.3 Tolerances. The net dry weight of the packages shall not deviate fromthe recorded weight by more than ± 5 percent. Objections to the weight of the mate-rial received shall be based on a certified unit weight of not less than 10 percent ofthe packages shipped, which are selected at random from the entire shipment.

6.2.4 Bulk shipments. Bulk shipments of activated carbon shall be in cleancars or trucks with tight closures to avoid loss and contamination of the material intransit. The interior of the cars or trucks shall be clean and free from dirt, corrosion-scale, and other sources of contamination. Shipments in open-top hopper bottomcars are acceptable only with adequate provisions for covering the material andkeeping it contained and protected during shipment. The type of railcar or hoppertruck shall be agreed on by the supplier and the purchaser before shipment. Thecriteria for choosing a car or truck are the type of handling equipment and theunloading facilities at the destination. Caution is advised in unloading bulk contain-ers since particle stratification may occur during shipment. If the entire bulk ship-ment is used to fill a single contactor or filter, no special precautions are required.


*Governmental marking, packaging, and shipping references reflect US requirements.Users of AWWA B604 in Canada, Mexico, and non-North American countries should verifyapplicable local and national regulatory requirements.

†Because of frequent changes in these regulations, their specific provisions should not beincluded in the purchaser’s specifications.


Where the bulk shipment will be divided between or among contactors or filters,different bays should be used to fill the various units or GAC additions should berotated among various contactors or filters.

6.2.5 Weight certification (bulk). Bulk shipments shall be accompanied byweight certificates of certified weighers, if specified by the purchaser, or the weightsmay be checked by certified weighers for the purchaser on delivery.

Sec. 6.3 Affidavit of Compliance

When requested by the purchaser, the supplier shall provide an affidavit ofcompliance stating that the activated carbon furnished complies with the applicableprovisions of this standard and the purchaser’s specifications.

SECTION 7: PLACING GAC FILTER MATERIAL

Sec. 7.1 Preparation

7.1.1 Cleaning. Each filter cell shall be cleaned thoroughly before any filtermaterials are placed. Each cell shall be kept clean throughout placement operations.

7.1.2 Marking each layer. Before any materials are placed, the top elevation ofeach layer shall be marked by a level line on the inside of the filter cell.

7.1.3 Storage and handling of materials. Filter materials shall be kept clean.Bulk materials shall be stored on a clean, hard, dry surface and covered to preventcontamination during storage. Materials shipped in bags or semibulk containersshall be covered with a durable, opaque material to block sunlight and provide pro-tection from weather. Bags and semibulk containers shall be stored separately.When materials are shipped in bags or semibulk containers, under no circumstancesshall the material be removed from the bags or semibulk containers prior to place-ment in the filter, except for sampling.

Sec. 7.2 Placement of Support Media

7.2.1 Caution in installing material. The bottom layer of gravel shall be care-fully placed to avoid damage to the filter underdrain system. For materials smallerthan 1⁄2 in., workers shall not stand or walk directly on the gravel but shall walk onboards or plywood that will support their weight without displacing the material.

7.2.2 Placement of layers. Each layer shall be completed before beginningplacement of the layer above. Each layer of filter material shall be deposited in auniform thickness, with the top surface screeded and brought to a true level planeusing backwash water. Care shall be exercised in placing each layer to avoid dis-turbing the surface of the layer beneath.

7.2.3 Alternate material placement. Bulk materials may be placed dry by us-ing a chute or conveyor to discharge the materials onto a platform, from which theymay be distributed with a hand shovel. Alternatively, bulk materials may be placedhydraulically by pump or ejector.

For filter sand placed using the wet method, the materials shall be addedthrough the water and then backwashed for leveling.

7.2.4 Placement of materials from bags or semibulk containers. When filtermaterial is shipped in bags or semibulk containers and hydraulic placement is notused, the bags or semibulk containers shall be placed in the filter and the materialdistributed directly from them. To provide for initial expansion of the bed due to

16 AWWA B604-96


segregation of particle sizes, the elevation of the top surface, before the initial wash-ing, shall be approximately 10 percent of the final bed thickness below the finishelevation.

7.2.5 Layer elevation. The elevation of the top surface of each layer shall bechecked by filling the filter with water to the level line previously marked on theinside of the filter cell (Sec. 4.4.1.2).

