Registration  Division
      Office of Pesticide  Programs
    Criteria and Standard!  Division
        Offics of Drinking Water

           Report of Task Fore*
          SubBittsd April, 1986
           Revised April, 198?

PREFACE . . . . . . . . . . . . . . . . . . . . . a . • . 1
S ’tZON 1 : GENERAL . . . . . . . . . , , • • • • • • • • 2
TEST PROC . ES . . . . . . . . . . . . . . . . . a a 8
TESTWATERPARAIIETER$ ................ 22
PUBLIC COMMENTS a a • . . a a a a • . . a a a a a 31


     The tails force began deliberations in July,  1984 and submitted its
initial report in April,  1986.  The  task force included a broad multi-
disciplinary group of  experts representing the interest areas of academic
and governmental- research,  product evaluation, development and testing,
manufacturer's product registration, and governmental enforcement.

     The report was provided for public comment*  in May, 1986.  A review
subcommittee -as constituted to prepare a response to the public comments
and to revise the report,  as herewith  submitted.  Additional  revision  has
been provided in response to review  by the Scientific Advisory  Panel
(Federal Insecticide,  Fungicide, and Rodenticide  Act).

     The recommended guide standard  and  testing protocol was  developed to
be useful in a number of ways,  not only  for  governmental but also  for
industrial and consumer purposes*

     as a basic framework, starting  point for the testing and evaluation
     of microbiological water purifiers  for EPA registration*

     as a guide to the acceptance of water treataent unit* for compliance
     with Safe Drinking water Act requirements where point of use units
     nay be needed temporarily to treat a contaminated public water
     supply or for emergency situations, but not for use in extreme
     overseas situations or for the conversion of waste water to micro-
     biologically potable water*

     as a testing guide to  manufacturers wishing to have their unit*
     considered as microbiological  water purifiers, whether  registered or
     not, and for  the evaluation of such testing.data;

     as a guide to consumer* regarding what  they can expect  from  micro-
     biological water purifiers tested according to  this  standard and

     to assist  in th«  research and  development of microbiological treat-
     ment units"for possible military applications.

      I want to  thank  the expert members of  the task force for their
participation in this  work and particularly the  chairmen of three work
groups >

          Charles Gerbai   Microbiological Challenge*
           Richard Tobint   Physical, Chemical and Operational Challenges
           Prank A. Bell,  Jr.i   Testing Protocol

                                  Stephen A. Schaub, Ph.D.
                                  U.S. Army  Medical  Bioengineering
                                  Research and Development laboratory

1.1 Introduction
The subject of microbiological purification for waters of unknown
microbiological quality repeatedly presents itself to a variety of
governmental and non—governmental agencies, consumer groups, manufac-
turers and others. Examples of possible application of such purification
capabilities include:
- backpackers and campers
- non—standard military requiraments
— floods and other natural disasters
— foreign travel and stations (however, not for extreme
contamination situations outaid. of the U.S.)
— contaminated individual sources, wells and springs
(however, not for th. conversion of waste water to
aicrobiologically potable water)
— motorhomes and trailers
Batch methods of water purification based on chlorine and iodine
disinfection or boiling are well known, b t many situations and personal
choice call, for the consideration of water treatment equipment. Pederal.
agencies specifically involvd in responding to questions and problems
relating to microbiological purifier equipment include:
Registration Division, Of tic. of Pesticide Programs (OPP),
Environmental Protection Agency (DA) z r.qistration of microbiological
purifiers (using Chemicals);
Compliance Monitoring Staff, As control of microbiological
purifier device claims (non-registerable products such as ultra-
violet units, ceonators, chlorin, generators,. others)
US. Army Medical Bioengineerinq Research and Development L.thc-
ratory (IJ$A1IBPDL), U.S. Army latick Research and Development Center
and othsr Army and military agencies: research and development ‘or
possible field applications,
Criteria and Standards Division, Office of Drinking Water (OUW),
EPA: Consideration of point-of—use technology as acceptable t.chnoioqy
under the Primary Drinking Water Regulations, consi er infersmticn
and service;
Drinking Water Research, Water Engineering Research Laboratory
(W L), k , responsible for water treatment technology research;

Microbiology Branch, Health Effects Research Laboratory (HERL),
EP7 ; r.sporsibl. for study of h•alth .ff.cts related to drinking
water fi lt.ri.
A nu tb.r of representatiVes of th. above mentioned agencies ptovided
.xceli•nt participation in the task force to develop microbiological testing
protocols for water purifiers. Major participation was also provided by
the folloViflgz
— a technical representative from the Water Quality Association;
- a technical representative from the Environmental Health Center,
Department of Health and Welfare of Canada: and
- an associate professor (microbicl.ogy) from the University of
1.2 Basic Principles
1.2.1 •Definition As set forth in EPA Enforcement Strategy and as
supported by a Federal Trade Commission (FTC) decision (FTC v. Sibco
Products Co., Inc., •t ii., Nov. 22, 196S),, a unit, inorder to be
called a microbiologicarvatex purifier, must remove kill or inacti-
vate all types of disease-causing microorganisms from the water,
including bacteria, viruses and protozoan cysts so as to render the
processed water safe for drinking. Therefore, to qualify. a micro-
biological water purifier must treat or remove all types of challenge
organisms to meet specified standards.
1.2.2 General Guidet The standard and protocol will be a general
quid . and in some cases, may present only the minimum features and
framework for testing. While basic features of the standard and
protocol have been tested it ves not feasible to conduct full-
fledged testing for all possible types of units. Consequently.
protocol users should include pre-t.sting of their units in a
tasting rig, inclndl’ q th. sampling techniques to be used. Where
users of the protocol find good reason to altar or add to the guide
in order to meet specific operational problems. to use an alt.Z!nste
organi er laboratory procedure, or to respond to innovative
trua’t unit. without decreasing th. level of testing or al erin
the intent of the protocol, they should feel free to do so. For
example, the OPP Bagistration Division might find it necessary to
amend the çaid. somewhat for different types of. treatment units.
Mother example would be ultraviolet (U.V.) units, which may have
spIcific requirements in addition to the guid. protocol.
1.2.3 Pert oraance—B.sad : The standard will be perforaaricebs$•d.
utilizing realistic worst case challenges and test conditions and
shall result in water quality equivalent to that of a public water
supply meeting the microbiological r.quireaiflts and intent of the
National Primary Drinking Water Regulations.

A aicrãbioloqical water purifier must remove, kill
Or inactivate all types of pathogenic organisms if claims are made
for any organism. However, an exception for limited claims may be
allowed for unitsrepoving specific organisms to serve a 4sf inabis
environmental need (i.e., cyst reduction units which can be used on
otherwise d .sinf.cted and microbiologically safe drinking water,
such as a disinfected but unfilter.d surfac. water containing cysts.
Such u.rtits are ‘tot to be called microbiological water purifiers and
should not be used as sole treatment for an untreated raw water.)
1 .25 Not to Cover Non-Microbioloqical Reduction Claims : The treat
ment of water to achieve specific chemical removal from water or
other non-microbiolOgical claims will. not be a part of this standard.
National Sanitation Foundation (NSF) Standards 42 (Aesthetic Effects)
and 53 (Health Effects) provide partial guides for chemical removal
and. other claims testing.
1.2.6 Construction and tnforaatienal Exclusions : While the standard
recommends safe, responsible construction of units with non—toxic
materials for optimum operation, all such items and associated opera-
tional considerations are excluded as being beyond the scope of the
standard. Included in the exclusion are materials of constuction,
electrical and safety aspects, design and construction details,
operational instructions and information. and mechanical pert ermance
I • 2 • 7 R.s.arch Needs Excluded : The guide standard and protocol must
represent a practical testing program and not include research rscoa
mendations. For exa.ple consideration of mutant organisms or
differentiatiOfl between injured and dead organisms would be research
items at this time and not appropriate for inclusion in the standard.
1.2.8 Net To Consider Sabotages Isotaric problems which could be pr.-
ssnted by a variety of hypothetical terrorist (or wartime) situations,
would provide an unnecessary complication. and are net appropriate
for inclusion in the standard.
1.2.9 Continuityt The guide standard and protocol will be a living
docut, subject to revision and updating with the onset of new
tecI noL and knowledge • It is recameended that the responsible
authodttee for reVistratiols and drinking water quality review
potential needs every two to thre year. and reconven, the task
force upon need or upon requmat from the water quality industry, to
review and update the standard and testing protocol.
1.3 Treatment Units Covera
1.3.1 Universe of Possible 1reata.rst Units : A review of treatment
units that might be considered as microbiolOgicaL purifiers discloses
a number of different types covering treatment principles ranging
from filtration and chemical disinfection tO ultraviolet tight

1.3.2 Coverag, of This Standard : In vi•w of the limited technical
data available and in order to expedit. th. work of the task force,
th. initial coverage is limited, on a priority basis, to three basic
types of microbiological, water purifiers or active cem on.nta with
their principal means of action as follows Ceramic Filtration Candles or Units (say or may not contain
a chemical bacteriostatic agsnt) : filtration, and adsorp-
tion, and chemical anti—microbial activity if a chemical is
included. Maloqer*at.d Resins and Units: chemical disinfection and
possibly filtration. (Not.: While not includ.d in this
guide standard, halogen products for disinfection or systems
using halogen addition and fin, filtration say be tested
using many of its elements, i.e., test water paraa.t.rs,
microbiological challenge and reduction requirements, -
analytical techniques and other pertinent elements. 3 Ultraviolet (UV) Units: W / irradiation with possible
add-on treatment for adsorption and filtration (not
applicable to WI units for treating potable water from
public water supply systua).
1.3.3 Application of Principles to Other Units : While only three
types of units are covered in this standard th. principles and
approaches outlined should provide an initial quid. for the tasting
of arty of a nusber of other types of units and/or systems for the
microbiological purification of contaminated water.

