DRAFT
              MARCH 31, 1989
             GUIDANCE MANUAL
                    FOR
           COMPLIANCE WITH  THE
FILTRATION AND DISINFECTION REQUIREMENTS
                    FOR
          PUBLIC WATER SYSTEMS
                   USING
         SURFACE WATER SOURCES
        SCIENCE AND TECHNOLOGY BRANCH
        CRITERIA AND STANDARDS DIVISION
              OFFICE OF WATER
     U.S. ENVIRONMENTAL PROTECTION AGENCY
               WASHINGTON, D.C.

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                                GUIDANCE  MANUAL
                                      FOR
                             COMPLIANCE WITH THE
                   FILTRATION AND DISINFECTION REQUIREMENTS
                                      FOR
                             PUBLIC WATER SYSTEMS
                                     USING
                             SURFACE WATER SOURCES
                                      for
                         Science and Technlogy Branch
                        Criteria and Standards Division
                           Office of Drinking Water
                     U.S. Environmental Protection Agency
                               Washington,  D.C.
                            Contract No. 68-01-6989

                                     DRAFT

                                       by
Malcolm Pirnie, Inc.
100 Eisenhower Drive
Paramus, NJ  07653
CWC-HDR, Inc.
3461 Robin Lane
Cameron Park, California 95682
                                March 31, 1989

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                               TABLE OF CONTENTS
1.   INTRODUCTION                                                     1~1

2.   GENERAL REQUIREMENTS                                             2-1
     2.1  Application                                                 2-1
          2.1.1  Types of Water Supplies                              2-2
          2.1.2  Determination of Applicable Services                 2-2
     2.2  Treatment Requirements                                      2-11
     2.3  Operator Personnel Requirements                             2-13

3.   SYSTEMS NOT FILTERING                                            3-1
     3.1  Source Water Quality Criteria                               3-2
          3.1.1  Coliform Concentrations                              3-2
          3.1.2  Turbidity Levels                                     3-4
     3.2  Disinfection Criteria                                       3-5
          3.2.1  Inactivation Requirements                            3-5
          3.2.2  Determination of Overall Inactivation
                 for Residual Profile, Multiple
                 Disinfectants and Multiple Sources                   3-23
                   and Multiple Sources
          3.2.3  Demonstration of Maintaining a Residual              3-31
          3.2.4  Disinfection System Redundancy                       3-34
     3.3  Site-Specific Conditions                                    3-35
          3.3.1  Watershed Control Program                            3-35
          3.3.2  On-site Inspection                                   3-37
          3.3.3  No Disease Outbreaks                                 3-40
          3.3.4  Monthly Coliforn MCL                         '        3-41
          3.3,5  Total Trihalomethane  (TTHM) Regulations              3-43

4.   CRITERIA FOR DETERMINATION OF FILTRATION AND DISINFECTION        4-1
       TECHNOLOGY TO BE INSTALLED
     4.1  introduction                                                4-1
     4.2  Selection of Appropriate Filtration Technology              4-1
          4.2.1  General Descriptions                                 4-2
          4.2.2  Capabilities                                         4-3
          4.2.3  Selection                                            4~7
     4.3  Available Filtration Technologies                           4-9
          4.3.1  Introduction                                         4-9
          4.3.2  General                                              4-9
          4.3.3  Conventional Treatment                               4-11
          4.3.4  Direct Filtration                                    4-12
          4.3.5f,-Slow Sa^id^Filtration                                 4-14
          44.3;.6  Diatomacepus Earth Filtration                        4-16
          '4.3V7  Alternate^Technologies                               4-18
          4.3.8  Other Alternatives                                   4-19

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                         TABLE OF CONTENTS (Continued)

                                                                      Page

     4.4  Disinfection                                                4-19
          4.4.1  General                                              4-19
          4.4.2  Recommended Removal/Inactivation                     4-20
          4.4.3  Total Trihalomethane (TTHM)  Regulations              4-22
5.   CRITERIA FOR DETERMINING IF FILTRATION AND DISINFECTION
       ARE SATISFACTORILY PRACTICED                                   5-1
     5.1  Introduction                                                5-1
     5.2  Turbidity Monitoring Requirements                           5-1
          5.2.1  Sampling Location                                    5-1
          5.2.2  Sampling Frequency                                   5-2
          5.2.3  Additional Monitoring                                5-2
     5.3  Turbidity Performance Criteria                              5-4
          5.3.1  Conventional Treatment or
                 Direct Filtration                                    5-4
          5.3.2  Slow Sand Filtration                                 5-6
          5.3.3  Diatomaceous Earth Filtration                        5-6
          5.3.4  Other Filtration Technologies                        5-7
     5.4  Disinfection Monitoring Requirements                        5-7
     5.5  Disinfection Performance Criteria                           5-7
          5.5.1  Minimum Performance Criteria Required
                 Under the SWTR                                       5-7
          5.5.2  Recommended Performance Criteria                     5-8
          5.5.3  Disinfection By-Product Considerations               5-9
          5.5.4  Determination of Inactivation by
                 Disinfection                                         5-11
     5.6  Other Considerations                                        5-21

6.   REPORTING                                                        6-1
     6.1  Reporting Requirements for Public Water Systems
            Not Providing Filtration                                  6-1
     6.2  Reporting Requirements for Public Water Systems
            Using Filtration                                          6-2

7.   COMPLIANCE                                                       7-1
     7.1  Introduction                                                7-1
     7.2  Systems Using a Surface Water Source
            (Not Ground Water Under the Direct
            Influence of Surface Water)                                7-1
     7.3  Compliance Transition with Current NPDWR
            Turbidity Requirements                                    7-3
     7.4  Systems Using a Ground Water Source Under
            the Direct Influence of a Surface Water                   7-3
     7.5  Responses for Systems not Meeting the SWTR Criteria         7-5
          7.5.1  Introduction                                         7-5
          7.5.2  Systems Not Filtering                                7-5
          7.5.3  Systems Currently Filtering                          7-7

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                         TABLE OF CONTENTS (Continued)


                                                                      Page

8.   PUBLIC NOTIFICATION                                              8-1

9.   EXEMPTIONS                                                       9-1
     9.1  Overview of Requirements                                    9-1
     9.2  Recommended Criteria                                        9-2
     9.3  Compelling Factors                                          9-3
     9.4  Evaluation of Alternate Water Supply Sources                9-6
     9.5  Protection of Public Health                                 9-7
     9.6  Notification to EPA                                         9-10

                                LIST OF TABLES

Table                                                              Following
 No.      Description                                                 Page

2-1       Survey Form for the Classification of Drinking
          Water Sources                                               2-6

4-1       Removal Capabilities of Filtration Processes                4-3

4-2       Generalized Capability of Filtration Systems to             4-8
          Accommodate Raw Water Quality Conditions

6-1       Source Water Quality Conditions for Unfiltered systems      6-3

6-2       Long Term Turbidity Record Sheet for Unfiltered systems     6-3

6-3       CT Determination for Unfiltered Systems                     6-3

6-4       Disinfection Information for Compliance Determination for
          Unfiltered Systems                                          6-3

6-5       Distribution Ssystem Disinfectant Residual Data for
          Unfiltered and Filtered Systems                             6-3

6-6       Monthly Report to Primacy Agency for Compliance
          Determination - Unfiltered Systems                          6-3

6-7       Daily Data Sheet for Filtered Systems                       6-3

6-8       Monthly Report to Primacy Agency Compliance Deterimination
          Filtered Systems                                            6-3

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                         TABLE OF CONTENTS (Continued)

                                LIST OF FIGURES

Figure                                                             Following
 No.      Description                                                 Page

2-1       Steps to Source Classification                              2-3

3-1       Single Chamber Contactor                                    3-16

3-2       Multiple Chamber Contactor                                  3-17

3-3       Turbine Contactor                                           3-18

3-4       City of Tuscon Ozone Contactor                              3-20

3-5       Average Ozone Residuals Los Angeles Aqueduct Filtration
          Plant                              .                         3-21

3-6       Determination of Inactivation for Multiple                  3-24
          Disinfectant Application to a Surface Water Source

3-7       Individually Disinfected Surface Sources Combined           3-27
          at a Single Point

3-8       Multiple Combination Points for Individually                3-27
          Disinfected Surface Sources

4-1       Flow Sheet for a Typical Conventional Water                 4-11
          Treatment Plant

4-2       Flow Sheet for a Typical Direct Filtration Plant            4-13

4-3       Flow Sheet for a Typical Direct Filtration Plant            4-13
         .with Flocculation

                              LIST OF APPENDICES

Appendix  Description                                                 Page

   A      Use of Particulate Analysis for Source and Water
          Treatment Evaluation                    ,                    A-l

   B      Institutional Control of Legionella                         B-l

   C      Tracer Test Procedures                                      C-l

   D      A Survey of the Current Status of Residual Disinfectant     D-l
          Measurement Methods for all Chlorine Species and Ozone

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                         TABLE OF CONTENTS (Continued)

                                LIST OF FIGURES

Figure                                                             Following
 No.      Description                                                 Page

2-1       Steps to Source Classification                              2-3

3-1       Single Chamber Contactor                                    3-16

3-2       Multiple Chamber Contactor                                  3-17

3-3       Turbine Contactor                                           3-18

3-4       City of Tuscon Ozone Contactor                              3-20

3-5       Average Ozone Residuals Los Angeles Aqueduct Filtration
          Plant                                                       3-21

3-6       Determination of Inactivation for Multiple                  3-24
          Disinfectant Application to a Surface water Source

3-7       Individually Disinfected Surface Sources Combined           3-27
          at a Single Point

3-8       Multiple Combination Points for Individually                3-27
          Disinfected Surface Sources

4-1       Flow Sheet for a Typical Conventional Water                 4-11
          Treatment Plant

4-2       Flow Sheet for a Typical Direct Filtration Plant            4-13

4-3       Flow Sheet for a Typical Direct Filtration Plant            4-13
          with Flocculation

                              LIST OF APPENDICES

Appendix  Description                  .                               Page

   A      Use of Particulate Analysis for Source and Water
          Treatment Evaluation                                        A-l

   B      Institutional Control of Legionella                         B-l

   C      Determination Of Disinfectant Contact Time                  C-l

   D      A Survey of the Current Status of Residual Disinfectant     D-l
          Measurement Methods for all Chlorine Species and Ozone

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TABLE OF CONTENTS  (Continued)
Appendix
E
F
G
H
I
J
K
L
M
N
0
LIST OF APPENDICES
Description
Inactivation Achieved by Various Disinfectants
Basis for CT Values
Protocol for Demonstrating Effective Disinfection
Sampling Frequency for Total Coliforms in the
Distribution System
Maintaining Redundant Disinfection Capability
Watershed Control Program
Sanitary Survey
Small System Considerations
Pilot Study Protocol for Alternate Filtration Technology
Protocol for the Demonstration of Effective Treatment
Protocols for Point-of-Use Treatment Devices
Page
E-l
F-l
G-l
H-l
1-1
J-l
K-l
L-l
M-l
N-l
0-1

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                              1.  INTRODUCTION

     This Guidance  Manual complements the  filtration  and disinfection treat-
ment  requirements for  public water  systems using  surface  water  sources or
ground  water under  direct influence  of surface  water  as  presented  in the
Surface Water Treatment Rule  (SWTR).
     The  purpose of  this manual is  to provide  guidance  to United  States
Environmental Protection  Agency  (USEPA)  Regional Offices,  individual  states
and affected utilities  in the implementation of the SWTR, and to help assure
that  actions taken toward  implementation  are  consistent.   This manual is
advisory  in nature  and  is meant to 'supplement the criteria  of the SWTR.   For
example, the SWTR sets treatment requirements which encompass a large range of
source water conditions.   The guidance manual suggests  design,  operating and
performance criteria for  specific surface water  quality conditions to provide
the   optimum    protection   from   microbiological    contaminants.     These
recommendations  are  presented as guidelines  rather  than an extension  of the
rule.  They are offered to give the Primacy Agency flexibility in establishing
the  most  appropriate   treatment  requirements  for  the  waters  within  their
jurisdiction.
     Throughout  this  document,  the  term "Primacy Agency"  refers to  a State
with primary enforcement responsibility for public water systems or "primacy,"
or to mean EPA in the case of a State that has not obtained primacy.
     In order to facilitate the use of this  manual,  it has  been structured to
follow the framework of the SWTR  as  closely as possible.  In this manual, the
term "SWTR" will always refer to the criteria of the rule.  Brief descriptions
of the contents  of each section of this  manual are presented in the following
paragraphs.

Section 2
     This section  provides guidance  for determining  whether  a water  supply
source is subject to the requirements of the SWTR;  including the determination
of whether a ground water source  is  under  direct influence of  surface water
and at  risk  to  the presence  of  Giardia cysts or other  large  microorganisms.
The overall treatment requirements of the SWTR are  also presented, along with
recommendations  for the qualifications of operator personnel.
                                      1-1

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Section 3
     For systems which are  subject  to  the requirements of the  SWTR  and which
do not  currently provide filtration,  this section  provides guidance  to  the
Primacy Agency for determining if a given source:
       -  Meets the source water quality criteria
       -  Meets the disinfection requirements including:
            -  Maintenance of adequate  disinfection
            -  Provision for disinfection system redundancy
       -  Maintains an adequate watershed control program
       -  Meets the on-site inspection  requirements
       -  Has not had an identified waterborne disease outbreak
       -  Complies with the requirements of the Total Coliform Rule
       -  Complies with total trihalomethane (TTHM) regulations

Section 4
     This section  pertains  to systems  which  do not meet  the  requirements to
avoid filtration outlined in Section 3 and therefore  are  required to install
filtration.  Guidance is given for  the selection of an appropriate filtration
technology based on  the  source  water quality  and the  capabilities  of  the
technology  in  achieving  the  required  performance criteria.   In  addition,
recommended  design and  operating  criteria are  provided  for the  available
filtration technologies.

Section 5
     Section 5  presents  guidance  to  the  Primacy  Agency  for  determining
compliance with the  turbidity  and  disinfection performance  requirements to
determine  if   filtration   and   disinfection   are  satisfactorily  practiced.
Recommendations are made for the level of disinfection to be provided in order
to meet the overall treatment requirements of the SWTR.  This section includes
the recommended use of CT (disinfectant residual concentration x contact time)
tables for chlorine, chlorine dioxide,  ozone and chloramines, or demonstration
of effective disinfection for chlorine dioxide, ozone and chloramines.
                                      1-2

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Section 6
     Section 6 provides  guidelines to the Primacy Agency for establishing the
reporting requirements associated with the SWTR.  The requirements include the
report content and frequency, and are applicable to both filtering and nonfil-
tering systems.

Section 7
     This  section provides  an  overview  of the  time  schedule  for  Primacy
Agencies  and  utilities  to meet the  requirements  of the SWTR.   Examples are
presented to provide guidance for  corrective measures  which can  be taken by
systems which are not in compliance with the treatment requirements.

Section 8
     This  section of  the manual  presents  guidance  on public  notification.
Included are examples  of occurrences which  would  require  notification,  lang-
uage of notices and the method of notification.

Section 9
     Section 9 provides guidance to the Primacy Agency for determining whether
a system  is. eligible for an exemption.   The criteria for  eligibility  for an
exemption include:
       -  Compelling factors (economic or resource limitations)
       - - No available alternate source
       -  The protection of public health
This section  also covers  an evaluation  of the  financial  capabilities of  a
water system, the review of the availability of alternate sources and measures
for protecting public health.
                                      1-3

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Appendices
     The manual also  contains  several appendices which provide  more detailed
guidance in specific areas.  These include:

Appendix A - Use of Particulate Analysis
for Source and Water Treatment Evaluation
     A  study  involving 150 water  sources resulted  in the  identification  of
particulate matter which  is  indicative of  a surface  water or  ground  water
under the influence of surface water.  A paper  summarizing the results of the
study is included in this appendix.

Appendix B - Institutional
Control of Legionella	
     Filtration  and/or  disinfection  provides  protection  from  Legionella.
However, it does not assure that recontamination or regrowth will not occur in
the hot water or cooling  systems of  buildings within the distribution system.
This appendix provides guidance for  the monitoring and treatment which can be
used by institutional systems for the control of Legionella.

Appendix C - Tracer Test Procedures
     In many cases, the determination of  disinfectant contact times needed to
evaluate the CT of  a  water system  will necessitate the use of tracer studies.
This appendix provides  guidance for conducting these  studies.   In  some  cases
it may not be practical to conduct a tracer study.  For such cases guidance is
given for estimating the detention time based on the physical configuration of
the system.

Appendix D - A Survey of the Current
Status of Residual Disinfectant
Measurement Methods for all Chlorine
Species and Ozone	
     This appendix includes a listing of the analytical methods required under
the  SWTR.   A copy of  an executive  summary of  a  report on the  analytical
methods  used   to   measure  the   residual  concentrations  of   the  various
                                      1-4

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disinfectants  is  also included.  The  reliability and limitations  of each of
the methods are also presented.

Appendix E - Inactivations Achieved
by the Various Disinfectants	
     This appendix presents the log inactivations of Giardia cysts and enteric
viruses which are achieved at various CT levels by chlorine, chlorine dioxide,
chloramines  and  ozone.   Inactivations  of  enteric  viruses  achieved  by  UV
absorbance are also included.

Appendix F - Basis for CT Values
     This appendix provides  the background and rationale utilized in develop-
ing the CT values for the various disinfectants.  Included is a paper by Clark
et al.f 1988,  in  which a mathematical  model was used in the calculation of CT
values for free chlorine.

Appendix G - Protocol for Demonstrating
Effective Disinfection	
     This appendix  provides the  recommended protocols  for  demonstrating the
effectiveness  of  chloramines,   chlorine   dioxide   and  ozone   as  primary
disinfectants.

Appendix H - Sampling Frequency for
Total Colifoms in the Distribution System
     The sampling frequency  required by the Total Coliform  Rule  (	 FR 	)
is presented in this appendix.

Appendix I - Maintaining
Redundant Disinfection Capability
     This  appendix  details  the  disinfection  conditions  which  should  be
maintained by a system using chlorine,  chlorine dioxide, ozone or chloramines,
to assure that compliance with the SWTR requirement for redundant disinfection
is met.
                                      1-5

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Appendix J - Watershed Control Program
     This appendix  provides a detailed  outline of a  watershed program which
may be  adjusted by the Primacy Agency  to serve the specific  needs of a par-
ticular water system.

Appendix K - Sanitary Survey
     This appendix provides guidance  for a comprehensive sanitary survey of a
supply  source,  its  treatment and delivery to  the  consumer.   The contents for
an annual on-site inspection are included in Section 3.

Appendix L - Small System Considerations
     This appendix  presents difficulties which may be faced by small systems
in complying with  the SWTR along with  guidelines  for  overcoming these diffi-
culties.

Appendix M - Pilot Study Protocol
for Alternate Filtration Technology
    . This appendix  presents pilot study protocols to  evaluate the effective-
ness  of  an  alternate  filtration  technology  in  attaining  the  performance
requirements of the SWTR.

Appendix N - Protocol for the
Demonstration of Effective Treatment
     This appendix  provides guidance for  conventional  and  direct filtration
plants to demonstrate that adeguate filtration is being maintained at effluent
turbidities between 0.5 and 1 Nephelometric Turbidity Unit (NTU).

Appendix O - Protocol for
Point-of-Use Treatment Devices
     In  some  limited cases,  it may  be appropriate  to  install  point-of-use
(POU)   or point-of-entry  (POE)  treatment  devices as  an  interim  measure  to
provide protection  to the public health.   This appendix provides  a protocol
for evaluating and determining the efficacy of POU/POE treatment devices.
                                      1-6

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                           2.  GENERAL REQUIREMENTS

2.1  Application
     The SWTR pertains to  all public water  systems which utilize  a surface
water  source  or ground  water source  under the  direct influence of surface
water.  The SWTR defines  a  surface water as all  waters which  are open to the
atmosphere  and subject  to  surface  runoff.   Ground water  under the  direct
influence of  surface  water is defined as:   any water  beneath  the surface of
the ground with (i) significant occurrence of insects or other macroorganisms,
algae, organic debris, or large-diameter pathogens such as Giardia lamblia, or
(ii) significant and relatively rapid  shifts  in water characteristics such as
turbidity,  temperature,  conductivity,  or  pH  which  closely  correlate  to
climatological  or  surface  water  conditions.    Direct  influence   must  be
determined for each individual source  in accordance with criteria established
by  the  Primacy  Agency.    The  Primacy Agency  criteria  may  provide  for
documentation  of  well  construction and geology, with field  evaluation,  or
site-specific measurements of water quality as explained in Section 2.1.2.
     The traditional  concept that  all water  in  subsurface aquifers  is free
from pathogenic organisms is based upon soil  being an  effective  filter that
removes microorganisms and  other  relatively large particles by straining and
antagonistic  effects  (Bouwer,  1978).    In most cases  pathogenic  bacteria
retained in the soil find themselves in a hostile environment,  are not able to
multiply'and  eventually  die.  However,  some  underground  sources  of drinking
water may be  subject to contamination  by pathogenic organisms  from the direct
influence of nearby surface waters.
     Only those  subsurface  sources which are  at risk to  contamination from
large microorganisms  such as  protozoa  (specifically  Giardia  cysts) will be
subject to the requirements of the SWTR.   Subsurface  sources which  may be at
risk to contamination from bacteria and  enteric viruses, but which are not at
risk from Giardia cysts will be regulated either under the Total Coliform Rule
or  forthcoming  disinfection treatment requirements  for ground waters.   EPA
intends to promulgate  disinfection requirements  for ground water systems in
conjunction with regulations for disinfection by-products by 1991.
                                     2-1

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     2.1.1  Types of Water Supplies
     Surface Waters
     Surface water supplies  that  are often used as  sources  of drinking water
include  two  major classifications,  running and  quiescent  waters.   Streams,
rivers  and  brooks are  examples  of  running water,  while lakes,  reservoirs/
impoundments and  ponds are  examples of  quiescent  waters.   The exposure  of
surface waters to the atmosphere  results  in exposure to precipitation events,
surface water runoff and contamination with micro and macroorganisms resulting
from activities in their surrounding areas.  These  sources are subject to the
requirements of the SWTR.
     Systems with rain  water catchments  not subject to surface  runoff (e.g.
roof  catchment areas)  are  not considered vulnerable  to contamination  from
animal populations which  carry protozoan  cysts pathogenic to humans  and are
thus not  subject  to  the SWTR requirements.  However, such  systems  should  at
least  provide  disinfection  to  treat  for potential  bacterial  and  viral
contamination coming from bird populations.
     Ground Waters under Direct Influence of Surface Water
     Ground  water  sources  which  may   be subject  to  contamination  with
pathogenic organisms  from surface waters  include,  springs,  infiltration  gal-
leries,  wells  or  other collectors  in  subsurface  aquifers.   The  following
section presents a recommended procedure for determining whether a source will
be subject to the requirements of  the SWTR.
     2.1.2  Determination of Applicable Sources
     The  Primacy  Agency has  the  responsibility for determining which water
supplies  must  meet  the  requirements  of the  SWTR.   However,  it  is  the
responsibility of the water  purveyors  to  provide the Primacy  Agency with the
information needed to make this determination.   This section provides guidance
to the Primacy Agency for determining which water  supplies are surface waters
or  ground waters  directly   influenced  by  a  surface water  and are  thereby
     1.   One study  (Markwell and Shortridge, 1981}  indicates  that a cycle of
          water  borne  transmission  and maintenance  of  influenza virus  may
          exist within duck communities, and that  it is conceivable for virus
          transmission to occur  in  this manner to other susceptible animals,
          including humans.
                                     2-2

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subject to the requirements of the SWTR.  Following the determination that the
source is subject to the SWTR  the  requirements  enumerated in Sections 2.2 and
2.3 must be met.
     The Primacy  Agency must  develop a program  for evaluating  ground water
sources for direct influence within 18 months of the promulgation of the rule.
All community  ground  water systems must be evaluated  within 5 years  of the
SWTR promulgation/ while all non-community systems must be evaluated within 10
years.  Primacy Agencies with  an approved Wellhead  Protection  (WHP)  Program,
may be able to use the WHP program's requirements which include delineation of
wellhead  protection  areas,   assessment  of  sources   of  contamination  and
implementation of management control measures.  These same requirements can be
used for meeting the requirements  of  the watershed control program for ground
water under the direct influence of a surface water.
     A multiple step approach  has  been  developed  as the recommended method of
determining whether  a  ground  water  source is  under  direct influence  of  a
surface water.   This approach includes  the review  of  information  gathered
during sanitary surveys.   As  defined by the USEPA,  a sanitary survey  is an
on-site  review of  the  water  source,   facilities,  equipment  operation  and
maintenance  of a  public  water  system for  the  purpose  of evaluating  the
adequacy of such source, facilities,  equipment, operation and maintenance for
producing and distributing safe drinking water.   Sanitary surveys are required
under  the  Total  Coliform Rule  and  may be  required  under the  forthcoming
disinfection  requirements  for  ground  water  systems  as  a  condition  for
obtaining a variance  or for determining  the level of  disinfection required.
Therefore,  it is recommended that the determination of direct influence be
correlated with the sanitary surveys conducted under these other requirements.
     As illustrated on  Figure  2-1, the determination of whether  a source is
subject  to  the requirements  of  the SWTR  may  involve  one  or more of  the
following steps:
     1.   A review  of  the records  of  the system's  source(s)  to determine
          whether the source  is obviously  a  surface water,  i.e.  pond,  lake,
          streams, etc.
     2.   If the source  is a  well, determination of whether it is clearly  a
          ground  water  source,  or  whether  further analysis  is  needed  to
          determine possible surface water influence.
                                     2-3

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Obvious Surface
Sources:
Lakes, Reservoirs,
Streams, Creeks,
Rivers, etc.
j
SWTR Applies

~^-(Yes J 	
All Public Water
Systems


Identify Source Type




Source is Spring
Infiltration Gallery, or
Ranney Well


Review System File
and Conduct
Sanitary Survey


Source Influenced by
Surface Water?



Source is Well

Well is Protected from
Surface Influence
Based on State
Criten'a?
\ 6S J
SWTR Does Not Apply
                              Undecided -

 Conduct Paniculate
  Analysis. Monitor
  Changes :n Water
Quality, Temperature,
       etc.
                         Summary of Findings
                           Indicate Source is
                         Influenced by Surface
                           Water and Could
                           Contain Giardial
    FIGURE 2-1   STEPS TO  SOURCE CLASSIFICATION

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     3.   A complete review of the system's files followed by a field sanitary
          survey.   Pertinent information  to  gather  in  the  file  review and
          field  survey  includes:  source design  and  construction;  evidence of
          surface water contamination;  water quality analysis;  indications of
          waterborne disease  outbreaks; operational procedures;  and customer
          complaints  regarding  water  quality  or  water related  infectious
          illness.
     4.   Conducting particulate analysis and other water quality sampling and
          analyses.
Step 1.  Records Review
     A review of information  pertaining to each source  should  be carried out
to  identify those  sources which  are  obvious  surface  waters.  These  would
include ponds,  lakes,  streams,  rivers, reservoirs,  etc.   If the source  is  a
surface water, then the SWTR  would apply,  and criteria in the rule would need
to be applied to determine if filtration is necessary.   If  the source is not
an obvious  surface  water,  then further analyses, as presented  in Steps 2, 3,
or 4, are  needed to determine  if the  SWTR will apply.   If the source  is  a
well, go to Step 2.   If the source is  a spring, infiltration gallery, Ranney
well, or any other subsurface source,  proceed to Step 3 for a more detailed
analysis.

Step 2.   Review of Well Sources
     While  most well  sources have  historically been considered  to be  all
ground water,  recent evidence  suggests that  some  wells, especially shallow
wells constructed  near surface waters, may be  influenced by  surface water.
One  approach in determining  whether a well is  subject to contamination  by
surface water  would be to  evaluate the  water quality  of the  well by the
criteria in Step 4.  However, this process  is  rather time consuming and labor
intensive.    In   an  attempt  to  reduce the effort  needed  to  evaluate  well
sources, a set of criteria have been developed to identify wells in deep, well
protected aquifers which are  not subject to contamination from  surface water.
While these  criteria  are  not as definitive as water quality analysis,  it is
believed that they  provide a reasonable degree  of  accuracy, and allow  for  a
relatively rapid determination for a large number of well sources in the U.S.
     Wells less than or equal to 50 feet in depth are considered to be shallow
wells, and  should be  evaluated for  surface influence  according to  steps  3

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and/or 4.   For  wells greater  than 50 feet  in depth,  State or  system  files

should be reviewed for the criteria listed below:


     1.  The well construction should include:

            -  A surface sanitary seal using bentonite clay, concrete or other
               acceptable material.

            -  A well  casing  that penetrates consolidated  (slowly permeable)
               material.

            -  A well casing that is only perforated or screened below consol-
               idated (slowly permeable)  material.

     2.   The source  should be  located  at  least 200  feet from  any  surface
          water.

     3.   The water quality records should indicate:

            -  No record of total  coliform or  fecal coliform contamination in
               untreated samples collected over the past three years.

            -  No history of turbidity problems associated with the source.

            -  No history of known or  suspected outbreak of Giardia, or other
               pathogenic  organism   associated   with   surface   water  (e.g.
               Cryptosporidium), which has been attributed to that source.

     4.   If  data  is  available  for particulate   matter   in  the  well;   or
          turbidity or  temperature data  from  the  well  and a  nearby  surface
          water there should be:

            -  No  evidence  of  particulate  matter associated  with  surface
               water.

            -  No turbidity or temperature data which  correlates  to that of a
               nearby surface water.

     Wells that meet  all of the criteria listed  above are  not  subject to  the

requirements of the SWTR, and no additional  evaluation is needed.  Wells that

do  not  meet all  the  requirements   listed require  further  evaluation  in

accordance with Steps 3 and/or 4 to determine whether or not they are directly

influenced by surface water.

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Step 3.    Sanitary  Survey
      For  sources other them a well source, the State or system files should be
reviewed  for the well construction and  water quality conditions as listed in
Step 2.   Reviewing historical records in State or  system files  is a valuable
information  gathering tool.   However,  the  results  may be  inconclusive.   A
sanitary  survey in the field may be  helpful in  establishing a  more definite
determination of whether the water source is at risk to pathogens from surface
water influence.

      Information to obtain during a sanitary survey include:

       -   Evidence  that surface water enters the  source through defects in the
           source such as lack of a surface seal on wells, infiltration gallery
           laterals  exposed  to surface water, springs  open  to the atmosphere,
           surface runoff entering a spring or other collector, etc.

       -   Distances to obvious surface water sources.

      If  the  survey indicates  that  the well is  subject  to  surface  water
influence, the  source must  either be  reconstructed  as explained  later in this
section or it  must be treated  in accordance with the  requirements  for the
SWTR.   If the  survey does not  show conclusive evidence  of  surface  water
influence,' the  analysis outlined in Step 4 should be conducted.
      The  Washington State Department  of  Social and  Health Services has devel-
oped  a  form  to guide them and  provide consistency  in their  evaluation  of
sources for  surface water influence  (Notestine  & Hudson,  1988).    Table 2-1
provides  a copy of  this form as a guide for evaluating sources.

Step  4.    Particulate Analysis and Other Indicator Parameters.
      Particulate analysis is  intended to identify  organisms  which only occur
in surface waters as opposed to ground waters, and  whose presence in a ground
water would  clearly indicate  that at least some  surface  water has been mixed
with  it.   Method 912K  in  Standard Methods,  for Giardia  cyst  analysis,  can be
                                     2-6

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                                   TABLE 2-1

         SURVEY FORM FOR THE CLASSIFICATION OF DRINKING WATER SOURCES
General
 1.  Utility Name (ID#)
 2.  Utility Person(s) Contacted
 3.  Source Type (As shown on state inventory)

     ________ Spring                    _________ Ranney Well
     	 Infiltration System       	 Shallow Well
 4.  Source Name                          '	 Year constructed 	

 5.  Is this source used seasonally or intermittently?  No 	 Yes	
     If yes, are water quality problems the reason?  No 	 Yes	

 6.  Has there  ever been a  waterborne disease outbreak  associated  with this
     source?  Yes 	 No 	 If yes, explain 	
 7.  Have there  been turbidity  or bacteriological MCL  violations  within the
     last five years associated with this source?  No	 Yes 	
     If yes, describe frequency, cause, remedial action  (s) taken 	
 8.  Have there been consumer complaints within the past five years associated
     with  this  source?   No  	  Yes  	   If  yes,  discuss  nature,
     frequency, remedial action taken	
 9.  Is  there  any  evidence of  surface  water  intrusion  (pH,  temperature,
     conductivity, etc. changes) during the year?  Yes 	 No 	
     If yes, describe 	
10.  Sketch of source in plan view  (on an additional sheet)
Shallow Wells

 1.  Does  the  well meet  good  sanitary practices  regarding  location,  con-
     struction, seal etc. to prevent the entrance of surface water?
     Yes 	  No 	  If no, describe the deficiencies 	
                                     -  1  -

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 2.  Hydrogeology (Attach copy of well log or summarize it on reverse)
     a.   Depth to static water level? (Feet) 	
     b.   Drawdown? (Feet)                            	
     c.   What is the depth to the highest screen or perforation?  (Feet)

     d.   Are there impervious layers above the highest screen or perforation?
          Yes        No        Unknown
          If yes, please describe
 3.  Is there a permanent or intermittent surface water within 500 feet of the
     well?  Yes 	  No 	  If yes, describe (type, distance etc.)
4.   Additional comments:
Springs

 1.  a.   What is the size of the catchment area (acres)? 	
     b.   Give a  general  description of  the  area  (terrain;  vegetation;  soil
          etc.)   '	              	
 2.  What is the vertical distance between  the  ground surface and the nearest
     point of entry to the spring collector(s)  (feet)? 	
 3.  How rapidly does rainfall percolate into the ground around the spring?

     	 Percolates readily; seldom if ever any runoff.
     _____ Percolates readily but there is some runoff in heavy rain.
     	 Percolates slowly.  Most local rainfall ponds or runs off.
     	 Other 	

 4.  Does an impervious  layer prevent direct percolation of  surface  water to
     the collector (s)?  Yes 	 No 	 Unknown 	

 5.  Is  the  spring  properly  constructed to prevent  entry of  surface  water?
     Yes 	 No	

 6.  Sediment
     a.   Is the spring box free of debris and sediment?  Yes 	 No 	
     b.   When was it last cleaned (Date)             	
     c.   How often does it need to be cleaned? (month)
                                     - 2 -

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     d.    How much  sediment  accumulates  between  cleaning?    (estimate  in
          inches)
 7.   Additional comments:
Infiltrations System and Ranney Wells

 1.  What are the  shortest distances  (vertical and horizontal separating the
     collector from the nearest surface water?  (Feet)  	
 2.   Does turbidity of  the  source vary 0.2 NTU  or more throughout the year?
     Yes 	 No ^^^^^^ Not measured 	
     If yes, describe how often and how much  (pH,  temperature,  conductivity,
     etc.)                        	
 3.  Additional Comments
Survey Conducted By: 	________________^_^_ Date:
Decision? Surface Impacted Source      Yes 	  No 	 If no,  further
evaluation needed (particulate analysis, etc.)

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applied for general particulate analysis as discussed in the paper in Appendix
A (Hoffbuhr, et al, 1986).
     In  1986  Hoffbuhr  et.  al.  listed  six  parameters  identifiable  in  a
particulate  analysis  which were believed  to be  valid indicators of surface
contamination  of ground water.   These  were:   diatoms,  rotifers,  coccidia,
plant debris,  insect  parts,  and Giardia cysts.   Later work by  Notestine  and
Hudson  (1988)  found that microbiolegists did not  all define plant  debris  in
the same way, and that deep wells known  to be  free of surface  water  influence
were shown by particulate  analysis  to contain  "plant debris" but none  of  the
other five indicators.   Their  work  suggests that  "plant debris" may not cur-
rently be a useful tool in determining surface water  influence,  but  may be  in
the future when a standard definition of "plant debris"  is  developed.  There-
fore, it is  recommended  that only the presence of the other five parameters;
diatoms, rotifers, coccidia,  insect parts, and Giardia, be  used  as  indicators
of  direct  surface  contamination.   In  addition,  if  other  large   diameter
(> 7 urn) organisms  which are  clearly of  surface water  origin are  present,
these  should  also be   considered  as  indicators  of  direct  surface  water
influence.  Methods of collecting samples and  interpreting  results are  listed
below:
     Sampling Protocol
       -  Sampling Procedure
          Samples should be collected using the equipment outlined in Standard
          Methods 912K.