7.2.6 Washing gravel layer. After all filter gravel is placed, and before anyfilter sand and GAC are placed, the filter should be washed for 5 min at the maxi-mum available rate, not to exceed 25 gpm/ft2 of filter area. This step may be elimi-nated if fines or contaminants are not apparent to the purchaser. Any gravel thatbecomes intermixed after placement with another material or size shall be removedand replaced with clean material of the proper type and size.

7.2.7 Washing other material. With a dual- or multiple-media filter bed, eachfilter material shall be washed and scraped or skimmed as deemed necessary toremove excess fine materials before the next material is installed.

7.2.8 Disinfection of filter. Prior to installation of GAC, the filter shall be dis-infected with chlorine according to ANSI/AWWA C653 or as otherwise specified. Dis-infection shall be performed after the filter underdrain has been added and thesupport gravel and sand have been added and leveled.

Sec. 7.3 Placement of GAC

7.3.1 Slurry transport. To avoid dust in the filter area, it is recommended thatall GAC be added hydraulically through an eductor, slurry pump, blow case, or di-rectly from specially built bulk trucks. Where bags, bulk boxes, or other bulk con-tainers are used, the construction of an eduction system is recommended. Althoughthe volatiles have been removed from the GAC during the activation step and thecarbon dust is not an explosive hazard, it is a nuisance dust and should be pre-vented or precluded by a slurry addition. This will also provide an opportunity forthe GAC to become wetted. Since GAC is filled with internal pores, it is vitallyimportant for it to become thoroughly wetted before backwashing to prevent theundue loss of materials.

7.3.2 Placing GAC. The filter box should be filled with water prior to addingcarbon. The water level should be approximately one-third of the GAC filter mediumvolume. In filling the filter box with GAC, care should be taken to avoid disruptionof the supporting gravel or sand layer. The GAC slurry delivery hose should bedirected to various locations in the filter to provide as uniform a distribution aspossible. If the delivery is made in large bulk trucks, it is also advisable to rotatethe addition of carbon among filters to avoid any differences in particle size thatmay result from the stratification of the media during transport. Any graded mediacan stratify during bulk transport and care must be taken to ensure that the mate-rials placed in the filter beds are uniform.

GAC should be added to the filter box to bring the carbon level to approxi-mately 85 percent of the final volume. A permanent expansion of approximately15 percent will occur as the GAC medium is backwashed due to stratification of thebed. Since the uniformity coefficient of GAC is typically larger than that of sand oranthracite, the permanent expansion will be greater. The actual amount of the per-manent expansion will depend on the uniformity of the GAC, the effectiveness of thebackwash system, and the control of the backwash sequence.

7.3.3 Backwashing and leveling. After placing GAC into the filter box to pro-vide approximately 85 percent of the filter volume, the carbon should be leveled by



backwashing. If the carbon was added via a slurry transport system, backwashingmay be accomplished at a controlled rate within 4 hours. If the carbon was placeddry, the bed should be allowed to set for approximately 24 hours in a completelysubmerged condition to allow the carbon pores to fill with water. Otherwise, thereduced density of the GAC due to air in the pores may result in excessive backwashlosses.

After ensuring that the GAC is completely wetted, it should be backwashed ata reduced rate (<5 gpm/ft2) to remove the carbon fines. As the fines are removed andthe granular medium is clearly visible, the backwash rate should be increased toprovide at least 30 percent expansion for approximately 10 min to allow the GACbed to thoroughly stratify by particle size. The bed should be backwashed twice toensure that the particles are completely stratified. The bed level should then benoted and additional carbon added with subsequent backwashing to reach the finaldesired level. Bags of GAC can be added to control the final fill elevation. Careshould be taken to avoid overfilling the filter. The removal of material from the topof a GAC bed to achieve the final depth will remove the top layer and change theparticle size distribution in the filter. Neither air backwash nor surface sweepsshould be operated during this filling procedure. The backwash curves provided bythe supplier should be used as guidance, if available.

Sec. 7.4 Top Surface Elevation

GAC should be added with periodic backwashing until the final surface eleva-tion is achieved after a normal backwash cycle and the bed is allowed to settle. Itshould be noted that any graded filter media, including GAC, will compact duringthe filtration cycle causing the surface elevation to be reduced. The surface of GACshould not be scraped.

Sec. 7.5 Contamination

Granular activated carbon is manufactured at high temperatures and packagedor stored directly following production. Therefore, it should be free from contamina-tion and care should be exercised to ensure that it does not become contaminatedduring transport, filling, or the backwash process. Should contamination occur, thecontaminated materials should be removed and replaced with virgin GAC.