21 Microbiological Water Purifier
In order to mak. the claim of micrcbiologica]. water purifi.r, units
ust b. tested and demonstrated to mast the microbiological, reduction
requirements of Table I according to the test procedures described in
Section 3 for the specific type of unit involved.
2.2 C emjcaj. Health Limits
Wher, silver or some other pesticida]. chemical is used in a unit.
that chemical concentration in the effluent water must meet any N tional
Primary Drinking Water Maximum Contaminant Lve I (I4CL) • additional Federal
guidelines or otherwise be demonstrated not to constitute a threat to...
health from consumption or contact where no MCL exists.
2.3 Stability of P.sticidal Chemical
Where a p.sticidal. chemical is used in the tr.a ent unit, the
stability of the chemical for disinfectant effectiveness should be
sufficient for the potential shelf life and the proj.ct.d use Life of the
unit based on manufacturer’s data. Where stability cannot be assured
from historical data and information, additional tests will be required.
2.4 Performance Limitations
2.4.1 Effective Lifetime
The manufacturer must provide an explicit indication or assurance
of the unit’s effective use Lifetime to warn the consumer of potential
diminished tr.ataent capability either through:
a. Having the unit terminate discharge of treated water, or
b. - liowiding an alarm, or
C. Providing simple, explicit instructiens for servicing or
replacing units within the r.cosaend.d ass life (measurable
in t.r of volume throughput, specific time frees or other
appropriat, method).
2.4.2 Limitation on Use of Iodine
EPA policy initially developed in 1973 and reaffirmed in 1982
(memo of March 3. 1982 from J.A. Cotruvo to G.A. Jones, subject:
Policy on Iodine Disinfection) is that iodine distnfectiDfl La
acceptable for short-term or’ limited or emergency use but that it is
not recommended for long—term or routine coáunity water supply
application where iodine-containing species say remain in the drinking

Klebsis]la t.rrigena , a common e oliform, was selected as the
challenge organism to represent the coLifor group. Poliovirus I
(LSc) and rotavirus (We or SA—il) are common environmental viruses
and show resistance to different trea ant processes, thereby pro-
viding good challenges for the virus group. Giardia was sel•ct.d as
the cyst challenge representative bcause of its widespread disease
impact and its resistanc, to ch.aical disinfection. The use of 4—6
micron particles or beads for testing the occlusion filtration of cysts
has been demonstrated to be an accurate and practical substitute for
the use of live cyst challenges. It is included as an option where
disinfection or other active processes are not involvsd.
Influent Required Reduction-
Organism challenge* _______
Kiebsiella t.rrig.na 1O /1OO ml 6 99.9999
a. Polievirus 1 (LSc) I x 10 7 /L
(ATCC-VR-59) and,
4 99 99**
b. Rotavirus (Wa or sA—Il) 1 x 10 7 /L
(&TCC—VR-899 or VR—2018)
Cyst (Protozoan): Giardia 0
a. Giardia suns or 10 6 /L 3 99.9
Giardia ] aablia
b. As an option for units or 10 7 /L 3
components based on occlusion
filtration: particles
or spheres, 4—6 microns
(Testing s zdinq to Wationa] Sanitation ?onndation Standard 53 for
cyst reduction will be acceptable)
The influent challenges say constitute greater concentrations than would
be anticipated in source waters, but these are necessary to properly
test, analyze and quantitatively detezaine the indicated log reductions.
Virus types are to be mixed in roughly equal I x I o It. concentrations
and a joint 4 log reduction will be acceptable.
*..Zt should bus noted that new data and information with respect to cysts
(i.e.. Cryptosporidium or others) may in the.future necessitate a
review of the organism of choice and of the challenge and reduction

3.1 !2E !2.
These tests are performed on ceramic filtration candles or units,
halogenated resins and units and ultraviolet (rJV) units in order to
substantiate their microbiological removal capabilities over the effective
use life of the purifier as defined in Table I and, where a pesticide].
chemical is used, to determine that said chemical is not present in the
effluent at excessive Levels (see Section
3.2 Apparatus
Three production units of a type are to be tasted simultaneously,
if feasible; otherwise, in a manner as similar to that as possible.
Design of the testing rig must parallel and simulate projected field
use conditions. For plumbed—in units a guide for design of the test rig
may be taken from Figure 1: Test Apparatus-Sch.matic (p. A-2 of Standard
Number 53 Drinking Water Treatment Units -- Health Eff.cts,R National
Sanitation Foundation). Otherwise, the test rig must be designed to
simulate field use conditions (vorit case) for th. unit to be tested.
3.3 Test Waters —- Non-Microbiological Parameters
In addition tO th. microbiological irifl.uent challenges, th. various
teat waters will be constituted with ch.mical. and physical characteristics
as follows:
3.3.1 Test Water *1 (Gen.ral. Test Water )
This water is intended for th. normal non—stressed (non-chaUenge)
phase of testing for aU units and shall have specific characteristics
which may easily be obtained by th. adjustment of many publ.ic system
tap waters, as fotlows
(a) t shall be fr.s of any chlorin, or other disinfectant residual;
(b) p1 — 6.5 — 0.5,
Cc) Total Organic Carbon (WC) 0.1 - 5.0 mg/La
Cd) Turbidity 0.1 — S NTU;
Ce) Temperature 20C 5’C; and
(f) Total Dissolved Solids CTDS) 50 - 500 mg/I..

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3.3.2 Test Water *2 (Challenge Test Water/Halogen Disinfection )
This wats is intended for the stressed challenge phase of
testing where units involve halogen disinfactants (halogen resins or
other ‘units) and shalt have the following specific characteristics;
(a) Free of chlorine or other disinfectant residual;
(b) (1) pH 9.0 .2, and
(2) for iodine—based units a pH of 5.0 .2 (current
thfor atiofl indicates that the Low pH wit], be the most
severe test for virus reduction by iodine disinfection);
(C) Total Organic Carbon (TOC) not less than 10 ag/Ls
(4) Turbidity not less than 30 NTU;
Ce) Temperature 4C 1C and
(f) Total Dissolved Solids (TDS) 1.500 g/L 150 mg/L.
3.3.3 ‘ Nat Water *3 (Challenge Test Watar/Cersaic Candle or Units
With or Without Silver Impregnation )
This water is intended for th. stressed chall.nge phase of test-
ing for the indicated units but not for such units when impregnated
with a halogen disinfectant (for the latter is. Test Water 02). It
shall have the following specific characteristic$
(a) It shalt be free of any chlorine or other disinfectant residual;
(b) pH 9.0 * .2:
Cc) Total Organic Carbon (TOC) -— not less than 10 eg/L
Cd) Turbidity -— not Less than 30 NTUs
(a) rs.per*ture 4C *1C; and
(f’) Total Dissolved SoUds (‘rOS) -— 1,500 mg/L * 150 mg/L.
3.3.4 Toat water *4 (Challenge Test Water for Ultraviolet Units )
This water is intended for the stressed phase of testing for CJV
units and shall have the following specific charactSristiCS
(a) Free of chlorine or other disinfectant residuaL;
(b) pH 6.5 — 8.5;
(c Total. Organic Carbon (TOC) -- not less than 10 ag/Li
(4) Turbidity -— not less than 30 NTU;
- 0-

(e) Tespezature 4°C ± 1°C;
(t) Total Dissolved Solids (TDS) —— 1,500 atg/L 150 eq/Li
(q) Color u.v.. absorption (absorption at 254 tie) -— Sufficient para-
hydroxybetizoic acid (PHBH) to be just below the trigger point of
the warning alarm on the U.V. unit. (Note that Section
provides an alternative of adjusting the (J.V. Lamp electronically,
especially when the U.V. lamp is preceded by activated carbon
treatment. J
3.3.5 Test Water #5 (L.aching Test Water for (Jnita Containing Silver
This water is intended for stressed leaching tests of units
containing silver to assure that excess levels of silver will, not be
leached into the drinking water. It shall have the following specific
(a) Free of chlorine or other disinfectant residua]j
(b) pH —— 5.0 t 0.2;
Cc) Total Organic Carbon (TOC) -- approximateLy 1.0 mg/Li
(d) Turbidity —— 0.1 — 5 NTtJ;
Ce) Temperatire -- 20°C * 5°Cs and
Ct) Total Dissolved SoLids (TOS) —— 25 - 100 eg/L.
3.3.6 Recommended Materials for Adjusting Test Water Characteristics
(a) pH: inorganic acids or bases (i.e., Nd, SaOH);
(b) Tots]. Organic Carbon ClOd) buaic acids;
Cc) Turbidity: A.C. Fine Test Dust (Part No. 1543094)
frost A.C. Spark Plug Division
General Motors Corporation
t300 North Dart Highway
Flint, Michigan 48556
Cd) Total Dissolved Solids (TDS): sea salts, Sigma Chemical Co.,
S9803 (St. Louis, MO) or another equivalent source of TDS;
(e) Color U.V. Absorption: p—hydroxybenzoic acid (grade: general
purpose reagent).