       -  Location
          Samples should always be collected as close  to the source  as  possi-
          ble, and prior to  any  treatment.   If samples must  be taken after
          disinfection,   samples  should  be  noted  and analyzed as  soon  as
          possible.
       -  Number
          A minimum of two samples  should  be collected during the period  the
          source is most susceptible  to  surface water influence.  Such crit-
          ical periods will  vary from system  to  system and will need  to  be
          determined case by case.   For  some systems, it may  be one or more
          days following a significant rainfall  (eg. 2" in  24 hours) .   For
          other  systems  it  may be a  period  of maximum  flows  and  stream
          turbidities  following spring snowmelt,  or during the  summer  months
          when water tables are elevated as  a  result of irrigation.  In each
                                     2-7

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          case, particulate  samples should  be  collected when  the source  in
          question  is  most  effected.   A surrogate  measure such as  source
          turbidity or  depth  to water  table may be  useful  in  making  the
          decision to monitor.   If  there is any ambiguity  in the  particulate
          analysis results, additional samples should be  collected when there
          is the greatest  likelihood  that the source will  be contaminated  by
          surface water.
       -  Volume
          Sample volume should be between 500 and  1000  gallons,  and should  be
          collected over  a  4  to 8  hour time  period.    It is  preferable  to
          analyze  a similar  (+/-  10%)  volume of water  for  all  sources,
          preferably a large volume, although this  may  not  always  be  possible
          due  to  elevated  turbidity' or  sampling  logistics.   The  volume
          filtered should be recorded for all samples.
     Interpretation
     A standardized process  for  sampling and analyzing  particulates in drink-
ing water has  not  been established.  Therefore the  interpretation of results
may differ depending on the  sampling  and analytical procedures  used,  and also
on the training and experience of the  microbiologist.   At present  the methods
simply do  not  have  the precision  to  establish  a  numerical  ranking  of  the
degree to which a  source  is influenced, or  the risk that it presents.   Until
such time as the particulate analysis process is standardized, the  presence of
any of  the  five   (or  other)  surface  water indicators  should  be considered
strong evidence of surface water influence.
     There may be times when the particulate results are  not definitive.  For
example when only a single  rotifer  is observed  in  a sample  collected during a
critical period, and ^11  other  information  indicates  the  source  is  a  ground
water.   For such  ambiguous results,  it  is recommended that  several  other
particulate analyses be collected at critical times in an attempt to reproduce
the original results.
     Consistent identification of surface indicators, even  few  in  numbers,  is
strong evidence of surface  influence.   However, if the  initial  results  cannot
be reproduced  during  critical  times,  it  may be  concluded  that the  source  is
more likely a ground water.
     Other Indicators
     A number of other indicators could be used to provide  supportive evidence
of surface  influence.  While particulate analysis probably provides  the most
                                       - fl

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direct evidence  that pathogens from surface  water could be  migrating into a
ground water  source,  other parameters such as  turbidity,  temperature, pH and
conductivity could provide supportive, but less direct, evidence.
     Turbidity fluctuations of greater than 0.5 - 1 NTU over the course of a
year  may be  indicative  of surface  water  influence.  Considerable  caution
should be used when evaluating turbidity changes  though,  since the turbidity
could be caused  by  very small particles (< lum) not originating in a surface
water or it could be that larger particles are being filtered out and only the
very smallest particles migrate into the water source.
     Temperature  fluctuations  may  also indicate surface  water  influence.
Fortunately these are  easy to obtain  and if  there is a surface water within
500  feet  of  the  water source, measurements  of both  should be  recorded for
comparison.  Large  changes in surface water  temperature closely followed by
similar changes  in  source  temperature would be  indicative of  surface  water
influence.  Also, temperature changes  of greater than  15-  20% over the course
of a year appear to be a  characteristic of  some sources influenced by surface
water  (Randall,  1972) .   Changes   in  other chemical   parameters  such as  pH,
conductivity, hardness,etc. could  also be monitored.  Again,  these would not
give a  direct indication  of  whether  pathogens  originating  in  surface  water
were present, but could indicate whether the water chemistry was  or  was not
similar  to  a  nearby  surface water   and/or  whether  source" water chemistry
changed in  a similar  pattern to  surface  water chemistry.   At  this  time no
numerical- guidelines are available to differentiate what is or is not similar,
so these comparisons are more qualitative than quantitative.
     Seasonal Sources
     Some sources may  only be used  for part of the year,  for  example during
the  summer  months  when  water usage  is high.   These sources  should not be
excluded from evaluation  and,  like other sources, should be evaluated during
their period(s)  of highest  susceptibility.  Particular  attention  should be
given to those sources which appear to be influenced  by surface water during
part of  the year.   There may be  times during which  these  subsurface  water
sources are not influenced bysurface water and other times when they are part
or all surface water.   If that is  the case,  then  it is  critical that careful
testing be  done  prior to,  during  and  at  the end of  the  use of the  source.
                                     2-9

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This should  be  done over  several  seasons to account  for  seasonal variation.

In practice,  it is  preferable to use  sources  which  are  less  vulnerable  to

contamination since  susceptible sources  will necessitate ongoing monitoring

and close attention to operation.

     Modification of Sources

     Sources  influenced  by  surface  water  may  be  altered in  some cases  to

eliminate the surface water  contamination.   States  may elect  to allow systems

with such  sources  to modify  the construction of  the  source and/or  the  area

surrounding the source in  an effort  to  eliminate  surface water contamination.

Since  this  could  be expensive  and  take  considerable  time  to evaluate  for

effectiveness, careful consideration should be given to the decision to modify

a source.  In deciding whether source modification is appropriate,  systems and

States should consider the following points:

       -  Is  the  cause  of  the  surface  water  contamination  known?  If  the
          specific cause or point of surface water contamination is not known,
          it will not be possible  to determine  an effective  control strategy.
          Further, there may be  several reasons why the source is  susceptible
          to  surface water  influence.   For example, an  infiltration gallery
          may receive surface water  because some of its  laterals  are exposed
          in  the  bed of a nearby stream,  and  also because  laterals  distant
          from  the stream  are shallow  and are  affected  by  surface  runoff.
          Simply modifying or  eliminating  one or  the other set of  laterals in
          this case would not entirely eliminate surface water influence.

       *  What  is  the  likelihood that modification  of  the  source will  be
          effective?  Assuming  that the  source  of  contamination has  been
         . identified, the expected effectiveness of control measures should be
          evaluated.  If the cause is relatively discreet, a  crack in a  well
          casing or an uncovered spring  box for example,  then  there is a  high
          degree of  confidence that  an  effective  solution could be developed.
          Should the nature  of  the  contamination  be  more diffuse,  or  wide-
          spread,  then  the merits of spending time and money  to  modify  the
          source should be carefully considered.   In the  case  of  the example
          above, eliminating the use of the laterals  under the  stream  will
          solve part of the  problem.  Without considerably more hydrogeologic
          information  about  the  aquifer  and  the placement   of  the  other
          laterals,  though,  it  is not  clear what,  if any,  control measures
          would effectively  eliminate surface water influence  in those later-
          als distant from the stream.

     If a source is identified as being influenced by surface water, and it is

decided  to  attempt  to modify it, interim disinfection practices  which  will

ensure at least 99.9%  inactivation of Giardia should  be considered.  Methods
                                    2-10

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and levels  of disinfection which can be used  to  achieve such removals can be
found in Subsection 141.72  (a) of the SWTR and in Section 3.2 of this manual.
     A  partial listing  of  types of modifications  which could  be undertaken
includes:
     i)   Diverting surface runoff from springs by trenching, etc.
     ii)  Redeveloping springs to capture them below a confining layer.
     iii) Covering open  spring collectors
     iv)  Reconstructing wells  to  install  sanitary  seals,  and/or  to screen
          them in a confined  (protected) aquifer.
     v)   Repairing  cracks  or breaks  in any type  of source collector  that
          allows the entry of surface contaminants.
     vi)  Discontinue the use of infiltration laterals which intercept surface
          water.
     An  extended  period  of  monitoring  should  follow  reconstruction  (eg.
through at  least two years or critical periods) to evaluate whether the source
is still  influenced  by surface water.  Preferably particulate  analysis would
be used to  make such evaluations, but  it may be helpful to  use simpler mea-
sures,  such as temperature and  turbidity, as screening tools.   Longer  term
monitoring  at critical times  may also be  an appropriate agreement between the
system  and  the Primacy  Agency  if there  is still doubt  about the  long  term
effectiveness  of the solution.
     If modification  is  not feasible,  another alternative to  avoid having to
comply  with  the  SWTR may  be to develop  a new  well either  deeper or  at  a
different location.

2.2  Treatment Requirements
     According to the   SWTR,  all  community  and noncommunity  public  water
systems which use a surface  water  source  or a ground water  under the direct
influence of  a surface water must  achieve  a minimum  of  99.9 percent (3 log)
removal and/or inactivation of  Giardia  cysts, and a minimum  of  99..99 percent
(4 log) removal and/or inactivation of  viruses.   In  the  SWTR  and this manual,
"viruses" means  viruses  of fecal origin  which are  infectious  to  humans  by
waterborne  transmission.  Filtration  plus disinfection or  disinfection alone
                                    2-11

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may be utilized  to achieve these performance levels, depending on the source
water  quality and site  specific  conditions.    The  SWTR  establishes  these
removal and/or inactivation requirements based  on Giardia and viruses because
this level of treatment will  also provide  protection  from heterotrophic plate
count (HPC) bacteria and Legionella    as required in the SDWA amendments.
     Guidelines for meeting the  requirements  of the SWTR are  provided in the
remainder of this  manual as outlined  in  Section 1.  All systems must meet the
operator qualificiaitons presented in Section 2.3.

2.3  Operator Personnel Qualifications
     The SWTR requires that all  systems must  be operated by qualified person-
nel.  It  is recommended that the Primacy Agency set  standards  for operator
qualifications,  in accordance with  the  system type  and  size.  In  order  to
accomplish this, the  Primacy  Agency should develop a method  of evaluating an
operator's competence in operating a water treatment system.  Primacy Agencies
which do not currently have a certification program are thereby encouraged, to
implement  such  a  program.   An  operator certification program provides  a
uniform  base  for operator   qualifications  and  an  organized  system  for
evaluating these qualifications.
     It is recommended that plant operators have a basic knowledge of science,
mathematics  and  chemistry  involved  with  water  treatment and  supply.   The
minimum requirements  for  at   least  one  key  staff member  should  include  an
understanding of:
       -  The principles of water treatment and distribution and their charac-
          teristics
       -  The uses of potable water and variations in its demand
       -  The importance of water quality to public health
       -  The equipment,  operation and maintenance of the distribution system
     f.   In the SWTR and this manual  "Legionella"  means  a genus of bacteria,
          some  species  of  which  have  caused  a  type  of  pneumonia  called
          Legionnaires  Disease;  the   etiologic  agent  of  most   cases   of
          Legionnaires Disease examined has been L.  pneumophila.
                                    2-12

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       -  The treatment process equipment utilized,  its operational parameters
          and maintenance

       -  The principles of each process unit  (including  the  scientific basis
          and purpose of  the  operation and  the mechanical components  of  the
          unit)

       -  Performance  criteria  such  as  turbidity,  total  colifonn,   fecal
          coliform,  disinfectant residual, pH,  etc. to determine  operational
          adjustments

       -  Common operating problems  encountered in  the system and  actions  to
          correct them

       -  The current National Primary Drinking Water  Regulations,  the  Secon-
          dary  Drinking  Water  Regulations  and   monitoring and  reporting
          requirements

       -  Methods of sample collection and sample preservation

       -  Laboratory  equipment  and  tests   used to  analyze  samples  (where
          appropriate)

       -  The use of laboratory results to analyze plant efficiency

       -  Record keeping

       -  Customer relations

       -  Budgeting and supervision (where appropriate)

     Training in  the  areas listed  above  and others is available  through  the
American - Water  Works  Association  (AWWA)  training  course series  for  water
supply operations.  The course series includes  a set of four  training manuals
and one reference book as follows:
       -  Introduction to Water Sources and Transmission (Volume  1)

       -  Introduction to Water Treatment (Volume 2)

       -  Introduction to Water Distribution (Volume 3)

       -  Introduction to Water Quality Analyses (Volume 4)

       -  Reference Handbook:   Basic Science Concepts and Applications

       -  Instructor Guide and Solutions Manual for  Volumes 1, 2, 3 and  4
                                    2-13

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     These manuals are available through the American Water Works Association,
6666 West Quincy Avenue, Denver, Colorado 80235 USA, (303) 794-7711.
     The State  of California  also offers  a series of  training manuals  for
water treatment  plant operators prepared  by the California  State  University
School of Engineering in Sacramento.  The manuals include:
     1.    Water Supply System Operation.  (1 Volume)
     2.    Water Treatment Plant Operation.   (2 Volumes)
     These  operator   training  manuals  are  available  from  California  State
University,  Sacramento,  6000 J Street,  Sacramento, California  95819,  phone
(916) 454-6142.
     Completion  of an  established training and  certification  program  will
provide  the  means of  assuring  that the  operators  have received training  in
their respective  area,  and are qualified  for their position.   The education
and experience requirements for certification should be  commensurate with the
size and the  complexity of the treatment  system.   At the present  time,  some
states have instituted a certification program while others have not.  Follow-
ing is a summary of  the basic contents of  a certification program, which can
serve as a guide to the Primacy Agency in developing a complete program.
       -  Board  of examiners  for  the development  and  implementation  of  the
          program.
       -  Classification of  treatment  facilities  by grade  according  to  the
          size and technology of the facilities.
       - * Educational and experience requirements for operators of the various
          treatment facilities according to grade.
       -  A written/oral examination  to determine   the knowledge, ability  and
          judgement of the applicants with certification obtained upon receiv-
          ing a passing grade.
       -  Renewal  program  for  the  license of  certification,   including  the
          requirement of additional coursework or participation in workshops.
     The certification program should  provide technically qualified personnel
for the  operation of the plant.
     The extensive responsibility  which is placed  on the  operating personnel
warrants the  development of an  outline of  the  responsibilities  and authority
of the personnel members to aid them  in the efficient  operation  of  the plant.
                                    2-14

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The major  responsibilities which  should  be delegated  in the outline  of re-
sponsibilities include:  the normal day-to-day operations,  preventive mainte-
nance, field engineering, water quality monitoring, troubleshooting, emergency
response,  cross-connection control,  implementation  of  improvements,  budget
formulation,  response  to  complaints  and public/press  contact.   A reference
which  the  Primacy Agency  may  utilize in  developing  the  outline is  "Water
Utility Management Practices" published by AWWA.
                                    2-15

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                          3.0  SYSTEMS NOT FILTERING


     The provisions  of  the SWTR  require that  filtration  or a  particulate

removal technology as approved by the  Primacy Agency, must be included in the
treatment train unless certain criteria are met.   These  criteria are enumerat-

ed in this chapter and include:

     Source Water Quality Conditions
     1.   Coliform concentrations (total or fecal).

     2.   Turbidity levels.

     Disinfection Criteria

     1.   System maintains at least 99.9 percent Giardia cyst inactivation and
          99.99 percent virus inactivation, for all but  one day per month.

     2.   System must have redundant backup components with an auxiliary power
          supply, automatic start-up  and  alarm to  ensure  continuous  disin-
          fection, or automatic  shutoff of  delivery  of  water  to the  dis-
          tribution system  when  the residual  drops below  0.2  mg/L.  To allow
          the automatic  shutoff,  the Primacy  Agency must  determine  that this
          would not result in an unusal risk to health.

     3.   System maintains a minimum residual  of 0.2 entering the distribution
          system.  The residual  level must not  drop below 0.2 mg/L for more
          than a 4 hour period.

     4.   System maintains  a detectable disinfectant residual  in  the  distri-
          bution system or a level of less than 500 HPC  colonies/ml in  no less
         . than 95 percent  of the samples each month for  any  two  consecutive
          months.  For systems which cannot practically monitor for HPC,  the
          Primacy  Agency  may establish  site   specific  criteria  to   ensure
          adequate disinfection is provided.

     Other Criteria

     1.   System maintains a watershed control program.

     2.   System has an  on-site  inspection each  year conducted by the  Primacy
          Agency, or  a  party approved  by  the Primacy Agency,  to  demonstrate
          that the system has adequate watershed control and disinfection.

     3.   System in its current configuration  has not had a waterborne  disease
          outbreak, as determined by State or local health officials.

     4.   System complies  with the  total coliform  MCL for  the  distribution
          system.
     5.   System is in  compliance with  the Total Trihalomethane  (TTHM)  reg-
          ulation.  Currently  this  only applies to  systems  serving  more than
          10,000 people.

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     The purpose of this section is to provide  guidance to the Primacy Agency
for determining compliance with these provisions.

3.1  Source Water Quality Criteria
     The first step in determining if filtration is required for a given sur-
face water supply is to determine if the supply meets the source water quality
criteria as specified  in  the SWTR.   The site-specific  criteria pertaining to
systems which do not filter are not applicable unless the source water quality
criteria are met.
     Sampling Location
     The SWTR requires that  the source  water samples be collected at a loca-
tion just  prior to the point of disinfection  where the  water is  no longer
subject to surface runoff.  When multiple sources are used, sampling should be
conducted at  a location  just prior to  the point  of disinfection  or disin-
fection sequences used for calculating the  CT [disinfectant residual (mg/L)  x
contact time  (min.}].  Sampling at  this location is  appropriate  because this
is the water which will be disinfected  in  accordance with  the requirements of
the SWTR and is, therefore, the source water.
     3.1.1  Coliform Concentrations;  Specifically, the SWTR  states that the
system must demonstrate that either the fecal  coliform concentration is less
than 20/100 ml or the total  coliform concentration  is less than 100/100 ml in
                          
the water prior to the point of disinfectant application in 90 percent of the
samples taken during any  consecutive  six month period.  Where monitoring for
both parameters  has been  conducted,  the rule  only  requires  that  the  fecal
coliform limit be  met.  However, EPA recommends that  the  analytical results
for both total coliforms and fecal coliforms be reported,   in addition, if the
turbidity of a surface water  source is greater  than 5 MTU  and is blended with
a ground water to reduce the turbidity,  EPA recommends that the high turbidity
water prior to blending meet the fecal coliform source water quality criteria.
     Ongoing monitoring  is  required  to ensure that these requirements  are
continually met.  The  samples may be  analyzed  using  either the multiple tube
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fermentation method or the membrane filter  test  (MF)  as described in the 16th
Edition of Standard Methods.
     Sampling Frequency
     Minimum sampling frequencies are as follows:
          Population Served        Coliform Samples/Week*
               <500                          1
               ?01-3,300                     2
               3,301-10,000                  3
               10,001-25,000                 4
               >25,000                       5
     ^Samples must be taken on different days as approved
      by the Primacy Agency.
     In  addition,  one  sample must  be  taken  every  day  during  which  the
turbidity exceeds  1 NTU.   Also, under  the  Total Coliform Rule,  systems must
take one  coliform  sample  near the first service connection within  24  hours
after a  source water  turbidity measurement  exceeds  1 NTU.  This measurement
must be included  in the  total  coliform  compliance determination.   The purpose
of these  requirements is  to  ensure that the monitoring includes  worst case
conditions.  The  Primacy Agency may determine on  a  case-by-case  basis that
coliform samples  do not  have  to be collected during  times when the turbidity
exceeds 1 NTU on a weekend or holiday.
     The initial  evaluation of the source water quality is based on the data
from  the previous 6  months.   After  the  initial evaluation,  systems  must
continue  to conduct  the  sampling each  month  to  fulfill  the  source  water
quality criteria.   If the criterion has not been met,  the system must filter.
     Utilization of An Historical Data Base
     Some  systems may  already monitor  their source  water  for  total  and/or
fecal  coliform concentration.   The resulting  historical  data  base may  be
sufficient for the  Primacy Agency to make the initial determination of whether
the system meets  the  source water  quality criteria.  The historical data base
is considered sufficient for making this determination if:
       -  The raw water  sampling  location is upstream of the point of disin-
          fectant application as previously defined.
       -  The  samples  represent  at  least  the minimum  sampling  frequency
          previously mentioned.
       -  The sampling period covers at least the previous six months.
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     3.1.2  Turbidity Levels;  The SWTR  requires  that,  prior to disinfection,
the turbidity  of the water must  not exceed 5 NTU, unless  the  following con-
ditions are met:
     a.   There are not more than two events in any 12 consecutive months and
          not more than five events in any 120 consecutive months during which
          the turbidity exceeds  5 NTU.   An event is defined as any number of
          consecutive days in which at least one turbidity measurement exceeds
          5 NTU each day, and;
     b.   The Primacy Agency determines that exceedance of 5 NTU is unusual or
          unpredictable.
     Turbidity  events  which do  not meet  the above condition  result  in  the
requirement to install filtration.
     Utilizing  the same  sampling  location requirements  as stated in  Sec-
tion 3.1, the determination of compliance is based upon the collection of grab
samples at  least once every four hours.      EPA recommends  that  the initial
determination  of whether the  turbidity  criterion is met  be based  upon data
from 6 consecutive months.  However,  the Primacy  Agency may be  able to deter-
mine whether  the criterion can  be  met based  on  historical data for a given
system.
     Any  system which  exceeds the  5 NTU  maximum  limit at any time  should
notify the Primacy Agency as soon as possible and no later than the end of the
next business  day.   The Primacy  Agency  should evaluate additional  data from
the utility  to determine the  significance of the event with  respect  to  the
potential health risk to  the  community and determine  whether a boil water
notice  is necessary.   Boil water  notices are  not required  under  the  SWTR
although  they  may be issued at the  discretion  of the  Primacy Agency.  Data
which may be .used to make this determination  include raw water  fecal coliform
     1.   The SWTR  permits the  use  of continuous  turbidity monitoring  as  a
          substitute for grab sample monitoring if the measurement is validated
          by  the system  for  accuracy with  grab  sample measurements  on  a
          regular basis as  determined  by  the  Primacy  Agency.   Validation
          should be  performed  at least  twice a  week  based  on  the  procedure
          outlined in Part 214A in the 16th Edition of Standard Methods.
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levels,  duration  and  magnitude  of the  turbidity  excursion,  disinfectant
residual entering  the system during  the  excursion and/or coliform  levels  in
the distribution system following the excursion.
     In order to determine if the periods in which the turbidity exceeds 5 NTU
are  unusual or  unpredictable,  it is  recommended  that  in  addition to  the
historical  turbidity  data,  the water purveyor should collect and provide  to
the  Primacy Agency  current and  historical information  on  flows,  reservoir
water  levels,  climatological conditions,  and  any other information  that  the
Primacy  Agency  deems  relevant.   This  information  should  be  evaluated  to
determine if the event was  unusual or unpredictable.  Examples  of unusual  or
unpredictable events include:  hurricanes, floods, avalanches or earthquakes.
     A system may be able to avoid a high turbidity event by:
       -  Utilization of an  alternate source which is not a surface  water and
          does not have to meet the requirements of the SWTR.
       -  Utilization  of  an  alternate  source  which is  a  surface  water  and
          which does meet the requirements of the SWTR.
       -  Utilization  of storage water  to supply the  community   until  the
          source water quality meets the criteria.
3.2  Disinfection Criteria
     3.2.1  Inactivation Requirements
     To avoid  filtration, a system must demonstrate  that  it maintains disin-
fection conditions  which  inactivate 99.9 percent of Giardia  cysts  and 99.99
percent of viruses every day of operation.  If the disinfection level provides
less than these  inactivations  for more  than one day  of the  month, the system
is in  violation  of a  treatment technique requirement.  If  the  system incurs
such a violation  during  any  two months in  any  12 consecutive months,  the
system must install  filtration.  To make this  demonstration,  the  system must
monitor  and   record   the   disinfectant(s)   used,  disinfectant  residual(s),
disinfectant contact time(s), pH, and water temperature, and use these data to
determine if it is meeting the minimum total percent inactivation requirements
in the rule.
     A  number of  disinfectants  are  available,   including  ozone,  chlorine,
chlorine  dioxide  and  chloramines.   The  SWTR establishes  CT  [disinfectant
residual  concentration  (mg/L)   x   contact  time  (min)]   levels   for  these
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disinfectants  which  will  achieve different  levels  of  inactivation  under
various conditions.
     A system  is deemed- in  compliance  with the  inactivation  requirements if
the CT value(s)  calculated for  its  disinfection conditions meet  (or exceed)
the CT value specified  in the rule.   The system  must  make this determination
each day that it is delivering water to its customers.
     For the purpose  of calculating  CT values, disinfection contact time (in
minutes)  is  the time it takes  the  water,  during  peak  hourly flow,  to move
between  the point  of  disinfectant  application  to  a  point  where  residual
disinfectant concentration is measured  prior to  the first customer.  Residual
disinfectant concentration is the  concentration of  the disinfectant (in mg/1)
at a point before or at the first, customer.   Contact time in pipelines must be
calculated based on "plug flow"  (i.e.,  where all  water moves homogeneously in
time between two points)  by dividing the internal  volume of  the  pipeline by
the peak hourly  flow  rate through that pipeline.   Contact time  within mixing
basins and storage reservoirs  must be determined by  tracer studies  or an
equivalent demonstration  as  determined by  the Primacy Agency.  Guidance for
determining contact times for basins  is provided in Appendix C.
     Systems with only one point of disinfectant application may determine the
overall inactivation based  on one point of residual measurement prior to the
first customer, or on a profile  of the  residual  concentration  after the point
of disinfectant application.  Methods of disinfection measurement are present-
ed in Appendix D.  The residual profile and the total inactivation provided is
calculated by:
          Measuring the disinfectant residual,  C,  at any  number of  points
          within the treatment train.
          Determining the  travel time,  T,  between  the point  of  disinfectant
          application and the point(s)  where C is measured.
          Calculating  CT for each point of residual measurement (CT  . ).
                                                                    calc
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      -   Determining  the  inactivation  ratio  (CT  .  /^qq q'   ^or  eac^  se~
          quence.
          Calculating  CT for each point of residual measurement (CT  . ) .
          Summing the inactivation ratios  for each sequence, i.e. C T ', /CT
          +  C.T./CT--    +  C T /CTaQ . to determine  the total  inactivation
            . ,i  2    99.9     n n   99.9
          ratio.
If the total inactivation  ratio (CT  . /  CTQ   )  is equal to  or  greater than
                                    CcL JLC    -77  y
1.0, the  system provides  greater than 99.9  percent inactivation  of Giardia
lamblia cysts) ,  and the  system is  meeting  the disinfection  performance re-
quirement.  Further explanation of this is contained in Section 3.2.2.
     Systems need only  calculate  one CT (CT    )' each day,  for a point at or
                                            calc
prior to  the first customer,  or alternatively they have the option of cal-
culating numerous CTs after the point of disinfectant application but prior to
the  first  customer to determine  the  inactivation  ratio.   Profiling the
residual gives credit for  the higher residuals . which  exist  shortly after the
disinfectant is applied.   However,  if one CT is  calculated  (CT  , )  and this
                                                                calc
exceeds the applicable  CT     ,  the  system is  meeting the disinfection perfor-
                         99 . 9
mance requirement.  For systems with  a very  low oxidant demand  in the water
and long contact times  are available,  this approach may be the most practical
to use.
     For systems with  multiple points  of disinfectant application (e.g.,  if
ozone followed by chlorine, or chlorine is applied at two different points in
the treatment  train) ,   the  inactivation ratio  of each disinfectant  sequence
prior to the first  customer must be used  to  determine the total inactivation
ratio.    The disinfectant  residual  of  each  disinfection  sequence  and  the
corresponding contact time must be measured at some point prior to the subse-
quent disinfection  application point (s)  to  determine the inactivation ratio
for each sequence, and whether the total inactivation ratio of 1.0 or greater
          CT      is  the CT  value  required to  achieve 99.9 percent  or 3-log
          Giardia cyst inactivation for  the conditions of pH,  temperature and
          residual concentration for each sequence.  A sequence is the portion
          of the  system with a measurable contact time between  two  points of
          disinfection application or residual monitoring.
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is  achieved.   For  example,  if  the first  disinfection sequence  provided an
inactivation ratio  of  2/3  (or 99 percent inactivation)  and  the second disin-
fection  sequence  provided  an inactivation  ratio of 1/3  (or  90 percent inac-
tivation) ,  the total  inactivation  ratio would equal  1.0 (2/3  + 1/3  =  1) .
Further explanation of this is contained in Section 3.2.2.
     If the system  fails to achieve at  least 99.9 percent inactivation  (i.e.,
the  inactivation  ratio is  less than 1.0) any two or more days in one month,
the  system is  in violation  of a  treatment technique requirement.   If  the
system incurs  such a  violation during any  two months in any  12 consecutive
months, the system must install filtration.
     Maintaining Inactivation Level
     The  SWTR  establishes  CTs  for  chlorine,   chlorine  dioxide,  ozone  and
chloramines  which will  achieve various  inactivations  of Giardia  cysts  and
viruses,  as presented  in  Appendix E.   A  system  determines  whether  it is
meeting the inactivation requirements by  measuring  the residual disinfectant
concentration  daily, during  peak hourly  flow for each disinfection sequence
prior to the first service connection in the distribution system or immediate-
ly following the point at which the contact time is determined and calculating
the overall inactivation ratio.  Since  a  system can only identify peak hourly
flow after it  has  occurred,  it  is suggested  that residual measurements be
taken each hour during the day.  If the sampling points are remote, or manpow-
er is limited and it is impractical to collect hourly grab samples, continuous
monitors may be installed.   Measurements for the hour of peak flow can then be
used in  calculating CT.  The  temperature  and pH  (for  systems using chlorine)
must be  determined daily for each disinfection  sequence prior  to  the first
customer.
     Although  the  inactivation  maintained in the  system is  determined during
peak hour  flow, it should be noted that the disinfectant dosage  applied to
maintain this  inactivation may  not  be necessary during lower flow conditions.
Continuing to apply a disinfectant  dosage based on the peak  hourly flow could
possibly  result in increased levels of  disinfectant  by-products,  including
THMs.  Under lower  flow  conditions, a higher contact time is available and a
lower residual may provide the CT needed  to meet the inactivation require-
ments.   The system should,  however, maintain a disinfectant residual which
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will  still  provide a 3-log  inactivation of Giardia  cysts and  a 4-log inac-
tivation  of viruses at  non-peak hourly  flows.   The system  should therefore
evaluate  the  residual   needed  to  provide  the  required  inactivation  under
different  flow  conditions and  set  the dosage  accordingly.   The following
provides an example of maintaining the required inactivation.
     Example
     A 5 mgd non-filtering system disinfecting with free chlorine at one point
of application, has a contact time of 165 minutes during a peak  flow of 5 MGD.
The flow varies  from 1  to 5 MGD.  The pH and temperatures  of the water are 7
and  5 C,  respectively.   At  a residual  0.9 mg/L,  a CT  of 145  mg/L-min is
required to meet the disinfection requirements at a  5 MGD flow.  Under lower
flow  conditions, the available  contact time is  longer and  a  lower residual
would be needed to provide the  required  disinfection.   Based  on existing
contact time and using  the appropriate CT tables (in this case. Table E-2) in
Appendix E  for a 3-log  Giardia  cyst inactivation, the  required disinfection
would be provided  by  maintaining  the following  chlorine residuals  for the
indicated flow:

                              Contact     CT (mg/l-min)     Free Chlorine
     Flow  (MGD)              Time  (min)      Required      Residual  (mg/L)
        5                     165              148               1.0
        4                     206              144               0.7
        3                     275              143               0.6
        2"                    412              139               0.4
        1                     825              139               0.2
     This table  indicates  the variation  of  residuals  needed for the system to
provide  the required inactivation.   For chlorine, the  disinfectant residual
cannot be adjusted in direct proportion  to  the  flow because the CT needed for
disinfection is  dependent upon  the residual.  Since it is  not practical to
continuously adjust the  residual and, since a disinfection  level for a 3-log
Giardia cyst inactivation  must be  maintained under all flow conditions, it is
suggested that the flow variation  at the utility be divided into ranges and
the residual needed at the higher -flow rate of  each range be  maintained for
all flows within the range to ensure the required disinfection.
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The following flow ranges and residuals are suggested for the system:

                                     Free Chlorine
     Flow Range (MGD)         Residual (mg/L) Maintained
          1 - 1.9                       0.4
          2 - 3.9                       0.6
          4-5                         0.9

By maintaining these residuals,  the  utility is ensuring the  provision of the
required  disinfection  while  minimizing the  disinfectant application,  which
should result in lower disinfection by-products.
     Although these  residuals  will meet the  inactivation  requirements,  main-
taining a residual in the  distribution system must  also be  considered.   If
there is no other point of  disinfection prior to the distribution system, the
residual  for  disinfection  must be  maintained  at a  level  which will  also
provide a residual throughout  the  distribution system.   The  complete range of
flows occurring at the plant should  be  evaluated for determining the required
residual.  The utilities  may  establish the residual requirements  for as many
flow ranges as is practical.
     The  CTs  determined  from  these data  for the  system  each day  should be
compared to the values in the  table for the pH and temperature  of the water,
to determine if the CT needed for the required inactivation has been achieved.
Only the  analytical  methods prescribed  in the SWTR, or  otherwise  approved by
EPA, may be used for measuring disinfectant residuals.   Methods  prescribed in
the SWTR  are  listed in  Appendix O.  The  Appendix also  contains  a  paper to
offer guidance in  selecting monitoring methods for various  disinfectants and
conditions.
     The Primacy Agency should make periodic checks on its utilities to assure
that they are maintaining adequate disinfection at non-peak flow conditions.
     Meeting the Inactivation Requirement Using Free Chlorine
     When free chlorine is used as a disinfectant, the efficiency of inactiva-
tion is influenced by the temperature and pH of the water.  Thus, the measure-
ment of the temperature  and pH for  the  determination of the  CT is required.
The SWTR  provides  the CT requirements  for free chlorine at  various tempera-
tures and pHs which  may  occur in a  source water.   These  values  are presented
in Table E-l through Table  E-7 in Appendix E.  The basis  for these values is
discussed in Appendix F.   For free  chlorine  a 3-log inactivation of Giardia
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cysts will provide greater than a 4-log  inactivation  of viruses,  thus meeting
the SWTR inactivation requirements.
     As indicated in Table E-2, a raw water temperature of 5 C,  a pH of 7.0,
and a  residual chlorine concentration of 1.4 mg/L result  in  a CT of  155  to
provide a 3-log  inactivation of Giardia  cysts.  Therefore, to  meet  the inac-
tivation requirement under  these  conditions  with  one point of residual mea-
surement, a contact time  of  125 minutes  prior to the first customer  would  be
required.
     Meeting the Inactivation Requirement Using Chloramines
     Chloramines  are  a much weaker  oxidant  than  free  chlorine,  chlorine
dioxide and ozone.  The CT values for Chloramines presented in Table E-12, are
based  on  disinfection  studies  using  preformed   Chloramines  and  in  vitro
excystation  of  Giardia muris  cysts  (Rubin, 1988).   No  safety factor  was
applied to  the laboratory data on  which the  CT values were based  since EPA
believes that  chloramination,  conducted  in the-field,  is  more  effective than
using preformed chloramines.
     In the laboratory  testing using preformed chloramines, ammonia  and chlo-
rine were  reacted to form chloramines before the  addition of  the  microorga-
nisms.  Under  field conditions,  chlorine  is  usually added first followed  by
ammonia addition  further  downstream.  Also, even after the addition  of ammo-
nia, some free chlorine residual may persist for a period of time.  Therefore,
free  chlorine  is  present for a  period of  time  prior  to the  formation  of
chloramines.   Since this  free chlorine contact time  is not duplicated in the
laboratory when testing with preformed chloramines, the CT values obtained by
such tests may provide  conservative values when compared to those CTs actually
obtained  in the  field with  chlorine applied before  ammonia.  Also,  other
factors such as  mixing in the field {versus  no  mixing  in  the laboratory) may
contribute  to  disinfection  effectiveness.  For these  reasons,  systems using
chloramines for disinfection may demonstrate  effective  disinfection  in accor-
dance with  the procedure in Appendix  G in lieu of meeting the  CT  values  in
Appendix E.
     If a  system uses  chloramines  and is able  to achieve the CT values for
99.9 percent inactivation of Giardia  cysts,  it  is not always  appropriate  to
assume  that  99.99  percent   or  greater  inactivation   of  viruses  was  also
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achieved.  New  data indicate  that  Hepatitis A  virus  is more  sensitive than
Giardia cysts to inactivation by preformed chloramines (Sobsey, 1986).  The CT
values  required to achieve  99.99 percent  inactivation of  Hepatitis A with
preformed  chloramines  are lower than  those  needed to  achieve  99.9  percent
inactivation  of Giardia cysts.   These data  contrast with  other  data  which
indicate  that rotavirus is  more resistant  than  Giardia  cysts  to preformed
chloramines  (Hoff,  1986).   However,  rotavirus  is  very  sensitive to  inac-
tivation  by  free chlorine,  much more so  than  Hepatitis  A  (Hoff,  1986;
Sobsey,  1988).    If  chlorine  is applied  prior  to  ammonia,  the  short term
presence of free chlorine would be expected to  provide at  least 99.99 percent
inactivation  of rotavirus prior to  the  addition of  ammonia  and  subsequent
formation  of chloramines.   Thus,  EPA  believes  it  is appropriate  to  use
Hepatitis  A  data,  in'  lieu  of rotavirus data,  as  a  surrogate  for defining
minimum  CT values  for  inactivation  of  viruses  by  chloramines,  under  the
condition  that  chlorine is  added to the water  prior  to the addition  of am-
monia.
     A system which achieves a 99.9 percent or greater inactivation of Giardia
cysts with chloramines can  be considered to achieve  at least  99.99  percent
inactivation of viruses, provided that chlorine is added to the water prior to
the addition of ammonia. Table E-13 provides CT values for achieving different
levels  of virus  inactivation.   However,  if  ammonia  is added first, the CT
values in the SWTR  for achieving 99.9 percent inactivation of Giardia  cysts
cannot  be" considered  adequate for  achieving  99.99 percent inactivation of
viruses.
     Under such cases  of chloramine production,  the SWTR  requires  systems to
demonstrate through on-site challenge studies, that  the system is achieving at
least a  4-log inactivation of  viruses unless the  CTs  for  a  4-log virus inac-
tivation  are  maintained.  Guidance  for conducting  such studies is  given in
Appendix G.
     3.   CT values ranging from 0.025  to  2.2 achieve 99 percent inactivation
          of rotavirus  by free chlorine at  pH  = 6  -10 and  4 -  5~C (Hoff,
          1986).
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     Meeting the Inactivation Requirement Using Chlorine Dioxide
     Under the SWTR, the CT values for the inactivation of Giardia cysts using
chlorine dioxide  are independent  of pH.  Under  the SWTR the  only parameter
affecting the CT  requirements  associated with the use of  chlorine dioxide is
temperature.  Table E-8 in Appendix  E  presents  the chlorine  dioxide CT values
required for the inactivation of Giardia cysts at different temperatures.  The
basis  for  these  CT  values  is  discussed  in Appendix F.  Systems which  use
chlorine dioxide  are  not  required to measure the pH of  the  disinfected water
for the  calculation of CT.    For chlorine  dioxide,  as for  free  chlorine,  a
3-log inactivation of Giardia cysts  will  result  in greater than a 4-log virus
inactivation, meeting the SWTR inactivation requirements.   The Primacy Agency
may allow  lower CT  values  than  those specified  in  the SWTR  for individual
systems based  on information  provided by  the  system.   Protocols  for demon-
strating effective disinfection at lower CT values is provided in Appendix G.
     As  indicated in Tables E-8  and  E-9,  the  CT requirements  for  chlorine
dioxide  are  substantially   lower than  those  required  for free  chlorine.
However, chlorine dioxide is not  as  stable  as free chlorine or chloramines in
a water system  and  may  not  be capable of providing the required disinfectant
residual throughout the distribution system.   In addition, out of concern for
toxicological effects, EPA's current guideline  is that the  sum of the  chlo-
rine dioxide,  chlorate  and chlorite residuals,  be less than 1.0  mg/L at all
consumer taps.   This guideline  may be  lowered as  more health  effects data
become  available.  These concerns  further  reduce  the  feasibility of using
chlorine  dioxide  as  a  secondary  disinfectant  for  distribution  systems.
Therefore,  the use of chlorine dioxide as a primary disinfectant may result in
the need for the application of a secondary disinfectant,  such as chlorine or
chloramines,  that will persist  in  the distribution system and  provide  the
required residual protection.
     Meeting the Inactivation Requirement Using Ozone
     A third  disinfectant which can be  used to inactivate  Giardia cysts and
viruses is ozone.  As with chlorine dioxide, under the SWTR,   the CT values for
ozone are independent of pH.  Tables E-10 and E-ll present the CT requirements
                                     3-13

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for ozone at different source  water temperatures.  The SWTR does  not require
the measurement of the finished water pH for purposes of CT calculations.  The

basis for the CT values for ozone  is given in Appendix F.  As  for free chlo-
rine and chlorine dioxide, a  3-log Giardia cyst  inactivation with ozone will
result in greater  than a 4-log virus inactivation.   The Primacy  Agency may

allow lower CT values for individual  systems based on information  provided by

the system.   Recommended protocol for demonstrating effective disinfection is
provided in  Appendix G.