SECTION 8: PREPARATION OF FILTER FOR SERVICE

Sec. 8.1 Backwashing

8.1.1 Backwash controls. Since GAC serves as both a filter medium and ad-sorbent in filtration systems, it is imperative that an effective backwash system bein place. This should include a backwash control system that gradually increases thebackwash rate to provide for the expulsion of entrapped air and ensures that thefilter expands from the top downward. Surface sweeps and air backwash systemsshould be turned off before backwash water reaches the overflow trough to avoidloss of GAC. Air scour should be turned off as the water level reaches the bottom ofthe trough to allow air to be purged prior to overflow. To promote stratification ofthe GAC bed, improve adsorption efficiency, and reduce cost, the backwash rateshould be decreased gradually over a period of 3 min to 5 min at the end of the

18 AWWA B604-96


backwash cycle. The backwash rate can be calibrated by comparing the rise rate inthe filter box with the recorded flow rate.

8.1.2 Backwash procedures. When the GAC filter is initially placed in service,or after it has been idle, it should be backwashed before being placed in operation.The water level in filters should be maintained above the GAC level when the filtersare out of service to prevent oxygen adsorption, and new carbon beds should beflooded to ensure wetting for 24 h unless the carbon has just been hydraulicallytransported. The backwash shall then be commenced at an initial flow rate not toexceed 5 gpm/ft2. The flow rate should be gradually increased to provide the desiredexpansion.

8.1.3 Backwash rate. During each backwash, the water shall be applied in anupward direction at an initial rate not to exceed 5 gpm/ft2. The upflow rate shouldthen be increased gradually over a period of several minutes until the desired ex-pansion is achieved. The expansion and backwash rate should be based on themanufacturer’s recommendations and the backwash rate should be adjusted to com-pensate for changes in temperature. The density and viscosity of water can have asignificant influence on the expansion properties of GAC and carbon losses becauseboth vary with temperature. Surface sweeps and air washes should be turned offbefore the backwash water begins to flow over the wash water trough to preventGAC losses.

8.1.4 GAC filter bed stratification. Since the maintenance of a stratified bedand adsorption wave front is vital to providing an efficient adsorption process andreducing operating costs, the backwash flow should always be turned off gradually.This will promote stratification and adsorption efficiency. Quick opening or quickclosing valves should not be used on any granular media filter, including GAC ad-sorption systems.

Sec. 8.2 Scraping

GAC filters should not be scraped because (1) the fines will be removed duringthe extended backwash period; (2) the materials as manufactured are clean, andsince GAC cannot be disinfected with chlorine, it is advisable to not risk contamina-tion by working on the surface; (3) GAC is friable, and movement on the surface cangenerate more fines while fines are being removed. However, should undue head lossdevelop as a result of fines, the filters can be scraped to restore capacity.

Sec. 8.3 Disinfection

Chlorine will be rapidly removed by the GAC through an oxidation-reductionreaction. Thus, a residual chlorine concentration cannot be provided throughout thefilter. Disinfection is not effective and should not be practiced. However, backwash-ing with a chlorinated backwash water will assist in controlling biological growth,but will not completely disinfect the filter. Microbial testing of the filter should beconducted before placing the filter in service.

Sec. 8.4 Cleaning

GAC systems will remove dirt and debris similar to other filter media andmust be periodically cleaned. This can be accomplished by backwashing the GACbed with water or an air–water wash. The particle density of GAC is appreciablyless than sand so care must be exercised during the backwash procedure. In addi-tion, the water backwash should be slowly increased when initiating the backwashto prevent the carbon from rising as a plug and should be turned off slowly at the



conclusion of the backwash cycle to promote GAC bed stratification, improve theadsorption process, and reduce operating costs.

Sec. 8.5 Safety

8.5.1 Fire. Although activated carbon is not an explosive hazard, it does burnand will react with strong oxidizing agents. Therefore, it should be stored away fromoxidizing agents and potential sources of heat and ignition.

8.5.2 Oxygen depletion. Wet granular activated carbon will rapidly adsorboxygen and create an oxygen-deficient condition. Idle filters should be covered withwater and workers should follow all safety precautions when entering enclosedspaces containing wet activated carbon.