3.4 Analytical Methods
3.4.1 Microbiological Methods
Methods in this section are considered state—of the—art” at
the tims of its preparation and subsequent improvements rhould be
expected. Methods used fer microbiological analyses should be
compat .ble with and equal to or better than those given below. Bacterial Testa
a. Chosen Organism: Kiebsiella terrig.na (ATCC—33257).
b. Method of Production: The test organism will, be prepared by
overnight growth in nutrient broth or equivalent to obtain
th. organism in the stationary growth phase tR.ference:
Aaburg E.D., 1983, Methods of Testing Sanitisers and
Bacteriostatic Substances; in Disinfection, Sterilization
and Preservation (Seymour S. 8lock, ed.), pp. 964—980).
The organism will be collected by centrifugation and
washed three times in phosphate buffered saline before
use. Alternatively, the organisms may be grown overnight
on nutrient agar slants or equivalent and washed from the
slants with phosphat. buffered saline. The suspensions
should be filtered through sterile Whatman Number 2 filter
paper (or equivalent) to remove any bacterial clues. New
batches of organisms must be prepared daily for us. in
challenge tasting.
c • Stats of Organism: Organisms in the stationary growth
phase and suspended in phosphate buffered saline will be
d • Assay Techniques: Assay may be by the spread plate, pour
plate or brane filter technique on nutrient agar, MJ.C.
or a. do medium ( standard Methods for the Exa*tnetien of
Water sod Wastevater , 16th .dttion, 1985, APHAT. Bach
sap e dilution will be assayed in triplicate. Virus Tests:
a. c..n Organisms: Polioviru. type 1 (LSc) (ATCC-VP.S9) • &nd
Botavtrus Strain 3k—i I (ATCC—VR -899) or WA ( ATCC -VI—201 8).
b. Method of Production: All stocks should be grown by a
method described by Smith and Gerba (1982, in Methods in
viron.ental Virology , pp. 15—47) and purified by th.
procedure of Sharp, et c i. (1975, Appi. Nicrobiol.,
29:94—101), or similar procedure (Berman and Hoff, 1984,
Appi. !nviron. Microbiol., 48:317—323), as these methods
will, produce largely senodispersed viriott particles.
c. State of the Organism: Preparation procedure will largely
produce .onodispsrs.d particles.

d. Masy Tchni.quas: Poliovirus type 1 may be grown in the
8GM, —104 ot other cell line which will support the
growth of this virus. The rotavirusas are best grown i t t
the PiA—104 cell line. Since both viruses can be assayed
on theMA—104cell line a challenge test may consist of
equal amounts of both viruses as a mixture (i.e.,the
mixture must contain at least 1.0 x °7/ x. of each virus).
Assays may be as plaque forming units (PFU) or as imrnano—
fluorescence foci (I?) (Smith and Gerba, 1982, in Methods
in tvironmental Virology , pp. 15—47). Each dilution will
be assayed in triplicate. cyst Tests:
a. chosen Organism:
(1) Giardia lmbtia or the related organism, Giardia suns ,
may be used as the challenge cyst.
(2) Where filtration is involved, tests with 4—6 micron
spheres or particles have been found to be satisfactory
and may be used as a substitute for tests of occlusion
using live organisms (see Table 1). Spheres or par-
ticles may only be used to evaluate filtration efficacy.
Disinfection efficacy can only be evaluated with the
use of viable Giardia cysts.
b. Method of Production: Giardia suns may be produced in
laboratory sic. and Giardia iambus say be produced i tt
Mongolian gerbils, inactivation results based on .xcystation
asasuremants correlate well with sniasi infectivity results.
c. State of the Organism: Organisms say be separated from
fecal material by the procedur. described by Sauch (1984,
Appi. vviron. Microbto].., 48:454—455) or by th. procedure
described by Singham, et el. (1979, Xp. Parasitol..,
47 284 —291).
d. Mely ?sehniques: Cysts are first r.conc.ntrat .d (500 ml.,
minimum sample size) according to the method of Rice. Hoff
nd Schaefer (1982, Appi. viron. Nicrobiol., 43:250—251).
The excystation method described by Schaefer, !.
(1984, Trans., Royal Soc. of Trop. Med. I Ryg. 78:795—800)
shall be used to evaluate Giardia auris cyst viability.
Por Giardis iambUs cysts the excystation method described
by ainghas end Meyer (1979, Nature. 277:301—302) or Pies
end Schaefer (1901, J. din. Microbiol.. 14z709—710) shall
be used. Cyst viability may also be determined by an assay
sthod involving the counting of t.xophozoite s as wsll. as
intact cysts (Ringham , stat., 1979, Exp. Parasitol.,
—1 3—

3.4.2 e*ical and Physical Methods
LIl physical and chemical analyses shall be conducted in
accordance with procedures in Standard Methods for the Exanination
of Water and Wastewater , 16th Edition, Axerican Public Health Associ-
ation, or equivalent.
3.5 Test Procedures
3.5.1 Procedure - Plumbed—in Units
a. (1) Install three production units of a type as shown in
Figure 1 and condition each unit prior to th. start of the
test in accordance with the manufacturer’s instructions
with th. test water without th• addition of the test con-
taminant. Measur. the flow rate through each unit. The
unit shall be tested at the maximum system pressure of
60 pug static and flow rat. will not be artificially
(2) Test waters shall have the defined characteristics contin-
uously except for test waters 2, 3 and 4 with respect to
turbidity. Th. background non—sampling turbidity level
will be maintained at 0.1-5 NTU but th. turbidity shall be
increased to the challenge level of not 1... than 30 NTU
in the following manner:
- in the ‘on’ period(s) prior to th. sampling ‘on’ period.
- in the sampling ‘on’ period when th. sample actually
will be taken. (Note: at least 10 unit void volumes
of the 30 NTU water shall pass through the unit prior
to actual sampling so as to provide ad.quate seasoning
and uniformity before sample collection.1
b. (1) 3cc appropriate techniques of dilution and insure continual
mixing to prepar. a challeng, solution containing the
bacterial, contaminant. Then spike tact water continuously
with the influent concentration specified in Table 1.
(3) Use appropriat, techniques to prepare concentrated virus
and Giardia suspensions. Feed these suspensions into the
influent stream so as to achieve the influent concentrations
specified in Teble 1 in the following manner:
- in the •on ’ period(s) prior to the sampling ‘on’ period.
- in th. sampling ‘on’ period when th . sample actually
will be taken. (Not.: at least 10 unit void volumes of
seeded water shall pass through th. unit prior to sam-
pling so as to provide adequat. seasoning and uniformity
before sample collsction.1

a. Purge th. system of the uncontaminated vae.r with a •uffi jent
flow of contaminated test water. Start an operating cycl, of
10 percent on, 90 percent of f with a IS to 40 minute cycle
(Example: 3 minutes on, 27 minut.s off) with th. contaminated
test water. This cycle shall be continued for not more than 16
hours per day (minimum daily rest period of 8 hours). The total
program shall extend to 100% of estimated volume capacity for
haloqenat.d resins or units and for 10—1/2 days for ceramic
candles or units and for U.V. units.
d. Sampling: Sample, of influent and effluent water at the specified
sampling points shall be collected as shown below for the various
units; these are minimum sampling plans which may be increased
in number by th. investigator. All samples shall be collected
in duplicat, from the flowing water during the sampling ‘on
portion of the cycle and they shall be one unit void volum.
in quantity (or of appropriate quantity for analysis) and repre-
sent worst case challenge cenditiáns. Effluent samples shall
usually be collected near the middle of the sampling on period.
(or the whole volume during one on period) except for samples
following the specified stagnation* periods, for which sampling
shall b. conducted on the first water volume out of the unit.
Each sample will be taken in duplicate and shall be retained and
appropriately preserved, if required, for chemical or microbio-
logical analysis in the event verification is required. (For
units where the volume of a single ‘on’ period is insufficient
for the required analysis, samples from successive ‘on’ periods
may be accumulated until a sufficient volume has been collected.)
1(a). Sampling Plan: $alogenat.d Resins or Units ($on—iodine Based)
Test Point
(% of Estimated
Influent Aqent/
Background Residual Nicrobio] .oqical.
After 4$ rs
After 4$ hours
p —
9.0 0.2
x x

x X

1(b). Sa*pling Plan: todinsted R.sins or Units
Test Point
(% of Es
timated Test
) Water
Influent AgerLt/
Background Residual
After 48 hours
75% l.nge
Alter 48 hour. pH —
stagnation 9.0 0.2
X -
C l iii —
100% Lang.
Alter 48 hours pH -
stagnation 5.0 0.2
2. Saspting Plan: C.raaic Candles or Units
Test Influent
Test Point Wa t er Background
and U.V. Units
Start General X X
Day 3 (middle) X
Day 6 (middLe) X
After 48 hours
itagnatiom X
a a
Day 7 (aiddi.) X
Day 8 (near end) Chal— X
After 48 hours l.ngs
stagnation X
Day 10—1/2 X
(Note: A lL days are running days and exclude stagnation periods.
When th. units contain silver, a L.aching test shall be conducted as
shovn in Section 3.51.. and silver residual. vi ii be sasursd at each
microbiological saapling point.)