     Ozone  is  extremely  reactive  and dissipates  quickly after application.
                      (4)
Therefore, a residual    can  only be expected  to persist a short  time after
application.  In  addition to  this,  the  application of  ozone to water  is

dependent on mass  transfer.  For these reasons,  the method of  CT determination
used for the other disinfectants is impractical  for ozone.  The  CT   ,   must be
                                      r                          calc
determined for the  ozone basin alone.  The portion of the ozone  basin where
the ozone is applied will be  referred to as the contactor, and  the portion of

the basin where ozone is  no longer applied will  be referred to as the reactor.

     For many ozone contactors, the  residual  in  the  contactor will  vary  in

accordance with the method and rate of application and there will be a portion
     4.    The residual  must be  measured  using the  Indigo Method   (Bader  &
          Hoigne,  1981)  or automated methods which  are calibrated in  reference
          to the results obtained by the Indigo method, on  a regular basis as
          determined by  the  Primacy  Agency.   The   Indigo  method  has  been
          submitted for  inclusion in the 17 Edition of Standard Methods.   This
          method is  preferable  to  current  standard  methods  because of  the
          selectivity  of   the   indigo-reagent  in   the   presence   of   most
          interferences  found in ozonated waters.  Indigo trisulfonate  is the
          indicator used in  this test method.  The  ozone degrades  an  acidic
          solution of indigo trisulfonate  in a 1:1 proportion.   The decrease
          in absorbance  is linear with increasing  ozone concentrations  over a
          wide range.  Malonic acid can be  added  to block interference  from
          chlorine.  Interference from permanganate,  produced by the  ozonation
          of manganese,   is corrected by  running  a  blank in  which   ozone  is
          destroyed prior to addition of the indigo reagent.   The samples can
          be analyzed using a spectrophotometer  at a 600 ran wavelength which
          can detect residuals as low  as  2 ug/L or a visual color comparison
          method which can measure down to 10 ug/L ozone.   Although  currently
          available monitoring probes do not use  the Indigo Method,  they can
          be calibrated  via this  method.
                                     3-14

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of  the  contactor which  does not  contain an  ozone  residual.  As  previously
indicated,  the CT  is based  on the  presence of  a known  residual during  a
specific  contact time.   Thus disinfection  credit  is-only  provided for  the
time, T effective during  which  a residual is present.   The method of monitor-
ing the residual will have an impact on the determination of  the CT for each
basin, thereby affecting the disinfection credit.
     In addition to  the  difficulty in determining the ozone  residual  for the
CT calculation,  the  contact  time  will  vary  between  basins depending on their
configuration.   Several  types  of contactors  are  available  including  porous
diffusers,  submerged  turbines,  injector, packed  towers  and static  mixers.
Each  type of  contactor   is  available  in  either single  or multiple  chamber
units.  The flow through a  single  chamber turbine unit will approximate  a
completely mixed unit, while flow through a single chamber diffused contactor,
or  a  multiple chamber diffused contactor,  will more closely represent plug
flow.   However,  the  contact time  for  the contactor  should be  determined
through a tracer study  or an  equivalent method with  air or oxygen  applied
during testing,  as  approved by  the  Primacy  Agency.   Guidance for  the  deter-
mination  of detention time  is  included  in Appendix  C.   The detention time
(T  ) obtained from  the  tracer  study   should  be used to determine  the  CT of
the ozone basin.  The following section provides guidance  for determining CT
for the two types of  ozone contactors (diffused  and  turbine)  most widely used
in the United  States.  A  recent survey  of operating ozone systems in drinking
water treatment  plants  in the  United  States  indicated that  all  40  plants
employ either bubble  diffusers  or submerged  turbine  contactors (Robson  et al.
1988}.  It  should be  noted that  this  does  not  preclude  the  use of other types
of contactors for disinfection.
     Diffused Ozone Contactors
     In diffused contactors,  the ozone  is  bubbled into  the water  through
diffusers at the bottom of the basin.   The contactor may be designed for even
application  across  the  length  of the  basin,  or tapered application where  a
higher ozone dose is applied at  the beginning of the basin.
     Diffusers may also be operated in different flow regimes, either counter-
current or  co-current.   That is, the  water  flows  in  the  same or opposite
                                     3-15

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direction to  the  flow of rising gas bubbles.  Regardless  of the flow regime,
the ozone residual will  vary  throughout  the contactor, depending on the rate,
and mode of application,, and the quality of the influent water  (eg. pH, TOO.
In determining  the CT,  the portion of the  basin  containing a residual should
must be determined as explained later in this section.
     Single Chamber Unit
     A typical countercurrent flow  single chamber contactor is illustrated on
Figure 3-1.   The  first  step in determining the CT  should  be to ascertain the
point in the  contactor at which a  residual is first  detected.  A monitoring
probe should  be placed within  the  contactor near  the  inlet at approximately
mid-depth and moved to sampling ports towards the effluent until a residual is
detected.   The  time  (T,n) obtained from  the tracer study  should  then  be
multiplied  by the fraction of  the contactor  volume  which has  a  residual,
generating  the  time, T effective  for  the CT calculation.   A  second  probe
should then be placed at the contactor effluent and the average residuals from
the two probes  calculated.   The CT provided by the basin  can be approximated
as [average ozone residual x T effective].   An example of this  follows.
     Example
     A 5 mgd utility  has a single chamber ozone contactor.   A tracer study for
     the contactor indicated  a  3 minute contact  time.  Using an ozone probe,
     the first detectable  residual, 0.1 mg/L,  was detected  one-third of the
     way through the  contactor volume.   The time for disinfection, T effective
     is therefore, two-thirds  of the contact  time, or 0.67  x 3 minutes =  2
     minutes.    The  effluent  residual  is  1.0 mg/L.   The CT  ,   for   the
                                                                calc
     contactor is [(0.1 + 1.0)72] x 2 min = 1.1 mg/L-min.
     A more accurate  representation of  the residual within the  basin can  be
obtained by placing a number of probes  within the  basin and taking the average
of the measured residuals.   The probes  should  be located  so  that each  probe
monitors a  detectable residual.   The  probes  should be  equally  spaced  both
horizontally and from the top to bottom of the basin in the area of detectable
residual.  Profiling  the ozone  concentration  in this way will  provide a more
accurate measurement  of  the  ozone  concentration  gradient and  may  allow  a
higher ozone concentration  to be used  in the CT  calculation  than the average
                                     3-16

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UNOZONATED
   WATER
                        CONTACT
                        CHAMBER
                        OFF-GAS

             *'
                  . *
                          ^r-fej
                               I *"
                                OZONATED
                                 WATER
   OZONE *
                    FLOW METER
               VALVE
  FIGURE 3-1 SINGLE CHAMBER CONTACTOR

-------
determined from only  two points.  The average  of these measurements  is then
used to calculate CT so that CT  average residual x T effective.
     One way to increase the CT credit for the ozone basin may be to provide a
reactor following the contactors.  Although ozone is not added in the reactor,
a  residual  is maintained to  provide additional  disinfectant  contact  time.
Ozone is not  added to the reactor,  therefore mixing will not  interfere with
plug flow.  The reactor  can  also be baffled to more  closely approximate plug
flow, maximizing its detention time.  The detention time of the reactor should
be  determined through a tracer  study  and  the average  residual within  the
reactor should be measured as  it is  for  the  contactor to determine the CT for
the reactor.  If the reactor provides the necessary CT,  the  need to determine
the portion of the contactor that contains a residual would be eliminated.
     Multiple Chamber Units
     A multiple chamber  diffuser  contactor  is a  unit containing ozone dif-
fusers in each of the chambers separated by  baffles,  as illustrated  on Figure
3-2.  Initially  the portion  of the  first chamber or chambers  containing a
residual should be determined  for use in generating  CT      for each chamber.
However, in multiple chamber contactors/reactors,  the determination  of CT may
be simplified by operating to  satisfy the ozone demand  in the  first chamber,
using the remaining contactor/reactor volume for  disinfection,  similar to the
French  application.   This  mode  of operation  would  eliminate  the need  to
determine the portion of the first chamber containing a residual.
     Monitoring probes can be placed near the inlet and  outlet  of each of the
subsequent chambers  downstream  of  the  first  chamber.   The  average residual
measured will be  used  to  determine the  CT      provided  in   each  chamber.
                                             CcL J.C
Within each chamber,  additional probes  may  be  placed to get a more accurate
representation of the average residual.   The contact time for each chamber may
be calculated as a fraction of  the  overall detention  time determined from the
tracer study.  The  fraction  will be a ratio of  the  volume of  the chamber to
the overall volume of the contactor, as  follows:
       -  An  ozone  contactor  has  a  total  volume of 10,000  gallons and  an
          overall T  of 10 minutes at peak flow. The contactor'is baffled into
          four  chambers.  The  volume  of   each  chamber  is  2,500  gallons.
          Therefore, the detention time  of each chamber is:

                         1    x 10 minutes = 2.5 minutes
                       10,000
                                     3-17

-------
UNOZONATED
   WATER
               o ;-..;*/
    OZONE-
                                       CONTACT
                                       CHAMBER
                                       OFF-GAS
                              v
                               'f
. 9' 
        4
                                                OZONATED
                                                 WATER
                                     FLOW METER
                                VALVE
        FIGURE 3-2 MULTIPLE CHAMBER CONTACTOR

-------
     The CTcalc will then be calculated for each chamber using the correspond-
ing average residual and detention time.  As with  the  single chamber basin, a
reactor may  be used  following the  contactors  to increase  the  disinfectant
contact time.  The overall inactivation ratio  for  the  ozone basin can then be
calculated as outlined in Section 3.2.2.

     Turbine Contactors
     In turbine contactors, the ozone  is  added across  the entire depth of the
water as  illustrated  on Figure  3-3.   This type of contactor  approximates a
completely mixed system, and a residual should exist throughout the contactor.
Initially, probes  should  be placed in the contactor, evenly spaced horizon-
tally and from top  to bottom  to confirm that the  contactor is  completely
mixed, and to determine the  average  residual within  the contactor.   A com-
pletely mixed reactor can be  assumed  if all probes indicate approximately the
same measurement.   A rule of  thumb which may be used  is  for all  the measure-
ments to  be  within  20 percent  of each  other.   During  daily operation one
monitoring probe  within  the  contactor  will  be  sufficient  to  measure the
average  residual   of   a completely  mixed  reactor.   The  CT  value  for the
contactor will be  [average  residual x  T   ] .   The contactor  should  be tested
following changes in ozone  application rate and  seasonal, changes  to confirm
that  it  is a  completely  mixed unit.   To  increase  the  CT  for the  basin,  a
reactor may be provided following the  contactor as suggested for the diffused
contactor'.
     The  short life of ozone in water will usually result  in  a  system which
utilizes ozone as a primary disinfectant and applies a secondary disinfectant,
such as chlorine or chloramines, in order to  maintain a disinfectant residual
in  the  distribution system.   However, consideration  should be given  to the
fact  that when ozone  comes  in contact with  either chlorine or chloramines,
reactions between the two may result  in the mutual destruction of both disin-
fectants.  In order  to prevent  the  two  disinfectants  from destroying each
other, the secondary disinfectant  should be applied after the  ozone residual
has fully dissipated.
                                     3-18

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                                 OZONE
                                   IN
WATEH
 OUT
WATER
  IN
         FIGURE 3-3 TURBINE CONTACTOR

-------
     Ozone Case Studies
     Three case studies are presented here to demonstrate the determination of
CT for  existing ozone basins.   In cases 2  and 3,  the  basins are  in  use at
filtration plants, although the same method  of CT determination is applicable
for ozone  basins whether  they are being used  for  a filtered  or unfiltered
supply.
     Case 1 - North Andover(from USEPA, 1988b)
     During  early  1986,  18  cases of  Giardiasis were reported in  the North
Andover, Massachusetts  area.   The outbreak  was  traced to  the presence  of
Giardia cysts in the raw water supply, Lake  Colchichewick.   At the time, lake
water was  transported through two  pumping  stations  and chlorinated (without
filtration) before entering the North Andover distribution system.
     As  an  interim  solution, while  the  design  and construction  of  a  new
treatment plant  which included filtration was in progress,  ozonation facil-
ities were installed  at  each pumping station.   Each station pumps an average
of 2.5 to 3 mgd.  Chlorine is added at four points in the distribution system,
to provide a residual.
     Each ozone  contactor is  10  ft wide  and 20  ft long,  with 16  ft water
depth.   Baffles  are  included  in the  contactors to  separate each  into five
chambers, with  ozone being  applied equally  in  each chamber.   Applied ozone
dosages are 5 mg/L.
     At the  outlet  of the last chamber  of  each ozone contactor,  the concen-
tration of dissolved  ozone  is between 0.9 and 1.0 mg/L. The total hydraulic
flow time of water through each ozone contactor  is 10 minutes at peak flow in
summertime.  During winter,  with lower water demand,  pumping rates are reduced
by 50%,  thereby doubling the hydraulic residence time to 20 minutes.
     Tracer  studies  need to be  conducted at  the  plant  to determine  the  T
values  of  the  contactors.    Additional  probes  are  also  needed within  the
contactors to determine the ozone profile needed to calculate the inactivation
ratio.
     Since the temperature of Lake Colchichewick varies from 5C in winter to
20C in  summer,  the CT values  for  attaining  3-log activation  of Giardia cyst
inactivation range  from  2 mg/L-min at  5~C  to 0.75  mg/L-min at  20~C.  If  the
tracer  study results  in a  T   value  which  is one-half  of  the   hydraulic
detention time,  the  contact  time in the winter  would be 10 minutes requiring
                                     3-19

-------
an average ozone residual of 0.2 mg/L throughout the contactor to provide a CT
of 2 mg/L-min.   During  the summer months, the contact time  would be approxi-
mately 5  minutes,  requiring an  average  residual of 0.15 mg/L  throughout the
contactor to provide a CT of 0.75 mg/L-min.
     Case 2 - City of Tucson (from Joost et al., 1988 )
     The  City  of Tucson  is  currently designing a  150  mgd  direct filtration
plant.  A single application of ozone is to be applied prior to the rapid mix,
for a number of oxidative purposes, including primary disinfection.
     The Tucson plant will have  four,  parallel,  countercurrent, 6-stage ozone
contactors,  each with  a  37.5  mgd design capacity  and  a  12  minute  design
hydraulic residence  time.   The plant flow ranges  between 60 to  150  mgd, and
one or two  ozone contactors will  be  taken off-line during  low flow periods,
varying the  actual detention  time of the basins.   As illustrated  on  Figure
3-4,  the  contactors will be  divided into six  chambers.   The  T   of  this
configuration was estimated to be about half the hydraulic residence time.
     A baffled section  at the end of  each of these contactors will  not have
diffusers, although  the  ozone  residual will be  at  least  partially maintained
in these sections, which will contribute to the overall inactivation attained.
     Based on  pilot plant testing,  applied  ozone doses of 1.5  to  3.0  mg/L
should produce a maximum of 0.50 mg/L  dissolved  ozone residual  in the contac-
tors, and a minimum of 0.25 mg/L providing  CTs from  1  to 2  mg/L-min which
provides greater than a 1-log  inactivation of Giardia cysts required for the
system.   To  assure that  the  CT values  are being maintained,  each contactor
will have several ozone  residual  analyzers operating continuously.  A minimum
of three  analyzers will  be used  per  contactor,  to generate a residual profile
across the contactor.
     Case 3 - Los Angeles  (from Stolarik et al., 1988)
     At this  600 mgd plant,  ozone was  installed for pretreatment oxidation
ahead of  coagulation,  flocculation and filtration before  the  CT requirements
for primary disinfection were proposed in the SWTR .  Consequently, the ozone
contactors were not.designed with CT considerations in mind.
     There are  four ozone contactors at the plant  --  one for  each  of the
plant's four pretreatment process trains.  Each ozone contactor is designed to
                                     3-20

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UNOZONATEO
  WATER
                                                                       CONTACT
                                                                       CHAMBER
                                                                       OFF-OAS
                                                                      	fc.
   OZONE
                *J
*J
                                                                  -_.
                                                        i
                                                                             OZONATEO
                                                                              WATER
         FLOW METER
                                                                  VALVE
              FIGURE 3-4 CITY OF TUSCON OZONE  CONTACTOR

-------
contain two ozone contact chambers, with ozone added to each chamber.  Between
the two  chambers is  a baffled  section in  which no  ozone  is  applied.   The
purpose of this section is  to  allow the flow of water to change direction, so
that water in  each  contacting chamber  flows  downward,  counter-current to the
flow of rising ozone/gas bubbles.  After the second ozone contact chamber, the
water exiting the base of the chamber rises in a second baffled section to the
outlet of the ozone contactor, as it does for the Tucson contactor.
     Dye tracer studies were performed in accordance  with  recommendations in
Appendix C in  one of  the  process trains at this plant, and residual ozone was
measured by the Indigo trisulfonate method as well  as by standard iodometxy.
Rhodamine  WT  was   selected as  the  tracer  for  the  studies.   Since  ozone
decolorizes this  dye  rapidly,  when  tracer  tests were conducted,  the  ozone
generators were turned off,  but  the flow of oxygen was maintained through the
system / in  order to induce  the mixing and  bulk fluid  changes which  occur
normally in the contactor.  Sampling of dye tracer concentration was conducted
over a five day test period at 10 sample locations and at five different water
flow rates  (40 to 100 percent  of capacity).  Samples  taken during ozonation
(to measure dissolved  ozone concentrations)  were taken at  taps located after
the first  chamber,  at  the top of  the  intermediate flow-changing  baffled
section,  at the outlet of the second  ozone contacting chamber,  at the exit of
the ozone contactor, and  at the  inlet and outlet of the rapid mixers as shown
on Figure 3-5.
     Analysis  of the  data collected showed that T    times  for  the the entire
ozone  contact  system  were   approximately  half of  the theoretical  hydraulic
detention  time,  depending  upon  the  water  flow  rates.   During  periods  when
ozone  was  applied,  residual  concentrations varied  across  the  system  as
follows:   residuals  were detected at  0.15  mg/L  after the  first  chamber,
0.09 mg/L at the top of the intermediate flow-changing baffled section,  0.16
mg/L at the outlet  of the second chamber, and 0.05  mg/L  at the outlet of the
rapid mixers.
     Based on  determinations of  actual  contactor detention  times and measure-
ments of ozone residuals, projected CT  values were compared with EPA's crite-
ria for 1-log  reduction of  Giardia.   It was  determined that the plant's 7,900
Ibs./day design capacity  ozonation  system would be  capable  of  meeting the CT
                                     3-21

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      OZONE CONTACT BASIN
          RAPID MIXERS     FLOCCULATORS

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1 1 1 1 1 1
1 1 1 1 1 1
1 1 1 1 1 1
1 1 1 1 1 1
1 1 1 t 1 1
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1 1 1 1 1 1
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t 1 1 1 1 1
1 t 1 1 1 1
1 1 1 1 1 1
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     70%
30%
   BASED ON AVERAGE OF 7 DATA SETS
NOVEMBER 19. 1987 TO DECEMBER 1. 1987
                                     APPLIED OZONE DOSE 1.10 - 1.65 mg/L
               WATER TEMPERATURE RANGE:  11.8 - 14.5 C
1. FROM STOLARIK AND CHRISTIE, 1988
2. RESIDUALS IN mg/L

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requirements  throughout the  year.  However,  reduced  operating margins  and
correspondingly higher costs  for  increased power consumption and supplemental
liquid oxygen feed would occur during seasonal periods of peak ozone demand.
     Summary
     Many systems  which do  not  provide  filtration will  have  difficulty  in
providing the contact time necessary to satisfy the inactivation requirements
prior to the  first  customer.   For example, a system using  free  chlorine  at a
water temperature  of 5 C, a  pH of  7.0 and a  chlorine residual of  1.4  mg/L
would require  111 minutes  of contact  time to meet the inactivation require-
ment.  Options which are available to these systems include:
       -  Installation of  storage facilities that  will provide  the required
          contact time under maximum flow conditions.
       -  Use of an alternate disinfectant such as ozone  or chlorine dioxide
          which has CT values lower  than  those  required for free chlorine for
          the required inactivation.
     For some  systems,  the difficulty  in  obtaining the required inactivation
may  only  be a  seasonal problem.  A system that  has  raw  water temperatures
which reach 20 C during the summer months at a  pH of 7.0, may have sufficient
contact time  to meet  the CT  of  56 at a  chlorine concentration  of 1 mg/L.
However, assuming  the  same  pH and  chlorine concentration,  it may  not  have
sufficient contact  time to meet the CT requirement at 5 C  (149) or at 0.5 C
(210).  Under those conditions, a system could choose to use ozone or chlorine
dioxide on a seasonal basis, since they are stronger disinfectants requiring a
shorter contact time.
     As indicated in Table E-12,  the CT values  for chloramines may be imprac-
tical to attain for most systems.  Systems which currently utilize chloramines
as  a primary  disinfectant may  need  to  use either  free  chlorine,  chlorine
dioxide or  ozone in order to  provide  the required  disinfection.   However,
systems using  chloramines  as  a primary disinfectant may chose to demonstrate
the  adequacy  of the  disinfection.  Appendix G  presents a method  for making
this demonstration.
                                     3-22

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     3.2.2  Determination of Overall Inactivation for Residual Profile,
            Multiple Disinfectants and Multiple Sources
     For systems which apply disinfectant(s) at more than one point, or choose
to profile the residual  from one  point of  application,  the total inactivation
achieved is the  sum of the inactivation ratios between each  of  the points of
disinfection or  between  each  of the residual  monitoring  points respectively.
The portion of the system with a measurable contact time between two points of
disinfection  application or  residual  monitoring  will be referred  to  as  a
section.  The calculated CT (CT    )  for each section is determined daily.
                               C21XC
     The CT needed to  fulfill  the  disinfection requirements is CT   _, corre-
sponding to a 3-log inactivation of Giardia cysts and greater than or equal to
a  4-log inactivation  of  viruses  (except  for  chloramines  as  explained  in
Section 3.2.1).   The inactivation ratio for  each  section is  represented by
CT  . /CT__ _, as explained in Section 3.2.1, and indicates the portion of the
  caxc   77.9
required inactivation  provided by the  section.   The sum  of  the inactivation
ratios from each section can be used to determine the overall level of disin-
fection provided.  Because  inactivation is a  first order  reaction,  the inac-
tivation ratio corresponds to log and percent inactivations as follows:

     CT  ,  /CT__ _            Log Inactivation         Percent Inactivation
     calc	99.9            *	         	
     0.17 CT_.           =         0.5 log        =              68 %
            77  7
     0.33-CT99>9         =         1   log        =              90%
     0.50 CT             =         1.5 log        =              96.8%
     0.67 CT99^g         =         2   log        =              99%
     0.83 CToa           =         2.5 log        =              99.7%
            .77  7
     1.00 CTQQ                    3   log        =              99.9%
            77  y
     1.33 CT             =4   log        =              99.99%
            77* 7
     The CT     can be determined  for  each  section  by referring to Tables E-l
through E-13 in  Appendix E, using the pH  (when  chlorine  is the disinfectant)
and  temperatures of  the water  for the respective  sections.  These  tables
present the log  inactivation of Giardia cysts  and enteric viruses achieved by
CTs at various water temperatures and pHs.
                                     3-23

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     Log inactivations are additive, so:
          0.5 Log +1.0 Log =1.5 Log or

          -17CT99.9 + '33CT99.9 = '5CT99.9
     If the  sum of the inactivation  ratios  is greater than or  equal  to one,
the  required 3-log  inactivation  of  Giardia cysts  has  been  achieved.   An
inactivation  ratio of  at least 1.0  is all  that is  needed to  demonstrate
compliance with the  Giardia  cyst  inactivation  requirements  for  unfiltered
systems.
     The total  log inactivation that is provided can be  determined by multi-
plying  the  sum  of the inactivation ratios,  (CT    /CTgg g'  fay  three.  The
total log inactivation can be determined in this way because CT     is equiva-
                                                               yy  y
lent to  a 3-log inactivation.  The overall  percent inactivation can  then be
determined as follows:
          y = 100 - 100                      Equation  (1)
                    10X
     where:     y = % inactivation
               x = log inactivation
     For example:
          x = 3.0 log inactivation
          y = 100 - 100       = 99.9 % inactivation
                    103'
     The following is  an  example of the determination of the  overall percent
inactivation for multiple points of disinfection.
     Example
     A community of 6,000 people obtains its water supply from a lake which is
10 miles from the city limits.  Two 0.5 MG storage tanks are located along the
12-inch transmission line to the city.  The water is disinfected with chlorine
dioxide at the  exit from  the lake and with chlorine at the discharge from the
first and second storage  tanks.  The  average  water  demand of the community is
1 MGD with a peak hourly  demand of  approximately 2 MGD.   For the calculations
of the overall  percent  inactivation,  the supply  system is  divided  into three
sections as shown on Figure 3-6.
                                     3-24

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                                            1 st GUST!
1 STORAGE STORAGE
71
k TANK 1 + TANK 2
I I
1
t
CHLORINE CHLORINE CHLORINE
DIOXIDE

SECTION

SECTION



SECTION
FIGURE 3-6 DETERMINATION OF IN ACTIVATION FOR
          MULTIPLE DISINFECTANT APPLICATION
          TO A SURFACE WATER SOURCE

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     Section 1 - from the lake to the discharge from the first storage tank,

     Section 2 -  from the discharge  from  the first storage tank  to the dis-
     charge from the second tank

     Section 3 -  from the discharge  of  the second storage tank  to the first
     customer

The overall  inactivation is  computed daily  for  the  peak hourly  flow condi-

tions.  On the day of  this  example  calculation, the  peak  hourly  flow  was

2 MGD.  The pH,  temperature  and  disinfectant  residual  of  the  water  were

measured at the end of  each section just prior to the next point of disinfec-
tion and the first customer during the hour of peak demand.  The water travels

through the 12-inch transmission main at  237'ft/min  at  2 MGD,      The deten-
tion times of  the storage tanks were determined  to be  290 min and 285 man as

the result of tracer studies.
     The data for the inactivation calculation are as follows:

                                   Section 1       Section 2      Section 3
     length of pipe (ft)             15,840         26,400          10,560
     contact time (min)
       pipe                              67            111         .    45
       tank                              290            285              0
       total                             357            396             45
     disinfectant                  chlorine        chlorine       chlorine
                                   dioxide
     residual  (mg/L)                      0.1            0.2            0.4
     temperature  (C)                      5              5              5
     pH                                   888


This information  is then  used in conjunction with the CT     values in Appen-
                                                         yy  y
dix E to determine  the  (CT    /CTQQ Q) in each section as follows:
                                 yy * y
Section 1  - Chlorine dioxide

CT  ,  - 0.1 mg/L x 357 minutes = 36 mg/L-min
  calc
From Table E at a temperature of 5 C and pH = 8,
 CT     is 54 mg/L-min
   yy  y
5.
2 -
A
2 X lO^gal/day X
(1 ft"fT /4)
1ft3
7.48 gal
X day
1440 min
                                                     = 237 ft/min
                                      3-25

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CT  , /CHnn  = 36 mg/L-min  0.67
  calc   99'9   54 mg/L-min
Section 2 - Chlorine

CT  ,  =0.2 mg/L x 396 minutes  79 mg/L-min
  calc
From Table E at a temperature of 5 C and pH = 8,
 CT__   is 202 mg/L-min
   99* 9

      / CT__ _ = 79 mg/L-min = 0.39
                 202mg/L-min
Section 3 - Chlorine

CT  ,  = 0.4 mg/L-min x 45 min - 18 mg/L-min
  calc
From Table E at a temperature of 5 C and pH = 8,
  CT     is 202 mg/L-min

CT  , /CTQQ   = 18 mg/L-min = 0.09 = 0(6)
  calc   99.9
The sum of CT  .  /CT   _ is egjual to 1.06, which is greater than 1, therefore,

the system meets  the requirements of providing a 3-log inactivation of Giardia
cysts.  The log inactivation provided is:


     x = 3 x   CT
                  caJ-C  -  3 x 1.06 = 3.18

               CT99.9

The percent inactivation can be determined using equation 1.


     y - 100 - 100 = 100 - 100 = 100 - 0.07  =  99.93% inactivation

               ID3*18      1514
          The generation  of reliable  CT values  for inactivations  less than
          (0.17CT    }  0.5  log was not  feasible by  extrapolation  from the
          existing 3ata.  Thus,  no credit  is  given for  less than  a 0.5 log
          inactivation.
                                     3-26

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The system meets the  requirement of providing a  99.9  percent inactivation of
Giardia cysts.
     The SWTR also requires  that the public be provided  with protection from
Legionella as well  as Giardia cysts and viruses.  Inactivation levels have not
been set  for Legionella because the required  inactivation of  Giardia  cysts
will provide protection from Legionella.     However, this  level of  disin-
fection cannot  assure that  all Legionella  will  be  inactivated and that no
recontamination or  regrowth in recirculating hot water systems of buildings or
cooling systems will  occur.   Appendix B provides guidance  for monitoring and
treatment to control Legionella in institutional systems.
     The above  discussion pertains to one source with sequential disinfection.
However, other systems may blend more  than  one source,  and  disinfect  one or
more of the sources independently prior to blending.   System conditions which
may exist include:
       -  All the  sources  are  combined at one point prior  to  supplying the
          community but  one  or more of the  sources are  disinfected  prior to
          being combined, as shown on Figure 3-7.
       -  Each source is disinfected  individually and enters the distribution
          system at a different point,  as shown on Figure 3-8.
     For all systems  combining sources, the first step in  determining  the CT
should be to determine the CT  - provided from the point of blending closest
                              CclXC
to the first customer using  the  contact time  and  residual at peak hourly flow
for that portion of the distribution system.  This corresponds to Section D on
Figure 3-7  and  Section E  on Figure 3-8.  If  the CT     for section D  or E
     7.   Kuchta et al.   (1983)  reported a maximum CT requirement of 22.5 for
          a 99 percent inactivation of Legionella in a 21 C tap water at a pH
          of 7.6-8.0 when using  free chlorine.  Using first order kinetics, a
          99.9 percent inactivation requires a CT  of 33.8.  Table A-5 presents
          the  CTs  needed  for  free  chlorine  to  achieve  a  99.9  percent
          inactivation of  Giardia  cysts  at 20 C.  this  table  indicates that
          the  CT  required  for  a   3  long  inactivation  of Giardia  at  the
          temperature  and pH  of the  Legionella test  ranges  from 67  to 108
          depending on chlorine  residual,  this  is  2 to  3  times  higher than
          that which is needed to achieve  a 3  long inactivation of Legionella.
                                      3-27

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                                            1st CUSTOMER
                FIGURE 3-7 INDIVIDUALLY DISINFECTED
                           SURFACE SOURCES COMBINED
                           AT A SINGLE POINT
                                        c
                                              e
                                             1 st CUSTOMER
	DISINFECTANT
   APPLICATION

   COMBINATION POINT

   SAMPLING POINTS
FIGURE 3-8 MULTIPLE COMBINATION POII
           FOR INDIVIDUALLY DISINFECl
           SURFACE SOURCES

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provides the required  inactivation,  no additional CT  credit  is needed and no
further evaluation is required.  However, if  the  CT  for section D or E is not
sufficient to achieve  the required inactivation,  then the inactivation ratio
(CT    )/(CT   g)  should be determined for each section to determine the

overall  inactivation provided for  each  source.   The overall  inactivation
provided must be  greater than or equal  to one  for  all sources in  order to
comply with the requirements for 3-log inactivation of Giardia cysts.
     On Figure 3-7, sections A, B, C and D contain sampling points, a, b c and
d respectively.   The sum  of  the inactivation ratios for sections A+D, B+D and
C+D must each be  greater than  or  equal  to one for  the disinfection require-
ments to be met.
     The overall inactivation provided for each source on Figure 3-7 should be
determined as:

Source I
  -  Determine CT  .  for sections A  and D based on the residual measurements
     at sample- point! a and  d,  and the  travel time through each section under
     peak hourly flow conditions for the respective section.
  -  Determine CT      for the  pH  and temperature conditions  in each section
     using the tables in Appendix E
  -  Calculate the inactivation ratios ^CTcalc/CT99 9) for sections A and D.
  -  Calculate the sum of the inactivation ratios for sections A and D.
  -  If the sum of the inactivation ratios  is greater than or equal to 1, the
     system has provided the required 3-log Giardia cyst inactivation.
Source II
  -  Determine CT     for section B based  on the residual measured at sample
     point b and ^e travel time  through the section  under  peak hourly flow
     conditions.
  -  Determine CT     for section B  for the  pH and temperature conditions in
                 CfcQ Q
     the section using the appropriate tables  in Appendix E.
  -  Calculate the inactivation ratio  f^/      } for section B.
                                     3-28

-------
     Add the inactivation ratios for Sections B and D to determine the overall
     inactivation for source II.

     If the sum of the inactivation ratios is greater than or equal to 1, the
     system has provided the required 3-log  Giardia  cyst inactivation for the
     source.
Source III
      Determine CT  ,  for section  C based on the residual measured at sample
                  C3.J.C
      point c and  the travel time  through the section under peak hourly flow
      conditions.

      Determine CT     for section  C for the pH and temperature conditions in
      the section using the appropriate tables in Appendix  E.
  -  Calculate the inactivation ratio (CT  .  /CTQQ Q)  for  section C.
                                          CaXC   77. y

  -  Add  the inactivation ratios for section C and D  to determine the overall
     inactivation for source III.

  -  If the sum of the inactivation ratios is greater than or equal to 1, the
     system has provided, the required 3-log Giardia cyst  inactivation for the
     source.

     'The  determination of  the overall  inactivation provided  for  each source

may  require more calculations  for  systems  such  as that on Figure  3-8 th>.n on

Figure 3-7.   On Figure 3-8 sections A,  B,  C, D, and E contain sampling points

a, b, c,  d,  and e respectively.  In order to  minimize  the  calculations needed,

the  determination of the overall inactivation  provided should begin with the

source closest to the first customer.

     The  overall inactivation provided for each  source on  Figure 3-8 should be

determined  as follows:


Source III

  -  Determine CT     for sections C  and E based on the  residual measurement
     at sample points c and  e  and  the travel time through each section under
     peak hourly flow conditions for the respective  section.

  -  Determine CT     for  the  pH and temperature conditions  in each section
     using  the tables in Appendix E.

  -  Calculate the inactivation ratios (CT   /CT    _)  for sections C and E.
                                           caxc   99.9
                                      3-29

-------
  -  Calculate the sum of the inactivation ratios for sections C and E.