8.5.3 Proper disposal. The only two spent granular activated carbons specifi-cally listed as hazardous are those GACs used in the treatment of munitions wasteand those used in veterinary medicines. However, any spent GAC can be hazardousif it meets certain criteria under the Toxic Substance Control Act (TSCA). Therefore,the user should refer to TSCA, Resource Conservation and Recovery Act (RCRA) andthe latest edition of other applicable state, provincial, and federal laws before dis-posing of any spent granular activated carbons. Manufacturers will often acceptspent GAC for regeneration and reuse.

20 AWWA B604-96


APPENDIX ABibliography

This appendix is for information only and is not a part of AWWA B604.

ASCE & AWWA. 1990. Water Treatment Plant Design. 2nd ed. New York, N.Y.: McGraw-HillBook Company.

Carpenter, F.G. 1957. Development of a New Test for the Abrasion Hardness of Bone Char.Proc. 5th Tech. Sess. Bone Char. National Bureau of Standards Supplement to Miscella-neous Publication 240 (Apr. 3, 1967).

Cheremisinoff, P.N., and F. Ellerbusch. 1978. Carbon Adsorption Handbook. Ann Arbor, Mich.:Ann Arbor Sci. Publ. Inc.

Clark, R.M. 1987. Modeling TOC Removal by GAC. The General Logistic Function. Jour.AWWA, 79:33–37.

Coughlin, R.W., and F.S. Ezra. 1968. Role of Surface Acidity in the Adsorption of OrganicPollutants on the Surface of Carbon. Enviro. Sci. Technol., 2:4:291–297.

Crittenden, J.C., D.W. Hand, H. Arora, and B.W. Lykins Jr. 1987. Design Considerations forGAC Treatment of Organic Chemicals. Jour. AWWA, 79:1:74–82.

Crittenden, J.C., P.J. Luft, D.W. Hand, and G. Friedman. 1987. Prediction of Fixed-Bed Adsor-ber Removal of Organics in Unknown Mixtures. Jour. Envir. Engrg. Div., ASCE,113:3:486–498.

Crittenden, J.C., et al. 1989. Prediction of GAC Performance Using Rapid Small Scale Col-umn Tests. Denver, Colo.: AWWA Research Foundation and AWWA.

1989. Design and Use of Granular Activated Carbon—Practical Aspects, Proceedings. AWWAResearch Foundation. Proc. AWWA Annual Conference.

Dobbs, R.A., and J.M. Cohen. 1980. Carbon Adsorption Isotherms for Toxic Organics. EPARpt. EPA—600/8-80-023. Cincinnati, Ohio: USEPA.

———. 1983. Treatments of Organic Compounds in Drinking Water. EPA Rpt. EPA—600/8-83-019. Cincinnati, Ohio: USEPA.

National Academy of Sciences. 1988. Food Chemicals Codex. Washington, D.C.: Com. on Speci-fications, Food Chemicals Codex; Com. on Food Protection, Nat. Res. Council. Nat. Acad.Press.

Grase, L.S., V.L. Snoeyink, and R.G. Lee. 1987. GAC Filter Adsorbers. Denver, Colo.: AWWAResearch Foundation and AWWA.

Hashimoto, K., K. Miura, F. Yoshikawa, and I. Imai. 1979. Change in Pore Structure of Carbo-naceous Materials During Activation and Adsorption Performance of Activated Carbon.Ind. Engrg. Chem. Process Dec. Dev., 18:1:72–80.

Hassler, J.W. 1967. Activated Carbon. London: Leonard Hill.

———. 1963. Activated Carbon. New York, N.Y.: Chem. Publ. Co.

———. 1941. The History of Taste and Odor Control. Jour. AWWA, 33:2124–2152.

Herzing, D.R., V.L. Snoeyink, and N.F. Wood. 1977. Activated Carbon Adsorption of the Odor-ous Compounds 2-Methylisoborneol and Geosmin. Jour. AWWA, 69:4:223–228.

Mallevialle, J., ed. 1987. Identification and Treatment of Taste and Odor in Drinking Water.Denver, Colo.: AWWA Research Foundation and AWWA.

21


Juhola, A.J. 1977. Manufacture, Pore Structure and Application of Activated Carbons Part 1.Kemia-Kemi, 11:543–551.

———. 1975. Iodine Adsorption and Structure of Activated Carbons. Carbon, 13:437–442.

Juntgen, H. 1976a. Manufacture and Properties of Activated Carbon. In: Translation of Re-ports on Special Problems of Water Technology, EPA Rpt. EPA—600/9-76-030, Ofce. Res.Devel. Cincinnati, Ohio: USEPA.