•. Leaching Tests for Silverized Units: Wher, the unit contains
silver, additional tests utilizing Test Water *5 will be
Conducted as follOws:
Test Point
Background Silver/Residual.
After 4$ hours
x x

f. Alternate Sampling Plans:
1 • Since some laboratories aay find it inconvenient to test
s e units on a 16 hour on/B hour off cycle, two alternates
are recognized:
-- go to a shorter operational day but lengthen the days
of test proportionally
—- use up to 20 percent on/$0 percent ‘of V for a pro-
portional ly shorter operational day
2. Sampling points suet be appropriately adjusted in any
alternate sampling plan.
g. Application of Test Waters:
The application of test waters is designed to provide
inforsation on performance under both normal and stressed con-
ditions it should be the sane or equivalent to the following:
• (a) Ratogenated Resins or Units (Non-iodin, based) --
?irst 50% of test period: Test Water I (General)
Last 50% of test period: Test Water 2 (Challenge)
(pH — 9.0 ± 0.2)
(b) todtnated Resins or Units --
Pint 50% of test period: Test Water I (General)
Next 25% of teat period: Test Water 2 (ChalLenge)
(pH — 9.0 ± 0.2)
Last 25% of test periods Test Water 2 (Chalt•nge)
(but with pH - 5.0 * 0.2)
2. Ceramic Candles or Units --
First 6 days of testing: Test Water I (G.nisrat)
Last 4—1/2 days of tasting: Test Water 3 (challenge)

3. Ultraviolet (U.V.) Units ——
First 6 days of testing: Test Water I (General.)
LaSt 4—1/2 days of testing: Test Water 4 (ChaLlenge)
h. Analyses and Monitoring:
1. Microbiological sampling and analysis shall, be conducted
of the specified influent and effluent sampling points
during each indicated sampling period.
2. Test Water Monitoring: The specified parameters of the
various test waters (a.. S•ction 3.3) will be measured and
recorded at each microbiological sampling point, the specified
parameters will be measured at least once on non—sampling
days when the units are being operated.
3. Background chemical analyses of influent vatar shall be
conducted at least once at the start of each test period to
determine the concentration of the U.S. A primary inorganic
contaminants, secondary contaminants and routine water para-
meters, not otherwise covered in the described test waters.
4. In addition, quality assurance testing shall be conducted
for the seed bacteria under environmental conditions on the
first and last days of testing to sake sure that there is
no significant change over the test day. Populations will
be measured (for example, as dispers.d in th. supply tank)
at the beginning and and of the test day to detect possible
incid.ntaL effects such as proliferation, die—off, adsorption
to surfaces, etc. ReLatively stable bacterial seed popula-
tions are essential to an acceptable test program.
5. When a emit contains a halogen or silver, the active agent
residual will, be measured in the effluent at each microbio-
logical test (sampling) point.
6. SiLver wILL additionally be measured three times in the
effluent as specified in Section 3.5.1.e.
alizatiob of Disinfection Activity: Immediately after
l,lction, each teat sample must be treated to neutralize any
rsaidual , disinfectant. For halogen— and silver-based disinfec—
tents this say be done by addition of thioq],ycouat.—thiosu]fate
neutralizer solution (Chambers. et at., 3. Amer. Water Works
Assoc., 54 2O8—216, 1962). This solution should be prepared
daily. All results are invalid unless samples are neutralized
immediately upon collection.
j. Special Provisions for Ceramic Candles or Units:
1 • Provisions for slow flow: Ceramic units may be subject to
clogging and greatly reduced flow over the test period.
An attempt should be made to maintain, manufacturer rated

or claimed flow rates, but even at reduced flows the sampling
program s•t forth in Section 3.5 ,I.d.2. shall be maintained.
2. Cleaning of ceramic units: Units should be cleaned according
to manufacturer’s dir .:tions. Two cleanings should occur
during the period of test (in order to prove th. unit’s dura-
bility through the cleaning procedure). However, near the
time of microbiological sampling, the units should not be
cleaned until after the sampling. Further, no anti—microbial
chemical (for cleaning or sanitizing) may be applied to the
units during the test period unless the manufacturer specifies
the same as part of routine maintenance.
k. Halogenated units or U.V. units with mechanical filtration pro—
ceases separate from th. microbiological disinfection components
shall have the mechanical filtration components replaced or
serviced when significant flow reduction (clogging) occurs in
accordance with the manufacturer’s instructions in order to
maintain th. test flow rat.. Units with non—removable mechanical
filtration components viii b run until flow is blow that
considered acceptabl. for consumer convertience. (U premature
clogging presents a problem, some specialized units may require
a customized test plan.)
1. Special Provisions for Ultraviolet (U.V.) Units:
1. Th. units will be adequately challenged by the prescribed
test waters consequently they will, be operated at normal
intensity. How.v.r where the U.V. treatment component is
preceded by activated carbon treatmsnt, th. output of the
U.V lamp shall be adjusted electronically, such as by
reducing th. current to th. lamp or other appropriate means,
to b just above the alarm point. This option shall be
availabl, for use under other U.V. configurations, at the
choice of the persons responsibl. for testing, as an alter-
native to th. us. of the UV. absorbent, p-hydroxyb.nzoic
2. rail/safe: Units Viii provide and will b ’s tested for failI
safe warnings in th. event of water quality changes or
qui nt failures which may interfere with its sicrobto—
logical, purification function.
3. Cleaning: Manufacturer’s guidance with respect to cleaning
will be followed.
3.5.2 Procedures Won—Plumbed Units
a. General: The basic procedures given in Section 3.5.1 shall be
used with n.c.ssary adaptat ons to allow for th. specific design
of th. unit. In any event the testing procedures shall provide
a test challenge equivalent to those for plumbed—in units.

b. Test conditions and apparatus should be adapted to reflect
proposed or &ctu*l use conditions in consultation with the
aanufactur.r, including flow rate and number of people to be
served per day. In some cases variable flow or other non—stan-
dard conditions may be necessary to reflect a worst—case test.
3 .5 3 Acceptance and Records To qualify as a microbiological water purifier, three production
units of a type must continuously east or exceed the reduction
requirements of Table 1, within allowable measurement tolerances
for not more than ten percent of influ.nt/sffluent sample pairs,
defined as follows
Virus: one order of magnitude
Mctsria: one order of magnitude
Cysts: one/half order of magnitude
The geometric mean of all microbiological reductions must meet
or exceed the requirements of Table I • An example is given as
— Unit: iodinat.d resin.
- Number of sample pairs over the completed test program:
IOp.runit—— 3unit53 3 .
- Number of allowable sample pairs where log reduction is
insufficisnt; 10% of 30 s 3 sample pairs.
- Allowable minimum log reductions in these 3 pairs:
• bacteria - 5 log
• Virus — 31oq
• Cyst — 2—1/2 log
- Conclusions If the geometric mean of all reductions meets
or exceeds the requirements of Table 1, th. indicated
insufficient sample pairs wi].]. be allowed. Records AU pertinent procedures and data shall be recorded
La a standard format and retained for possible review until the
report of results has been completely accepted by review
authorities, in no case for less than a year. scaling up or downs Where a manufacturer has several similar
units using the same basic technology and parallel construction
and operation, it may sometimes be appropriate to allow the
test of one unit to be considered represent*t.tVS of others.
Where any serious doubt exists, aU units of various sizes may
require testing. P. rule of thrss s suggested as a matter of
udq.ent. Scaling up to three times larger or one—third, based
on the size of either the test unit or of its operative element.
may be allowed. However,- for UV units any size scale—up must
be accompanied by a parallel increase in radiation dose.

3•5•3•4 Wlt•rs gitv.r or some other c1 .micaL is usd in the unit,
conc.ntrattons jfl. the elf Ltient water must meet any National
Primary Drinking Water Maximum Contaminant Level (HCL), addi-
tional Federal guidelines, or otherwise not constitute a threat
to health where no MCL exists.