  -  If the sum of the inactivation ratios is greater  than  or equal to  1,  the
     system has  provided  the required  3-log Giardia  cyst  inactivation  for
     source III.
Source II

  -  Determine CT  .  for section D  based on the residual  measured  at  sample
     point D and  Qie  travel time through the section under peak  hourly  flow
     conditions.

  -  Determine CT   g for section D  for the pH  and  temperature  conditions  in
     the section  using the appropriate tables in Appendix E.

  -  Calculate the inactivation ratio (CT  .  /CTQQ Q) fr section D.
                                         caj.c   yy  y

  -  Add the inactivation ratios for sections D and E to determine the overall
     inactivation.

  -  If the sum of the inactivation ratios is greater than  or  equal  to  1,  the
     system has  provided the  required  3-log Giardia  cyst inactivation  for
     source II, as well as source I  since the water from each of these sources
     are combined prior to sections  D and E.

  -  If the total inactivation ratio  for sections  D  and  E  is  less than  1,
     additional calculations are needed.  Proceed as follows for source III.

  -  Determine CT  .  for section B  based on the residual  measured  at  sample
     point B and ^le3 travel time through the section under peak  hourly  flow
     conditions.

  -  Determine CT     for section B  for the pH  and  temperature  conditions  in
     the section  using the appropriate tables in Appendix E.

  -  Calculate the inactivation ratio 
-------
inactivation.  However,  if this  sum is less  than 1 additional calculations
will  be needed  to determine  the  overall .inactivation provided for source I.
The calculation is as follows:

Source  I
  -   Determine CT     for  section A based  on the residual measured at sample
      point b and  Qie travel time through  the  section under peak hourly flow
      conditions.
  -   Determine CT__   for  section A for the pH and temperature conditions in
      the section using the appropriate tables in Appendix  E.
  -   Calculate the inactivation ratio (CT  -  /CT    )  for  section A.
                                          caxc-   77.7
  -   Add the inactivation  ratios  for sections  A,  D,  and E  to determine the
      overall inactivation for source I.
  -   If the sum of the inactivation ratios is greater than or equal to 1, the
      system has provided the required 3-log  Giardia cyst  inactivation for the
      source.
      3.2.3 Demonstration of Maintaining a Residual
      The SWTR establishes two requirements pertaining to the maintenance of a
residual.   The  first requirement is  to maintain a minimum  residual of 0.2 mg/L
entering the distribution  system.   Also, a detectable residual must be main-
tained  throughout  the distribution  system,   these requirements are further
explained  in the  following sections.
      Maintaining  a Residual Entering the System
      The SWTR requires that a residual of 0.2 mg/L be maintained in the water
entering the distribution  system  at all times.  Continuous  monitoring at the
entry point (s)  to the distribution system is  required  to ensure that a detect-
able  residual is  maintained.  Any time the residual drops below 0.2 mg/L, the
system  must notify the Primacy  Agency prior to the end of  the next business
day.  The  system is  in  violation of  a treatment technique if  the residual
level is not restored to 0.2 mg/L  within  four hours and filtration  must be
installed.   In cases where the continuous  monitoring equipment fails,  grab
samples  every four hours may be used for a period of 5 working days while the
equipment  is restored to  operable  conditions.
                                      3-31

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     The  system must record,  each day of  the  month,  the lowest disinfectant
 residual entering the system and  this  residual  must  not be less  than 0.2 mg/L.
 Systems serving less than or equal to  3,300 people may take  grab samples in

 lieu of continuous monitoring  at  frequencies as follows:
          System Population             Samples/day*
            <500                             1
             501-1,000                       2
             1,101-2500                      3
            >2,501-3300                      4
    *Samples must  be taken  at dispersed time  intervals  as approved  by  the
     Primacy Agency.
     If the residual  concentration falls below 0.2  mg/L,  another sample must
be taken within 4 hours and sampling continued  at least every four hours until
the disinfectant residual is at least  0.2 mg/L.
     Maintaining a Residual Within the System
     The SWTR  also  requires  that  a detectable  disinfectant  residual be main-
tained  throughout   the  distribution   system,   with  measurements  taken at  a
minimum frequency equal  to that  required by  the Total Coliform Rule  as pre-
sented  in Appendix H.   The   same sampling  locations  as  required for  the
coliform regulation must be used  for  taking the disinfectant  residual  or HPC
samples.  However,  for  systems  with  both ground  water  and  surface water
sources or ground water under  the direct  influence of surface water, entering
the  distribution  system,  residuals  may  be  measured  at points other  than
coliform  sampling  points  if  these points are more  representative   of  the
disinfected surface water and  allowed  by  the  Primacy Agency.  An HPC level of
less than 500/ml  is considered  equivalent to  a detectable residual for  the
purpose of determining compliance with this requirement,  since the absence of
a disinfectant residual does  not  necessarily   indicate microbiological  con-
tamination .
     Disinfectant residual can be measured as  total chlorine,  free chlorine,
combined chlorine  or chlorine dioxide (or HPC level).   The  SWTR  lists  the
approved analytical methods  for  these analyses.   For example,  several  test
methods can be used  to  test  for  chlorine residual in the water,  including
                                     3-32

-------
amperometric titration, DPD  colorimetric,  DPD ferrous titrimetric method and
                                                                           (8)
iodometric method, as  described in the  16th  Edition of Standard Methods.
Appendix D provides a  review and  summary  of available disinfectant residual
measurement techniques.
     The SWTR requires that  a detectable disinfectant residual  be present in
95 percent or more of  the monthly distribution system samples. In systems that
do  not  filter,  a  violation  of  this  requirement for  two  consecutive  months
caused  by a deficiency in treating the source  water will trigger a requirement
for filtration to be installed.   Therefore,  a  system  which does not maintain a
residual in 95 percent of the samples  for one  month because of treatment defi-
ciencies,  but is maintaining  a  residual  in  95 percent of  the samples for the
following month,  will  meet this requirement.
     The absence  of  a detectable  disinfectant residual in  the distribution
system  may be due to a number of factors, including:
        -  Insufficient chlorine applied at the treatment plant
        -  Interruption of chlorination
        -  A change  in chlorine demand  in either  the source  water or  the
           distribution system
        -  Long standing times and/or,  long transmission distances
     Available options for systems to correct the problem of low disinfectant
residuals  within  their  distribution system include:
        - " Routine flushing
        -  Increasing disinfectant doses at the plant
        -  Cleaning of  the pipes  (either mechanically by pigging  or by  the
           addition of  chemicals to dissolve the deposits)  in the distribution
     8.   Also,  portable test  kits are  available  which can be  used in  the
          field  to detect residual  upon the approval of the Primacy Agency.
          These  kits  may employ titration  or colorimetric  test methods.   The
          colorimetric  kits  employ  either a visual  detection  of a  residual
          through  the use of a color wheel,  or the detection of  the  residual
          through  the use of a hand  held  spectrophotometer.
                                      3-33

-------
          system  to  remove  accumulated  debris  which  may  be  exerting  a
          disinfectant demand;
       -  Flushing and disinfection of the portions of the distribution system
          in which a residual is not maintained; or
       -  Installation of satellite disinfection feed facilities with booster
          chlorinators within the distribution system.
For systems unable  to maintain a  residual,  the Primacy  Agency  may determine
that it is not  feasible  for the system to monitor  HPCs  and judge that disin-
fection is adequate based on site-specific conditions.
     Additional  information  on  maintaining  a  residual  in  the  system  is
available in the AWWA Manual  of Water  Supply Practices and Water Chlorination
Principles and Practices.

     3.2.4  Disinfection System Redundancy
     Another disinfection  requirement  that  unfiltered  water supply  systems
must meet is disinfection system  redundancy.   A system providing disinfection
as the only treatment is required to  assure that the water delivered to the
distribution system is continuously disinfected.  This can be  accomplished by
providing either redundant  disinfection equipment or  an  automatic  shutoff of
delivery of water  to the distribution  system when the  disinfectant  residual
level drops below 0.2 mg/L.   The provision of redundant disinfection equipment
includes:
       -  Both  a  primary and a  secondary  disinfection  system  in which  all
          components have backup 5inits  with capacities  equal to  or  greater
          than the largest unit on-line.
       -  A minimum  of  two storage  units of disinfectant which can  be  used
          alternately -  e.g., two  cylinders of chlorine  gas,  two tanks  of
          hypochlorite solution
       -  Where generation  of the disinfectant  is  needed  (such as ozone),  a
          backup unit with  a capacity  equal to or greater than that  of  the
          largest unit on-line.
       -  Automatic switchover equipment  to  change  the feed from one  storage
          unit to the other before the first empties or becomes inoperable
       -  Feed systems with backup units with capacities  equal  to  or greater
          than the largest unit on-line.
                                     3-34

-------
        -  An alternate  power  supply such  as a  standby generator with  the
          capability of running all the electrical equipment at the disinfec-
          tion  station.  The  generator  should be on-site and functional with
          the capability of automatic start-up on power  failure
     Appendix I contains more specific information for the Primacy Agency for
determining  compliance with this requirement.
     Providing  automatic shutoff  of water  delivery  requires  approval  by  the
Primacy Agency.  The Primacy Agency  must  determine  that this  action will  not
result  in an unreasonable  risk  to health.  This determination should include
the  evaluation  of the  system  configuration to protect against negative pres-
sures in  the system and high demand periods including fire flow requirements.
This provision  should  only be allowed if systems have  adequate distribution
system  storage  to maintain  positive pressure for  continued water use.

3.3  SITE -  SPECIFIC CONDITIONS
     In addition  to meeting  source  water  quality  criteria  and disinfection
criteria, nonfiltering systems utilizing surface water supplies must meet  the
following criteria:
        -  Maintain a watershed control program
        -  Conduct a  yearly  on-site inspection
        -  Determine  that no waterborne disease outbreaks have occurred
        -  Comply  with the revised annual  total coliform MCt
        -  Comply  with TTHM  regulations  (currently applies  to  systems  serving
          >10,000 people)
     Guidelines for  meeting these other criteria are presented in the follow-
ing  sections.
     3.3.1   Watershed Control  Program
     A  watershed  control program is a  surveillance and  monitoring  program
which is  conducted to protect  the quality of  a  surface water  source.   It is
desirable to have an  aggressive and detailed watershed control program to
effectively  limit or  eliminate  potential  contamination  by  human  enteric
viruses.  A  watershed program  may impact parameters  such as turbidity,  certain
organic compounds, viruses, and total and  fecal  coliforms  and  areas of wild-
life habitation.   However,  the'program is  expected to have little or no impact
on  parameters  such  as  naturally occurring  inorganic  chemicals,  naturally
occurring organic materials,  and pathogens transmitted by wildlife with  the
                                      3-35

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 exception of preventing  animal activity near the source water intake prior to
 disinfection.
     It may be difficult to quantify  the effect of a watershed program since
 there  are  many variables  which influence  water quality that are  beyond the
 control or  knowledge of  the water supplier. ~~ As a result,  the  benefit of a
 watershed control  program or specific control  measures  must in  many cases be
.based on accumulated cause and effect  data  and  on the  general knowledge of the
 impact of  control  measures rather  than  on actual quantification.  The effec-
 tiveness of a  program to limit or eliminate potential contamination by human
 enteric viruses will be determined based on:  the comprehensiveness  of the
 watershed review;  the ability  of the water  system to effectively  carry out and
 monitor the management  decisions  regarding control of detrimental activities
 occurring in the watershed; and the potential for the  water  system to maximize
 land ownership and/or control  of land use within the  watershed.  According to
 the SWTR, a watershed control  program  should include as  a minimum:
     1.   A description of  the watershed including  its hydrology  and land
          ownership
     2.   Identification, monitoring  and control of watershed characteristics
          and  activities  in  the watershed which may have an adverse effect on
          the  source water quality
     3.   A program to  gain  ownership  or control  of  the land  within the
          watershed  through  written  agreements with land  owners,   for the
          purpose  of controlling  activities  which will  adversely  affect the
         -microbiological quality  of the water
     4.   An annual  report which identifies special concerns in  the watershed
          and  how  they  are  being  handled,   identifies  activities  in  the
          watershed,  projects  adverse  activities  expected  to   occur  in the
          future and how the utility expects to address  them.
     Appendix  J contains a  more detailed  guide  to a comprehensive watershed
 program.
     For systems utilizing ground  water  sources under  the influence of surface
 water,  the control measures   delineated  in   the  Wellhead  Protection   (WHP)
 program encompass  the  requirements of the  watershed  control program, and can
 be used to  fulfill the requirements of  the watershed control program.  Guid-
 ance on the content  of  State wellhead Protection Programs and the delineation
 of wellhead protection  areas is given in:  "Guidance  for Applicants for State
                                      3-36

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Wellhead  Protection Program Assistance Funds  Under the  Safe  Drinking Water
Act,"  June,  1987,  and "Guidelines  for  Delineation of  Wellhead Protection
Areas," June,  1987, available  from the EPA office of Ground-Water Protection
(WH-550G).
As a minimum, the  WHP  program must:
  -  Specify  the  duties  of  State agencies, local  governmental  entities and
     public water  supply systems with respect to the development and implemen-
     tation of  Programs;
  -  Determine  the wellhead protection  area  (WHPA)  for  each   wellhead  as
     defined   in   subsection  1428 (e)   based  on  all  reasonably  available
     hydrogeologic information ground-water  flow,  recharge  and discharge and
     other  information the  State deems necessary to adequately determine the
     WHPA;
  -  Identify within each  WHPA all potential anthropogenic sources of contami-
     nants which may have  any adverse effect on the health of persons;
  -  Describe  a Program that contains, as appropriate, technical assistance,
     financial   assistance,   implementation  of  control measures,  education,
     training and  demonstration projects to protect the  water supply within
     WHPAs  from such contaminants;
  -  Include  contingency  plans  for  the location  and  provision  of alternate
     drinking water supplies for each public water system  in the event of well
     or wellfield contamination by such contaminants;
  -  Include  a requirement that consideration  be given  to all  potential
     sources  of such  contaminants within the expected wellhead area of a new
     water well which serves a public water supply system; and
  -   Include  a requirement for public participation.

      3.3.2  On-site Inspection
     The watershed control program and the on-site inspection are  interrelated
preventive strategies.  The on-site  inspection is  actually a program which
 includes and  surpasses the  requirements  of a  watershed  program.  While the
 watershed program is  mainly  concerned with  the water  source,  the on-site
 inspection includes  some  additional  requirements  for source water quality
 control and is also concerned with the disinfection system.  As defined by the
 USEPA, an on-site  inspection includes review of the water  source,  disinfection
 facilities and operation and  maintenance of  a public water  system  for the
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purpose of evaluating the adequacy of such systems for producing safe drinking
water.
     According to the  SWTR, an on-site  inspection to  evaluate  the watershed
control program and disinfection  system is required  to be conducted annually
by a party approved  by the Primacy Agency.  The inspection should be conducted
by competent  individuals such as  sanitary and civil engineers/ sanitarians,
and technicians who  have experience  and knowledge in  the operation,  mainte-
nance, and design of a  water  system, and who have  a  sound  understanding of
public health principles  and waterborne diseases.  Guidance  for the contents
of an  inspection  are included in  the following  paragraphs.   Appendix K pre-
sents  guidelines  for  a  sanitary  survey  which  includes  and  surpasses  the
requirements  of the  on-site inspection.
     At the onset of determining  whether or not  a source  is  to  be classified
as a surface  water,  EPA  recommends  that  utilities conduct a detailed,  compre-
hensive sanitary survey.   Appendix K presents  a  comprehensive  list of water
system features that the person  conducting the survey  should be aware of and
review as appropriate.  This initial  investigation establishes the quality of
the water source,  its treatment and delivery to the consumer.  EPA recommends
that this comprehensive  evaluation be repeated every three years for  systems
serving 4,100 people  or  less  and every five  years  for  systems serving more
than 4,100 people.  Also, under the  Total  Coliform  rule,  systems  which take
less  than  5  coliform  samples  per  month must  conduct such  sanitary  surveys
within every  5 or 10 years depending  upon whether the source  is protected and
disinfected.
     The annual  on-site  inspection  to  fulfill  the  SWTR requirements  must
include as a  minimum:
     A.   Source Evaluation
          1.    Review of  the  effectiveness  of the watershed control  program
               (Appendix J)
          2.    Review of  the physical condition  and  protection  of the source
               intake
          3.    Review of  maintenance  program to  insure that  all to disinfec-
               tion  equipment is appropriate and has  received repair as needed
               to assure  a high  probability  for prevention  of disinfection
               system failure
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     B.   Treatment Evaluation
          1.   Review of  improvements and/or  additions  made to disinfection
               processes  during  the  previous year  to  fulfill inadequacies
               detected in earlier surveys

          2.   Review of disinfection equipment for physical  deterioration

          3.   Review of operating procedures

          4.   Review of  data  records to assure that  all  required  tests are
               being  conducted and recorded  and  disinfection  is effectively
               practiced

          5.   Identification of  any  improvements which  are  needed in the
               equipment, system maintenance and operation, or data collection

     In  addition to  these requirements,  it is recommended  for all systems,
including those  with filtered  and  unfiltered supplies, that  a periodic  sani-

tary survey also be  conducted. The  sanitary survey  should include  the  items
listed in A and  B above as well as:


     C.   Distribution System Evaluation

          1.   Review of storage facilities  for construction  condition

          2.   Determination  that  sufficient  pressure  has  been maintained in
               the system throughout the year

          3.   Verification that system equipment has received regular mainte-
               nance

          4.   Review of  additions/improvements incorporated during the year
               to correct inadequacies detected in  the  initial inspection

          5.   Review of cross connection prevention program,  including annual
               testing of backflow prevention devices

          6.   Review of routine flushing program for effectiveness

          7.   Evaluation of  the  corrosion  control  program  and   impact  on
               distribution water quality

          8.   Review of the periodic  storage reservoir  flushing program for
               adequacy

          9.   Review of practices  in  repairing  water main  breaks  to  assure
               they include disinfection
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     D.   Management/Operation Evaluation
          1.   Review the operations  to insure that  any difficulties experi-
               enced during the year have been adequately addressed
          2.   Review to  decide  whether  a reorganization  of management  is
               needed
          3.   Determine whether the budget is adequate
          4.   Review of staffing to  insure adequate  personnel  are available
               and they are adequately trained and/or certified
          5.   Verify that a regular maintenance schedule is followed
          6.   Review the systems  records  to verify that  they are adequately
               maintained
          7.   Review bacteriological  data from  the  distribution  system  for
               coliform occurrence, repeat samples and action response
     3.3.3  No Disease Outbreaks
     Under the provisions of  the SWTR, a  surface water  system which does  not
filter must  not have had  an  identified waterborne  disease outbreak  in  its
current configuration which  has been  determined  by the Primacy  Agency to be
attributable to a treatment  deficiency.  If an identified waterborne disease
outbreak has occurred in the past and  the  outbreak was attributed to a treat-
ment deficiency, then the system must install filtration unless the system  has
upgraded its treatment  system  to remedy the deficiency  which  led to the out-
break and the Primacy Agency has determined that the system is satisfying this
requirement.  The  system may  not be  required to  install filtration  if  the
Primacy Agency  has  determined  the disease outbreak  to be  the   result of  a
distribution system problem rather than a source water treatment deficiency.
     In order  to determine  whether  the  requirement  is being  met, the  re-
sponsible federal,  state and   local  health agencies should  be  surveyed  to
obtain the current and historical  information  on  waterborne disease outbreaks
which may  have occurred  within  a given  system.  Whether  conducted  by  the
Primacy Agency  or  submitted by the water purveyor,  this  information  should
include:
     A.    Source of the  Information:
          1.   Name of agency
          2.   Name and  phone number of person contacted
          3.   Date of inquiry
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     B.   Outbreak Data
          1.   Known or suspected incidents of waterborne disease outbreaks
          2.   Date(s) of occurrence(s)
          3.   Type or identity of illness
          4.   Number of cases
     C.   Status of Disease Reporting:
            -  Changes in  regulations; e.g., giardiasis was not  a reportable
               disease until  1985
     D.   If a Disease Outbreak has Occurred:
          1.   Was  the reason for  the outbreak  identified; e.g.,  inadequate
               disinfection
          2.   Did  the outbreak  occur while  the system was  in  its  current
               configuration
          3.   Was remedial action taken
          4.   Have there been any further outbreaks since the remedial action
               was taken
     If  a review of  the available  information  indicates that the  system or
network  for  disease reporting is inadequate within  the Primacy Agency's area
of responsibility,  efforts should be  made to  encourage the appropriate agen-
cies to upgrade the disease reporting  capabilities within the area.
     3.3.4  Monthly Coliform  MCL
     Monthly MCL
     Systems must comply with the monthly coliform MCL on an ongoing basis in
order to avoid filtration.  The monthly coliform MCL criteria include:
     a.   The  three test  methods which  can  be used within  the distribution
          system are the membrane filter  technique  (MF), the multiple tube
     9.   The  P-A is  a  modification of  the MPN  method in  which a  single
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          fermentation test reported  in terms  of the  most probable  number
          (MPN).or the presence of  coliforms  using the presence-absence test
          (P-A)Iy'.

     b.   Systems which analyze less than 40  samples/month for  coliforms must
          have coliform-positive results in no more than one sample/month.

     c.   Systems which analyze 40  or more samples/month  must  maintain coli-
          form-positive results in 5.0 percent or less of the samples of each
          month

     d.   For systems  analyzing fewer than  1 sample/month, no  more  than  1
          sample per  3-month period may be  total coliform-positive,  except
          that,  at  the discretion  of  the  Primacy Agency, compliance  may  be
          based upon sampling during a one-month period.

     e.   Unfiltered surface  water systems must analyze  one coliform sample
          each day the raw water turbidity exceeds one NTU.

The culture medium  of  each positive sample must be analyzed for  fecal coli-

forms or  Escherichia  cgli  and  five repeat samples must  be  collected  within

24 hours at the same sampling location or the next closest sampling point.  If

any repeat sample is total-coliform positive but fecal-coliform-negative, five

additional repeat samples  must  be  taken within  24 hours  of being  notified of

the results.  The system must repeat this process  until  either coliforms are

not detected in one set  of five repeat  samples  or the system determines that
the monthly coliform MCL has been  exceeded and notifies  the  Primacy Agency.

If fecal  coliforms  or  &._ coli  are  present  in any repeat samples,  the system

must notify the Primacy  Agency.  The results  of the repeat sample are to be

included in the calculation of the MCL and can be used to  satisfy the minimum
          culture bottle is innoculated with a 100 ml sample.  The test method
          is currently listed as a tentative procedure; however, past research
          has indicated that  the P-A method has  a  detection efficiency which
          surpasses that of the  MPN test and is  equivalent  to  that  of the MF
          method  (Fujioka  et al.,  1986).   The   test  procedure is  also  more
          easily performed than the aforementioned methods.

     10.  Systems using an unfiltered surface supply are required to collect a
          minimum of 5 samples per month, regardless of population.
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number  of monthly coliform  samples  required.   The frequency of monitoring to
meet  the above  regulations  is  based on  population served, as  indicated in
Appendix  H.
     Although  a  Maximum  Contaminant  Level  Goal/Maximum  Contaminant  Level
(MCLG/MCL)  for Heterotrophic Plate  Count (HPC)  has  not been proposed,  the
Total Coliform Rule  uses the HPC to  invalidate total coliform samples based on
interference from HPC.   If a coliform sample produces a turbid culture in the
absence of  gas production, using the multiple-tube  fermentation technique, or
produces  a  turbid  culture   in  the  absence  of  an acid  reaction using  the
presence-absence  (P/A)  test, or produces  confluent growth or a colony number
that is too numerous to count using the membrane  filter technique, the system
may  declare the  sample invalid (unless  total coliforms are  detected),  and
collect and analyze  another  water sample.   The second sample is to be analyzed
for  total  coliform using a media less prone  to  interference by heterotrophic
bacteria.   The sample is considered coliform-positive if the coliform test is
positive  and is considered coliform-negative if the coliform test is negative.
     Systems which fail to meet  the  total  coliform MCL because of a failure in
the disinfection  treatment of the source water is  required to install filtra-
tion.
     3.3.5  Total Trihalomethane (TTHM) Regulations
     For  the system  to continue  to use disinfection as the only treatment, it
must be in compliance with  the total trihalomethane  (TTHM)  MCL regulation.
The current regulation has established an  MCL  for total TTHM of 0.10 mg/L for
systems serving a population greater than 10,000.   This level may be reduced
in the  future  and this should be considered when planning disinfectant appli-
cation.
     One  alternative for utilities  to meet the CT requirements of the SWTR is
to  increase the  disinfectant  dose.  However,  for many systems, this  will
result in an increased formation of  TTHMs.  Any increase which results in TTHM
levels greater than  0.10 mg/L is unacceptable.   However, considering that more
stringent TTHM requirements  are  expected in the future, disinfection applica-
tion which  increases THMs to levels close to  0.10 mg/L  should not  be imple-
mented.   In such  cases, an  alternate  disinfectant which produces fewer TTHMs
may  be  used.  Alternate  disinfectants include  the use of  ozone  or chlorine
dioxide  as  primary  disinfectants with chlorine or chloramines  as  secondary
(residual)   disinfectants.   However,   the   EPA  will  be   promulgating  a
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disinfection  by-product  regulation  in  1991  which  may  put limitations  on
by-products of these disinfectants also.  EPA recommends that Primacy Agencies
require systems  which  are  going  to  change  their disinfection  practices  to
conduct testing prior to the  change  to determine  the  resulting by-products.
Any changes  which  will  result  in an exceedance  of  by-product regulations
should not be implemented.
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                      4.   DESIGN AND  OPERATING CRITERIA FOR
                          FILTRATION  AND DISINFECTION TECHNOLOGY
4.1  Introduction
     In  accordance with the  SWTR,  public water  systems  must  include filtra-
tion,  or some other approved particulate  removal technology,  in their treat-
ment  process  unless  they are  able  to  satisfy certain conditions.   Those
conditions  include  compliance  with source  water quality criteria  and  site-
specific criteria,  for which guidance  is provided in Section 3 of this manual.
Systems  not  able to  satisfy these  conditions  will  be  required  to provide
particulate  removal  and  meet  criteria pertaining to operation and  design
(specified  in part  in the definitions  of technologies  in the  SWTR and more
specifically  as determined by the Primacy  Agency),  and performance.
     This section provides guidance for  those water systems which currently do
not have filtration  equipment  and must add it, and  for systems  which have
existing filtration processes.   Guidance on additional alternatives for small
systems  is discussed in Appendix L.
     This section includes guidance on the following topics:
       - Filtration Technology:   Descriptions, capabilities,  design criteria
          and operating requirements  for each  technology,  and a  listing of
          major  factors to be  considered in  their selection,  including  raw
          water quality considerations.
       - Disinfection:    Descriptions  of  the  most  applicable  disinfection
         * technologies used with filtration  systems, and a presentation of the
          relative  effectiveness of the  disinfection technologies with respect
          to  inactivation  of bacteria, cysts and  viruses.
       - Alternate  Technologies:   Descriptions  of some  currently available
          alternate filtration technologies.
       - Other  Alternatives:   Includes a  description  of  some nontreatment
          alternatives including  regionalization  and use  of  an  alternate
          source.
4.2  Selection of Appropriate Filtration Technology
     Filtration is generally provided by passing water through a bed of sand,
a layer  of diatomaceous earth, or  through  a combination of coarse anthracite
coal overlaying finer sand.   Filters are classified and named  in  a number of
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ways.  For example,  based on application rate,  sand  filters  can  be classified
as either slow or  rapid;  yet these two  types  of filters differ in many  more

characteristics  than  just application  rate.   They  differ  in their  removal

process,  bed material, method  of cleaning, and operation.   Based  on  the  type
of bed material,  filters can  be  classified  as sand,  diatomaceous  earth,

dual-media  (coal-sand),  or even tri-media  in which  a third  sand layer  is

added.

     4.2.1  General  Descriptions
     Definitions  of currently used technologies,  as  contained  in the  SWTR are

as follows:
     a.   Conventional Treatment:   A  series  of processes  including  coagu-
          lation,  flocculation, sedimentation and filtration.

     b.   Direct  Filtration:   A series of processes including coagulation  (and
          perhaps flocculation) and filtration, but excluding sedimentation.

     c.   Slow Sand Filtration:  A process which involves passage of raw water
          through a  bed  of  sand  at  low  velocity  [generally  less  than  0.4
          meters/hour  (1.2 ft/hr)] resulting in particulate  removal by physi-
          cal and biological mechanisms  and  changes  in chemical parameters by
          biological actions.

     d.   Diatomaceous Earth Filtration:   A process that meets  the following
          conditions.

            -  A  precoat cake  of diatomaceous  earth  filter  media is deposited
               on a support membrane (septum)

         "  -  The water  is  filtered by passing it  through the  cake  on the
               septum; additional filter media, known as body feed, is contin-
               uously  added to the feed water in order to  maintain  the  per-
               meability of the  filter cake.

     e.   Alternate  Technologies:   The  available alternate filtration tech-
          nologies include, but  are not limited to:
            -  Package Plants
          Depending  upon the  type of  treatment  units  in  place,  historical
          performance  and/or   pilot   plant  work,   these   plants   could  be
          categorized  as  one  of  the  technologies  in  a-d  above  at  the
          discretion  of  the State.   Several  studies have  already indicated
          that some package plants effectively remove Giardia cysts.  If such
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            -  Cartridge Filters
     4.2.2  Capabilities
     Filtration  processes  provide various  levels of  turbidity  and  microbial
contaminant  removal. When  properly designed  and operated and  when treating
source waters  of suitable  quality,  the above  filtration  processes  (with the
exception of cartridge  filters  regarding virus  removal) are capable of achiev-
ing  at  least  a 2-log  (99 percent)  removal  of Giardia  cysts and a  1-log
(90 percent) removal of viruses without disinfection  (Logsdon,  1987b;  USEPA,
1988a; Roebeck,  1962).   A summary of the removal capabilities  of  the various
filtration processes is presented  in Table 4-1.
     As indicated in Table  4-1, conventional treatment without disinfection is
capable of achieving up to a 3-log removal of Giardia cysts and up to a. 3-log
removal  of  viruses.  Direct  filtration  can  achieve up to a  3-log removal of
Giardia  cysts  and  up to a  2-log  removal  of viruses.  Achieving  the maximum
removal  efficiencies  of those constituents with  these  treatment  processes
requires the raw water to  be properly coagulated and filtered.   Factors which
can adversely impact removal  efficiencies include:
       -  Raw water turbidities less than 1 NTU
       -  Cold water conditions
       -  Non-optimum or no coagulation
       -  Improper  filter operation including:
            -  No filter to waste
            -  Intermittent operation
            -  Sudden rate  changes
            -  Poor housekeeping
            -  Operating the  filters beyond turbidity breakthrough
     Studies of  slow sand  filtration have  shown that this technology (without
disinfection) is capable of providing greater than  a 3-log removal of Giardia
cysts and greater than  a 3-log  removal of viruses.  Factors which can adverse-
ly impact removal efficiencies  include:
          plants  provided adequate disinfection as demonstrated by satisfying
          CT  values, so  that  the complete treatment train achieves  at  least
          3-log    removal/inactivation    of    Giardia cysts    and    4 log
          removal/inactivation of viruses,  use  of  this  technology  would
          satisfy the minimum  treatment requirements.
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                                   TABLE 4-1
                REMOVAL CAPABILITIES OF FILTRATION  PROCESSES
                                                             (1)
                                            Log  Removals
Process

Conventional Treatment

Direct Filtration

Slow Sand Filtration

Diatomaceous Earth
  Filtration
Giardia
 Cysts

 2-3

 2-3
                                      (2)
 2-3
 2-3
      (5)
      (5)
Viruses
1-3
1-2
1-3
1-2
     (3)
     (3)
     (4)
     (2)
                                     (2)
 Total
Coliform

  >4

 1-3

 1-2


 1-3
Note:
     1.   Without disinfection
     2.   Logsdon, 1987b.
     3.   Roebeck et al 1962
     4.   Poynter and Slade, 1977
     5.  _These technologies generally achieve greater  than  a  3-log removal.