Kim, B.R., and V.L. Snoeyink. 1980a. The Monochloramine-Activated Carbon Reaction: AMathematical Model Solved Using the Orthogonal Collocation Method on Finite Ele-ments. In: Activated Carbon Adsorption of Organics from the Aqueous Phase, Vol. 1. I.H.Suffet and M.J. McGuire, eds. Ann Arbor, Mich.: Ann Arbor Sci. Publ. Inc.

———. 1980b. The Monochloramine-GAC Reaction in Adsorption Systems. Jour. AWWA,72:488.

Kim, B.R., V.L. Snoeyink, and R.A. Schmitz. 1978a. Removal of Dichloramine and Ammoniaby Granular Carbon. Jour. Wtr. Pollution Control Federation, 50:122–133.

KIWA–AWWARF. 1983. Activated Carbon in Drinking Water Technology. Denver, Colo.: AWWAResearch Foundation.

Mantell, C.L. 1951. Adsorption. New York, N.Y.: McGraw-Hill Book Company.

McGuire, M.J. 1977. The Optimization of Water Treatment Unit Processes for Removal ofTrace Organic Compounds with an Emphasis on the Adsorption Mechanism. Ph.D. the-sis. Philadelphia, Pa.: Drexel University.

McGuire, M.J., and I.H. Suffet. 1980. Activated Carbon Adsorption of Organics From theAqueous Phase. 2 vols. Ann Arbor, Mich.: Ann Arbor Sci. Publ. Inc.

———. 1983. Treatment of Water by Granular Activated Carbon. Advances in ChemistrySeries, no. 202. Washington, D.C.: American Chemical Society.

Malaiyandi, M., ed. 1987. Organic Pollutants in Water: Sampling, Analysis and Toxicity Test-ing. Advances in Chemistry Series, no. 214. Washington, D.C.: American Chemical Soci-ety.

Robeck, G.G., K.A. Dostal, J.M. Cohen, and J.F. Kreissl. 1965. Effectiveness of Water Treat-ment Processes in Pesticide Removal. Jour. AWWA, 57:2:181–200.

Snoeyink, V.L., and M.T. Suidan. 1975. Dechlorination by Activated Carbon and Other Reduc-ing Agents. In: Disinfection of Water and Wastewater, J.D. Johnson, ed. Ann Arbor, Mich.:Ann Arbor Sci. Publ. Inc.

Suidan, M.T., K.A. Chacey, and W.H. Cross. 1978. Pulsating Bed Activated Carbon Dechlorina-tion, Jour. Envir. Engrg. Div., ASCE, 104:1223.

Suidan, M.T., V.L. Snoeyink, and R.A. Schmitz. 1977a. Reduction of Aqueous Free ChlorineWith Granular Activated Carbon—pH and Temperature Effects. Envir. Sci. Technol.,11:785.

———. 1977b. Reduction of Aqueous HOCl With Activated Carbon. Jour. Envir. Engrg. Div.,ASCE, 103:677.

Summers, R.S., F. Fuchs, and H. Sontheimer. 1988b. The Fate and Removal of RadioactiveIodine in the Aquatic Environment. In: Influences of Aquatic Humic Substances on Fateand Treatment of Pollutants. P. MacCarthy and I.H. Suffet, eds. Advances in ChemistrySeries no. 219. Washington, D.C.: American Chemical Society.

Summers, R.S. 1986. Activated Carbon Adsorption of Humic Substances: Effect of MolecularSize and Heterodispersity. Ph.D. dissertation. Stanford, Calif.: Dept. of Civil Engineer-ing, Stanford University.

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Summers, R.S., et al. 1992. Standardized Protocol for the Evaluation of GAC. Denver, Colo.:AWWA Research Foundation and AWWA.

Weber, W.J. Jr. 1972. Physiochemical Processes for Water Quality Control. New York, N.Y.:Wiley Inter-Science.

White, G.C. 1972. Handbook of Chlorination. Cincinnati, Ohio: Van Nostrand Reinhold Co.



APPENDIX BAdsorptive Capacity Tests

This appendix is for information only and is not a part of AWWA B604.

These tests were added because they are referred to in Sec. II.D, AdsorptiveCapacity, of the foreword, and can aid in the analysis of granular carbon used forwater treatment.