A. M.icrobiol.ogical Reduction Requirements
• Bacteria
Current standards for the microbiological. safety of drinking
water are based on the presenc, of coliferm bacteria of which
Klabsiella is a member. 4smbers of the genus Kiebsiella are
also potential pathoq.ns of man (Viassof, 1977). Kl.ebsiel.le
terrigena is designated as the test organism since it is commonly
found in surface waters (Izard, .tal., 1981).
Experience with the use of coliferm bacteria to estimate
the presence of enteric bacterial pathoqens in drinking water
as performed over the last 75 years indicates a high degree of
reliability. Required t.sting of more than one bacterial
pathogen appears unjustified since viral and Giardia testing
will, be required. Ent.ric viruses and Giardia are known to be
more resistant to common disinfectants than enteric bacterial
pathogsns and viruses are more reuistant to removal by treateenta
such as filtration. Thus, any trea ent which would giv, a good
removal of both virus and Giardia pathogens would most Likely
reduce ent.ric bacteria below levels considered infectious
(Jarroll, etal., 1981, Liu, stal., 1971).
Th. concentration of coliform bacteria in raw cewage is
approximately 109/100 ml. Concentrations in polluted stream
waters have been found to exceed iOS par 100 ml (Cul.p, et al.,
1978, Table 10).
Based en the over 105/100 ml concentrations observed in
highly polluted stream water and a target effluent concentration
of teas than 1/100 ml, a 6 log reduction is recommended.
2. Virus
In the United States concentrations of entrovir’uses are
estimated to rang. from 10 3 -10 4 /]itsr in raw s•wags (Parrah and
Schaub, 1971 ) • Based on this observation it is estimated that
natural waters contaminated with raw sewage may contain from
1 1 to 102 enteric viruses per liter.
There are currently no standards for viruses in drinking
water in the United States. However, EPA has proposed a non—
enforceable health-based recommended maximum contaminant level
(RIICL) of zero for viruses (EPA, 1985). Several individuals
and organizations have developed guidelines for th. presence
of viruses in drinking water and various experts have proposed
standards (WHO, 1979, 1984; Berg. 197i Metnick. 1976). It has

generally been felt that drinking water should be free of
infectious virus since even one virus is potentially infectious
and suggested standards are largely based on technological
limits of our detection methodology. Guidelines suggested by
the world i.alth Organization (1984) and others recommend that
volumes to be tested be in the order of 100—1,000 liters and
that viruses be absent in these volumes.
Msumirtg a target effluent level of less than one virus in
100 liters of water and a concentration of 104 enteric viruses
in 100 liters of sewage—contaminated waters, the water purifier
units should achieve at least 4 logs of virus removal..
The relative resistanc. of enteric viruses to different
disinfectant.a varies greatly among the enteric viruses and even
among sembers of the same group (i.e., enteroviruses). For
example, while f2 coliphage is one of the most resistant viruses
to inactivation b chlorine it is one of the most susceptible
to inactivation by ozone (Iiarek.h and Butler, 1984). Ionic
conditions and pH can also affect the relative resistance of
different viruses to a disinfectant (Engelbrecht, eta]., 1980).
On this basis it ii felt that more than one enteric virus should
be tested to ensure the efficacy of any disinfection system.
Poliovirus type I (Strain LSc) was chosen as one of the test
viruses because it has been extensively used in disinfection
and environmental studies as representative of the enterovirus
family. It is recognized that it is not the most resistant virus
to inactivation to chlorine, but is still resistant snough to
serve as a useful indicator. Rotavirus is selected as th. second
test enteric virus since it represents another group of antaric
viruses in nucleic acid composition and size. It is also a major
cause of viral gaatro.nt.ritis and has been documented as a cause
of waterborns gistxoentsrttis (Gerba, et al., 1985). The human
rotaviru. or the similar Simian rotavi a ay be used in the
test procedure. A net 4-Log reduction for a joint challenge of
1 x 1 0 7 /L each for poliovirus and rotavirus is recommended.
3. Cysts (Protozoan )
Over the peat several years, giardiasis has consistently
been one of the most frequently reported vaterborne diseases
smsaitt.d by drinking water in the United States (Crawi,
1904). A has proposed a R$CL of zero for Giardia (EPA, 1985).
Its occurrence has generally been associated with treatment
deficiencies including either inadequate or no filtration.
Giardiasis has not bean kno m to occur from drinking water
produced by well—operated filtration treatment plants.
Oe Walls, et a]. (1984), in a study of filtration treatment
plant effi ie ies, cited percent removals for Giardia in
pilot plant tests as follows:
- rapid filtration with coaguLation sedimentatiOflZ
96. 6—99 .9%
- direct filtration with coagulation: 95.9—99.9%.

Pros this research and from the lack of Giardia cases
in eystesa where adequate filtration exists a 3—log (99.9%)
rduction requirement is considered to be conservative and to
provid, a comparable level of protection for water purifiers
to a well-operated filtration treatment plant.
Data on environmental levels for cysts in natural waters is
limited because of the difficulties of sampling and analysis.
Unpublished data indicate very low levels from less than I/L to
less than tOIL. Here a 3-log reduction would provide an effluent
of less than 1/100 I ., comparabl. to the r.cemeendad virus
reduction requirements.
Either Giardia Lamblia or the related organism, Giardia suns
vhi ch is reported to be a satisfactory test organism (Hoff,
etal., 1985), may be used as the challenge organism. Tests
will, be conducted with a challeng, of 106 organisms p .r liter
for a 3—log reduction.
Where the trea ent unit or component for cysts is based on
the principl, of occlusion filtration alone, tasting for a 3—Log
reduction of 4—6 micron particles or spheres (Hational Sanitation
Foundation Standard 53, as an example) is acceptable. Diff i-
cultie. in the cyst production and seasurement technologies
by lesser—equipped laboratories may require the use of such
alternative tests where applicable.
8. MicrobiolOgical Purifier Test Procedur
I • Test Waters
a. The general test water (test water *1) ii designed for the
normal, ion—stressed phase of testing with characteristics
that say aaily be obtained by the ad us erit of many public
system tap waters.
b. Test water 02 is intended for th. stressed phase of testing
wbere unit. involve haloqen disinfectants.
1) since the disinfection activity of some halogens falls
with a rising H , it is important to stress test at an
•1svat.d p0. The recommended level of 9.0 * 0.2 while
exceeding the r.cosmended secondary level ( viroft*SfltaL
Protection Agency, 1984) is still, within a range seen
in coma natural waters ( tvironuertt*L Protection Agency.
1976). However, for iodine—based units, a sscond
stressful condition is provided -— a pH of 5.0 t 0.2
since curr.nt information indicates that the disinfec-
tion activity of iothne falls Mith a Low pH (Wational
Research Council. 1980). While beneath the recommended
secondary level (Env ronaental protection Aq.ncy 1984)
a p11 of 5.0 is not unusual in natural waters (Vwirofl
ent.sl Protection Agency, 1976).

2) Organic matter as total organic carbon (Toe) is known
to interfere with halogen disinfection. While this
TOC is higher than levels in many natural waters, the
designated concentration of 10 mg/L is cited as typical
in stream waters (Cu Ip/Wesner/Cuip. 1978).
3) High concentrations of turbidity can shield sicroorgartiuts
and interfere with disinfection. Whil, the recommended
level of not less than 30 NTU is in the range of turbid—
ides seen in secondary wastewater effluents, this level
is also found in many surface waters especially during
periods of heavy rainfall and snow melt (Culp/Wesn.r/Culp ,
4) Studies with Giardie cysts have shown decreasing halogen
disinfection activity with lower temperatures (Jarrol.L,
etal., 1980), 4’ C, a co on low temperature in many
natural waters, is recoan endad for the stress test.
5) The amount of dissolved solids (TDS) may impact the dis-
infection effectiveness of units that rely on displaceable
or exchange elements by displacement of halogens or resins,
or it may interfere with adsorptive processes. While TDS
levels of 10,000 sg/L are considered unusable for drinking.
many supplies with over 2,000 ag/L at. used for potable
purposes (Environmental Protection Agency, 1984) The
recommended level of 1,500 mg/L represents a realistic
stress chafleng..
c. Test water 03 is intended for the stressed phase of testing
of ceramic filtration candles or unita with or without
silver impregnation.
1) Since viruses are typically sluted f roe adsorbing media
at high p85 (Environmental Protection Agency • 1978) it
say be concluded that a high p8 will provide th. most
stressful testing for a ceramic-type unit, consequently.
the high natural water pH of 9.0 is recommended.
2) Expert opinion also holds that organic material will
interfere with adsorption of viruses • Thus, a high
total organic carbon Level of not less than 10 mq/L is
3) Turbidity may enhance the entrapment and removal of
microorganisms but it also say stimulate ‘short-
circuiting’ through some units. A. turbidity level of
30 NTU will provide stress at time of sampling but the
non—sampling level of 0.1—5 NTU will, allow routine
operation of units.
4) Expert opinion was that low water temperatures and
high TDS would most likely interfere with virus reduc-
tion by adsorptioni consequently, a 4’C temperature
end 1,500 mg/I TDS are recommended.