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        -   Poor source water quality
        -   Cold water conditions
        -   Increases in filtration rates
        -   Decreases in bed depth
        -   Improper sand size
        -   Inadequate ripening
     Also,  as indicated in Table 4-1, diatomaceous  earth (DE)  filtration can
achieve greater than a 3-log removal of Giardia cysts when sufficient precoat
and  body  feed  are used.  However, turbidity and  total  coliform  removals are
strongly influenced by the grade of DE employed.  Conversely, DE filtration is
not  very  effective  for  removing viruses  unless  the  surface  properties of the
diatomaceous  earth  have been altered by  pretreatment of the body  feed  with
alum or a suitable  polymer.   In general,  DE filtration  is assumed to achieve
only a  1-log  removal of viruses unless demonstrated otherwise.   Factors which
can  affect the removal of  Giardia cysts and  viruses include:
        -   Precoat thickness
        -  Amount of body feed
        -  Grade of DE
        -   Improper conditioning of septum
     Package  plants can be used  to  treat water supplies for  communities  as
well as  for  recreational  areas, parks,  construction  camps,  ski  resorts,
military installations and others where potable water is not available from a
municipal  supply.   Operator  requirements vary  significantly  with  specific
situations.   Under unfavorable  raw water conditions they could  demand full-
time attention.   Package plants are most widely used to treat surface supplies
for  removal of turbidity,  color and coliform organisms prior to disinfection.
They are available in capacities up to 6 mgd.
     Colorado  State  University conducted a series  of  tests on  one  package
plant over a  5-month period during the winter of 1985-86  (Horn and Hendricks,
1986).  Existing installations in Colorado had proven effective for turbidity
removal, and  the  tests  at the university were designed  to  evaluate  the  sys-
tem's effectiveness in removing coliform bacteria and Giardia  cysts  from low
turbidity,  low temperature  source waters.   The test results showed  that the
filtration  system could remove  greater  than 99 percent of  Giardia  cysts for
waters  which had less than 1 MTU turbidity and less than 5 C temperatures,  as
long as proper  chemical   treatment  was   applied,  and  the   filter  rate  was
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10 gpm/ft  or less.  In addition, an alternate water source having a turbidity
ranging from  3.9 to 4.5 NTU was used  in 12  test runs with  coagulant  doses
ranging from  15  to 45 mg/L.   The effluent  turbidities  from these  runs  were
consistently less than 0.5 NTU.
     Surveys of existing facilities  indicate that while  package plants may be
capable of achieving effective treatment, many have not consistently met the
MCL for turbidity, and in some  cases, colifonns  were  detected in the filtered
water  (Morand et  al.,  1980;  Morand and Young,  1983).   The performance diffi-
culties were related to the short detention time inherent in the design of the
treatment units, the lack of skilled operators with sufficient time to devote
to operating  the  treatment  facilities  and  the  wide-ranging  variability  in
quality of the  raw water source.  Raw  water turbidity  was  reported to often
exceed  100 NTU  at one  site.   Improvements  in  operational   techniques  and
methods at this site resulted  in substantial improvement in effluent quality.
After adjustments  were made,  the plant was  capable  of producing  a filtered
water with  turbidities less .than 1 NTU,  even when influent  turbidities in-
creased from  17  to 100 NTU  within  a 2-hour  period as  long as proper coagu-
lation was provided.
     One of  the major  conclusions   of  these  surveys  was that package  water
treatment plants manned by competent operators can  consistently remove turbid-
ity and bacteria from surface waters of  a  fairly uniform  quality.  Package
plants applied where raw water turbidities are variable require a high degree
of operational skill and nearly constant  attention by the operators.  Regard-
less of the  quality of the  raw water  source, all package  plants  require at
least a minimum level of maintenance and operational skill and  proper chemical
treatment if they are to produce satisfactory water quality.
     Cartridge filters  using microporous  filter elements  (ceramic,  paper or
fiber) with  pore  sizes as  small  as 0.2 urn may  be  suitable for producing
potable water from raw water supplies containing moderate levels of turbidity,
algae and  microbiological contaminants.   The advantage to small  systems of
these cartridge filters is that,  with the exception of disinfection, no other
chemicals are required.   The process is  one of  strictly  physical  removal of
small particles by straining as the water passes through the porous cartridge.
Other  than   occasional  cleaning   or   cartridge  replacement,  operational
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requirements  are not  complex and do  not require skilled personnel.   Such a
system may  be suitable for some  small systems where,  generally,  only mainte-
nance personnel  are  available for operating water  supply facilities.  However,
the use of  cartridge filters  should be limited to low turbidity source waters
because  of  their susceptibility to  rapid headless  buildup.   For  example,
manufacturer's  guidelines  for achieving  reasonable  filter  run lengths  with
certain polypropylene filter  elements are that the raw water  turbidity  be 2
NTU or less (USEPA,  1988a).
     Lcr-7  (1983)  analyzed the efficacy of a variety of cartridge filters using
turbidir.  measurements,  particle  size analysis,  and  scanning  electron micro-
scope ar. -lysis.   The filters  were challenged, with a  solution  of microspheres
averaging 5.7 urn in  diameter  (smaller  than a Giardia cyst) , at a concentration
of 40,000 to 65,000  spheres per mL.   Ten  of 17 cartridge filters removed over
99.9 percent  of  the  microspheres.
     In  tests using live  infectious  cysts  from a  human  source,  cartridge
filters were found to be highly  efficient in  removing Giardia  cysts  (Hibler,
1986).   Each  test  involved  challenging  a  filter with  300,000 cysts.   The
average removal  for five tests was 99.86 percent, with  removal efficiencies
ranging from 99.5 percent to  99.99 percent.
     The application of  cartridge filters to small water systems using either
cleanable  ceramic or disposable  polypropylene cartridges,  appears  to  be a
feasible method  for  removing turbidity and most microbiological contaminants,
although data are needed regarding the ability of cartridge filters to remove
viruses.  Since  disinfection by  itself could  achieve  a 4-log  inactivation of
viruses, if the  cartridge  filter removes greater than or equal to 3 logs of
Giardia, then the filter plus disinfection would achieve the  overall minimum
requirements.  However,   consideration should  be given to the  feasibility of
multiple barriers of  treatment for each  target  organism, i.e.,  some Giardia
and  virus   removal by each barrier as a protection  if  one of  the barriers
fails.  The efficiency and economics of the process must be closely evaluated
for  each application.   Pretreatment  in  the  form of  roughing  filters (rapid
sand  or multi-media)  or  fine mesh screens  may  be  needed  to  remove larger
suspended  solids, which  could  cause the rapid buildup of headloss  across the
cartridges.  (USEPA, 1988a)
                                       4-6

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     In general, conventional  treatment,  direct filtration, slow sand filtra-
tion and diatomaceous earth filtration can be designed and  operated to achieve
the maximum removal of water quality parameters of concern.  However, for the
purpose of selecting  the appropriate filtration and disinfection technologies
and  for determining  design criteria,  these  filtration processes  should be
assumed to achieve a 2-log reduction in Giardia cysts and a 1-log reduction of
viruses.  This  conservative  approach will assure  that  the treatment facility
has  adequate  capabilities  to  respond  to  non-optimum performance due  to
changes in raw water quality,  plant  upsets,  etc.   The balance of the required
removals and/or  inactivation of  Giardia  cysts and viruses must therefore be
achieved through the application  of appropriate disinfection.  The performance
of  alternate  technologies  such  as  cartridge  filters,  and  possibly package
plants, depending upon the unit under consideration, however, cannot be stated
with certainty at this time.   These performance uncertainties necessitate the
use of pilot studies in order to  demonstrate their efficacy for a given water
supply.
     4.2.3  Selection
     For any specific site  and situation, a  number  of factors will determine
which filtration technology is  most  appropriate.   Among these are:   raw water
quality  conditions,  site  specific  factors,  and economic  constraints.   A
discussion of the impact of  raw water quality on  the  technology selection is
presented here.  The impact of site  specific factors and economic constraints
are presented in the USEPA document "Technologies and Costs for the Removal of
Microbial Contaminants from Potable Water Supplies" (USEPA, 1988a).
     Raw Water Quality Conditions
     The number of treatment barriers provided should be commensurate with the
degree of contamination  in the source  water.   The four available technologies
vary in their  ability to meet  the performance criteria when a  wide range of
raw water quality is considered.   While  numerical values of raw water quality
that can be accommodated  by each  of the four technologies will vary from site
to site, general guidance can  be  provided.   General  guidelines  for selecting
filtration processes, based on  total coliform count,  turbidity,  and color are
presented in Table 4-2.   It  is not recommended that  filtration  systems other
                                      4-7

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than those listed in Table 4-2 be utilized when  the general raw water quality
conditions exceed the  values listed, unless it  has been  demonstrated through
pilot testing that the technology can meet the performance criteria under the
raw water  quality  conditions expected  to occur  at  the site.   The  filtration
processes listed in  Table 4-1 are  capable  of achieving  the  required perfor-
mance criteria  when properly  designed and  operated if  they are  treating  a
source water of suitable quality.  One of the causes of filtration failures is
the use of  inappropriate technology  for a  given  raw water quality (Logsdon,
1987b).
     However, these criteria are general  guidelines. Periodic occurrences of
raw water coliform,  turbidity or color levels in excess  of the values present-
ed  in Table 4-2 should  not preclude  the selection or  use  of a  particular
filtration technology.  For  example, the  following alternatives are available
for responding to occasional raw water turbidity spikes:
       -  Direct Filtration
            -  Continuous monitoring and coagulant dose adjustment
            -  More frequent backwash of filters
            -  Use of presedimentation
       -  Slow Sand Filtration
            -  Use of a roughing filter
            -  Use of an infiltration gallery
       -  Diatomaceous Earth Filtration
            -  Use of a roughing filter
            -  Use of excess body feed
     For  the above  alternatives,   it  is recommended that  pilot  testing  be
conducted to demonstrate the efficacy of the treatment alternative.
     The characteristics  of  each filtration technology are a  major factor in
the selection  process.   Characteristics  of significance  include  performance
capabilities  (contaminant  removal  efficiencies),  design  and  construction
requirements, and operation  and maintenance requirements.   Details regarding
each of the  four filtration  technologies  are presented in  the following sub-
section.
                                      4-8

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                                                TABLE 4-2
                             GENERALIZED CAPABILITY OF FILTRATION SYSTEMS
                             TO ACCOMMODATE RAW WATER QUALITY CONDITIONS
Treatment

Conventional with predisinfection

Conventional without predisinfection

Direct filtration with flocculation

Direct filtration without flocculation

Slow sand filtration

Diatomaceous earth filtration
General Restrictions
Total
Col {forms
(#/100 ml)
ion (20,000(3)
(3)
ection (5,000
ation (500(3)
ouia-,(3)
Notes:
(800
    (5)
 (50
    (3)
(5
  (3)
                                                  (5
                                (3)
                                                                                                     (5
(3)
    1.   Depends on algae population, alum or  cationic polymer coagulation  (Cleasby et al., 1984.)

    2.   USEPA, 1971.

    3.   Letter-man, 1966.

    4.   Bishop et al., 1980.

    5.   Slezak and Sims, 1984.

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4.3  Available Filtration Technologies

     4.3.1  Introduction
     As indicated  in the SWTR, the historical responsibility of the states to

establish design and operating criteria for public drinking water plants will

continue.  The purpose of the  following sections is to provide guidance on how

the design  and operating  criteria may  need to be changed  in  order to assure

that the performance criteria  in the  SWTR are met.
     The design criteria for the various filtration technologies found in the

1987 edition  of the Recommended Standards for Water Works (Ten States Stan-
dards) are the minimum design  criteria  that a majority of states are currently
following.     The  design criteria contained in the Ten States Standards have

not been  duplicated here.   Rather, the reader is referred to  the  Ten States

Standards.  EPA recommends the following additions and/or  changes  to  the Ten

State Standards in  order to  assure compliance with the performance criteria of
the SWTR.

     4.3.2 General

     The following  recommendations apply to all filtration plants:

     A.   All filtration plants should  provide continuous turbidity monitoring
          of the effluent turbidity from each individual filter.

     B.   All  new  water treatment plants  should include  the  capability  of
          filter-to-waste on each filter, and where possible, existing filtra-
          tion plants should install  a  filter-to-waste capability.
     2.   Based upon the  results  of a survey conducted for the American Water
          Works Association Research Foundation  (AWWARF), some 38  states  use
          the  Ten  States Standards  entirely  or in  modified form  (AWWARF,
          1986).

     3.   Although  this  is not part  of the  requirements  of the SWTR,  it is
          recommended  because of .the possibility that  not  all filters in  a
          treatment plant will produce the same effluent turbidity.   This  may
          be due  to a variety of conditions  that include  bed upsets, failure
          of media  support or underdrain systems, etc.  Although  the combined
          effluent from all the filters may meet  the turbidity requirements of
          the  SWTR,  the turbidity  level   from an  individual  filter  may
          substantially exceed the  limits.   This  may result  in the passage of
          Giardia cysts,  or other pathogens.

     4.   For  most high  rate  granular bed  filters,  there is  a period  of
          conditioning, or break-in,  immediately  following backwashing,  during
                                      4-9

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C.   In  order  to establish  filter-to-waste  operating  guidelines,  the
     following procedure is suggested:

     a.   Review  the  performance  (effluent  turbidity)   data  for  each
          filter  and  determine which filter  has  the poorest performance
          historically  (highest effluent turbidity).

     b.   Following backwashing  of the  filter with  the  poorest  perfor-
          mance, place  that  filter into service and collect grab .samples
          every minute  for a period of at least 30 minutes.

     c.   Analyze the  grab samples for turbidity  and determine how long
          the filter  must  be in operation  before  the effluent turbidity
          drops to  less than  or  equal to  0.5 NTU (or 1.0  NTU in cases
          where a filtered water  turbidity of less than  or equal to 1.0
          NTU is allowed).

     d.   The filter to waste period is then defined as the time it takes
          for the filter effluent  of  the  worst filter to reach a turbid-
          ity of  less  than  or equal to  0.5  NTU  (or  1.0 NTU)  following
          filter start-up at the normal production flow rate.  If the raw
          water is less than 1.0 NTU then  at  least 50 percent turbidity
          removal across the  filter should be achieved before the filter
          is brought back on-line.

     e.   Since not all filters  may be capable of  filtering to waste at
          normal production  flow  rates,  an alternative may  be  to define
          the quantity of water which must be filtered to waste.

     f.   In addition,  the filter-to-waste period should  be determined
          during  each of  the seasonal  variations in water quality  to
          account for their impact on filter performance.

D.   All water treatment plants should increase filtration rates gradual-
     j/p  when placing  filters back  into  service  following  backwashing
     and/or after the filter-to-waste valve is closed.
     which turbidity and particle removal is at a minimum.  In some cases
     the addition of a suitable polymer to the backwash water or starting
     the  filter  at  a low  rate and  gradually increasing  the rate  may
     reduce the amount of time required for the break-in of a filter.

5.   Continuous  turbidity  monitoring  can  be used   in  place  of  grab
     sampling.
                                4-10

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      4.3.3  Conventional Treatment
      Conventional treatment  is  the most widely  used technology for removing
 turbidity and microbial contaminants from surface water supplies.  Convention-
 al treatment  includes the pretreatment  steps  of chemical coagulation, rapid
 mixing,  flocculation  and sedimentation followed  by  filtration.   The  filters
 can be either sand,  dual-media, or multi-media.  Figure  4-1  is  a flow sheet
 for a conventional treatment plant.
      Single media rapid sand filters are generally designed with a filtration
 rate of 2 gpm/ft  .  Newer plants which use dual- or tri-media filters often
 have a design filtration  rate  of 4  to 6 gpm/ft .   When properly operated,
 filter plants are generally capable of producing  filtered  water turbidities of
 0.1 or 0.2 NTU.   Site-specific  raw water  quality  conditions  influence  the
 design criteria for each component of  a conventional  treatment system.
      Design Criteria
      The  minimum  design criteria  presented  in  the  Ten  State  Standards  for
 conventional treatment are considered sufficient for the purposes of the SWTR
 except for the following addition:
       -   The criteria for sedimentation should  be  expanded to include other
           methods of  solids removal including plate separation, dissolved air
           flotation, and upflow-solids-contact  clarifiers.
      Operating Requirements
      In addition  to the operating  requirements in the Ten State Standards,  a
primary coagulant must be used at  all  times during  which  the treatment plant
is  in operation.      The operation  of conventional  and  direct  filtration
plants is more demanding than for DE or slow sand  filter plants.  Conventional
and  direct filtration plants must be monitored  carefully because  failure to
maintain optimum  coagulation  can result in poor filter performance and break-
through of cysts and viruses.     Although the  detention time provided by the
     6.   Dependable removal of Giardia cysts can not be guaranteed if a clear
          water  (raw water  turbidity less  than 1  NTU)  is  filtered  without
          being properly coagulated  (Logsdon, 1987b; Al-Ani et al., 1985).
     7.   As indicated in the preamble to the proposed SWTR, 33 percent of the
                                     4-11

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COAGUL/i

kNTS


RAPID MIX
30 SEC-2 MIN
DETENTION
             FLOCCULATION

                20-45 MIN
SEDIMENTATION

  1-4 HOURS
FILTRATION

 RAPID SANO: 2 gpm/ft*
  DUAL AND TRI-MIXEO
  MEDIA: 4-6 gpm/ft?
FIGURE 4-1 FLOW SHEET OF A TYPICAL CONVENTIONAL

                      WATER TREATMENT PLANT

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settling  basins results  in some  margin of  safety,  the loss  of coagulation

control at  the  chemical feed and rapid mix points may not be noticed until the

poorly  coagulated  water  reaches  the  filters  and the  process has  failed.

Failure  to  effectively  monitor and  control  filter  operation  can  result in

undetected  poor filter performance (Logsdon,  1987a; Logsdon, 1987b).

     Effective  operation of a  conventional  treatment plant  requires  careful

monitoring  and  control of:

       -  Chemical  Feed
       -  Rapid Mix
       -  Flocculation
       -  Sedimentation
       -  Filtration

     For the purposes of  the SWTR, effective  operation of a conventional water
treatment plant can be summarized  as  follows:

     a.   The   application  of  a  primary coagulant  and the maintenance  of
          effective coagulation and flocculation at all times when a treatment
          plant is  in operation.

     b.   Maintenance  of  effective  filtration.   Unless  terminal  headless
          occurs before  the  effluent turbidity exceeds 0.5 NTU,  the  filter
          effluent  turbidity of  less  than 0.5 NTU should be used to initiate:
          1) the start of a backwash  cycle
          2) the start of a filter run at the end of a filter-to-waste cycle

     c.   Filters removed from service should always be backwashed  upon start
          up.

     4.3.4   Direct  Filtration
     A direct filtration  plant can include several  different pretreatment unit
processes depending upon the application.  In its  simplest form, the process
          reported  cases of  giardiasis  in waterborne  disease  outbreaks were
          attributed to  improperly operated filtration plants.

     8.   Some  conventional  water treatment plants which  treat low turbidity
          source  waters  (<1  NTU)  reportedly  discontinue  the  application  of
          coagulant (s)  during periods of low  turbidity  since the  raw water
          already meets  the  turbidity MCL.  However,  studies  have  shown that
          cyst  removal  for  low  turbidity waters  is  the  most difficult  to
          achieve and requires optimum pretreatment (including coagulation)  to
          achieve effective removals  (Al-Ani et al., 1985).
                                     4-12

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includes only  in-line  filters  (often  pressure units)  preceded by  chemical
coagulant application and mixing.  The mixing requirement, particularly in

pressure filters, can be satisfied by influent pipeline turbulence.   In larger
plants with gravity filters, an open rapid-mix basin with mechanical mixers is
typically used.  Figure 4-2 illustrates the unit processes of a typical direct
filtration plant.
     Another variation  of the  direct  filtration  process  consists  of  the
addition of a coagulant to the raw water  followed  by rapid mixing and floccu-
lation, as illustrated  on  Figure 4-3.   The chemically conditioned and floccu-
lated water is  then applied directly to a dual or mixed-media filter.  Floccu-
lation results  in better performance  of certain dual-media filter designs for
specific water  supplies  (USEPA, 1988a).
     Design Criteria
     The 1982 edition of Ten  State Standards requires pilot studies to deter-
mine most  of the design criteria.   The requirement  is considered  sufficient
for the purposes of the SWTR with the following exception:
     A.   Primary coagulant must be used at all times when the treatment plant
          is in operation.
     Operating  Requirements
     Operating considerations and requirements  for direct  filtration plants
are  essentially  identical  to those  for  conventional  treatment  plants.   The
major difference is that a  direct filtration plant^wi11 not have a clarifier,
and may or may not have a flocculation or contact basin.  In addition, it is
recommended  that all  direct  filtration  plants,  both new and  existing,  be
                                                                     (10)
required to initiate a filter-to-waste period following backwashing.
     9.   Optimum  coagulation   is  critical   for  effective  turbidity  and
          microbiological  removals  with  direct   filtration  (Al-Ani  et  al.,
          1985).
     10.  As  with  conventional   treatment,  direct  filtration  produces  a
          relatively poor quality  filtrate at  the  beginning of filter  runs and
          therefore requires a filter-to-waste period  (Cleasby et al., 1984).
                                      4-13

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     COAGULANTS
 INFLUENT'
 RAPID MIX
30 SEC - 2 Mil
 DETENTION
DUAL OR MIXED
 MEDIA FILTER
 4-5 Bpm/ft 2
                  FIGURE 4-2 FLOW SHEET FOR A TYPICAL
                               DIRECT FILTRATION PLANT
    COAGULANTS
INFLUENT
RAPID MIX
30 SEC  2 MtN
DETENTION
 ^
FLOCCULATION
15-40 MIN
*
DUAL OR MIXED
MEDIA FILTER
4-5 opm/ft 2
           FIGURE 4-3 FLOW SHEET FOR A TYPICAL DIRECT
                     FILTRATION PLANT WITH FLOCCULATION

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     As with  conventional treatment, the priorities  for initiating the back-
washing of  a filter should  be filter effluent  turbidity values, followed by
headloss and run time.  Effluent turbidity monitoring equipment should be set

to initiate filter backwash  at an effluent value lower than 0.5 NTU, in order
to meet finished  water quality requirements.  Also,  any filters removed from
service, should always be backwashed upon start up.
     4.3.5  Slow Sand Filtration
     Slow sand filters differ from single-media rapid-rate filters in a number
of important  characteristics.  In  addition to  the difference of  flow rate,
slow sand filters:
     A.   Function using  biological mechanisms  as well  as physical-chemical
          mechanisms
     B.   Use smaller sand particles
     C.   Are not backwashed,  but rather are cleaned by removing the surface
          media
     D.   Have much longer run times between cleaning
     E.   Require a ripening period at the beginning of each run
     Although rapid  rate  filtration is the  water treatment  technology used
most extensively in the United  States,  its use has often proved inappropriate
for small communities since rapid-rate filtration is a technology that requir-
es skille'd operation by trained operators.  Slow sand filtration requires very
little control by an operator.   Consequently,  use of this  technology  may be
more appropriate  for  small systems  where  source water quality  is  within the
guidelines recommended in Section 4.2.3.
     As indicated in this section,  slow sand filtration  may be applicable to
other source water quality conditions with the  addition of pretreatment such
as a roughing filter or presedimentation.

     Design Criteria
     The minimum design criteria presented in the Ten State Standards for slow
rate gravity  filters  are considered  sufficient  for the  purposes of the SWTR
with the following exceptions:
                                     4-14

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     a.   Raw  water quality  limitations  should be  changed  to  reflect  the
          values given in table 4-2.
     b.   The  effective  sand  size should be between  0.15mm  and  0.35mm rather
          than the current 0.30 mm to 0.45 mm.
     Operating Requirements
     Maintenance of  a  slow sand filter requires  two  periodic  tasks:   removal
of the  top 2 to 3 cm  (0.79-1.2 inches) of  sand and replacement of  the sand
(Bellamy et al., 1985).  The top 2 to 3 cm (0.79-1.2 inches)  of the surface of
the sand bed should be removed when the headless exceeds 1 to 1.5 m.
     Slow-sand filters produce  poorer quality filtrate at the beginning of a
run (right after scraping), and require a filter-to-waste (or ripening) period
of one to  two days before  being used to  supply  the system.   The  ripening
period  is  an  interval  of time immediately after  a  scraped filter is  put back
on-line, when the turbidity or particle count results are significantly higher
than  the  corresponding  values  for  the  operating  filter.   Filter  effluent
monitoring  should be used to determine the  end of the  ripening  period.  For
example, a turbidimeter  could be set at 1.0 NTH  or less  to  initiate  start of
the filter run.

     When  repeated  scrapings  of the  sand  have reduced the' depth of  the sand
bed to approximately one-half  of its  design depth,  the sand should  be  re-
placed.  Filter bed  depths of less  than  0.3 to 0.5 m  (12 to  20  inches) have
     11.  Without pretreatment, limitations exist in the quality of water that
          is  suitable for  slow sand  filtration  (Logsdon, 1987b;  Cleasby  et
          al., 1984; Bellamy et al., 1985; Fox et al., 1983).
     12.  Significant  decreases  in total  coliform  removals were shown  at
          effective  sand  sizes greater  than  0.35 mm  (Bellamy et  al.,  1985).
          As  defined in the AWWA Standard for Filtering  Material, effective
          size is  the size opening  that will pass 10 percent by  weight  of a
          sample of filter material.
     13.  Removal of  this  top  layer of  the  "Schmutzdecke" should restore the
          filter to its operational capacity and initial headloss.
                                     4-15

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been shown to  result in poor filter performance (Bellamy et al., 1985).  The
replacement procedure should include removal of  the remaining sand down to the
gravel support, the  addition of the new sand  to one  half of the design depth
and placement of the sand previously removed on  top of the new sand.
     The amount of time  for the biological population to mature in a new sand
filter (also called curing) and to provide stable and full treatment was found
to vary.  The World Health Organization  (1980) reported that curing requires a
few weeks to a few months.  Fox et al.,  (1983) found that "about 30 days" were
required to  bring particle  and bacterial effluents  down to a  stable level.
All researchers agree that a curing time for  a  new  filter is required before
the filter operates at its fullest potential  (Bellamy et al., 1985).
     4.3.6  Diatomaceous Earth Filtration
     Diatomaceous earth  (DE)  filtration,  also known as  precoat  or diatomite
filtration, is applicable to direct treatment  of surface waters for removal of
relatively low levels of turbidity and microorganisms.
     Diatomite filters consist  of a layer of DE about  3 mm (1/8 inch)  thick
supported on a septum or filter element.  The  thin precoat layer of DE must be
supplemented by a continuous body feed of diatomite, which is used to maintain
the porosity  of the  filter cake.  If  no body  feed is  added,  the particles
filtered out will build  up on the surface of  the  filter cake and cause rapid
increases in headless.  The problems inherent  in maintaining a perfect film of
DE on the  septum  have restricted  the  use of  diatomite  filters  for municipal
purposes," except under certain favorable raw water quality conditions, i.e.,

low turbidity and good bacteriological  quality.   Specific upper limits of raw
water quality parameters  are  not well-defined  because dratomaceous  earth
     14.   This procedure results in clean sand being placed in the bottom half
          of  the  filter bed  and  biologically active  sand  in  the top  half
          reducing the amount of. time required for the curing period.  It also
          provides for  a  complete exchange  of  sand  over time,  alleviating
          potential problems  of excessive  silt accumulation and  clogging  of
          the filter  bed (Bellamy et al., 1985).
                                     4-16

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process performance  depends on the nature,  as  well as the  concentration,  of

the raw water particles and the grades of diatomite employed.  Logsdon (1987b)

reported  that  littered water  turbidities  above 1  NTU  and short  filter  runs

were observed  for several diatomaceous earth plants having  maximum  raw  water
turbidities above 20 NTU.

     Design Criteria

     The  minimum design  criteria presented  in the Ten  State Standards  for

diatomaceous earth  filtration are  considered sufficient  for the  purposes  of
the SWTR with the following exceptions:

     A.   The  recommended  quantity of  precoat is 1 kg/m   (0.2  pounds  per
          square  foot)  of filter  area,  and  the  minimum  thickness  of  the
          precoat filter cake is 3mm to 5mm  (1/8 to 1/5-inch).   '

     B.   Treatment plants should be encouraged to provide a coagulant coating
          [alum or suitable polymer] of the body feed.

     Operating Requirements
     Operating requirements specific to DE filters include:

       -  Preparation of body feed and precoat

       -  Verification that dosages are proper

       -  Periodic backwashing and disposal of spent filter-cake

       -  Periodic inspection of the septum(s) for cleanliness or damage

       -  Verification that the  filter is  producing  a  filtered  water  that
         .meets the performance criteria
     4.3.7 Alternate Technologies
     15.   Studies"have shown that a precoat thickness of 1 kg/m  (0.2  Ibs/ft  )
          was most  effective  in Giardia cyst  removal  and  that  the precoat
          thickness  was  more important  than  the grade  size in cyst removal
          (DeWalle et al.,  1984;  Logsdon et al., 1981; Bellamy et al., 1984).

     16.   Although enhancement  of  the  DE  is not  required  for Giardia  cyst
          removal,  coagulant coating  of  the body  feed  has been  found to
          significantly improve  removals  of viruses, bacteria and  turbidity.
          (Brown et al.,  1974;  Bellamy et al., 1984).
                                     4-17

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     The SWTR indicates  that filtration technologies  other  than those speci-
fied above  may be  used  following demonstration  (e.g.,  through  the use  of
on-site pilot studies) that  the  alternate  technology is at least as effective
as conventional treatment.   Guidance  for the pilot studies required to demon-
strate this effectiveness is given in Appendix M of this manual.
     Alternate filtration technologies which are currently available include:
       -  Package Plants
       -  Cartridge Filters
     Package  plants  are  not  a  separate  technology  in  principle from  the
preceding technologies.  They are, however,  different enough in design crite-
ria, operation and maintenance requirements  that they should be handled as an
alternate technology.  The package plant is  designed  as a factory-assembled,
skid-mounted unit  generally  incorporating a single,  or at  the most,  several
tanks.  A complete  treatment process typically  consists of  chemical coagula-
tion, flocculation, settling and filtration.  Package plants generally can be
applied to flows ranging  from about  25,000 gpd to approximately 6 mgd (USEPA,
1988a).
     The application  of cartridge filters  using either cleanable  ceramic or
disposable polypropylene  cartridges  to small water  systems  may be a feasible
method for removing turbidity and some microbiological contaminants,  such as
Giardia cysts although no data are available regarding the inability to remove
viruses.  As  previously  indicated, pilot studies  are required to demonstrate
the efficacy  of  this technology  for  a given supply.   If the technology were
demonstrated to be effective through pilot plant studies at one  site, then the
technology  could be  considered  to  be  effective  at  another  site  which had
similar source water  quality conditions.   Pilot plant testing at the new site
might not be necessary.

     Design Criteria
     Upon completion  of the pilot studies  and assuming successful demonstra-
tion of performance,  design  criteria  should  be  established and approved by the
Primacy  Agency.    Eventually,  a  sufficiently   large  data  base  will become
available to apply the alternate  technology  on  other water supplies of similar
quality.
                                      4-18

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     Operating Requirements
     Upon  completion  of the pilot studies  and assuming successful demonstra-
tion of performance, operating requirements should be established and approved
by the Primacy Agency.
     4.3.8  Other Alternatives
     Under  certain circumstances,  some systems  may have  other alternatives
available.  These  alternatives include regionalization and the  use  of alter-
nate sources.
     For small water  systems which must provide filtration, a feasible option
may be  to  join  with  other  small  or large systems  to  form a regional water
supply system.  Alternative water sources located within a reasonable distance
of a  community which meet  the  requirements of the  SWTR  and  other applicable
drinking water regulations may be developed to provide a satisfactory solution
to a community water quality problem.  Alternative ground water sources may be
available  depending upon the  size and location  of  the system  and  the costs
involved.

4.4  Pi s infection
     4.4.1  General
     The SWTR requires  that  disinfection be included as part of  the  treatment
of water  for potable  use.   EPA has already  recommended  that  the  number  of
treatment  barriers  be  commensurate  with the  degree of contamination  in  the
source water in accordance with Table 4-2.  For example, as indicated in Table
4-2, when  the  total coliforms in the source water are  greater than  5,000/100
ml, conventional treatment with predisinfection  is recommended.   However,  the
selection  of  appropriate disinfection  requires more detailed  considerations
than those provided in Table 4-2. These considerations include:
       -  Source water quality and the overall removal/inactivation of Giardia
          cysts and viruses
       -  Formation of TTHMs
       -  Need  for  an  oxidant  for  purposes   other  than disinfection,  e.g.,
          control of taste, odor, iron,  manganese, color, etc.
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     4.4.2  Recommended Removal/Inactivation
     The SWTR requires  a  minimum 3-log removal/inactivation  of  Giardia cysts
and a minimum 4-log removal/inactivation  of viruses.   For purposes of design-
ing disinfection systems,  filtration which is operated  to meet  the turbidity
performance requirements presented in Section 5 should be assumed to achieve a
2-log removal of Giardia cysts and a 1-log removal of viruses.
     However,  well  operated  conventional  treatment  plants  optimized  for
turbidity removal can be expected to achieve a 2.5 to 3-log removal of Giardia
cysts  and diatomaceous  earth,  slow  sand filtration  and direct  filtration
plants can  be expected to achieve  greater than a  2-log removal  of Giardia
cysts.  EPA  recommends that  conventional  filtration systems provide  disin-
fection to achieve  a minimum of  0.5-log  inactivation of  Giardia  cysts and a
2-log  inactivation  of viruses.    Other   systems  should  provide  sufficient
disinfection to achieve a minimum of 1-log inactivation of Giardia cysts and a
3-log inactivation of viruses as  a  margin of safety.   CT values for achieving
these inactivations are given in  Appendix E.   Systems which achieve a 0.5-log
inactivation of Giardia cysts, using free chlorine, would achieve greater than
a 4-log  inactivation of  viruses.  Ozone  and  chlorine  dioxide  are generally
more effective at  inactivating  viruses than Giardia  cysts however, there are
some conditions  at which  the  viruses are  more  difficult  to inactivate (see
Tables E-8 to E-12).   Because of this,  a system utilizing ozone  or chlorine
dioxide  for  disinfection  must check  the  CT values needed to provide  the
required inactivation  of  both Giardia  and viruses and  provide  the higher of
the two disinfection levels.
     Chloramines are  much less effective for inactivating Giardia cysts and
viruses than the other disinfectants.  Also, chloramines may  be applied to the
system in sevejral  ways,  either with chlorine  added prior to ammonia, ammonia
added prior to chlorine or performed.   For systems applying  chlorine ahead of
ammonia, the required level of disinfection may be determined as follows:
       -  determine  the CT  needed   to  provide  the  required  inactivation  of
          Giardia and viruses
       -  provide the higher of the two levels
       -  follow the protocol  in Appendix  G  to  demonstrate  effective inacti-
          vation, allowing lower  levels of disinfection.
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     For  systems  applying ammonia ahead of chlorine or preformed chloramines,
the  EPA recommends  that  the system demonstrate  effective virus inactivation
according to  the  protocol in Appendix G.  The CT values for virus inactivation
in Table  E-13 only apply  to the addition of chlorine prior to ammonia.
     Although the SWTR requires a minimum of  a 3-log removal/inactivation of
Giardia cysts and a  minimum of a 4-log  removal/inactivation of viruses, it may
be appropriate for  the Primacy  Agency to require greater removals/inactiva-
tions depending upon the  degree of contamination within the source water.
     Rose,  1988 conducted a  survey of water  sources to characterize the level
of Giardia cyst  occurrence  for  "polluted"  and  "pristine"  waters.   Polluted
waters are  defined as waters receiving sewage  and agricultural  wastes,  while
pristine  waters  are  those  originating  from  protected  watersheds  with  no
significant  sources  of microbiological contamination from  human  activities.
EPA believes  that treatment should be provided to  assure less than one case of
microbiologically-caused  illness per  year per  10,000 people.   In order  to
provide this  level of protection, 3, 4  or 5-log Giardia cyst should be provid-
ed for the following source water qualities:
           Giardia Cyst Removal/inactivation Required Based
                      on  Source Water Cyst Concentration
Giardia Inactivation               3-log           4-log          5-log
Allowable daily avg
  cyst concentration/100 L         <1              >1-10          >10-100
  (geometric mean)

     According  to these   guidelines,   systems  with  sewage  and  agricultural
discharges  to the  source water  should provide  disinfection to  achieve  an
overall 5-log removal/inactivation of Giardia cysts, while 3-log  removal/inac-
tivation  should be provided for  sources  with no  significant  microbiological
contamination  from human   activities.   A  4-log removal/inactivation of  cysts
     17.  Rose, 1988.
            -4
     18.  10   annual  risk per  person based  on consumption  of 2  liters  of
          water daily.
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should be provided  for source waters with some microbiological contamination
between these two extremes.  These  levels of treatment for different general-
ized source water characterizations are presented as guidelines.  The Primacy
Agency could develop disinfection requirements based on these guidelines or it
may require  systems which have  the resources available to  conduct raw water
monitoring for Giardia cyst  concentrations to establish the appropriate level
of overall treatment and disinfection needed.
     In the  absence of a risk  analysis for exposure  to viruses,  a guideline
for virus inactivation, can be based on the occurrence of viruses vs.  Giardia
cyst  occurrence.    Using  a  direct  proportion  between  occurrence and  inac-
tivation provided,  for a 4-log Giardia cyst removal/inactivation a 5-log virus
removal/inactivation   is    recommended,    and   for    5-log   Giardia   re-
moval/inactivation,  6-log virus removal/inactivation if recommended.
     CT  tables  for  each  of   the   disinfectants  for various  removals  are
presented  in  Appendix E.   These  tables  should  be   reviewed  in  order  to
determine  the minimum  dosage  and  contact  time required  for the  selected
disinfectant  in  preparation for ascertaining  the  chemical  feed  and storage
requirements.
     In order for systems to meet the levels of inactivation  recommended here,
significant changes  in  the system  may  be required.   To avoid  changes  in the
system which may result  in conflicts  with  future regulations,  the EPA has
given  the Primacy  Agency  discretion  in  establishing interim disinfection
levels to" provide protection of public health prior to the promulgation of the
disinfection byproduct regulations.   Guidance for establishing interim disin-
fection requirements is provided in Section 5.5.
     4.4.3  Total Trihalomethane  (TTHM) Regulations
     In  addition  to  complying with  disinfection requirements,  systems  must
conform to the TTHM regulation.  Currently,  this  regulation includes  an MCL
for TTHMs of 0.1 mg/L for systems which serve greater  than 10,000 people.  EPA
expects to issue more  stringent regulations  in the near future.  These regu-
lations may  also pertain  to systems  serving  less than 10,000 people.  There-
fore, the selection of an appropriate disinfectant must include consideration
of current and future regulations.
                                     4-22

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                  5. CRITERIA FOR DETERMINING IF FILTRATION
                     AND DISINFECTION ARE SATISFACTORILY PRACTICED
5.1  Introduction
     Under the  SWTR,  new and  existing filtration plants must meet  specified
monitoring and  performance criteria  in order to  assure that filtration  and
disinfection are satisfactorily practiced.  These criteria include:
       -  Turbidity monitoring requirements
       -  Turbidity performance criteria
       -  Disinfection monitoring requirements
       -  Disinfection performance criteria

     The overall objective of these criteria is to provide control of:  Giardia
cysts; viruses; turbidity;  HPC and Legionella by assuring a  high probability
that:
     a.   Filtration plants are  well  operated  and  achieve  maximum  removal
          efficiencies of the water quality parameters of concern.
     b.   Disinfection will provide adequate inactivation of  viruses,  HPC  and
          Legionella,  and added protection against Giardia cysts.

5.2  Turbidity Monitoring Requirements
     5.2.1 Sampling Location
     The  purpose  of  the  turbidity  requirements  for  systems  which  utilize
filtration include:
     a.   To provide an indication of:
            -  Giardia cyst and  general particulate  removal  for  conventional
               treatment and direct filtration
            -  General particulate removal  for diatomaceous  earth  filtration
               and slow sand filtration
     b.   To indicate  possible interference with disinfection

     To  accomplish the  purposes  of  the  turbidity  requirements,  the SWTR
requires that the turbidity samples be representative of the  system's filtered
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water.  The sampling locations which would satisfy this requirement include:

     a.   Combined filter effluent prior to entry into a clearwell

     b.   Clearwell effluent

     c.   Plant effluent or  immediately prior to entry  into the distribution
          system

     d.   Average of measurements from each filter effluent.

     The  selection  of one  of  these  sampling  locations   for  demonstrating
compliance with the  turbidity performance criteria  is  left to  the  system or

the preference of the Primacy Agency.


     5.2.2  Sampling Frequency

     The  SWTR requires  that  the  turbidity  of  the filtered  water must be
determined:

     a.   At least once every four hours that the system is in operation, or

     b.   The Primacy Agency may reduce the sampling frequency to once per day
          for systems using slow sand filtration or filtration treatment other
          than conventional treatment, direct filtration or diatomaceous earth
          filtration.  For systems  serving less than 500 people,  the Primacy
          Agency may reduce the sampling  frequency  to once  per day regardless
          of the  type  of filtration  used;  if the historical  performance and
          operation  of  the   system   indicate  there  is  effective  turbidity
          removal   under variety  of  conditions  expected  to  occur  in  that
          system.

     A system may substitute continuous turbidity monitoring  for  grab sample
monitoring  if it validates  the  continuous  measurement  for  accuracy  on  a

regular basis using a protocol approved by the Primacy Agency.  EPA recommends

that the  calibration of continuous  turbidity monitors  be  verified  at  least

twice per week according to  the procedures established  in  Method  214A of the

16th Edition of Standard Methods.


     5.2.3  Additional Monitoring
     As indicated  in Section 4.3.2,  it has been recommended that systems equip

each filter with  a  continuous turbidity monitor.  This  recommendation  is not

part of  the requirements  of  the SWTR  and is  not  required  for establishing

compliance.  Rather, it is recommended  as  a  tool for systems to use to better

monitor their treatment  efficiency and  to provide  a method for  detecting  a

deterioration in filter performance.