SECTION B.1 TANNIN ADSORPTION TEST

Sec. B.1.1 Stock Tannic Acid Solution—500 mg/L

Dissolve exactly 1.0 g of NF-grade tannic acid in distilled water and dilute to2 L in a volumetric flask. Use tannic acid similar to Merck & Company, NF catalognumber 04541 or equivalent.

Sec. B.1.2 Test Procedure

A piece of 0.75-in. (19-mm) inside diameter (ID) tubing* (glass or acrylic) ap-proximately 7-in. (175-mm) long is fitted at the bottom with a one-hole rubber stop-per, a short piece of rubber tubing, and an adjustable hose clamp. A piece of 80-meshscreen is used in the bottom of the tube to support the carbon. The tube is markedto indicate a carbon volume of 32 mL. A weighed amount of granular carbon isadded to the tube to approximately the 32-mL mark, then gently washed upflow toremove any fines. If needed, additional carbon is added to the 32-mL mark, and thecolumn is backwashed again. After backwashing, the water level is allowed to fill tothe top of the carbon bed. Care should be taken so the carbon in the column iscompletely submerged at all times; otherwise, channeling will occur through thecenter of the bed.

One litre of 500-mg/L tannic acid solution is passed downflow through the col-umn at the rate of 15 mL/min (assuming 0.75-in. [19-mm] tubing is used), and theentire effluent is collected in a receiving flask. If a suitable pump is not available,the tannic acid solution can be fed from a separatory funnel held above the columnby adjusting the stopcock to give a flow of 15 mL/min.

The effluent is mixed and the concentration of tannin remaining is determinedby either ultraviolet (UV) absorbance at 275 mµm by evaporation of a portion of themixed filtrate or by the standard AWWA color method (see Sec. B.1.3.3) for the tan-nin analysis.

Sec. B.1.3 Determination of Tannin in Effluent

B.1.3.1 UV absorbance. A sample of mixed effluent and of the original500-mg/L tannin feed is read on a UV spectrophotometer at 275 mµm (maximumabsorbance peak). Samples are diluted with distilled water until a direct instrument

25

*A larger diameter tube can be used with appropriate adjustments of carbon volume, flowrate, and total volume of tannic acid solution used.


scale reading can be obtained and corrected for dilution. A standard curve is pre-pared by diluting the 500-mg/L tannin feed as follows in Table B.1.

The optical density of each dilution given in Table B.1 at 275 mµm is plottedagainst milligrams per litre tannin. From the standard curve, the milligrams perlitre tannin in each effluent sample is determined.

Calculation:

percentage tannin adsorbed = 100 1 −

effluent tannin (in milligrams per litre)influent tannin (in milligrams per litre)

weight tannin adsorbed (in grams)100 g carbon

= percentage tannin adsorbed × 5 g × litres used

weight carbon in column (in grams) × 100

B.1.3.2 Evaporation of mixed effluent. Exactly 200 g of mixed effluent and a200-g feed sample are evaporated in a 100°C convection oven to dryness and eachresidue is weighed on an analytical balance to the nearest milligram.

Calculation:

percentage tannin adsorbed = 100 1 −

effluent residue (in grams)influent residue (in grams)

weight tannin adsorbed (in grams)100 g carbon

= percentage tannin adsorbed × 5 g × litres used


B.1.3.3 AWWA-APHA-WPCF method. The residual mg/L tannin is determinedcolorimetrically for the mixed effluent and feed using the AWWA-APHA-WPCFmethod for tannin and lignin. Reagents and apparatus required are given in methodnumber 5550, Standard Methods for the Examination of Water and Wastewater.*

Calculations are made in the same manner as previously described.

SECTION B.2 PHENOL ADSORPTION TEST

Sec. B.2.1 Reagents

a. Stock phenol solution—5,000 mg/L. Dissolve 5.0 g of reagent-grade phenolin distilled water and dilute to 1 L. Phenol should be weighed in a glass weighingdish. Rinse the dish several times with distilled water to ensure the transfer of allphenol from the dish into the solution. Standardize the solution. If the concentrationof phenol is more than ± 200 mg/L, either dilute with distilled water or add more

26 AWWA B604-96

*Standard Methods for the Examination of Water and Wastewater, APHA, AWWA, WPCF,Denver (17th ed., 1989).


phenol to get the desired concentration. After two weeks, this solution should bediscarded and fresh solution prepared. (Reagent-grade phenol should be stored in arefrigerator.)