d. Test water *4 is intended for the stressed phase of testing
for ultraviolet (LIV) units.
1) In general, high TOC, turbidity and TOS and low tamperature
are considered most stressful for LIV, and the indicated
challenge levels are the same as for test water *2.
2) The pH is not critical and may range from 65 to 8.5.
3) In order to test the LIV units at their mast vulnerable
stage of operation, a color challenge (Light absorption
at 254 ne) is to be maintained at a level where LIV
Light intensity is just above th. unit’s Low intensity
warning alarm point. However, an alternat, to the
absorption challeng, I. provided through adjusting the
light intensity output of the LIV lamp electronically by
reducing current to the lamp, or other appropriate
means, to be just above th. alarm point; this approach
would b. particularly necessary where the LIV lamp is
preceded by activated carbon txsetment.
e. est water *5 is intended for th. stressed leaching tests
of units containing silver. Low pa, TOC turbidity, end
TOS and higher temperature are felt to be the characteristics
associated with increased leachebility. Th. recommended pH
of 5.0 .2, while being beneath th. recommended secondary
rang, of 6.5—8.5 (Environmental Protection Ag.rtcy, 1984) is
stilt found in some natural waters.
2. Test Procedures
The plan for testing and sampling is designed to reveal unit
performance under both noraal and stresssd operating condi-
tions. The stressed phas. would utiliz, a set of water quality
and operating conditions to give the units a realistic worst
case challenge. Testing plans for a specific model might
involve modifications to the recommended plan; more sample.
could be taken and analyzed; more units could he studied. The
principl, of demonstrating adequate pert ormanca even under
rmaU.stic worst case conditions should be maintained and the
final selected test procedures should be agreed as between
investigators and reviewers or regulators.
While some aspects of the testing procedures have been
utilized in actual experiments, the proposed protocol has not
been verified or utilized for the various units that may be
considered. Cons.qu.nt ly, investigators and users of this
protocol may find reasons to alter some aspects through their
practical experience; needed changes should be discussed and
cleared with involved reviewers/regulators.

Berg, C. 1971. Integrated approach to the problem of viruses in water.
.7. ASCE, Sanit. Eng. Div. 97:867—882.
Cu].p/Wesn.r/Culp. 1978. Guidance for planning the location of water
supply intakes downstream from municipal wastewater treatment facil-
ities. E A Report, Office of Drinking Water. Washington, DC.
Craun, G.F. 1984. Waterborne outbreaks of giardiasis: Current status,
pp. 243—261. In: D.L. Erlandeen and E.A. Meyer (eds.), Giardia and
giardiasie. Plenum Press, New York.
DeWalle, F.B., .7. Eng.set and P 1. Lawrence. 1984. RemovaL of Giardia
iambus cyst by drinking water tr.a 1snt plants. Report No. A—60O/
52-84-069, Office of Research and Development, Cincinnati, OH.
Engelbrecht, R.S., etal. 1980. Comparative inactivation of viruses by
chlorine. AppL. Environ. Microbiol. 40:249-256.
Environmental Protection Agency. 1976. Quality criteria for water.
Washington, DC.
Environmental Protection Agency. 1978. Human viruses in the aquatic
environment. Report to Congress. k—57O/9-78—OO6.
Environmental Protection Agency. 1984. National secondary drinking
water regulations. A—570/9—76—000, Washington, DC.
Environmental Protection Agency. 1985. National primary drinking water
regulations, synthetic organic chemicals, inorganic chemicals and
microorganisesi Proposed rule. Federal Register, Nov. 13, 1985.
Farrah, S.R., and S.A. Schaub. 1983. Viruses in wastewater sludges.
In: Viral Pollution of the Environment (C. Berg, •d.). CRC Press,
Boca Raton, Florida. pp. 161-163.
Gerba, C.P., .7.9. Ross and $.N. Singh. 1985. Waterborne gastroentaritis
and viral hepatitis. CRC Critical Rev. Environ. Contr. 15:213—236.
Harak.h, N., and H. Butler. 1984. Inactivation of human rotavirus.
SA—1 1 and other satiric viruses in effluent by disinf.ctants.
3. H . Cub. 93t157—163.
Hoff, J.C., LW. Rice and ?.W. Schaefer. 1985. Comparison of animal
infectivity and •xcystatton as measures of Giardia suns cyst
inactivation by chlorine. ppl. Environ. Microbiol. 50:1115—1117.
Izard, D., C. Farnagut, F. Gavini, K. Kersters, 3. DeLay and K. L..clsrc.
1981. Klsbsiella terrigena , a new species from water and soil.
Intl. 3. Systematic Bactsriol. 31:116—127.

Jakubcwski, ii. 1984. Detection of Giardia cysts in drinking water.
Ins Giardia and Giar&iasis (S.L.. Erlandsan and E.A. Meyer, eds.).
T.ni Press, NY. pp. 263-286.
Jarroll, E.L., A.K. gingham and E.A. Meyer. 1980. Giardia cyst destr ac—
tion: Effectiveness of six small—quantity water disinfection methods.
Am. 3. Trep. Med. 29:8—11.
JarroU, E.L., A.K. Bingham and E.A. Meyer. 1981. Effect of chlorine on
Giardia cyst viability. Appt. Environ. Microbiol.. 43s483-487.
Liu, O.C., etal. 1971. Relative resistance of 20 h aan .nt.ric viruses
to free chlorine in Potomac River water. Proceedings of 1 3th Water
Quality Conference (V. Snoeyink and V. Griffin, eds.), pp. 171—195.
University of. Illinois.
Melnick, J.L. 1976. Viruses in vater. In: Viruses in Water (G. Berg,
H.L. Bodily, E.H. Lennette, J.L. Hslnick and T.G. Metcalf, ads.-)
Amer. Public HIth. Meoc. Washington, DC. pp. 3—11.
National Research Council.. 1980. The disinfection of drinking water,
pp. 5-137. In: Drinking Water and Health. VoLuae 2. Washington, DC.
National. Sanitation Found*tiOn. 1982. Drinking water trea nt units:
Health effects. Standard 53. Ann Arbor, M I.
Viassoff, L.T. 1977. iClabsiella . In: Bacterial. Indicators/Health
Hazards Associated with Water A.W. Hoadley and B.J. Dutha, •ds.).
American Society for Testing and Materials. Philadelphia, PA.
pp. 275-280.
World Health Organization. 1979. Huaan Viruses in Water, Technical.
Support Series 639, World Health Organization, Geneva.
woi 1d Health Organization. 1984. Guidelines for Drinking Water Quality.
Vo]uae 1 • Recouend&tiefti. World Health Organization, Geneva.

Stephen A. Schaub, Chairman —— U.S. Army P dica]. Bioengine.ring Research
and Development Laboratory (USAMBRDL), Fort Detrick, Maryland 21701,
FTS: 8/935—7207 —— Coma: 301/663—7207.
Frank A. Bell, Jr., Secretary — — Criteria and Standards Division Office
of Drinking Water (WH—550), Environmental Protection Agency,
Washington, D.C. 20460, Phone: 202/382—3037.
Paul aerger, Ph.D. - — Criteria and Standards Division, Office of Drinking
Water (WH-550), Environmental Protection Agency, Washington, D;C.
20460, Phone: 202/382—3039.
Art Castillo -- Disinfectents Branch, Office of Pesticide Proqrans
(TS—767C), Environmental Protection Agency, Washington, D.C. 20460,
Phone: 703/557—3965.
Ruth Douglas —- Diathf.ctants Branch, Office of Pesticide Programs
(TS—767C), Environmental Protection Agency, Washington, D.C. 20460,
Phone: 703/557—3675.
Al Dufour —— Microbiology Branch, Health Effects Research Laboratory,
Environmental Protection Agency, 26 W. St. Cur Street, Cincinnati,
Ohio 45268, Phone: PTS: 8/684—7870 —— Coma: 513/569—7870.
Ed Geidreich - - Chief, Microbiological Treatment Branch, Water Engineering
Research Laboratory, Environmental Protection Agency, 26 W. St. Clair
Strict, Cincinnati, Ohio 45268, Phone: FTS: 8/684—7232 —— Com*
Charles Gerba. - — Associate Professor, Department of Microbiology and
Im inology, University of Arizona, Tucson, Arizona 85721,
Phonci 602/621—6906.
John Hoff — Microbiological Treatment Branch, Water Engineering Research
Laboratory, Environmental Protection Agency, 26 W. St. Clair Street,
Cincinnati, Ohio 4526$, Phone: S: 8/684—7331 —— Coma: 513/569—7331.
Art Kaplan —— U.S. Army, Natick R&D Center, AttA: SrR.NC_TE, Natick,
Massachusetts 01760—5020, Phone: 617/651—5525 (5526).
Bela Krishna.n -— Office of Research and Development (RD—681) Environmental
Protection Agency, Washington, D.C. 20460, Phone: 202/382—2583.
John Lee -— Disinfectants Branch, Office of Pesticid* Programs (TS—767C)
Environmental Protection Agency, Washington, D.C. 20460,
Phone: 703/557—3663.