                                      5-2

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      In  filtration, effective particle  removal depends on  both physical and
chemical  factors.  The  particles to be removed must  be transported  to the
surface  of  the media  and they  must attach  to the media.   When efficient
particle  removal does not occur, the deterioration  of  filter performance can
be  due to  either  physical  problems with  the filters  or problems with the
treatment chemistry.
      Physical  problems  which can result in a  deterioration  of filter perfor-
mance include:
       -  Media loss
       -  Media deterioration
       -  Mud  ball  formation
       -  Channeling or  surface cracking
       -  Underdrain failure
       -  Cross-connections
      In addition, the treatment  chemistry has  a significant  impact on filtra-
tion.  Specifically, effective particle removal is a function of the:
       -  Raw  water chemistry and the changes induced by the chemicals added;
       -  Surface chemistry of the particles to be removed
       -  Surface chemistry of the media
Consequently,  when  a filter experiences particle  breakthrough or turbidity
breakthrough prior  to the  development  of  terminal  headless/ the  search for
alternatives to  correct  the problem must include not only an evaluation of the
potential physical  causes but the treatment chemistry as well.  Generally this
involves an evaluation of one or more of the following:
     a.   Alternate coagulant type and/or dose
     b.   Alternate coagulant aid or flocculant aid type and/or dose
     c.   Need for  an alternate oxidant type and/or dose
     d.   Need for  a filter aid or alternate dose
                                      5-3

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     If continuous monitoring  of each filter  effluent  cannot be implemented,
then it is recommended that at least the following be conducted on a quarterly
basis:

       -  Monitor each filter, either  by  grab samples or continuous monitors,
          through  the course  of  a  routine  cycle of  operation,  i.e.,  from
          restart to backwash, and

       -  Visually inspect  each  filter where  appropriate for  indications  of
          physical deterioration of the filter.

     These are general  suggestions.    The  Primacy Agencies are  encouraged  to
work with the systems to determine the best overall monitoring program(s)  for
their particular filtration plants in order to assess the status of the filter
units.


5.3  Turbidity Performance Criteria

     The  SWTR establishes  turbidity  performance  criteria  for  each  of  the
filtration technologies.  As previously indicated, these  criteria  provide  an
indication of:

     a.   Effective particle and microbial removal and
     b.   Potential for interference  with disinfection


     5.3.1  Conventional Treatment or Direct Filtration

     Based upon the  requirements of the  SWTR, the minimum  turbidity  perfor-
mance criteria for systems  using conventional treatment or  direct  filtration

are:
       -  Filtered water turbidity must be less  than  or equal to  0.5 NTU  in
          95 percent of the measurements taken every month.

       -  At the discretion of the Primacy Agency, filtered water turbidity
          levels  of less than or equal to  1 NTU  in 95 percent of the measure-
          ments  taken every month may  be permitted on  a case-by-case basis  if
          the Primacy Agency determines that the  system is capable  of  achiev-
          ing the  minimum  overall performance requirements  of  99.9  percent
          removal/inactivation of Giardia cysts at the higher turbidity level.
          Such a determination could  be  based upon  an analysis of existing
          design   and operating  conditions and/or  performance  relative  to
          certain  water  quality characteristics.   The  design  and  operating
          conditions to be reviewed include the adequacy of treatment prior  to
          filtration, the percent turbidity removal across the treatment  train
          and level of disinfection.   Water quality analysis which may  also  be
          used to evaluate  the treatment effectiveness  include particle  size
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          counting before and after the filter.  Pilot plant challenge studies
          simulating  a  full size  operation may  also  be used  to demonstrate
          effective  treatment.   Depending  on  the source  water quality  and
          system  size,  the Primacy  Agency  will  determine  the extent  of  the
          analysis  and  whether a  pilot plant  demonstration is  needed.   For
          this demonstration,  systems are allowed to  include  disinfection in
          the determination of the overall performance by the system.

       -  Filtered water turbidity may not exceed 5 NTU at any time.

     Conventional treatment  plants that  are  meeting the minimum performance

criteria and have well  operating settling basins  are  assumed  to be achieving

at least a  2.5-log  removal of Giardia cysts  and at least a 2-log  removal of
                              (2)
viruses prior to disinfection.
     Direct  filtration  plants  that  are  meeting  the  minimum  performance

criteria are assumed to be achieving at least a 2-log removal of Giardia cysts

and a 1-log removal of viruses.

     Although the minimum  turbidity performance criterion has  been  set at  0.5

NTU, treatment  facilities  using conventional treatment  or  direct filtration,

whose raw  water supplies  have  turbidity  levels of  1  NTU or  less,  should be
                                                                           (4)
encouraged to achieve filtered water turbidity levels of less than 0.2 NTU.
1.   Recommended protocol for this demonstration is presented in Appendix N.

2.
The literature indicates that well  operated conventional treatment and plants
can achieve  up to  a  3-log reduction of Giardia cysts  and  viruses (Logsdon,
1987b and Roebeck et al., 1962).  Limiting  the  credit to 2.5-logs for Giardia
cysts and  2-logs for viruses  provides  a margin of safety  and  is consistent
with the multiple barrier concept.

3.
Literature indicates that well  operated direct  filtration plants  can achieve
up to a  3-log "removal of Giardia cysts  and up to a  2-log removal of viruses
(Logsdon, 1987b;  Roebeck et  al., 1962).   Limiting the  credit  to 2-log  for
Giardia  cysts and  1-log  for  viruses  provides  a margin  of safety and  is
consistent with the multiple barrier concept.

4.
Research has  demonstrated that  difficulty in obtaining  effective  removals  of
Giardia  cysts  and viruses with low  turbidity source waters (Logsdon,  1987b;
Al-Ani et al., 1985).
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     5.3.2  Slow Sand Filtration

     For  systems using  slow sand  filtration, the  turbidity performance re-
 quirements are:

       -  The filtered water turbidity must be less than or  equal to 1 NTU in
          95 percent of  the  measurements  for each month.

       -  At  the  discretion of  the Primacy Agency, a higher filter effluent
          turbidity may  be allowed  for well  operated plants  (Section 4.3.5) on
          a case-by-case basis,  if there is no interference  with disinfection
          and the turbidity  level never exceeds 5 NTU.  Non  interference with
          disinfection  could be  assumed if  the  finished water  entering the
          distribution system  is meeting the  coliform MCL  and HPC levels are
          less than 10/ml during  times of highest turbidity.

       -  Filtered water turbidity  may not exceed 5 NTU at any time.

     Slow  sand  filtration  plants,  with  appropriate design and  operating

 conditions  and  which  meet  the  minimum turbidity  performance  criteria are

 considered  to be well   operated  and  achieving  at least  a  2-log  removal of
 Giardia cysts and 2-log  removal of  viruses without disinfection.(5)
     5.3.3  Diatomaceous Earth Filtration

     For systems  using diatomaceous  earth filtration,  the  turbidity perfor-
mance criteria are:

     a.   The filtered water turbidity must be less than or equal to 1 NTU in
          95 percent of the measurements for each month.

     b.  - The turbidity level of representative samples of filtered water must
          at no time exceed 5 NTU.

     Diatomaceous earth  systems,  with appropriate  design and  operating con-

ditions and which  meet the minimum turbidity  performance criterion  are to be

considered well  operated  and  achieving  a minimum  2-log removal of Giardia

cysts and a 1-J.og. removal of viruses without disinfection.
5.
As indicated in Section 4, pilot studies have shown that with proper nurturing
of the  schmutzdecke,   operation at  a  maximum  loading rate  of  0.2 m/h  will
provide optimum removal of Giardia  cysts  and viruses  (Logsdon,  1987b;  Bellamy
et al.,  1985).
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     5.3.4  Other Filtration Technologies
     As specified in the  SWTR,  the turbidity performance criteria for filtra-
tion technologies,  other  than the  ones  presented above, are the  same  as for
conventional treatment and direct filtration.

5.4  Disinfection Monitoring Requirements
     The SWTR requires that each  system  continuously monitor the disinfectant
residual  of the water  as it  enters the  distribution  system and  record the
lowest disinfectant residual each  day.   Systems  serving less than or equal to
3300 people may take grab  samples in lieu of continuous monitoring at fre-
quencies as follows:
       System Population                Samples/Day*
          <500                               1
          "501-1,000                          2
          1,001 - 2,500                      3
          2,501 - 3,300                      4
            *  Samples must be  taken at dispersed time  intervals  as approved
               by the Primacy Agency.
     If the residual concentration  falls below 0.2 mg/L, the system must take
another sample within 4-hours and  notify the Primacy Agency by the end  of the
next business day.   Each system must also measure the disinfectant residual in
the distribution system  at the same frequency and  locations  for  which total
coliform measurements  are made pursuant to  the  requirements in  the  revised
coliform -rule (proposed at the  same time as the  SWTR).   For systems which use
both surface and ground water  sources, the Primacy  Agency may allow sampling
sites which are more representative of the surface water supply.

5.5  DISINFECTION PERFORMANCE CRITERIA
     5.5.1  Minimum Performance Criteria Required by the SWTR
     For systems which  provide filtration,  the  disinfection  requirements of
the SWTR are:
          The system must  demonstrate by continuous  monitoring  and recording
          that a disinfectant residual in the water entering the distribution
          system is never less than 0.2 mg/L for more than 4 hours.  If at any
          time the  residual  falls below 0.2   mg/L  for more than  4  hours the
                                      5-7

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          system  is  in violation.  The  system  must  notify the Primacy Agency
          whenever  the residual  falls  below 0.2 mg/L  before  the end  of  the
          next business day.
     b.   The system must demonstrate detectable disinfectant residuals or HPC
          levels  less than  500  colonies/ml in  at  least  95  percent  of  the
          samples  from  the  distribution  system each month,  for  any  two
          consecutive months.
     5.5.2  Recommended Performance Criteria
     The  SWTR requires  that the  overall treatment  provided  must achieve  a
minimum  of  a  3-log  removal/inactivation of  Giardia  cyst and  a 4-log  re-
moval/ inacti vat ion of  viruses.   As outlined in Section 5.3, it can be assumed
that well operated  filter plants   achieve between a 2  to 2.5-log removal of
Giardia cysts  and between a  1  to 2-log  removal  of  viruses.   It is therefore
recommended that  the Primacy agencies  adopt additional disinfection perfor-
mance criteria that includes:
     a.   As a minimum, primary disinfection requirements  that are consistent
          with the overall treatment requirements of the SWTR, or preferably.
     b.   Establishes  primary disinfection requirements as a  function of raw
          water quality as outlined in Section  4.4.
     Recommended Minimum Disinfection
     The  recommended  minimum  primary   disinfection  to  be provided  is  the
disinfection  needed to  provide  the  additional  inactivation  for  the entire
treatment process to meet the  overall  treatment requirement of 3-log Giardia
and 4-log virus inactivation.   The following table provides a summary of the
treatment performance and the recommended level of disinfection.
                                                  Recommended Disinfection
                        	Log Removal	     	(Log Removals)
Treatment               Giardia       Viruses     Giardia          Viruses
Conventional
Filtration               2.5              2          0.5               2
Direct Filtration        2                1          1.0               3.0
Slow Sand                2                2          1.0               2.0
Diatomaceous
  Earth                  2                1          1.0               3.0
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     Recommended Disinfection as a Function of Raw Water Quality
     Although the SWTR requires the  overall  treatment to provide  a minimum of
a 3-log Giardia and a 4-log  virus  removal/inactivation,  it may be appropriate
for the Primacy Agency to  require  greater removals/inactivations  depending on
the degree of contamination in the source water as presented in Section 4.4.
Following is  a  summary of the  recommended overall treatment which  should be
provided for the specified source water quality:
   Allowable daily avg
   cyst concentration/100 L          1        >1-10     >10-100
   (geometric mean)
   Giardia Removal/inactivation    3-log       4-log       5-log
   Virus Removal/inactivation      4-log       5-log       6-log

     Since it is not possible to increase removals previously outlined through
filtration,  in  order  to  provide  this  overall  treatment,  the  disinfection
provided  will  need to  be  increased  accordingly.    For  example,  if for  a
particular slow sand  filtration plant  on overall treatment for 4-log Giardia
removal/inactivation  and  5-log  virus  removal/inactivation  is  recommended,
disinfection  for a 2-log Giardia  inactivation and  3-log virus inactivation
would be needed to meet the  overall  recommended removal/inactivation.

5.5.3  Disinfection By-Product Considerations
     Although  the  EPA suggests  increased levels  of  disinfection for various
source  water conditions,  it is  also  recommended  that a  utility  should not
implement  such a change  without considering  the  potential conflict with the
requirements  of existing or  future disinfection  by-product regulations.  EPA
intends to promulgate  National  Primary Drinking Water Regulations to  regulate
levels  of  disinfectants  and  disinfectant by-products when  it promulgates
disinfection  requirements for ground water  systems  (anticipated  by  the end of
1991).    EPA  is  concerned  that  changes  required in  utilities'  disinfection
practices  to  meet  the  recommended  inactivations  for  the  SWTR   might  be
inconsistent  with  treatment changes  needed  to  comply with the  forthcoming
regulations  for disinfectants and disinfection by-products.   For this reason,
the   EPA  is   allowing   Primacy   Agencies  discretion   in  determining  the
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disinfection  conditions  needed for  filtered  systems  to  meet the  overall
treatment requirements specified  in the  rule or recommended based  on source
water quality.
     During the  interim period,  prior  to promulgation  of the disinfection
by-product  regulation,  EPA  recommends  that the  Primacy  Agency allow  more
credit for  Giardia  cyst  and virus  removal than generally  recommended.   This
interim level  is recommended in cases where the Primacy Agency determines that
a system is not currently at a  significant risk from microbiological concerns
at the existing level of disinfection and that a deferral is necessary for the
system to  upgrade its disinfection process  to optimally  achieve  compliance
with the SWTR as well as the  forthcoming disinfection by-product regulations.
The following paragraphs outline  the recommended  interim disinfection levels
for various treatment processes.
     For well operated  conventional filtration  plants that meet the minimum
turbidity requirements at  all  times, the Primacy Agency may  consider giving
the system  credit  for 3-log Giardia  cyst removal  (in lieu of  the generally
recommended 2.5-log  credit).   EPA recommends that credit be given  for 3-log
Giardia cyst removal by conventional treatment only if:
     a.   The  total  treatment  train  achieves at  least 99  percent turbidity
          removal, or  filtered  water turbidities  are consistently  less  than
          0.5  NTU, whichever is lower;
     b.   The  level  of  HPC in  the  finished  (disinfected)  water entering the
          distribution system is consistently less than 10/ml;
     c.   The  source water generally has Giardie cyst concentrations less than
          1 cyst/100 L.
     In establishing interim disinfection requirements for systems using slow
sand  filtration  and diatomaceous  earth filtration,  these  systems may  be
allowed credit, for 2.5 or 3-log Giardia  cyst removal in lieu of  the generally
recommended guideline  of   2-logs.    Pilot  plant   studies   have demonstrated
(USEPA, 1988a) that  these technologies,  when well operated, generally achieve
at least 2.5-log removals.
     The EPA  feels  that  interim disinfection requirements  are  appropriate in
some cases  depending upon  source  water  quality,  reliability of  system opera-
tion  and potential  increased  health  risks  from  disinfection by-products.
                                     5-10

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Since  EPA  intends  to  regulate  disinfectants  and disinfection  by-products
before  1992  and compliance with the SWTR is not  required until June of 1993,
it  is anticipated that  most systems will not  need  significant  time delays or
long interim periods to optimally address the  requirements of both rules.

     5.5.4  Determination of Inactivation by Disinfection
     The  inactivations  recommended above can  be achieved by  disinfection at
any point in the  treatment or distribution system prior to the first customer.
Disinfection provided prior to filtration is  referred  to as pre-disinfection
while disinfection after  filtration is referred  to  as  post-disinfection.   As
presented  in  Section  3.2,  the  inactivation  of  Giardia  cysts and  viruses
provided by disinfection are correlated to CT values.
     The SWTR defines CT as the residual disinfectant concentration(s)  in mg/L
multiplied  by  the contact  time(s)  in  minutes  measured from  the point  of
application to  the point of residual measurement or between points of residual
measurement.  The inactivation maintained can  be  determined by calculating CT
at  any  point along  the  process after  disinfectant application prior  to  the
first customer.  A system may determine the inactivation based on one point of
residual  measurement prior  to  the  first  customer, or on  a  profile  of  the
residual  concentration  after  the  point of  disinfectant application.   The
residual  profile  is generated  by monitoring  the residual at  several  points
between the point(s) of disinfectant application  and the first customer.  The
system  can  then use the method described  in Section 3.2  for  determining  the
total inactivation credit.   Profili^j the residual  allows for  credit  of  the
higher  residuals  which  exist  shortly  after  the  disinfectant is  applied.
Appendix D presents methods for determining various disinfectant residuals.
     In pipelines, the  contact time is calculated  by dividing the internal
volume  of the-pipeline by the peak  hourly  flow  rate  through  the  pipeline.
Within  mixing  basins and storage  reservoirs,  there may  be  short  circuiting.
Therefore, the  hydraulic  detention time may  not represent the  actual  disin-
fectant contact time.  The contact time should be determined by tracer studies
or an equivalent  demonstration.  The time determined from the  tracer study to
be  used for calculating  CT is T  .   T   is  equivalent  to  the time  for 10
percent of the  water to pass through the basin,  thus 90  percent of the water
                                     5-11

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will be  in  the  basin  for  this  length  of  time.   Guidance  for determining
detention time in basins is provided in Appendix C.
     The residual disinfectant  concentration should be measured daily, during
peak hourly flow for each  disinfectant section prior to the first customer in
the distribution system.  Unless a system knows from experience when peak flow
will occur, a system can only identify peak hourly flow after it has passed.
Therefore, it is suggested that residual measurements be taken every hour.  If
it is not practical to take grab samples each hour, continuous monitors may be
used.  The measurements taken during the hour of peak flow can then be used to
determine the  CT for  each  section  (CT  ,  }.  The determination of  CTs for
                                        calc
ozone contactors is explained in Section 3.2.1.
     Although the inactivation  maintained in the  system is determined during
peak hourly flow, it should be  noted  that the  disinfectant dosage applied to
maintain this inactivation may  not be necessary  under lower flow conditions.
Under lower flow conditions,  a  higher  contact time is generally available and
the  CT  needed to  meet  the  required  inactivation  may be  met with  a  lower
residual.  Continuing to apply  a disinfectant dosage based on the peak hourly
flow may provide  more  disinfection   than  is  needed,  possibly  resulting  in
increased levels of disinfectant by-products.  However,  the  system should also
maintain the  required  inactivation levels  at  non-peak  hourly flows.  There-
fore, the system should  therefore  evaluate  the dose needed  to provide the CT
necessary  for maintaining  the required  inactivation  under  different  flow
conditions and  set the  dosage  accordingly.   The  following example provides
guidelines for determining flow ranges and disinfection  levels to maintain the
required disinfection.
     Example
     A 20 mgd direct filtration plant  applying  free chlorine as a disinfectant
has  a  contact" time  of  27 minutes under  peak flow conditions.   The  pH and
temperature of the water are  7  and 5 C,  respectively.   Utilizing Table E-2, a
CT of 54 at a residual  of 2 mg/L is  required to  achieve  1-log Giardia cyst
inactivation.  However,  under low  flow conditions  the available contact time
is longer, and lower residuals are needed to provide the same level of inacti-
vation.   Based on the calculated contact time under various  flow rates and the
                                     5-12

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CT values in Table E-2, adequate disinfection would be provided by maintaining
the following chlorine residuals for the indicated flows:
                                      CT
                    Contact            (mg/l-min)              Free Chlorine
Flow  (MGD)          the (min)          Required               Residual  (mg/L)
   20                   27               54                       2.0
   15                   36               51                       1.5
   10                   54               48.5                     0.9
    5                  108               46.5                     0.5
     The variation  in CT required  with respect to  the  residual for chlorine
makes  it  impractical for the  utility to continually  change the disinfectant
dose as the flow  changes.   Therefore,  EPA suggests that the flow variation at
the utility be divided into ranges  and the  residual needed at the higher flow
of the range be maintained  for all flows within the range to ensure adequate
disinfection.   The following flow ranges  and residuals are suggested for this
plant:
                                             Free Chlorine
               Flow Range (MGD)              Residual  (mg/L)
                    5-10                          0.9
                    10-15                         1.5
                    15-20                         2.0

     In this  way,  the  utility is  assuring  the  provision  of  the  required
disinfection  while  minimizing  the  disinfectant  application  and  possibly
lowering disinfection by-products.
     Although these  residuals  will meet  the recommended CT,  maintaining  a
residual in the distribution  system must also be considered.   If there is no
other point of disinfection prior to the distribution system, the residual for
disinfection must' be maintained at  a  level  which will also provide a residual
throughout the distribution system.  The  complete  range  of flows occurring at
the plant  should be evaluated for determining the required  residual.   The
utilities  may  establish the  residual  needs for as many  flow ranges  as  is
practical.
     The Primacy Agency should make periodic checks to ensure that the utility
is maintaining  adequate disinfection  at  both peak  and non-peak  flow condi-
tions.
                                     5-13

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     Meeting the Recommended Inactivation Using Free Chlorine
     As previously indicated  in  Section  3.2.1,  the  effectiveness of  free
chlorine as a disinfectant is influenced by both the temperature and pH of the
water.  The inactivation of Giardia cysts by free chlorine at various tempera-
tures and pHs are presented in Appendix E (Table E-l through Table E-6).   The
CT value  for the  inactivation  of viruses  by  free chlorine  are  presented in
Table E-7.
     To determine  whether a system  is meeting these  inactivations,  the  free
chlorine  residual, pH  and temperature  must  be  measured,  at  one point  or
several points prior to the first customer where contact time is measured. The
contact time should  be  determined  from  the  point  of  application  of  the
disinfectant to  points where  the  residual is  measured for  determining CTs
prior to the first customer.   The CTs actually achieved  in  the system should
then be compared to the values  in the table for the pH and temperature of the
source water.   Guidance on calculating  the CT  for chlorine  is  presented in
Section 3.2.1.
     Meeting the Recommended Inactivation Using Chlorine Dioxide
     CT values for the  inactivation of Giardia  cysts  by chlorine dioxide are
presented  in Table E-8  and the CT values for  the  inactivation of viruses are
presented  in Table  E-9.   The disinfection  efficiency  of chlorine dioxide may
be significantly increased at higher pHs.   According  to the Tables  E-8 and
E-9, the only parameter affecting the CT requirements associated with the use
of chlorine dioxide is temperature.  The  CT values in  Tables E-8 and E-9 were
based on data at pH 6 and 7.  Thus,  systems with  high pHs may wish to demon-
strate that  CT  values lower than those presented  in  Tables E-8  and  E-9 may
achieve the desired level of inactivation.
     Chlorine dioxide residuals  are  short-lived.   Therefore,   sampling  and
residual analysis- at various points in the  treatment process downstream of the
point of application  may  be  necessary to establish  the  last point at which a
residual  is  present.   Subsequent  sampling and  residual analyses conducted
upstream of this point can .be used to determine the CT credit by utilizing the
demonstrated detention time between  the  point of application and the sampling
location.   Methods for calculating  CT values  are presented  in  Section  3.2.
Systems using   chlorine  dioxide  may  conduct  pilot  studies  to demonstrate
effective  disinfection in  lieu of calculating CT,  or for determing that lower
                                     5-14

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 CT values than those in Appendix E are  appropriate.  Guidelines for conducting
 these studies are presented in Appendix G.
      Meeting the Recommended Inactivation using Ozone
      CT values for the inactivation of  Giardia cysts by ozone are presented  in
 Table E-10 for various  temperatures  and inactivation  rates.   As  indicated  in
 this table,  the CTs needed for inactivation with ozone are substantially lower
 than those required for free chlorine.  This reflects the fact that ozone is a
 more powerful disinfectant.  The  CT  requirements  for  inactivation of viruses
 using ozone are presented in Table E-ll.   Because  of the reactivity of ozone,
 it is unlikely that a residual  will  exist for more  than a  few minutes.  As a
 result, the  application  of a  persistent  disinfectant  such  as   chlorine  or
 chloramines  is needed  to maintain the required disinfectant residual  in the
 distribution  system.   Guidance  for  calculating  CT  values  for  ozone  are
 presented in  Section 3.2.1.   In  lieu of  calculating  the  CT for  an ozone
 contactor or  to  demonstrate that  lower CTs  are  effective, the  disinfection
 efficiency  can  be  demonstrated  through pilot   studies   as presented  in
 Appendix G.
      Meeting  the  Recommended Inactivation Requirements using Chloramines
      CT values for the inactivation of Giardia  cysts by  preformed chloramines
 are  presented in Table E-12.   The high CT values associated with  the  use of
 preformed  chloramines  may be unachievable for some  systems.   In  these  cases,
 chlorine,  ozone,  or chlorine dioxide  should be  used  for  primary disinfection,
 and  chloramines for residual disinfection, as necessary.  Table E-13  presents
 CT  values for the inactivation  of viruses with  preformed chloramines.  For
 systems  applying  chloramines to meet the virus inactivation; it  is suggested
 that  these systems also monitor for HPC in the finished water,  as  presented in
 Section  5.6.   Systems may demonstrate effective disinfection with chloramines
 as  outlined  in Appendix  G.  Further guidance  on chloramines  is located  in
 Section 3.2.1.

Examples for Determining the Disinfection to be  Provided
     Recommended  0.5-log Giardia, 2-log Virus Inactivation
     A  community  of  70,000 uses  a  river  as  its  drinking  water  source.
Ozonation prior to a conventional treatment plant  is used to treat the  water.
                                     5-15

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The source has a protected watershed with limited human activity and no sewage
discharge.  The river water has the following water quality characteristics:
          turbidity                            10 - 200 NTU
          total estimated Giardia cyst level   <1/100 ml
          total coliforms                      20 - 100/lOOml
          pH                                   7.0-7.5
          temperature                          5-15
     The treatment plant has a design capacity of 15 mgd and treats an average
flow of 10 mgd.  A three chamber ozone contactor precedes the rapid mix.  Alum
and polymer  are  added as a  coagulant  and coagulant aid.   The  finished water
turbidity at the plant  is maintained  within the  range of  0.1  to  0.2  NTU.
Chloramines  are  applied after  the  filters, but  prior to  the  clearwells,  to
maintain a residual entering and throughout the distribution system.
     Based on  the raw water quality  and source water protection,  an overall
3-log Giardia  and 4-log  virus removal/inactivation  is  appropriate  for  this
water source.  However,  as  noted in Section  5.3,  Primacy Agencies may credit
well operated conventional filtration plants  with 2.5-log Giardia removal and
2-log virus  removal.   Therefore, disinfection  for 0.5-log Giardia and 2-log
viruses is recommended to meet the overall treatment requirements of the SWTR.
     On the day of this  example calculation,  the peak hourly flow rate of the
plant was 13 mgd.   The contact time of  the ozone basin,  T   determined  from
tracer study data is  6 minutes for this flow.  The water  had a pH of 7 and a
temperature  of  5 C  on the  day of the  calculation.  For ozone  under these
conditions of pH and temperature the following CTs are needed for inactivation
(Tables E-10, E-ll):
                            0.5-log Giardia      2-log virus
     CT                        0.3                   0.6
The CT values "indicate that viruses are the  controlling parameter for disin-
fection and  the  overall  inactivation provided  will  be calculated  based  on
viruses.   The  overall virus inactivation provided by the  ozone"  contactor  is
determined as follows:
                                     5-16

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Average
Residual
C (mg/L)
0.1
0.2
0.2
T
(minutes)
2
2
2
CT ,
(vfflS
0.2
0.4
0.4
CT
99 9
Minutes
0.9
0.9
0.9
CT , /C
calc
0.22
0.44
0.44
r99.9

Chamber
   1
   2
   3
The sum of CT  , /CT     is 1.1.  This corresponds  to more  than a 3-log virus
inactivation determined as 3 X CT  .  /CT_g  .  = 3 X 1.1 = 3. 3-log.  Therefore,
the system exceeds the recommended inactivation.
     Recommended 1-log Giardia, 2-log Virus Inactivation
     A  2 MGD  slow sand  filtration plant  treating reservoir water  provides
drinking water  for a community of  8,000  people.  The source has a protected
watershed and the following water quality characteristics:
     turbidity                            5-10 MTU
     total coliforms                      100 - 500/lOOml
     total estimated Giardia cyst level   < 1/100 ml
     pH                                   6.5 - 7.0
     temperature                          5 - 15 C
     The filtered water turbidity ranges  from 0.6 - 0.8  MTU.   Considering the
source water quality and plant performance, an overall 3-log Giardia and 4-log
virus removal/inactivation is considered sufficient for this system.  As noted
in Section  5.3, the  Primacy Agency  may  credit  slow  sand plants  with  2-log
Giardia and 2-log virus removal.   Therefore disinfection for 1-log Giardia and
2-log  virus is  recommended for  the  system  to meet  the overall  treatment
requirements .
     Chlorine is added prior to  the clearwells  to  provide disinfection.   The
clearwells  have a capacity  of 80,000  gallons.   A  one  mile, 16-inch  trans-
mission  main transports  the water from  the  treatment plant  to the  first
customer.  The  inactivation  provided  is determined daily  for the peak  hourly
flow conditions.  Tracer  studies  have been  conducted to  determine the T   for
the clearwells for different flow rates.   For the purposes of calculating the
inactivation the system is divided into two sections.
                                     5-17

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     Section 1 - clearwell

     Section 2 - transmission main

     The flowrate at peak hourly  flow was 1.5 mgd on the day of this example.
At this  flowrate, the  T   of the clearwell is 67  minutes,  as determined from

the results  of  the  tracer studies.   At  this flowrate,  water travels through

the transmission main  at  99  ft/min.   The data for  the calculation  of the

inactivation is as follows:

                             Section 1          Section 2

length of pipe (ft)               0                5280
contact time (min)
     pipe                        0                  53
     basin                      67            .       0
     total                      67                  53
disinfectant                 chlorine            chlorine
residual (mg/L)                 1.0                 0.6
temperature C                    5                   5
       pH                      7.5                 7.5


For free chlorine, a 1-log Giardia cyst  inactivation  provides  greater than a

4-log virus inactivation; therefore, Giardia is the controlling parameter, and

the inactivation provided is determined based on Giardia.  The calculation is

as follows:

     Section 1  - Chlorine

     CT  .   =  1.0 mg/L x 67 minutes = 67 mg/L-min
     From Table E-2,  at  a temperature of 5  C  and a pH of  7.5,  CT     is 179
     mg/L-min                                                        '


     CTcalc/CT99.9
                       179 mg/L-min

     Section 2  - Chlorine

     CT     =   0.6 mg/L x  53 minutes = 32 mg/L-min
     From Table  E-2,  at a  temperature  of 5 C  and a pH  of 7, CT      is 179
        t  .                                                       yy * y
     mg/L-min

     CTcalc/CT99.9 =   32mg/l-min =  0.18
                      179 mg/L-nun

The sum of  CT    /CTQQ Q is  equal  to 0.85. This  is equivalent to  a  2.5-log
              Ca J.C   yy . y
Giardia  inactivation  determined as  3x  CT  . /CTQQ Q  =  3  x 0.85  =  2.5.
 ^ ~ ~                                     caic   yy . y


                                     5-18

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Therefore,  the system exceeds the disinfection recommended to meet  the overall
treatment requirements.
     Recommended 2-log Giardia, 4-log Virus Inactivation
     A community of  200,000 people  uses a reservoir treated by direct filtra-
tion for its water supply.  The reservoir is fed by a river which receives the
discharge from  a wastewater treatment  plant  upstream of  the  reservoir.  The
reservoir water quality is as follows:
     turbidity                            5-15 NTU
     total  coliforms                      200 - 500/100 ml
     total  estimated Giardia cyst level   5/100 L
     pH                                   6 - 7
     temperature                          5 - 15 C
     Based  on  the source  water quality,  an  overall  removal/inactivation of
4-log Giardia and 5-log virus is recommended as outlined in Section 4.4.
     The source water  flows  by gravity  to  a  3 MG storage  reservoir prior to
pumping to  the water treatment  plant.   Chloramines are added to  the water at
the  inlet   of  the storage  reservoir  and chlorine  dioxide is  added to the
filtered water  prior to the  clearwells.  Chloramines  are applied  after the
clearwells  to  maintain a  residual  in  the distribution  system.    The  system
design flow is  8  mgd with an average  flow  of 5 mgd.  For. the  calculation of
the overall inactivation,  the system is divided into 2 sections.
     Section 1 - the storage reservoir and the transmission to the treatment
                 plant
     Section 2 - the clearwells
     The overall  inactivation  for  the  system is  computed  daily  at  the peak
hourly flow conditions.   The pH,  temperature,  and  disinfectant residual  is
measured at the  end  of each section prior  to the next point of  disinfectant
application and the  first  customer.  On  the  day of this  example calculation
the peak  hourly flow  was  6 mgd.   The  water flow  rate  through the 20-inch
transmission main  is 256  ft/min  at a  flow of  6 mgd.   Tracer  studies were
conducted on  the storage reservoir and clearwells.   As  determined  from the
testing the detention times,  T   ,  of the basins at a flow of 6 mgd are 380 and
                                     5-19

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80 minutes  for  the  storage reservoir and clearwells,  respectively.   The data

for the calculation of inactivation is as follows:
                                  Section 1                Section 2

length of pipe  (ft)                  4500                       0
contact time (min)
     pipe                             18                       0
     basin                           380                     130
     total                           398                     130
disinfectant                     chloramines             chlorine dioxide
residual (mg/L)                       1.5                     0.1
temperature C                       15 C                     5 C
pH                                     77


     For each  of the  disinfectants used,  the following  CTs are  needed for
2-log  Giardia  and   4-log  virus  inactivation for the  pH  and  temperature

conditions of the system.

                                 CT for 2-log       CT for 4-log
                                   Giardia             Virus

chloramines                         1435                1988

chlorine dioxide                      27                  33.5
     The CT required for the virus inactivation is higher than that needed for

Giardia inactivation for each of the disinfectants.  Since the viruses are the

controlling  parameter,  the  inactivation  calculation will  be  based on  the

viruses.  The calculation is as follows:

     Section 1  - Chloramines

     CT  ,  =1.5 mg/L x 398 minutes = 597 mg/L-min
       calc

     From Table E-13, at  a temperature of 5 C and  a  pH  of 7, CT      is 1988
        /_                                                        yy  yy
     mg/L-min

     CTcalc/CT99.99 =   597 mg/l-min =  0.3
                       1988 mg/L-min

     Section 2  - Chlorine Dioxide

     CT     =0.2 mg/L x 130 minutes = 26 mg/L-min
       Oci-LC
                                     5-20

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     From  Table E-9,  at  a  temperature of  5 C  and a  pH of  7,  CT   qq  is
     33.5 mg/L-min
     CTcalc/CT99 99 =  26  *<3/l-*^ = 0.78
       calc   99.99   33_5 mg/L.min
The sum of CT     /CT  _  OQ  is  equal to 1.08, which  is  equivalent  t<-> a 4.2-log
             CalC  99.99
inactivation of viruses, determined as follows:
                         CT
                         CT
         CT
x = 4 x    calc  = 4 x 1.08 = 4.3-logs
                           99.99

Therefore, the  system provides  sufficient disinfection  to meet  the  overall
recommended treatment performance.

5.6  Other Considerations
     Monitoring for HPC  is  not required under the  SWTR.   However, such moni-
toring may provide a good operational tool for:
       -  Measuring microbial breakthrough
       -  Evaluating process modifications
       -  Detecting loss of water main integrity
       -  Detecting  bacterial  regrowth  conditions within  the  distribution
          system
       -  Determining interference with the coliform measurements  (AWWA, 1987)
     Therefore, EPA recommends routine monitoring of HPC on the plant effluent
and  within the  distribution  system whenever  the  analytical  capability  is
available inhouse or nearby.  Systems which do not have this capability should
consider using a  semiquantitative bacterial water  sampler kit,  although this
is not acceptable.for compliance monitoring.

     As  presented in  the  preamble  to  the  SWTR,  EPA  believes  that   it  is
inappropriate to  include HPC  as a treatment performance criterion in the rule
since small systems would  not have in-house  analytical  capability to  conduct
the  measurement,   and  they  would need  to  send  the  samples   to a  private
                                     5-21

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laboratory.  Unless  the  analysis is  conducted  rapidly, HPC may  multiply and
the results may not be representative.
     EPA recommends that an HPC level of less than 10/ml in the finished water
entering the distribution system and levels of less than 500/ml throughout the
distribution system be maintained.
     Legionella  is  another  organism which  is  not  included  as  a  treatment
performance  criterion.   Inactivation  information on  Legionella  is  limited.
The  available   information  indicates  that  the  filtration  and  disinfection
requirements of the  SWTR will  remove  or inactivate  substantial  levels  of
Legionella which  might occur  in source waters.  Since  these organisms  are
similar in size to coliform organisms, removal by filtration should be similar
to those  reported for  total  coliforms.   In addition,  the available  disin-
fection information  indicates that  the CT  requirements  for  inactivation  of
Legionella are  lower  than  those  required  for the  inactivation of  Giardia
cysts.
6.   These treatment requirements  do not guarantee that  these  organisms will
     not be present in numbers sufficient to colonize hot water systems within
     homes and institutions  (Muraca et  al.,  1986).   Guidance  for  control  of
     Legionella by institutions is provided in Appendix B.
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                                 6.  REPORTING

6.1  Reporting Requirements for Public Water Systems Not Providing Filtration
     The SWTR requires  unfiltered systems to prepare  monthly  reports for the
Primacy Agency to determine compliance with the requirements for:
  -  source water fecal and/or total coliform levels
  -  source water turbidity levels
  -  disinfection level
  -  disinfectant residual entering the distribution system
  -  disinfectant residuals throughout the distribution system.
     The monthly reports must be prepared  and  submitted to the Primacy Agency
within 10 days after the end  of  the month.  The utility must maintain a daily
data log  used to prepare  the monthly  reports.  Tables  6-1 through  6-5  are
examples of daily data  sheets which the utilities may find useful for logging
the data needed to prepare reports for the Primacy Agency.
     Table 6-6 presents a concise  format which  can  be used  for  the monthly
reports to the Primacy Agency.  Tables 6-3 and 6-4 must also be submitted with
the monthly  report.   After the  initial 12  months  of  reporting,  the Primacy
Agency may remove the  requirement for reporting  the  information contained in
Table 6-3 if it is satisfied  that the system is computing compliance with the
CT requirements. correctly.   The  individual  sample  results  summarized  in  the
monthly  reports  should  be kept  on  file at  the  utility  for  a minimum of
5 years.
     In  addition  to  the  monthly  reporting  requirements  for  source  water
quality  conditions  and disinfection information,  systems  with  unfiltered
supplies are also required to submit  annual  reports for the watershed control
program and the on-site inspection within 10 days after the end of the federal
fiscal year.
                                     6-1

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     The Primacy Agency  will review the  reports  to determine whether  or  not
compliance has  been  met.   A recommended  report  format for  the  watershed
control program is:

          Summarize all activities in the watershed(s)  for the previous year.
          Identify activities or situations of actual and potential concern in
          the watershed(s).
     3.   Describe how the utility is proceeding to address them.