b. Sodium thiosulfate solution—0.1N. Dissolve 25 g of reagent-grade sodiumthiosulfate and 1.0 g of reagent-grade sodium carbonate (as a preservative) in boileddistilled water and make up to 1 L. Store in a brown bottle. Standardize thesolution.

c. Potassium bromate–bromide solution—0.1N. Dissolve 2.784 g of reagent-grade potassium bromate and 10.0 g of reagent-grade potassium bromide (bromate-free) in distilled water and make up to 1 L. Store in a brown bottle.

d. Potassium biniodate solution—0.1N. Dissolve 3.2499 g of potassium binio-date, primary standard, in distilled water and make up to 1 L.

e. Potassium iodide solution—12.5 percent. Dissolve 25 g of reagent-grade po-tassium iodide in 175 mL of distilled water. Store in a brown bottle. (Discard whenit develops a yellow color.)

f. Starch solution. Dissolve 5.0 g of soluble potato powder starch and 1.25 g ofreagent-grade salicylic acid in 50 mL of distilled water. Add the dissolved starch andsalicylic acid slowly, while stirring, to 950 mL of boiling distilled water. Rinse thebeaker with some of the hot starch solution to ensure removal of all the starch.

Sec. B.2.2 Standardization of Reagents

a. Sodium thiosulfate solution. Add 100 mL of distilled water; 4 mL of con-centrated, reagent-grade hydrochloric acid; and 8 mL of 12.5 percent potassium io-dide solution to a 500-mL iodine flask and mix. Rinse down sides of the flask withdistilled water. Using a transfer pipette, add 25 mL of 0.1N potassium biniodatesolution to the flask. Mix and allow to stand for 3 min. Titrate with the 0.1N sodiumthiosulfate solution using starch solution as the indicator.

Calculation:

phenol concentration (in grams per litre)

= (millilitres bromate−bromide × NF) (millilitres thiosulfate × NF)

millilitres phenol solution titrated × 15.685

Table B.1 Standard curve of tannin dilution

Tanninmg/L

500 mg/LTannin

mLDistilled Water

mL

5 1 9925 5 9550 10 90

100 20 80200 40 60300 60 40400 80 20



b. Stock phenol solution. Pipette 25 mL of stock phenol solution into a 500-mL iodine flask and add 15 mL of concentrated, reagent-grade hydrochloric acid.Titrate with the potassium bromate–bromide solution to a slight yellow color. (For5,000 mg/L phenol concentration, it will require approximately 80 mL–90 mL of so-lution to produce the yellow color.) Shake the flask and allow it to stand for 3 min.Add 8 mL of 12.5 percent potassium iodide solution, shake, and allow it to stand for3 min. Titrate the liberated iodine with the standardized 0.1N sodium thiosulfatesolution, using the starch solution as indicator.

Calculation:

normality sodium thiosulfate solution

= millilitres potassium biniodate × NF biniodate

millilitres sodium thiosulfate solution used

Sec. B.2.3 Test Procedure

a. Phenol adsorption. A piece of 0.75-in. (19-mm) ID tubing (glass or acrylic)about 7-in. (175-mm) long is fitted at the bottom with a one-hole rubber stopper, ashort piece of rubber tubing, and an adjustable hose clamp. A piece of 80-meshscreen is used in the bottom of the tube to support the carbon. The tube is markedat such a height as to indicate a carbon volume of 32 mL. The granular carbon isadded to the tube to about the 32-mL mark, then gently washed upflow to removeany fines. If needed, additional carbon is added to the 32-mL mark, and the columnis backwashed again. After backwashing, the water level is allowed to fall to the topof the carbon bed.

One litre of phenol solution at 5,000 mg/L is passed downflow through thecolumn at the rate of 15 mL/min, and the entire effluent is collected in a receivingflask.

The effluent is mixed and the concentration of phenol determined. b. Determination of phenol in effluent. A 25-mL aliquot of the mixed effluent

is placed in a 500-mL iodine flask. The same procedure and calculation used todetermine the concentration of the stock solution in B.2.2(b) is used to determinethe phenol in effluent.

Calculation:

percentage phenol adsorbed

= 100 1 −

effluent phenol (in milligrams per litre)influent phenol (in milligrams per litre)

weight phenol adsorbed (in grams)100 g carbon

= percentage phenol adsorbed × 5 g × litres used


28 AWWA B604-96


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