Dorothy Portn.r -- Disinfectanti aranch, Office of pesticide Programs
(1$767C), tnvironmefltal Protection Agency, Washington, D.C. 20460,
PkOeez 703/557—0484.
Don Reasoner -— jcrobiologicaL Treatment ranch, Water Engineering Research
L.aboratory. EnvirOnfl ental Protection Agency, 26 W. St. Clair Street,
Cincinnati, Ohio 45268, Phone: £rS: 8/684—7234—— Comm: 513/569—7234.
P. Regunathan (R.gu) -- Everpure, Inc., 660 N. Blackhawk Drive, Westeont,
Illinois 60559, Phone: 312/654-4000.
David Stangal —— Policy and Analysis Branch, Offic. of Co*pliance nitoring,
Environmental Protection Agency, Washington, D.C., Phon•z 202/382-7845.
Richard Tobin -— Monitoring and Criteria Divtston, Environmental Health
Center, Department of Halth and Welfare of Canada, 1’unney’s Pasture,
Ottawa, Ontario, K1A 0L2, Canada, Phone: 613/990—8982.
— 30-

A. Recommendation for the use of Giardia la nblia cyst. as a replacement
for Giardia suns cysts as the protozoan cyst test organisms.
The subcommittee concurs with the recommendation and further endorses
the use of Giardia lamblia as the preferred cyst test for evaluation
of all trea ent units and devices. Obviously the use of the proto—
zoan organisme of actual health concern in testing is amet desirable.
Anyone finding the Giardia lamblia strain feasible for testing and
coat-effective to rk with is encouraged to use seas instead of
Giardia mtznis .
B • Substitution of 4—6 micron bead or particle taste as an alternate
option instead of the Giardia cysts for evaluating devices that rely
strictly on occlusion filtration for microbiological removal:
Several commentens criticized the use of beads or particles (e.g.,
A.C. fine dust) and recommended only use of live Giardia cysts for
performance tests.
Discuss ion :
The subcommittee recognizes and favors the use of the natural human
parasite, Giardia lemblia , but was not aware of any convincing
scientific data which would disallow the optional use of tasting
with beads or particles for units or devices using on].y occlusion
filtration to remove microorganisms. Previous development of the
National Sanitation Standard (NSF) 53 (1982) r.quir.asnt for cyst
reduction (using 4—6 micron particles as cyst models) was based on
engineering and scientific opinion and experimental evidence at that
time. Specifically, Logsdon( 1 ) used radioactive cyst models in the
initial phas. of a study of removal efficiencies for diatceaceous
earth filt.rs, .u squ.nt experiments with Giardia muris cysts con—
firmed th. efficacy of the diatoaacsous earth filters. Further studies
by l4ricks( 2 ) and DeWalle( 3 ) with Giardia iambus cysts also shoved
cospa sb1,. reduction efficiencies for diatomaceous earth filters.
Subs usntly confirmatory parallel testing results have been developed
vie—a—vie 4—6 micron particles as compared to Giardia lamblia cysts.
Specifically, two units listed by NSF for cyst reduction (using 46
nicron pareiclea)( 4 ) have also been tested and listed for 100%
efficiency reduction (using Giardia iambus cysts) by Hjb] •r( 5 )g
S.A. Schaub; F.A. Bell, Jr.; P. Berger; C. Gerba; 1. hoff; P. Regunathan;
and R. robin. [ Includes additional revision pursuant to Scientific
Advisory Panel review (Federal Insecticide, Fungicide, and Rodenticide Act)1

(1) Everpura Model 4—SC
(2) Royal Doultott Model F303.
Again w prefer the use of the human pathogen, Giardia lamblia
however, no experi ientaL data has been provided regarding the lack
of validity or of failure in previous tests utilizing beads or
particles of 4-6 microns. In moat cases the bacterial or viral
challenges to occlusion filters will represent a greater problem in
terms of microbiological reduction requirements than vii i. cysts.
Therefore, without substantiation of deficiencies, the use of 4—6
micron beads or particles is considered to be as feasibl. as the use
of live cysts for routine performance tasting of water filtration
(occlusion) devices.
Recommendation :
Recom_mend retaining the optional use of 4—6 micron particles or
beads for cyst reduction tasting in occlusion filtration devic s
References :
( 1 )Logsdon, G.S., at al. Alternative Filtration Methods for Removal
of Giardia Cyst and Cyst Models, JAWWA, February, 1981.
( 2 )t.ogsdon . G.S., Hendricks, D.W., etai. Control of Giardia Cysts
by Filtration: The Laboratory’s Role, presented AWWA Water
Quality Tschnology Conference, December 6, 1983.
( 3 )DeWaUe, etal,. RmmOVai of Giardia lamblia Cysts by Drinking
Water Trsa nent Plants, Grant No. R806127, Report to Drinking
Water Research Division, US. EPA (ORD/MERL), Cincinnati, Ohio.
4 )Hetional Sanitation Foundation, 1986, Listing of Drinking at.r
Trea snt Units, Standard S3. May 21, 1986.
5 Kib1er, C.P. 1984. M Evaluation of Filters in the Removal of
Qiardia laeblia . Water Technology, July, 1984, pp. 34—36.
C. Alternate amsay techniques for cyst tests (J.naan): Proposed
aitsretions in cyst tests include a different method for separating
cysts from fecal material and an assay method involving the counting
of tro I ozoits as veil as intact cysts. Both alterations have been
uied by ain am, •tal. (1979, Exp. Parasito]., 47 284291).
Recommendation :
These alterations appear to be reasonable laboratory procedures.
supported by a peer-reviewed article and wilt be includd in the
Report as options for possible development and use by interested

D. The use of pour plate techniques as an option for Kiebsiella t.rrigefla
bacteria analyse 5.
The pour plate technique adds a heat stress factor to the bacteria
which constituteS a possible deficiency. However, it is a recognized
standard method and probably will not adversely affect the KIebsiella
terrigefla . Consequently, it will be added to the Report
the acceptable techniques.
E. Option of using Escherichia coil in lieu of Klabii.lla terrigerta for
the bacterial tests.
Discussion :
Appendix A, Section A.1 • of the Guide Standard and Protocol sets forth
the basis for selection of K. terrigefta as the tsst bacteria. The
selection was made along pragmatic lines emphasizing th. occurrence
of K. t.rrigerta in surface waters and that it would represent the
enteric bacteria. It was also pointed out that th. tests with virus
and Giardia were expected to be more severe than the bacterial tests.
Per compreheftsivsflss s bacterial tests were included in th. protocol
but were not felt to be as crucial as the virus and Giardia tests.
E. coli , or any number of other generally accepted indicator bacteria,
could be used for the test program if they were shown to-have good
testing and survival characteristics (equivalent to I C. . 3 !na) by
the interested research laboratory.
Recommendation :
Thi intent of the Guide Standard and protocol is to provids a base-
line program subject to modific*tion when properly supported bY an
interested laboratory. Cona.qusntty, any laboratory could propose
and with proper support (demonstrating challenge and test equivalency
to K. use Escherichl* colt or one of the other enteric
bacteria. This ides wiLl be included in revised wording Lit
Section i.i.a, Gen•rai Guids.
F • Perfox menCe requirements for Giardia cysts and virus in relation to
the D&—I.cos.endSd Msximum Contamination Levels (RMCL) of zero.
Discussion :
The RZ4CLs of zero for Giardia and viruses which have been proposed
by EPA are health goals. They are not enforceable standards since
to assure the presence of organusms would require n infinite
sample • The rationale for the recommended performance requirements
for Giardia cysts and virus is set forth in Sections A.2 and A.3 of
Appendix A. We feel that these requirements together with the
application of realistic worst case test conditions will provide a

conservative ,gt for units resulting in treated effluent water
equivalent to that of a public water supply see tirtg the inicrobic—
Logical r.quir •nt5 and intent of the National Primary Drinking
water Regulations.
Recommendation :
Retain recommended performance (log reduction) requirements for cyst
and virus reduction.
G. Rotavirais and its proposed assay: One commsntr states that the
rotavirus tests are impractical because Asirtharajah C 1986, J WWA,
78:3:34—49) cites ‘no satisfactory culture procedures available for
analysis of these pathog.nc and therefore, monitoring would not be
Discus ci on
Section, ‘Virus Testa ’ of the Report, presents means for
culturing and assaying rctav ruses. The means for doing the rota—
virus tests are available and are practical for application in the
Laboratory . Dr. Amirtharajah was referring to th. field collection,
identification in the presence of a wide variety of. microorganisms,
and quantification as not being ‘satisfactory.’ Laboratory analysis
of rotaviruses is practical but their field monitoring may not yet
be feasible.
Further, the selection of both poliovirus and rotavirue as teat
viruses was necessitated by the fact that the surface adsorptive
properties and disinfection resistance of th. various enteric viruses
have been shown to differ significantly by virus group and by strains
of a specific virus. 4hil. all •nt.ric viruses and their strains
could not be cono.ically tested, it was determined by th. task
force that at least two distinctly different virus types should be
tested to achiave some idea of the diversity of removal by the
various types of water purifiers. Polio and rota viruses have L. .
distinctly different physical and chemical characteristics repre-
sentative of th. viruses of concern. Polioviruses are small single
strandd RItA viruses with generally good adsorptive properties to
surface, and filter media while rotavirusas are over twice as large,
are double strand.d RNA and in some studies have been found to
P°$s $ lass potential for adsorption onto surfaces or filter media.
These two viruses also have bean demonstrated to have some ithit
different disinfection kinetics.
Recommendation :
Retain the rotaviru. test requirements.