     The SWTR requires each system to provide the Primacy Agency with a report
of the  on-site  inspection unless the  inspection  is conducted by  the  Primacy
Agency.  EPA suggests that:
     1.   A  report  of  the   inspection  containing  the  findings,  suggested
          improvements and dates  by which to  complete improvements is  to be
          prepared following the initial system review.
     2.   To lessen  the  burden on utilities,  a report containing  results of
          the general survey should be submitted in subsequent years.
     In addition to  these reporting requirements, the SWTR  requires that  the
reporting requirements of the Total Trihalomethane Regulation and the Coliform
Rule are also met.
     Records of waterborne disease outbreaks also must be maintained.   In  the
event of a waterborne disease outbreak, as defined in  part 141.2  of the SWTR,
the Primacy Agency must be notified within 48 hours.
     The report of the outbreak should contain:
     1.   Date of occurrence
     2.   Type of illness
     3.   Number of cases
     4.   System   conditions   at  the   time   of  the   outbreak,   including
          disinfectant    residuals,    pH,    temperature,    turbidity,    and
          bacteriologicol results.
     The records of an outbreak must be maintained permanently.
6.2  Reporting Requirements for Public Water Systems Using Filtration
     The SWTR requires filtered water systems to submit monthly reports to  the
Primacy Agency for determination of compliance with the requirements for:
  -  treated water turbidity
  -  disinfectant residual entering the distribution system
  -  disinfectant residuals throughout the distribution system
                                     6-2.

-------
Tables 6-7 and 6-8 present  a format which the utility can use as a daily data
log and to submit monthly reports to the Primacy Agency.
     Recommended Reporting Not Required by the SWTR
     The Primacy Agency  may also want  filtered  water systems  to  report some
information associated with  recommendations made  in this manual which are not
requirements of the SWTR.  EPA recommends that filtered water systems:
     1.   Report  the  percent  inactivation  of  Giardia  cysts  and  enteric
          viruses,  recommended by the Primacy Agency.
     2.   Report point of application for all disinfectants used.
     3.   Report the daily CT(s) used to calculate the percent inactivation of
          Giardia cysts and viruses.
     4.   If more than one  disinfectant is used,  report the CT(s)  and inac-
          tivation (s) achieved  for  each  disinfectant  and  the  total percent
          inactivation achieved.
     5.   Report the percent inactivation determined prior  to  filtration and
          the data  used to make this determination.
     6.   Note any difference between  the measured CT(s) and the  CT required
          to  meet   the  overall  minimum  treatment  performance  requirement
          specified by the Primacy Agency.
Tables 6-3 and 6-4  can be used to maintain the records necessary for numbers 2
through 6.
     This  information  can  be  used  to  determine  the  disinfection  level
maintained by the  system  to  assure  that  the  overall  removal/inactivation
required is maintained.
     The  Primacy  Agency  may  make provisions   to  minimize  the  reporting
requirements  for systems with  reservoirs,  large amounts  of storage  or long
transmission  mains  which provide a long disinfectant  contact time.   Since
these systems -typically  provide  inactivation in excess  of that  needed,  the
Primacy  Agency  may  require  the  system  only  to  report  the  minimum  daily
residual at the end  of the  disinfectant contact time.  The  CT  maintained can
then be estimated based on this residual and the  contact time under the system
design flow.   This  method of CT determination will  eliminate the need for the
system to determine the contact time under maximum flow conditions  each day.
                                     6-3

-------
                                                                       TABLE 6-1
Month
Year
Page 1
Date
1
2
3
k
5
6
7
8
9
10
11
12
13
H
15
16
17
IS
SOURCE WATER QUALITY CONDITIONS FOR UNFfLTERED SVS
CoHform Measurements*
No. of Samples .
Fecal


















Total


















No. of Samples Meeting Specified Limits
Fecal = 20/100 mL)


















Total ((= 100/100 mL)


















TEMS1
System/Treatment Plant
PWSID


Turbldits
Maximum
Turbidity
(NTU)


















Measurements
Turbidity
"Event"
(Yes or No)


















Notes:
     1.

     2.
     3.
Samples are taken from the source water immediately prior to the first disinfection point included in the CT determination.

As specified in 40 CFR HI.7<(b)(1),  a fecal  or  total coliform sample must be taken on each day that the
system operates and a source water turbidity  measurement exceeds 1 NTU.

For each day that the maximum turbidity exceeds  5  NTU,  the date should be entered for the day that the State was notified
of this exceedance; e.g., "5.8-22".

A "yes" response is required each day the maximum  turbidity exceeds 5 NTU and the previous day did not.  This is indicative
of the beginning of a turbidity "event".   The total number of "yes" responses equals the number of turbidity "events" in
the month.

-------
TABLE 6-1
Month
Year
Page 2
Date
19
20
21
22
23
24
25
26
27
28
29
30
31
Totals:
SOURCE WATER QUALITY CONDITIONS FOR UNFILTERED SYSTEMS1
System/Treatment Plant
PWSID

Colt form Measurements'
No, of Samples 
Fecal














Total














No. of Samples Meeting Specified Limits
Fecal  20/100 ml)














Total = 100/100 mi.)
















Turbidity
Maximum
Turbidity
(NTU)













Measurements
Turbidity
"Event"
(Yes or No)









t



Maximum daily turbidity = 	 NTU
Total number of turbidity "events" 



-------
TABLE 6-2
Year

Month
January
February
March
April
May
June
July
August
September
October
November
December
LONG-TERM SOURCE MATER QUALITY CONDITIONS RECORD SHEET
FOR UNFILTERED SYSTEMS
System
PWSID

Treatment Plant


Collform Measurements Turbidity Measurements
No. of Samples
Fecal












' Total












No. of Samples Meeting Specified Limits
Fecal * 20/100 ml)












Total - 100/100 ml)













Dates with
Turbidity )5 NTU












Total
Number of
Turbidity
Events














-------
                                   TABLE 6-3
Month
Year
CT DETERMINATION FOR UNFILTERED SYSTEMS*
System/Treatment Plant


Date
1
2
3
4
S
6
7
8
9
10
11
12
13
1*
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Disinfectant
Concentration,
C (mg/L)

























-





PWSID

2
Oi si nf ectant
Contact Time,
T (min)
































Disinfectant/Sequence of Application
CTcalc3
(=CxT)































PH2'"































Water
Temp
(C)































CT99.95































(CTca1c/CT99.9)































Notes:
    1.
    2.

    3.

    4.

    5.
Use a separate sheet for each disinfectant/sampling site.   Enter  disinfectant and
sequende position; e.g., "ozone/1st" or "C10 /3rd".

Measurement taken at peak hourly flow.

CTcalc = C (mg/L) x T (min).

Only required if the disinfectant is free chlorine.

From Tables 1.1  - 1.6, 2.1, and 3.1, 40 CFR U1,7i(b)(3).

-------
                                                                   TABLE 6-A
Month
Year
Page 1
Date
1
2
3
it
5
6
7
8
9
10
11
12
13
T>
Minimum Disinfectant Residual
at Point-of-Entry to
Distribution System(mg/L)














DISINFECTION INFORMATION FOR COMPLIANCE DETERMINATION
FOR UNFILTERED SYSTEMS
System/Treatment Plant
PWSID

(CTcalc/CT99.9)2
Disinfectant Sequence
1st














2nd














3rd














<>th














5th














6th















 (CTcalc/CT99.9)














 (CTcalc/CT99.9) <13
(Yes or No)














Notes:

  1.


  2.
For multiple disinfectants,  this  column must only be completed for the last disinfectant added prior to entering the distribution system.
If less than 0.2 mg/L,  the duration  of the period must be reported; e.g., "0.1-3 hrs".

If (CTcalc/CT99.9) (.17,  no  disinfection credit is given.  Enter zero for that sequence.  To determine I (CTcalc/CT99.9),
add (CTcalc/CT99.9)  values from the  first disinfectant sequence to the last.
          If I (CTcalc/CT99,9)  (1,  a treatment technique violation has occurred, and a "yes" response must be entered.

-------
TABLE 6-
-------
                                                         TABLE 6-5
Month
Year
Page 1
Date
1
2
3
<*
5
6
7
8
9
10
It
12
13
n
15
16
17
18
19
20
21
22
23
2 it
25
26
27
28
29
30
31
Total
No. of Sites Where
Disinfectant
Residua) Measured
<=a)































a=
DISTRIBUTION SYSTEM DISINFECTANT RESIDUAL DATA
FOR UNFILTERED AND FILTERED SYSTEMS
System/ Treatment Plant
PNSID

No. of Sites Where No
Disinfectant Residual
Measured but HPC
Measured (=b)































b=
No. of Sites Where
Disinfectant Residual
Not Detected, No HPC
Measured (=c)































c=


No. of Sites Where
Disinfectant Residual
Not Detected,
HPC >= 500/mL (=d)































d=
No. of Sites Where
Disinfectant Residual
Not Measured,
HPC )= 500 ml (=e)































e=
V~
                     =(
)  x 100 =

-------
                                                    TABLE  6-6
                                      MONTHLY  REPORT TO PRIMACY AGENCY FOR
                                            COMPLIANCE DETERMINATION
                                               UNFILTERED  SYSTEMS

Month ^__________                                            System/Treatment Plant
Year	
Page 1

bouree Water Quality Conditions

A.   Cumulative number of months for  which results are reported 
     1.   Earliest of 6 previous months  and the year                 , e9- if the current reporting month ij
          January 1989, the earliest of  6 previous months is July 1988.

     2.   Earliest of 12 previous months and the year           . i.e., the current month one year ago.

     3.   ?arT$est of 120 previous months and the year	, i.e., the current month ten years ago,

B.   Coliform Criteria1

                                      No. of Samples    No. of  Samples Meeting Specified Limits	
                                     Fecal      Total    Fecal(( 20/100 mL)   Total= 100/100 mL)

Previous 6-month cumulative:           ____    	    	       	
Current month's:                    +     _    + _____ +        .            +       '
Earliest of 6 previous month's:      - 	   - 	 -  ____^______    -  	
Current 6-month cumulative:         *        x       y 	        z
     Percentage of samples (* 20/100 ml  fecal  coliforms, F = y/w x  100   	%
     Percentage of samples (= 100/100 ml  total  coliforms, T  z/x x 100 =	%
     Is F < 90% ?: Yes 	 No	5 is T < 90% ?: Yes	No	


                                                         6
     If F and T <  90% system is  in violation  Violation? 	
C.   Turbidity Criteria

Maximum turbidity level for reporting (current)  month *	NTU

    Reporting Month-
Oate of
5 NTU               Date      	Dates of  5 NTU Exceedance	
Exceedance        Reported    Previous 12 months      Previous 120 months

-------
                                                  TABLE 6-6
                                     MONTHLY REPORT TO PRIMACY AGENCY FOR
                                           COMPLIANCE DETERMINATION
                                        UNFILTERED SYSTEMS (Continued)

Month      	                                             System/Treatment Plant	
Year    	                                             PWSID 	
Page 2


                             Number of Turbidity Events

Previous  120-month cumulative:               	  (= PI20)
Previous  12-month cumulative:                	  (= P12)
Earliest  of  120 previous month's;            	  (= E120)
Earliest  of  12 previous month's:             	  (= E12)
Current month:                               	  (= C)

Cunulative number of periods during which the turbidity exceeded 5 NTU in the previous 12 months
 P12 - E12 + C *	.    If ) 2, system is in violation -- Violation? 	

Cumulative number of periods during which the turbidity exceeded 5 NTU in the previous 120 months
 P120 - E120 + C 	.   If ) 5, system is in violation   Violation? 	

The system is in violation if the Primacy Agency does not  determine that any 5 NTU exceedances during the
current month were unusual and unpredictable  Violation? 	

Disinfection Criteria

A.   Point-of-Entry Minimum Disinfectant Residual Criteria

                                Days the residual was  (0.2mg/L
                            Day             Duration of Low Level
     Based on  the minimum disinfectant  residual data  reported  for  the month,  if the  residual disinfectant
     concentration was  less than 0.2 mg/L  for more than 4 hours  at one  time,  the  system is in violation 
     Violation? 	

B.   Distribution System. Disinfectant Residual Criteria

     The  values of a, b, c, d, and  e from  Table 6-5,  as specified  in > CFR HI .75 (b)(2)(iii)(A)-(E):
     a	. b=	, c=	, d=	, e=	

     The  value of "V" from Table 6-5 calculated for the reporting  month is 	 %.  If V  )5%, the system
     is in violation of a treatment technique -- Violation?	

-------
                                                   TABLE 6-6
                                      MONTHLY REPORT TO PRIMACY AGENCY FOR
                                            COMPLIANCE DETERMINATION
                                         UNFILTERED SYSTEMS (Continued)

Month 	                                             System/Treatment Plant 	
Year                                                               PWSID 	
Page 3


C.   Disinfection Requirement Criteria

     Based on the disinfection information reported for the month in Table 6-<, if I (CTca1c/CT99.9) (1 for
     any 2 days, a treatment technique violation has occurred  Treatment technique violation?	

     If a treatment technique violation occurred and this is the second (or higher) such violation within tii
     past 12-month period, the system is in violation  Violation? 	
Notes:
     1.   The current 6-month cumulatives are required to determine whether compliance with the col iform cri;
          has been achieved.  These totals are calculated front:  the previous 6-month cumulatives, the currn
          month's, and totals from the earliest of 6 previous months.

     2.   Enter cumulatives as appropriate from the previous month's monthly report (Table 6-6).

     3.   Enter totals from Table 6-1 for the current month.

     4.   Enter totals from Tables 6-2 for the month and year shown in A(1), A(2), and A(3), as appropriate

     5.   Determine the 6-month cumulatives for the currant month by performing the indicated computations,

     6.   Evaluate fecal or total coliform data as appropriate -- for systems which monitor both fecal am)
          coliforms only F must be 2. 90* for compliance,

     7.   A turbidity "event" consists of a series of consecutive days in which the maximum turbidity excee
          5 NTU.

-------
                                                                    TABLE 6-7
Month
Year


Page 1
Date
1
2
3
4
5
6
7
a
9
Minimum Disinfectant Residual
at Point-of-Entry to
Distribution System (mg/L)









DAILY DATA SHEET FOR
FILTERED SYSTEMS
2
Maximum Filtered Water Turbidity
Filter
#









Combined Filter
Effluent









Clear-well
Effluent









Plant
Effluent









System/Treatment Plant
PWSID

Filtration Techno 1 ogy
No. of Turbidity
Measurements









it
No. of Turbidity
Measurements (=
Specified Limit









No. of Turbidity5
Measurements
) 5 NTU









Notes:

  1.


  2.
        For multiple disinfectants, this column must only be completed  for the last disinfectant added prior to entering the distribution
        system.  If less than 0.2 mg/L, the duration of  the period must be reported; e.g., "0.1-3 hrs".

        For systems using conventional  treatment,  direct filtration, or technologies other than slow sand or diatomaceous earth filtration,
        turbidity measurements may be taken at the combined filter effluent, clearwell effluent, or plant effluent prior to entry into the
        distribution system.  The turbidity may also be  measured for each individual filter with a separate sheet maintained for each.

3.      For continuous monitors count each 
-------
TABLE fi-7
Month
Year


Page 2
Date
10
11
12
13
H
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Minimum Disinfectant Residual
at Point-of-Entry to
Distribution System (mg/L)






















DAILY DATA SHEET FOR
FILTERED SYSTEMS
System/Treatment Plant
PWSID

Filtration Technology

2
Maximum Filtered Water Turbidity
Filter
i















*






Combined Filter
Effluent























Clearwell
Effluent






















Plant
Effluent






















Totals:

No. of Turbidity
Measurements
























No. of Turbidity*
Measurements (*
Specified Limit























No. of Turbidity
Measurements
> 5 NTU
























-------
                                                  TABLE 6-8
                                       MONTHLY REPORT TO PRIMACY AGENCY
                                   COMPLIANCE DETERMINATION - FILTERED SYSTEMS

Month _^^^^^^_^__                                          System/Treatment Plant
Year	                                          PWSID 	
Page 1

Turbidity Performance  Criteria

A.   Total  number of filtered water turbidity measurements =	
B.    Total  number  of  filtered water turbidity measurements which  are less than or equal to the specified limits
     for  the  filtration technology employed = 	

C.    The  percentage of turbidity measurements meeting the specified limits = B/A x 100
                                                                          =	/	 x 100 = 	%

     If C ( 95%, system is  in violation  Violation?  	
0.    If  the effluent turbidity exceeded 5 NTU at any time during the month, the system is in violation 
     Violation? 	

     If  so, record the date  and turbidity value for any measurements exceeding 5 NTU:

         Date                     Turbidity. NTU
Disinfection Performance Criteria

A.   Point-of-Entry Minimum Disinfectant Residual Criteria

                   Days the  residual was  (0.2 mg/L
                   Day       Duration of  low level

-------
                                                   TABLE 6-8
                                        MONTHLY REPORT TO PRIMACY AGENCY
                                   COMPLIANCE DETERMINATION - FILTERED SYSTEMS

Month	                                           System/Treatment Plant
Year	                                           PWSID	
Page 2
     Based on the minimum disinfectant residual  data  reported  for  the month, if the residual disinfectant
     concentration was less than 0.2 mg/L for more than  4  hours  at one time, the system is in violation  
     Violation?	

B.   Distribution System Disinfectant Residual Criteria

     The values a, b, c, d, and e from Table 6-5,  as  specified in  40 CFR U1.75(b)(2)(iii)(A)-(E):
     a*	, b     , c*	, d*	,  e=	

     The value of "V" from Table 6-5 calculated  for the  reporting  month is	%.  If V ) 5%, the system is
     in violation of a treatment technique -- Violation?	

     If a treatment technique violation occurred and  this  is the second such violation in two consecutive montt
     the system is in violation  Violation? 	

-------
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-------
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Morand, Jl M.;  Young,  M. J.   Performance  Characteristics of  Package  Water
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                                      -3-

-------
Poynter, S. F. B.; Slade,  J.  S.   The Removal of Viruses by  Slow Sand Filtra-
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Environmental Protection Agency, MERL,  Cincinnati, Ohio, April,  1985.

Berman, D.; Hoff,  J.C.  Inactivation of  Simian Rotavirus  SA 11  by Chlorine,
Chlorine Dioxide  and Monochloramine.  Appl.  Environ.  Microbiol,   48:317-323,
1984.

Bishop,  S.;   Craft,  T.  F.;  Fisher,  D.   R.;   Ghosh,  M.;  Prendiville, P.W.;
Roberts, K. J.;  Steimle, S.;  Thompson,  J. The Status of  Direct Filtration,
Committee Report. J.AWWA, 72(7):405-411,  1980.

Bouwer,  H.   Ground  Water   Hydrology.   McGraw  Hill  Book  Co.,   New  York,
pp. 339-356, 1978.

Brown, T. S.; Malina,  J.  F.,  Jr.; Moore, B. D. Virus  Removal by Diatomaceous
Earth Filtration - Part 1 S  2. J.AWWA 66(2):98-102, (12):735-738, 1974.

Clark,  R.  M. ;-Read,  E. J.;  Hoff,  J.  C.  Inactivation  of  Giardia lamblia by
Chlorine:  A  Mathematical  and  Statistical  Analysis.   Unpublished  Report,
EPA/600/X-87/149, DWRD, Cincinnati, OH, 1987.

Cleasby, J.  L.;  Hilmoe,  D.  J.; Dimitracopoulos,  C.  J.  Slow-Sand  and Direct
In-Line Filtration of a Surface Water.  J.AWWA, 76(12}:44-55, 1984.

Cotruvo, J. A.;  Vogt,   C.  D.   USEPA  Office  of  Drinking  Water,  Regulatory
Aspects of Disinfection. AWWA Seminar Proceedings, AWWA Conference, pp. 27-32,
June, 1984.
                                      -1-

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DeWalle, F. B.; Engeset, J.; Lawrence, W.  Removal of Giardia lamblia Cysts by
Drinking Water  Plants.   EPA-600/52-84-069,  United States  Environmental  Pro-
tection Agency, MERL, Cincinnati, Ohio, May 1984.

Fox, K. R.; Miltner, R.  J.; Logsdon, G. S.; Dicks, D. L.; Drolet, L. F.  Pilot
Plant  Exploration  of  Slow  Rate  Filtration.  Presented  at  the AWWA  Annual
Conference Seminar, Las Vegas, Nevada, June 1983.

Fujioka, R.;  Kungskulniti, N.;   Nakasone,  S.   Evaluation  of  the  Presence  -
Absence Test  for  Colifonns and the Membrane Filtration Method for Heterotro-
phic Bacteria.  AWWA Technology Conference Proceedings, November, 1986.

Geldreich,   E.;  Nash, H.;  Reasoner,  D.;  Taylor R.   Necessity of Controlling
Bacterial  Populations  in  Potable  Waters:   Community Water  Supply.   J.AWWA,
64:596-602, 1972.

Geldreich,   E.;  Greenberg,  A.;   Haas,  C.;  Ho'ff,  R.;  Karlin, J.;  Means, E.;
Moser, R.;   Regunathan,  P.;  Reich,  K.  and  Victoreen,  H.   Microbiological
Considerations  for  Drinking Water  Regulation  Revisions,  Committee  Report,
Organisms in Water Committee.  JAWWA, 79(5):81, 1987.

Great Lakes-Upper Mississippi River  Board  of State Public Health and Environ-
mental  Managers  Committee.   Recommended   Standards   for  Water Works,  1987
Edition.

Hibler, C.  P.  Evaluation of the 3M  Filter 124A  in the FS-SR 122 Type 316 S/S
#150 Housing for Removal of  Giardia  Cysts.  Department of Pathology, Colorado
State University,  Performance Report submitted to 3M Corporation, 1986.

Hibler, C.P.  Protocol  - Sampling  Water for Detection of Waterborne Giardia.
Colorado State University, Undated.

Hoffbuhr,  J.  W.;  Blair,  J.; Bartleson,  M.; Karlin,  R.   Use of Particulate
Analysis "for Source and  Water Treatment  Evaluation.  AWWA  Water  Quality
Technology Conference Proceedings,  November 1986.

Hoff,  J.  C.  Inactivation  of  Microbial  Agents by  Chemical  Disinfectants.
EPA-600/52-86-067,  U.S.  Environmental  Protection  Agency,  Water Engineering
Research Laboratory, Drinking   Water Research  Division,  Cincinnati,  Ohio,
September,  1986.

Horn, J. B.;  Hendricks,  D.  W.   Removals of Giardia Cysts  and other Particles
from Low Turbidity Waters  Using the  Culligan Multi-Tech  Filtration  System.
Engineering Research Center, Colorado State University, Unpublished, 1986.

Joost, R. D.; Long,  B. W.; Jackson,  L.   Using  Ozone as a Primary Disinfectant
for  the  Tucson CAP Water  Treatment Plant, presented at  the  IOA/PAC  Ozone
Conference, Monroe, MI,  1988.

Kelly, Gidley, Blair and Wolfe,  Inc.  Guidance  Manual  - Institutional Alterna-
tives for Small Water Systems.   AWWA Research Foundation Contract 79-84,  1986.
                                      -2-

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Kuchta,  J.  M.; States,  S.  J.;  McNamara, A.  M.;  Wadowsky, R.  M.;  Yee, R. B.
Susceptibility  of Legionella  pneumophila  to  Chlorine  in Tap Water.  Appl.
Environ. Microbiol., 46(5): 1134-1139, 1983.

Letterman,  R.  D.   The Filtration Requirement  in  the Safe Drinking  Water Act
Amendments  of 1986.  U.S. EPA/AAAS Report, August 1986.

Logsdon, G. S.; Symons, J. M.; Hoye, Jr., R. L.; Arozarena, M. M.  Alternative
Filtration  Methods for  Removal of  Giardia  Cysts  and  Cyst  Model.   J.AWWA,
73:111-118, 1981.

Logsdon, G. S.  Report for  Visit to  Carrollton, Georgia, USEPA travel report,
February 12, 1987a.

Logsdon,  G. S.   Comparison  of Some Filtration  Processes  Appropriate  for
Giardia  Cyst  Removal.   USEPA Drinking Water  Research Division;  Presented at
Calgary Giardia Conference, Calgary; Alberta,  Canada, February 23-25, 1987b.

Long,  R. L.   Evaluation of  Cartridge  Filters for  the  Removal  of  Giardia
lamblia  Cyst  Models  from Drinking Water   Systems.   J. Environ.  Health,
45(5):220-225, 1983.

Markwell, D.  0.,  and  Shortridge,  K. F.  Possible Waterbome  Transmission and
Maintenance of Influenza Viruses in Domestic Ducks.   Applied and Environmental
Microbiology, Vol. 43, pp. 110-116, January, 1982.

McCabe, L.; Symons, J.;  Lee, R.; Robeck, G.  Study of Community Water Supply
Systems.  J.AWWA, 62:11:670, 1970.

Morand, J., M.; C. R. Cobb; R. M. Clark; Richard, G. S.   Package Water Treat-
ment  Plants,   Vol. 1,  A  performance Evaluation.   EPA-600/2-80-008a,  USEPA,
MERL, Cincinnati, Ohio, July, 1980.

Morand, J. M.;  Young,  M. J.   Performance  Characteristics of  Package  Water
Treatment   Plants,   Project   Summary.    EPA-600/52-82-101,    USEPA,   MERL,
Cincinnati, Ohio, March,  1983.

Muraca, P.; Stout, J. E.; Yu, V. L.  Comparative Assessment of Chlorine, Heat,
Ozone, and UV Light for Killing Legionella pneumophila Within  a Model Plumbing
System. Appl. Environ. Microbiol.,  53(2):447-453,  1987.

Notestine, T., Hudson, J.  Classification of Drinking Water Sources as Surface
or  Ground  Waters.   Final  Project Report.   Office of  Environmental  Health
Programs.  Washington Department of social and Health Services, August 1988.

Payment,  P.;  Trudel,  M.;  Plante,  R.  Elimination  of Viruses and  Indicator
Bacteria  at Each Step of Treatment During Preparation  of Drinking  Water at
Seven Water Treatment Plants.  Appl.  Environ.  Microbiol., 49:1418,  1985.

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Poynter, S. F. B.;  Slade,  J.  S.   The Removal of Viruses  by Slow Sand Filtra-
tion, Prog. Wat.  Tech. Vol. 9, pp.  75-88, Pergamon Press,  1977.   Printed in
Great Britain.

Randall, A.D.   Movement of Bacteria  From a River to a Municipal Well - A Case
History.   American  Water  Works  Association  Journal.   Vol.  62,  No.  11,
p.716-720.

Regli, S.;  Berger, P.,  (eds.).   Workshop  on  Filtration,  Disinfection,  and
Microbial  Monitoring,  April  15-17,   1985, Baltimore,  MD.  EPA 570/9-87-001,
Office of Drinking Water, 1987.

Regli, S.;  Amirtharajah,  A.;  Hoff,  J.;  Berger,  P.  Treatment  for Control of
Waterborne Pathogens:  How Safe is Safe Enough?  In:  Proceedings, 3rd Confer-
ence on  Progress  in Chemical Disinfection, G.E.  Janauer   (Editor), April 3-5,
1986.  State University of New York,  Binghamton, NY, in press.

Robeck,  G. G.; Clarke, N. A.; Dostal,  K.  A.  Effectiveness of Water Treatment
Processes in Virus Removal.  J. AWWA, 54(10):1275-1290, 1962.

Robson,  C.  M.;  Rice, R. G.;  Fujikawa, E.  G.;  Farver, B.  T.   Status of U.S.
Drinking  Water Treatment  Ozonation  Systems,  presented  at  IDA  Conference,
Myrtle Beach,  SC,  December 1988.

Rose, J.B.  Cryptosporidium  in Water;  Risk  of  Protozoan  Waterborne  Trans-
mission.  Report prepared for the Office of Drinking Water, U.S. EPA, Summer,
1988.

Slezak,  L. A.; Sims,  R.  C.   The  Application and  Effectiveness of  Slow Sand
Filtration in the United States.   J.AWWA,  76 (12):38-43, 1984.

Stolarik, G. F.;  Christie,  D.  J.   Projection of Ozone C-T Values Los Angeles
Aqueduct Filtration Plant, 1988.

U.S. Environmental Protection Agency.  Examination of Water Filter Samples for
Giardia Cysts Using EPA Consensus Method  (Modified), August 1984.

U. S. Environmental Protection Agency, Office of Drinking Water, Criteria and
Standards  Division.   Manual  for  Evaluating  Public Drinking  Water  Supplies,
1971.

U.  S.  Environmental  Protection  Agency,   Office  of  Drinking  Water.   Public
Notification Handbook for Drinking Water Suppliers, May 1978.

U. S. Environmental Protection Agency, Office of Drinking Water.  Workshop on
Emerging Technologies for Drinking Water Treatment, April, 1988a.

U. S. Environmental Protection Agency, Office of Drinking Water.  Technologies
and Costs  for  the Removal of  Microbial  Contaminants  from Potable Water Sup-
plies, October, 1988b.
                                      -4-

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World  Health  Organization  Collaborating  Center.  Slow  Sand  Filtration  of
Community Water Supplies in Developing Countries.  Report of  an International
Appraiser Meeting, Nagpur,  India, Bulletin Series 16,  September 15-19,  1980.
                                     -5-

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           -  APPENDIX A

   USE OF PARTICULATE ANALYSIS FOR
SOURCE AND WATER TREATMENT EVALUATION
                             Reprinted from 1986 Annual
                             Conference Proceedings, by
                             permission
                             Copyright  1986, American
                             Work Works Association

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                    USE OF PARTICULATE ANALYSIS FOR SOURCE
                        AND WATER TREATMENT EVALUATION
                            Jack w. Hoffbuhr; P.E.
                                Deputy Director
                           Water Management Division
                             U.S. E.P.A., Region 8
                          Denver, Colorado 8202-2413

                               John Blair, P.E.
                               District Engineer
                         Colorado Department of Health
                        Grand Junction, Colorado 81501

                               Michael Bartleson
                    Director of Water Treatment Operations
                              City of Broomfield
                          Brcornfield, Colorado 80020

                             Richard Karlin, P.E.
                         Chief, Drinking Water Section
                         Colorado Department of Health
                            Denver, Colorado 80220


     Coliform  bacteria and  turbidity  have been  traditional  procedures  for

evaluating the quality of  source  waters and  the effectiveness of  treatment
processes.  Many water systems have used  these  measures  exclusively  to deter-
mine  the microbiological  quality of  their finished  water.  This  sense  of

security  has  been severly  diminished  in recent  years  due to the  increasing
frequency of  reported waterborne  disease outbreaks where' water quality  was

judged  to be  excellent by the  traditional measures.   It is  evident  that
additional tools  are  needed to  determine the quality of  source and  treated

waters.   The  recent enactment  of the  1986 Amendments  to  the Safe Drinking

Water Act (SDWA) also highlights this need.


Background

     Giardia Lamblia has become  a most famous  (or infamous)  parasite  to  the

water utility  industry.   Its presence  in source  waters  across  the U.S.  and

role in numerous waterborne outbreaks has:

     1.   Emphasized the importance of  the  multiple barrier concept in  water
          treatment;
                                   -1-

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     2.    Illustrated  the need  for  additional  techniques  to  evaluate  the
          quality of water; and
     3.    Caused  a  major increase   in  sampling  and  analysis  for  Giardia
     These points were  clearly emphasized in  epidemiological  and engineering
studies conducted  by the  Colorado Department of  Health  (1) .   These  studies
also indicated  that all  surface waters are  susceptible  to  contamination  by
Giardia.   As a result,  the Department  of  Health adopted regulations requiring
filtration of all surface water sources.
     Ground water  sources weren't included since  it was  felt  that they were
protected by the natural barrier provided by the layers of earth.  However,  it
quickly became apparent that not all ground waters are created equally.  Wells
and  springs  that  are  properly  sited,  designed   and constructed  certainly
provide  a larger  degree  of  protection  from contamination  due  to  surface
influences.  However,  many  alluvial  wells plus  wells  and springs that are
poorly constructed don't provide that same level of protection.
     Infiltration  galleries  fall  into a  gray  area  since  they  can  collect
surface and  ground  water.  In  most  cases,  they  are heavily  influenced  by
surface water conditions.
     It was clear  that  a  technique was needed to determine  if the so-called
ground waters  were  susceptible  to  surface   water  and,  therefore,  Giardia
contamination.    Sanitary  surveys  can  identify problem  areas  and  potential
pathways- of  contamination but  aren't  conclusive  evidence.    Turbidity  and
coliform results,  as shown by the previous study  aren't  reliable indicators
(1).
     Sampling to determine the presence of only Giardia  cysts  isn't  helpful
either since  not  finding Giardia in  a single  sample  doesn't  obviate  the
potential for -contamination.   However,  the sampling and analysis procedure for
Giardia does  offer  a  useful  alternative.    A variety  of other  particulate
matter is  trapped  on the sampling filter and  appears  on  the  microscope  slide
along  with any  Giardia  cysts.    These particulates  can  be  identified  and
evaluated to provide a valuable insight into the quality of the water.
     To further explore  the usefulness  of this procedure  the  Colorado  Depart-
ment of Health conducted  a study of 70 water  systems in Colorado.   (A  special
                                   -2-

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study examined 10 systems  in  depth (2)).   The Region 8 office of the Environ-
mental Protection Agency conducted a  study of SO systems in Wyoming using the
same  procedures   (3).   The objectives  of  the  studies  were  to  (1) identify
particulate  types  that, by  their presence  in water, indicate  surface  water
contamination and  (2)  to  determine the  efficacy of  water  treatment systems.
This paper  discusses the  results  obtained pertaining primarily to  the  first
objective.

Methods
     The 150 systems selected for  the studies included surface water sources,
wells, springs and infiltration galleries.  This paper presents the results of
16 systems representing a cross-section of both studies.
     Untreated source   water  was  sampled  at each  site using a  one micron
cartridge filter  apparatus and  the protocols  for pathogenic  protozoans  de-
scribed in the 16th edition of Standard methods  (4).  All samples were shipped
packed in  ice and  analyzed  within 48 hours.   The Colorado  samples  were  an-
alyzed by the Health Department's Parasitology Laboratory.  Split samples were
analyzed  by  Or.  Charles Hibler  at  Colorado  State  University  for  quality
control.   The Wyoming samples were all analyzed by Or.  Hibler.  In  all  cases
the  particulate  analysis  was  conducted  using  the  zinc  sulfate  flotation
techniques  (4,5).  This  procedure  does not produce  100  percent  cyst recovery
or precise  particulate  analysis,  but it  does  provide results which provide
invaluable information about the quality of the sampled water.
     The particulate analyses provided results  for  14 particulate  categories
which have  been  summarized into  12 groups for purposes  of this paper.   The
particulates, except for Giardia, were enumerated using the  general  quantities
shown in  Table 1.   For Giardia  cysts the numbers  shown are  estimated  total
numbers of cysts -in the samples.

Discussion of Results
     The particulate categories  shown in Table 2 constitute  a broad  spectrun
of what  could be found in water.  Not  all  of them  are good indicators  of
surface water contamination of ground water.   By considering  these  categories
in detail a more  concise list of possible indicators can be  developed.
                                   -j-

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Sediment -  Includes  all the particulate matter  in a sample.  Since
this group is so inclusive, it is not a good indicator.

Amorphous Debris  - Consists of  pieces of  silica,  decaying vegeta-
tion,  micro-organisms and  unrecognizable  matter  with a  wide size
range.  Since  this material is  non-specific and  ubiquitous in all
water sources it is not a good indicator.

Algae - Comprises  a  large  group  of microorganisms which have a wide
variety of sizes and shapes.   Algae have been found in all types of
water sources, therefore, as a group they are not a good indicator.

Diatoms - A particular type of  algae that  contain  silica in their
cell walls.   Since diatoms require sunlight they are not normally
found in ground water, therefore they are a good indicator.

Plant Debris -  This  category consists of  undigested fecal material
from herbivorous mammals such as beavers and muskrats.  This catego-
ry  should be  an  excellent indicator of  animal  activity  in  the
watershed and of surface water influence.