H. Definition of microbiologicaL water purifieri One general comment
re v.st.d redefinition based on TM lack of any virus removal 0 require-
ment in the EPA primary drinking water regulations, so that no virus
reduction requirement should be included. Also, it was claimed that
the separatioriof purifiers from non—purifiers would be a 0 disservice
to consumers and other users.
Discussion :
Virus are recognized in the EPA regulations ris—a-vis a proposed
recommended maximum contaminant level of zero. Since virus monitoring
f or compliance with a possible MCL is not yet feasible, a treatnent
requirement is necessary. Virus control will be considered in the
Safe Drinking Water Act filtration arid disinfection tr.atnent regu-
lations. The reduction of viruses by treatment is discussed by
Amirtharajah (1986, JAWWA, 78:3:34—49).
With respect to consumers and other users, we feet that the cutrent
definition is appropriate arid necessary. The average consumer
cannot be expected to know the dift.renc. between viruses, bacteria
and cysts, or when a raw water will. oruill. not contain any of thess
organisms. In order to protect th. average consumer, the subject
units either alone or with supplementary traatnent should be able
to cop. with all, of the specified organisms.
Retain the current definition for microbiological water purifier.
I. Coverag, of units: Several comments related to the coverage of
units. These question.. are addressed individually as follows:
1. Ultraviolet units that are used for supplemental treatment of
water f roe public water system taps should not be covered. We
agree that sudt units are not covered and parenthetical Language
has been thaluded in Section to clarify this point.
2. & special itatias should be given to units which remove Giardia
and ba*tsrta bit not virus. Specifically, the meaning of
$ection 1.2.4, ‘Exceptions, was addressed. The ception$
section was specifically developed to relate to the problem of
ps blic water system. having disinfection but no filtration on a
surfac, supply. Cysts alone have been found to survive disin-
fection treatment and could be present in such treated, waters.
In this case an effective cyst filter serves art independent,
beneficial purpose and should not be required to be a microbio-
logical water purifier. However, such a unit should not be
used as sole treatment for untreated raw water. Additional.
parenthetical language has been added to Section 1.2.4.
3. This entire treatment unit or system should be tested, not )uSt
a single component. We agree but believe that it is sufficientlY
clear without providing additional language.
- —35—

4. The protocol should be expanded to cover units for the reduction
of ItS, SOB and other chemical pollutants. We felt that the
introduction of non—microbiological claims to the standard
would sake it large, unwieldy and duplicative of an existing
third-party standards and testing program (see Section 1.2.5).
J. Alleged preference of National Sanitation Foundation (NSF) over other
laboratories for conducting the microbiological water purifier
testing protocol. The comment indicated that we were giving NSF
preferential treatment to the detriment of other laboratories well
qualified to perform the required protocol.
Discussion :
We have made appropriate references to existing standards (*42 and
#53) developed by the NSF standards development process. Standard 53,
the health effects standard, was developed by a broadly based Drinking
Water Treatment Units Committee, including representatives from local,
State and Federal health and environmental agencies, universities,
professional and technical associations, as well as water quality
industry representatives. It was adopted in 1982 and the only test
from it utilized in our Report has been substantiated as described
in Part B of this Response.
Nowher, in our report have we advocated NSF (or any other laboratory)
as the prim, or only laboratory for implementing th. required
R,coiwa end&tiOXU
No action needed.
K. Instruction concerning affective lifetime. One comment described
an alternate means for determining lifetime where a ceramic unit Is
brushed’ to renew its utility and is gradually reduced in diameter.
A gauge is provided to measure diameter and to determine when
replacement is needed.
Recols m ftd tiOftS
Where a anufactur.r provides a satisfactory 0 other means of
determining lifetime, this should be accepted. Appropriate rds
have been added to Section 2.4.1C.
L. Ceramic candles should not be cleaned during testing because some
consumers would not clean them and this would’provide the worst
case teet. One comment asserted this point.

There is some truth to this proposition. However, the other approach
may also have validity. Frequent brushing may reduce filtration
efficiency. In any event, where a manufacturer prascribe5 filter
cleaning and how to do it, and provides a gauge to determine lifetime,
we fee ], the testing program is bound to follow the manufacturer s
Recommendation :
No change needed.
M. Scaling up or down. One comment points out that one or more manu-
facturers may vazy size of treati nt units by increasing or decreasing
the number of operative units rather than the •iz. of the operative
unit. The commet t suggests allowing scaling based on size of -
operative unit.
Recommendation :
We agree with the comment and have added clarifying words to
N. Turbidity level of not less than 30 NTU for ceramic candles or
units. One comment states that Such levels are impossibl. to
utilize in testing mechanical filtration devices which will clog
entirely or require such frequent brushing as to render the test
impossibl, as a practical matter.
Discussion :
We recognized the potential. clogging probl.ms in Section 3.5.1 .a(2)
where the 30 NTU water ii only to be appU.d immediately before and
during each •saplinq event; the non—sampling turbidity level, which
will be applied ever 90% of the on time, is currently set at not
less PKari 10
?urbtdIty levels, of 30 NTt1 are commonly found in surface waters
duriz*q heavy rainfall or snow melt. Treatment units may be used
under these circumstances, so this challenge level, should be retained.
However, most usage will, occur under background conditions so the
non—sampling turbidity levels should be 0.1—5 NTU.
R commendationS :
(1) Retain sampling turbidity Level of not less than 30 NTU, and
(2) ange non-sampling turbidity level 0.1-s NTU. Appropriate
wording changes have been introduced in Section 3.S.1.a(2) and in
Appendix A, Section B.

0. Ch.Loriz e in test water *5. One comment asserts that chlorine tertds
to increas, silver Ofl leaching acti vity and that a high chlorine
level should be included in the silver leaching tests but no reference
or evidence, however, £5 provided to back this assertion.
We have no compelling evidence or reason to expect that chlorine will
enhance th. leaching of silver. However, the prescribed l i pH and
‘TOS levels will provide, a clearly severe test for silver leaching.
Recommendation :
No change needed.
P. Unnecessary difficulty and expense of test protocols. Several
comments were made under this general heading. These coements are
outlined and discussed as follows:
• ibo many sampling events are required, sampling of a few units
at start, middle and finish should be satisfactory’ The
committee has carefully Laid out the standard and protocol and
we feel the minimum sampLing plan must be maintained for the
cons uasrs health protection.
2. Thre. units are too many to st y; parallel testing of two
units should be satisfactory: For consumer protection, the
Disinfectants Branch, Office of Pesticide Programs, has tradi-
tionally required the testing of three units. The committee
recognizes the additional cost involved in testing a third unit
but feels that this vi ii provide a minimum level of assurance
to prevent infectious disease and recommends retention of the
3—unit requirement.
3. The protocol requires larg. tanks and microbiological reseeding
on a daily bsis: We feel that the t&nk size requirements are
not extreme and can be set by an interested laboratory. With
respect to reseeding, it should be pointed out that virus and
• cyst seeding need only be conducted immediately before and
• during the sampling on• period (see Section 3.5.1.b(2)),
equivalent to less than 1 0% of the on time • This spot
seeding for viruses and cysts recognized the expense and
difficulty of maintaining larg. populations of these organisms.
Continuous seeding was provided for bacteria because they are
easier to grow and maintain and might have the capacity to grow
through come units, given enough time and opportunity’
4. Challenge levels of contaminants are too high compared to known
environmental conditions and the required log reductions exceed
Safe Drinking Water Act requirements: As explained in a footnote
to Table 1, Section 2, the influent challenges may constitute
greater concentrations than would be anticipated in source

waters. These levels are necessary to test properly for the
rsquir.d Log reductions without having to utilize sample concen-
tration procedures which are time/labor intensive and which may,
on their own, introduce quantitative errors to the microbio-
logical assays. As mentioned in P&rt I of this paper, the lo
reductions for bacteria, virus and Giardia have been suggested
for public water system trea nent in a paper by Amtrtharajah
(1986, JAWWA, 78 :3:34—49). The reductions in the microbiological
purifier standard are entirely compatibl. with the reductions
cited for public water supply treataent.