Giardia  -  This  infamous  protozoan pathogen  ranges  in  size from
7-14 microns.   The organism  is  transported by  beavers,  muskrats,
dogs, humans and  other mammals.   In  the cyst form  the organism is
fairly resistant to  environmental conditions and chlorine.  Giardia
cysts are excellent indicators of surface water influence.

Free-living and Parasitic  Nematodes - Worm-like microorganisms that
can exist in  a  wide  variety of  water  environments including  filter
beds, infiltration galleries and wells, therefore, they are not good
indicators.

Coccidia - Host specific parasites found in animals and fish.  They
range in size from 10 to 20 microns and make excellent indicators of
surface water influence.

Pollen - Powder-like material produced  by plants and found every-
where, therefore not a good indicator.

Protozoa (other than Giardia cysts) - Microorganisms which live in a
variety of water sources, therefore they are not good indicators.

Crustacea - Large microorganisms ranging in size from 250 to 500 mi-
crons, with  eggs   from  50  to 150 microns.   Since they can  live  in
many types of water  sources they are  not good indicators of surface
water  influence.   However,  their  presence in  finished water  can
indicate poor treatment performance.

Insects - This  category includes  insects,  insect  parts,  larvae  and
eggs.  Since many  insects live in  or  near  surface water they can be
good indicators.

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       -  Rotifers  - Microscopic  animals  commonly found  in  surface  waters
          ranging  in size from 150  - 600 microns.  They require  sunlight so
          are good indicators of surface water influence.
     Based on these  points, the list of  particulate types  that can indicate a
surface water  impact on  ground water are shown  in Table  3.   A key  to their
usefulness is  that they are the same  size or larger than Giardia cysts.   If
they are  not removed by  natural processes in the  earth or by treatment pro-
cesses, Giardia  cysts probably would  not be removed either.   Therefore,  the
presence  of these  indicator  particulates  in wells,  springs,  infiltration
galleries or treatment plant effluents indicates  that  these water  systems  are
also at risk of becoming contaminated by Giardia cysts.
     The particulate data from the studies were reviewed to  determine  if  the
above reasoning  was  valid.   Table 4 shows data  from 16 of the water systems
surveyed.   The symbols used are the same as those in Table  1.
     The  streams contained  a  broad spectrum of  all  the  particulate  types
including Giardia  cysts.   The influence  of animals on  these sources  is  in-
dicated by the  presence of plant  debris,  coccidia and Giardia.   It  is clear
that if adequate treatment isn't provided to these sources  that the respective
water systems would be at risk.
     The infiltration galleries  (except  for gallery 5}  also  contained  a wide
range of  particulate matter including plant  debris and Giardia cysts.  This
indicates  that little filtering action was being  accomplished by galleries 6,
7, and 8.   These installations  had collection systems buried  from a few  inches
to  about  six feet  below  the  streams.   Gallery. 5  had a  collection  system
constructed  10  feet  deep and  20  feet away  from  and parallel to  the  stream
which allowed  for  better filtration.  Many  times  infiltration  galleries  are
constructed  as   low  cost  alternatives  to more  complete  treatment.   It  is
evident that such installations  may be providing a false sense of security.
     The well  data  indicate a much different pattern.  The  wells only con-
tained a few particulate types  and, with the exception  of well 12,  none  of  the
types indicated  surface water  intrusion.  The characteristics of  these  wells
are  listed  by  Table 5.   Wells  9   and  11  would  have the most potential  for
contamination (assuming the geologic formations are roughly the  same  and good
construction practices were followed) since they are closest to surface  water.
                                   -5-

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Well 12 did  exhibit  some  plant  debris  and  should be  investigated  further.
Well 9 showed  the  smallest amount of  particulate matter.   However,  a sample
taken during the spring runoff contained plant debris and Giardia cysts which
illustrate  an  important  consideration.    Since  surface water  quality  can
fluctuate widely, judgments based on one sample can lead to serious errors.
     The  springs  showed  even   less  particulate  matter  than  the  wells.
Spring 14 did  contain  rotifers  and  spring 16  some  plant  debris  indicating
surface water  influence.  The  sanitary surveys  revealed that  the  catchment
areas in both cases were not fenced and there was evidence of heavy animal and
human traffic, illustrating the importance of proper source protection.
     Overall,  the  data  support  the  indicators  shown by  Table 3.   The  six
particulate  types  are present in  surface  waters and  absent  in  properly pro-
tected ground waters.  The results of  these studies indicate that particulate
analysis can provide an excellent tool in evaluating source water quality, the
potential for  surface  water  contamination of  ground  water  and the effective-
ness of infiltration galleries.

Conclusions
     1.   Particulate analysis can provide valuable information for evaluating
          source water quality, the potential for surface water contamination
          of ground waters and the effectiveness of infiltration galleries.
     2.   Diatoms,  rotifers, coccidia, plant  debris,  insect  parts and Giardia
          cysts are valid  indicators of surface water contamination  of ground
        -  water systems.
     3.   Infiltration galleries  are  providing  a false sense of  security in
          many  instances  particularly if  the  collection system  is  directly
          under the stream.   Infiltration galleries must be carefully evalu-
          ated to determine if treatment beyond chlorination is needed.
     4.   Sampling for particulate analysis  should be done seasonally to gain
          an understanding of the fluctuation of surface water quality and the
          impact on ground water.
     5.   Particulate analysis can also provide  information  on the effective-
          ness of water treatment processes in removing particulate matter.
Acknowledgements
     The  authors  express  their  sincere  thanks  to  Mr. Kurt Albrecht of  the
Colorado Department of Health's Laboratory Division and Dr. Charles Hibler and
                                   -o-

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his staff at  Colorado State University's Pathology  Laboratory.   Mr.  Albrecht

spent many  hours analyzing the  samples.   Dr. Hibler  and his staff  analyzed

numerous samples and provided expert advice on the studies.


References
     1.    Karlin, R.V. and Hopkins,  R.S.,  "Engineering Defects Associated  With
          Colorado Giardiasis Outbreaks  June 1980 - June 1982."  Proc.  AWWA
          ACE, Las Vegas,  Nev.  (June 1983).

     2.    Bartleson, M.E.    "Particulate  Indicators  for  Assessing Protected
          Ground  Water Sources  and  Water  Treatment  Efficacy."   Report  to
          Colorado Dept. of Health,  Denver, Co.  (June 1986).

     3.    Wiley, B.R.,  Harman, D.J.,  and  Benjes,  Jr., H.H.    "Survey   and
          Evaluation of 80 Public Water Systems  in Wyoming -  Project Summary."
          Culp/Wesner/Culp, Denver,  Co. (January 1986).

     4.    Standard Methods for the Examination of Water  and  Wastewater, APHA,
          AWWA & WPCF, Washington, D.C. (16th ed.,  1985).

     5.    Logsdon, G.S.,   et. all   "Control  of  Giardia  Cysts By  Filtration:
          The Laboratory's  Role."  Proc.  AWWA  WQTC,  Norfolk,  Va.  (December
          1983) .

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                                  TABLE 1




                PARTICULATE ANALYSIS QUANTITY DESIGNATIONS
Symbol
EH
H
M
S
0
R
VR
T
Verbal Rating
Extremely heavy
Heavy
Moderate
Small
Occasional
Rare
Very rare
Trace
Description
4 or more particles per microscope
field
3 particles per microscope field
2 particles per microscope field
1 particle per microscope filed
1 "particle every 3 or 4 microscope
fields
2 to 3 particles in entire slide
1 particle in entire slide
Visual observation, typically used
                                         only for sediment




N              None                      Not detected

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                            TABLE 2




                 SUMMARY OF PARTICULATE TYPES






Sediment:                                 Coccidia




Large Amorphous Debris                   Pollen




Fine Amorphous Debris                    Protozoa




Algae                                    Crustacea




Diatoms                                  Insect Parts & Larvae




Plant Debris                             Rotifers




Giardia




Free Living & Parasitic Nematodes

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                    TABLE 3




  PARTICULATE TYPES INDICATING SURFACE WATER






Diatoms                  Plant Debris




Rotifers                 Insect Parts & Larvae




Coccidia                 Giardia

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            TABLE  4




RESULTS OF  PARTICIPATE ANALYSES
Source
Infiltration
Particulate Type

Amorphous Material
Protozoa
Algae
Diatoms
Plant Debris
Nematodes
Rotifers
Crustacea
Coccidia
Insect Parts
Pollen
Giardia Cysts
Streams
1
H
T
T
H
O
T
N
N
T
R
N
4
2
M
T
T
T
O
M
I)
T
T
VR
N
20
3
0
R
R
O
II
N
R
R
R
R
N
98
4
O
R
O
O
S
0
R
0
N
O
O
129
Galleries
5
M
T
N
R
0
T
N
N
N
R
N
N
6
M
T
H
H
T
T
N
T
R
H
T
80
7
M
T
EH
T
T
T
R
N
N
N
N
20
8
0
N
R '
O
M
O
N
O
0
O
O
71
9
S
N
T
N
N
N
N
11
N
U
N
U
Wells
10
M
R
H
N
N
0 .
N
U
N
N
N
N
11
S
R
N
N
N
N
N
N
N
N
N
N
12
H
T
N
N
T
N
N
N
N
N
N
N
13
R
R
T
N
N
N
N
N
N
N
N
N
Springs
14
R
N
N
N
N
N
R
N
N
N
N
N
15
0
R
0
N
N
N
N
N
N
N
O
N
16
T
N
N
N
T
T
N
N
N
N
T
N

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       TABLE  5




V7ELL CHARACTERISTICS
Source
9
10
11
12
Depth, ft.
100
40
60
72
 i
Distance From Stream, ft.
20
300
20
100

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            APPENDIX B
INSTITUTIONAL CONTROL OF LEGIONELLA

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                                  APPENDIX B
                      INSTITUTIONAL CONTROL OF LEGIONELLA

Introduction
   Legionella is  a  genus name for bacteria  commonly found in  lake  and river
waters.  Some species of this genus  have been identified as  the  cause of the
disease  legionellosis.    In  particular,  Legionella  pneumophila  has  been
identified  as  the  cause  of  Legionnaires  disease,  the  pneumonia  form  of
legionellosis and with  Pontiac Fever,  a nonpneumonia disease.   Outbreaks  of
legionellosis are primarily  associated with inhalation of water  aerosols or,
less  commonly,   with  drinking  water  containing  Legionella  bacteria  with
specific virulence  factors  not yet identified.  Foodborne outbreaks  have not
been reported (USEPA,  1985).
     As discussed in this document, treatment requirements for disinfection of
a municipal water supply are thought to  provide  at  least a  3  log  reduction of
Legionella bacteria  (see Section  3.2.2).   However,  some  recontamination may
occur  in  the  distribution  system  due  to  cross  connections  and  during
installation and repair of water mains.  It has been hypothesized that the low
concentrations  of Legionella  entering  buildings  due  to these   sources  may
colonize and  regrow in  hot water systems  (USEPA, 1985).  Although all of the
criteria required for colonization are  not known,  large institutions, such as
hospitals, hotels,  and  public buildings with  recirculating hot water systems
seem to.be the  most  susceptible.   The  control  of  Legionella  in  health  care
institutions,  such  as  hospitals,  is  particularly  important  due  to  the
increased susceptibility of many of the patients.
     The  colonization  and growth  of Legionella  in drinking water  primarily
occurs  within the  consumer's plumbing  systems  after the water leaves  the
distribution .system.  Therefore,  the  control of these  organisms  must  be  the
consumer's responsibility.  This  appendix  is intended to provide  guidance  to
these institutions for the detection and control of the Legionella bacteria.

Monitoring
     It is suggested that hospitals,  and other institutions with potential for
the  growth  of  Legionella,  conduct   routine monitoring  of   their hot  water
                                      3-1

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systems at least quarterly.     The analytical procedures for the detection of
these  organisms  can be  found in Section  912.1 "Legionellaceae" of the  16th
edition  of  Standard  Methods.   Samples  should  be  taken  at,  or  closely
following, the hot water storage reservoir and from a number of shower heads.
It is  recommended  that showers with  the  least frequent usage be  included in
the  sampling  program.  Follow-up  testing  is suggested  for  all positive
indications  prior  to  the  initiation  of   any  remedial measures.  If the  the
presence of  Legionella is  confirmed,  then remedial measures  should  be  taken.
Although  the regrowth  of  Legionella  is  commonly  associated  with hot water
systems, hot and cold  water interconnections may provide a  pathway  for cross
contamination.   For  this reason,  systems detecting  Legionella  in hot water
systems should also monitor their 'cold water systems.

Treatment
     Because  the  primary  route  of exposure  to  Legionella   is  probably
inhalation,  rather  than  ingestion,   it  is  recommended  that  disinfection
procedures include an initial shock treatment period to disinfect shower heads
and hot water taps where the bacteria may  colonize  and later become  airborne.
The  shock treatment period should  also  include  disinfection  of  hot water
tanks.   After this time, a  point-of entry treatment system can be installed to
provide continual disinfection of the  hot water system.
     Initial Disinfection
     The. most applicable method  for  the  initial disinfection of shower heads
and water taps is heat eradication.   The  fittings can be removed and held at
temperatures greater than  60  C for at least 24 hours.  Disinfection of  fit-
tings  can also be  achieved  by  soaking  or  rinsing  with a  strong chlorine
solution.  When soaking  the  fittings, a  minimum chlorine strength of 50  mg/L
should be used for  a period of no less than 3 hours.  Rinsing with chlorine
should be performed with more  concentrated solutions.   Care nust be  taken not
     1.   Monitoring frequency based on the reported rate  of  Legionella
          regrowth observed during disinfection studies (USEPA,  1985).
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to  corrode  the  finished  surface on  the  fittings.   Commercially  available
bleaches, for example, are typically 5.25 percent chlorine by weight.
     Long-Term Disinfection
     Heat - Numerous studies have shown that increasing the hot water tempera-
ture to  50  -  70  C over  a period  of several  hours may  help to reduce  and
inhibit Legionella populations.   However, some instances  of  regrowth  after 3
to 6 months  have  been reported.  In  these cases, the authors have  concluded
that a periodic schedule of short-term temperature elevation  in the  hot water
may be an effective control against legionellosis  (USEPA, 1985; Muraca, 1986).
Disinfection by this  method  also requires periodic  flushing of  faucets  and
shower heads with hot water.   Although heat eradication  is easily implemented
and relatively inexpensive, a  disadvantage  is  the potential need for periodic
disinfection.  The potential  for scalding  from the unusually hot water also
exists (USEPA,  1985;  Muraca, et al.  1986).
     Chlorination   -   Several   studies  have  suggested that  a free  chlorine
residual of  4  mg/L will  eradicate  Legionella  growth.   There is, however,  a
possibility  for recontamination  in  areas  of  the  system where  the chlorine
residual drops below this  level.  A stringent  monitoring program is  therefore
required to  ensure that  the  proper  residual is  maintained throughout  the
system and under varying flow conditions.  It may also be necessary to apply a
large initial chlorine dose to maintain  the 4 mg/L residual.  This  may cause
problems of  pipe  corrosion and,  depending on  water  quality, high  levels  of
trihalomethanes (THMs).
     Ozone -  Ozone is  the most  powerful oxidant used in  the  potable water
industry. One study indicated  that  an ozone dosage of 1  to 2 mg/L was suffi-
cient to provide a 5 log reduction of Legionella  (Muraca, et al.  1986).  Ozone
is generated by passing a high voltage current of electricity through a stream
of dry  air  or oxygen.   The use  of high voltage  electricity requires proper
handling to  avoid creating  hazardous conditions.   The  ozone is applied  by
bubbling the  ozone containing gas  through  the water in  a  chamber called  a
contactor.
     One of the disadvantages of this system is its complexity.  It requires a
dry air or oxygen  source, a generator, and a contactor sized to provide 2 to 5
minutes  of  contact  time  and an ambient  ozone  monitor.  All  materials  in
                                      3-3

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contact  with the ozone  must be  constructed  of special ozone  resistant mat-
erials  to prevent leakage.   Leak detection is  also  required because  of  the
toxic nature of ozone and possible explosive conditions if pure oxygen is used
for generation.
     Another  disadvantage  of ozonation  is the  rapid decomposition  of ozone
residuals.  The  half-life  of ozone in drinking water is typically  around 10
minutes.  This makes  it  difficult, if not  impossible,  to maintain a residual
throughout  the  water system  and may  require  the  use of  a  supplementary
disinfectant such as  chlorine or heat.   For  these reasons it is  not thought
that ozonation is viable for institutional applications.
     Ultraviolet Irradiation  -  Ultraviolet  (UV)  light, in the  254  nanometer
wavelength range  can be used as a disinfectant.  UV systems typically contain
low-pressure mercury  vapor  lamps to maximize  output  in the  254 nm  range.
Water entering the unit passes through a  clear cylinder while the  lamp  is  on,
exposing  bacteria  to the  UV light.  Because  UV  light  can not pass through
ordinary  window  glass,  special* glass or  quartz sleeves are  used to  assure
adequate exposure.
                                            t
     The  intensity  of UV  irradiation is measured  in microwatt-seconds  per
square centimeter (uW-s/cm2).  Several studies have shown a 90  percent  reduc-
tion of Legionella with a UV dosage of 1000 -  3000 uW-s/cm2,  compared to 2000
to 5000  uW-s/cm2 for E.  coli,  Salmonella and Pseudpmonas  (USEPA, 1985).   In
another  study,   a  5  log  reduction  of   Legionella  was .achieved  at  30,000
uW-s/cm2j and the reduction was more rapid than with both ozone and  chlorine
disinfection (Muraca,  et  al. 1986).
     The  major advantage of UV disinfection is  that  it does not  require  the
addition of chemicals.  This eliminates the storage and feed problems associ-
ated with the use of chlorine, chlorine dioxide and chloramines.  In  addition,
the only  maintenance  required is periodic  cleaning of the  quartz sleeve  and
replacement  of  bulbs.   UV monitors  are  available  which measure  the  light
intensity  reaching  the  water  and  provides  a  signal  to  the  user when
maintenance  is  required.   These  monitors  are  strongly  suggested  for  any
application of UV irradiation for disinfection.   It should be noted,  however,
that these monitors measure light intensity which may  not be directly related
to disinfection  efficiency.   The UV  lamps should therefore  not be  operated
past the manufacturers use  rating even with a continuous L'V  monitor installed.
                                      3-4

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     Another disadvantage  of UV  disinfection,  as with  ozonation,  is  that  a
residual  is not  provided.  A  supplementary disinfectant may  therefore  be
required to provide protection  throughout  the system.   In addition,  turbidity
may interfere with  UV disinfection by  blocking the passage  of light  to  the
microorganisms.
     Other Control  Methods - In  addition  to chemical and heat disinfection,
there are system modifications which can be made to inhibit Legionella growth.
Many institutions have large hot water tanks heated by coils located midway in
the tank.  This type of design may result in areas near the bottom of the tank
which are not hot enough  to  kill Legionella.   Designing  tanks  for  more even
distribution of  heat  may  help  limit bacterial  colonization.  In  addition,
sediment build-up in  the  bottom of  storage   tanks  provides  a surface  for
colonization.  Periodic draining and  cleaning  may  therefore  help  control
growth.   Additionally,  other studies have  found  that hot  water systems with
stand-by hot water tanks used for meeting  peak  demands,  still tested positive
for Legionella  despite  using  elevated  temperature  (55 C)  and chlorination
(2 ppm)   (Fisher-Hoch,  et al. 1984.)   Stringent procedures for  the  cleaning,
disinfection and  monitoring  of these  stagnant tanks  should be  set  up  and
followed on a regular basis.
     In another study,  it  was reported that black rubber washers  and gaskets
supported Legionella  growth  by providing  habitats protected from heat  and
chlorine;  It was found, after replacement  of  the black  rubber washers with
Proteus BO compound  washers, that  it was  not  possible  to detect  Legionella
from any of the fixtures (Colbourne, et al. 1984).

Conclusions
     Legionella bacteria have  been  identified as  the  cause of the  disease
legionellosis.,  of  which  the  most   serious form  is  Legionnaires  Disease.
Although  conventional water  treatment practices  are  sufficient  to  provide
disinfection  of  Legionella,  regrowth  in  buildings  with  large  hot  water
heaters, and especially with recirculating hot water systems,  is a significant
problem.  This problem is  of particular concern  to  health care institutions,
such as hospitals, where patients may be more susceptible to the disease.
                                      3-5

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     This guideline suggests a program of quarterly monitoring for Legionella.
 If the monitoring program suggests a potential problem with these organisms, a
 two stage disinfection program is suggested consisting of an initial period of
 shock treatment followed by long term disinfection.
     Four methods of disinfection for the control of Legionella were presented
 in this  appendix;  heat,  chlorination,  ozonation, and ultraviolet irradiation.
 All  four  of  the  methods  have  proven  effective  in  killing  Legionella.
 Ultraviolet  irradiation and  heat eradication  are the  suggested methods  of
 disinfection  due,  primarily,  to advantages  in  monitoring and  maintenance.
 However, site  specific  factors  may make chlorination or  ozonation  more feas-
 ible  for certain  applications.   In addition,  it  is  recommended  that  all
 outlets, fixtures  and  shower  heads be inspected and  all  black rubber washers
 and  gaskets  replaced  with materials which  do  not  support  the  growth  of
 Legionella organisms.
     One problem associated with the application of  point-of-entry  treatment
 systems is the lack of  an approved program for certifying performance claims.
However,  the  National  Sanitation   Foundation  (NSF),   Ann  Arbor,   MI   an
unofficial,  non-profit  organization, does  have a  testing  program to  verify
disinfection efficiencies and  materials of construction.   Certification by  the
NSF,  or  other  equivalent organizations,  is  desirable  when   selecting  a
treatment system.

References
Colbourne, J.;  Smith,  M. G.;  Fisher-Hoch, S.  P.  and Harper, D.   Source  of
Legionella pneumophila  Infection in a Hospital  Hot Water System:  Materials
Used  in Water  Fittings Capable of  Supporting L. pneumophila  Growth.   In:
Thornsberry, C.; Balows,  A.;  Feeley, J. C. and  Jakubowski,  w.  Legionella  -
Proceedings  of  the  2nd  International  Symposium.   American  Society   for
Microbiology, pp.  305-307,  1984.
Fisher-Hoch,  S.  P.;  Smith, M.G.; Harper,  D.  and  Colbourne,  J.   Source  of
Legionella  pneumonia  in  a   Hospital  Hot  Water  System,  pp. 302-304   in
Thornsberry,  C.;  Balows, A.;  Feeley,  J.C.  and Jakubowski,  W.   Legionella
Proceedings  of  the  2nd  International  Symposium,   American  Society   for
Microbiology, pp.  302-304,  1984.
                                      3-6

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Muraca, P.; Stout, J.  E.  and Yu, V.  L.   Comparative Assessment  of  Chlorine,
Heat, Ozone, and  UV  Light for  Killing Legionella pneumophila Within  a  Model
Plumbing System.   Appl. Environ. Microbiol. 53(2):447-453, 1986.

U.S. Environmental Protection Agency, Office of  Drinking Water.  Control  of
Legionella in Plumbing Systems,  Health Advisory (1985).
                                      3-7

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         APPENDIX C

DETERMINATION OF DISINFECTANT
        CONTACT TIME

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                                  APPENDIX C
                  DETERMINATION OF DISINFECTANT  CONTACT  TIME

     As  indicated  in Section 3,  for  pipelines,  all fluid passing through  the
 pipe  is  assumed to  have a  detention time equal  to the  theoretical or mean
 residence time  at  a  particular flow rate.  However, in  mixing basins, storage
 reservoirs, and other treatment plant process units, utilities may be required
 to determine the contact time for the calculation  of CT  through  tracer studies
 or other methods approved by the  Primacy  Agency.
     For the purpose of determining compliance with the disinfection require-
 ments  of the SWTR,  the  contact  time of  mixing  basins and  storage  reservoirs
 used  in  calculating CT should  be the  detention  time  which is equalled  or
 exceeded by ninety  percent (90%)  of the  fluid passing  through the system.
 This  has been designated   as  T    according  to   the  convention  adopted  by
 Thirumurthi  (1969).  A profile of the flow through the basins over time  can be
 generated by tracer studies.  Information  provided by  these studies is used
 for estimating the detention time, T  , required for calculating CT.
     This appendix is divided into two sections.   The  first  section  presents a
 brief  synopsis  of  tracer study methods,  procedures,  and data evaluation.   In
 addition, an example is presented for a hypothetical tracer  study conducted to
 determine the T    contact time in a clearwell.   The second  section presents a
 method of determining T   from theoretical detention times in systems where it
 is impractical to conduct tracer  studies.

 C.I  Tracer Studies
     Tracer Study Considerations
     Because detention  time (T)  is proportional to flow rate (Q), a  relation-
 ship between these parameters is  necessary to determine  T  under  different flow
 conditions.  Therefore,  tracer  tests should be performed  for  at  least four
 flow  rates.   The  flow rates  should  be  separated  by  approximately  equal
 intervals with  one near average  flow, two greater than  average, and one at a
.less  than  average  flow.   The  flows   should  also  be  selected   to  avoid
 extrapolating to more than  110 percent of the highest  tested flow.
                                      C  -  1

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     Under normal  treatment  plant operation, the plant flow  is  indicative of
the  flow passing  through  any particular  process unit.   An  increase or  re-
duction  in plant flow will impart a proportional change  in  flow through each
process  unit  in the plant's treatment  train.   Therefore, "flow rate" in  the
previous paragraph refers to plant flow.
     In  addition to  plant  flow,  detention times determined by  tracer studies
are also dependent on  the  water  level  in the contact basin.   This is particu-
larly  pertinent to  storage tanks  and  clearwells  which  are often used  as
equalization storage for distribution system demands, as well as being contact
basins for disinfection.   In such instances, the water levels in  the reser-
voirs  vary  to meet  the  system demands.   The actual detention time  of  these
contact  basins  will  also  vary  depending  on  whether  they  are  emptying  or
filling.
     Tracer studies should be conducted during periods when the water level is
maintained in accordance with normal plant operation.  In the ideal case  where
the water  level is  maintained at  a near  constant  level, that  is, flow  in
equals flow out, the detention time determined  by  tracer tests is  valid  for
calculating CT when the tank  is operating  at  water  levels  greater than  or
equal to the level at which the test was performed.   If the water level during
testing  increases  above the normal operating  level,  the resulting  concen-
tration profile  will predict an  erroneously high detention time.   Conversely,
extremely low water  levels during testing may lead to  an overly conservative
contact time.   Therefore,  when a tracer study  is conducted  to  determine  the
contact  time  of a basin with a  constant water  level,  the  recommended  test
procedure is to maintain the basin's water level at or slightly below, but  not
above, the normal operating level.
     For many  plants,  the  water level  in  a clearwell or  storage  tank varies
between high and low levels in  response to distribution  system demands.   In
such  instances,  in order  to obtain a conservative  estimate of the  contact
time, the tracer study should be conducted during a period when the tank  level
is falling  (flow out  greater  than  flow in).   This  procedure will  provide a
detention time for the contact basin which is also valid  when the  water  level
is rising (flow  out  less than  flow  in)  from a level  which is at or above  the
level at which the T   detention time was  determined  during  the  tracer study.
                                     C - 2

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Whether the water  level is constant  or variable, the  tracer study should be
repeated for several different plant flows, as described above.
     For clearwells which are operated with extreme variations in water level,
conducting a tracer study  is  impractical.   Under such operating conditions, a
reliable detention  time is  not provided  for disinfection,  and disinfection
contact time will need to be provided elsewhere in the system.
     Detention time may also be influenced by differences in water temperature
within  the plant.   For plants with  potential  for thermal stratification,
additional tracer studies  are  suggested under the various seasonal conditions
which are likely to occur.   The contact times determined by the tracer studies
under  the  various  seasonal  conditions should  remain  valid as  long as  no
physical changes are made to the mixing basin(s)  or storage reservoir(s).
     As defined in Section 3.2.2, the portion of the system with a measurable
contact time  between  two  points of  disinfection  or residual  monitoring  is
referred to as a section.   For systems which apply disinfectant(s)  at  more
than one point, or choose  to  profile the residual  from one point of applica-
tion, tracer  studies  should  be conducted to  determine T    for  each  section
containing process unit(s). The T   obtained  for  a  section is used along with
the residual disinfectant concentration prior to the next disinfectant appli-
cation or  monitoring  point  to determine  the CT      for that  section.   The
                                                 C3iC
inactivation ratio for the  section is then determined.  The total inactivation
achieved in  the  system is  the  "sum"   of  the  inactivation  ratios for  all
sections,   and  the  log  inactivation  can  be  determined from  this total  as
explained in Section 3.2.2.
     Systems with more  than one section in the treatment  plant should begin
sequential tracer studies  at  the last  section and complete  the  studies  with
the first section of the treatment  train.   Therefore, residual concentrations
of the  tracer material  will  not affect successive  tracer studies, and  the
required time  for performing the studies will be minimized.
     If disinfectant application and/or residual monitoring is discontinued at
any point between two  sections  with known T   values,  the  sum of these indi-
vidual T   values should be used in calculating  CT  for  the combined sections.
This detention time  is conservative  in terms of calculating CT.   A separate
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tracer  study could be  conducted for  the combined  sections,  resulting  in  a
greater T Q value.
     When conducting  tracer  studies in ozone contactors,  flocculators  or any
basin containing mixing, tracer  studies  should be conducted for  the  range of
mixing used  in the process.   In  ozone  contactors,  air should be added in lieu
of ozone to prevent degradation of  the tracer.   Tracer studies  should then be
conducted at several air  to water  ratios  to provide  data for  the  complete
range of ratios used at the plant.  For flocculators, tracer studies should be
conducted for various mixing intensities to  provide  data  for  the  complete
range of operations.
     Tracer Study Methods
     Tracer  study  methods  involve  the  application of  chemical dosages  to  a
system  and  tracking  the  resulting  effluent  concentration as  a function  of
time.  An evaluation  of the  effluent  concentration profile  is used for de-
termining the detention time,  T  .  Two  common methods  of tracer  addition
employed in water treatment evaluations are available:
          the step-dose method
          the slug-dose method
     The step-dose  method entails   introduction  of  a tracer  chemical at  a
constant dosage  until the  concentration at  the desired  endpoint  reaches  a
steady-state  level.   Step-dose method  tracer studies  are. frequently  employed
in drinking water applications for the  following reasons:
       -  the resulting normalized  concentration vs.  time  profile is  directly
          used to determine,  T  , the contact time required for  calculating CT
       -  very often, the necessary feed equipment is available  to provide  a
          constant rate of application  of the tracer chemical
     One other advantage  of  the  step-dosage  method is that  the data  may  be
verified by  comparing the  concentration  vs.  elapsed time profile for samples
collected at  the  start of dosing with the profile  obtained when the  tracer
feed is discontinued.
     Alternatively, with the  slug-dose method,  a large instantaneous dose  of
tracer is added to the water  and timed as it passes through 'the  mixing basin
or storage reservoir.  A disadvantage  of this technique is that  very concen-
trated solutions  are  needed  for  the dose in order  to adequately define  the
                                     C - 4

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concentration versus time profile.  Intensive mixing may therefore be required
to minimize potential  density-current effects.  Other  disadvantages  of using
the slug-dose method include:
       -  the  resulting concentration  vs.  time profile  cannot  be  used  to
          directly determine T   without further mathematical manipulation
       -  a mass  balance on  the  treatment  section  is required  to determine
          whether the tracer was completely recovered
For these  reasons,  the  step-dose  method is  more  easily applied  in  drinking
water tracer studies and will be discussed for the remainder of this section.
     Tracer Selection
     The first step in  any  tracer study is the  selection of  a chemical to be
used as  the tracer.  The  most common  tracer chemicals employed  in  drinking
water plants are  chloride  and fluoride.  Both of these chemicals  are readily
available,  conservative (that  is,  they are not consumed  or  removed  during
treatment), and are easily monitored.   These chemicals are also nontoxic and
approved for potable water use.
     Tracer Addition
     The tracer chemical should be added at the same point(s)  in the treatment
train as the disinfectant to be used in the CT calculations.
     The duration of tracer addition  is mainly dependent on the volume of the
contact basin, and  hence, its  theoretical detention  time.   In order  to ap-
proach a  steady-state  concentration in the  contact basin  effluent,  the dose
usually should be continued for a period of two to three times the theoretical
detention time (Hudson,  1981) .
     In all cases, the  tracer chemical  should be dosed in  sufficient concen-
tration to  easily monitor a  residual at  the contact  basin outlet throughout
the test.  The required  tracer  chemical concentration,  is  generally dependent
upon the  nature  of  the chosen  tracer  chemical,   including  its  background
concentration, and  the  mixing characteristics  of  the contact  basin  to  be
tested.  Recommended chloride  doses for step-method tracer studies where the
background chloride level  is  less than 10  mg/L are on the order  of  20 mg/L
(Hudson, 1975).  Also,  fluoride concentrations as low  as 1.0  to  1.5  mg/L are
practical when the raw water fluoride level is not significant  (Hudson,  1975).
However,  tracer   studies   conducted   on   systems   suffering   from   serious
                                     C - 5

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shortcircuiting of flow may  require substantially  larger step-doses.   This
would be necessary to detect the tracer chemical  and  to  adequately define the
effluent tracer concentration profile.
     Test Procedure
     In preparation  for beginning  a tracer study, the  raw water  background
concentration  of  the  chosen  tracer  chemical  must be  established.    The
background concentration is essential, not only for aiding in  the selection of
the tracer dosage, but also to facilitate proper evaluation of the data.
     Pre-tracer study monitoring  should  be performed at  the same  sampling
point(s) selected  for the  tracer study to  determine  that the tracer  concen-
tration is  at or  below this  background  level.   The  monitoring procedure  is
outlined in the following steps:
       -  If the tracer chemical is  normally added for treatment,  discontinue
          its addition  to  the water in sufficient  time  to permit  the  tracer
          concentration to recede  to its  background level before the  test is
          begun.
       -  Prior to  the start of  the test, regardless of whether  the  chosen
          tracer material is a treatment chemical, the tracer  concentration in
          the water is monitored at  the sampling  point where  the disinfectant
          residual will be measured for CT calculations.
       -  If a background tracer concentration  is detected, monitor it until a
          constant concentration, at  or below  the raw water background  level
          is  achieved.   This  measured  concentration   is  the  baseline  tracer
          concentration.
     Following the  determination of  the  tracer  dosage,  feed and  monitoring
point(s),  and a baseline tracer concentration,  tracer  testing  can begin.
     At time  zero, the tracer  chemical  feed  will be started and left  at a
constant rate for the duration of the test.  Over the  course of  the test, the
tracer residual should be monitored  at the  required sampling point(s)  every 2
to 3 minutes  to provide data  for a well-defined plot  of  tracer  concentration
vs. time.  Depending  on the size of  the  contact basin and flow (theoretical
residence time),  less frequent  residual  monitoring may  be  possible until a
change in residual concentration  is first detected.   In  systems which have a
theoretical detention  time greater  than  2 hours,  sampling  may  be  conducted
every 10 minutes  for the  first 40 minutes, or until a  tracer  concentration
above the baseline level  is  first detected.   At  this time,   sampling  should
                                     C - 6

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continue at 2 to 3-minute intervals until the residual concentration reaches a
steady-state value.  The  time  and tracer residual of  each  measurement should
be recorded on  a  data  sheet.   In addition,  the water level, plant  flow,  and
temperature should be recorded during the test.
     If verification of the test is desired, the tracer feed should be discon-
tinued,  and the  receding  tracer  concentration  at  the effluent  should  be
nonitored at the  same  frequency until tracer  concentrations  corresponding to
the background  level are  detected.   The time  at which tracer feed  is stopped
is time  zero for the  receding tracer  test and must  be noted.  The  receding
tracer test will provide a replicate set of measurements which can be compared
with data derived from the rising tracer concentration vs. time curve.
     Data Evaluation
     Data  from  tracer  studies should  be  summarized  in tables  of  time  and
residual concentration.  These data  are  then analyzed to determine the deten-
tion time, T    to be used in  calculating CT.   The TIQ values may be found by
a graphical  method.   This method  involves  plotting a graph  of diraensionless
concentration vs. time  and  reading the value  for T    directly  from the graph
at  the appropriate  dimensionless  concentration.   The  specific details  and
steps  involved  with this  method of data evaluation  are illustrated  in  the
following example.
     Data Evaluation for Determining T   in a Clearwell
     A  tracer  study employing the  step-dose method  of tracer  addition  was
conducted" for a clearwell with a  theoretical detention time,  T, of 30 minutes
at an  average plant  flow of 2.5 MGD.  Because fluoride  is  added at the inlet
to the  clearwell  as  a  water treatment chemical, necessary  feed equipment was
in place for dosing a constant concentration of fluoride throughout the tracer
study.  Based on this convenience, fluoride was chosen as the tracer chemical.
Prior  to  the  start of testing, a  fluoride  baseline  concentration of 0.2 mg/L
was  established for the  water  exiting the  clearwell.   A  constant fluoride
dosage  of  2.0 mg/L  was added  to the clearwell inlet.   Fluoride levels in the
clearwell  effluent were  monitored  and  recorded  every  3  minutes.   The  raw
tracer  study  data, along with the  results  of further  analyses  are  shown in
Table C-l.
                                     C - 7

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                                   TABLE  C-l
                      CLEARWELL TRACER TEST  DATA
                                                 (1,2,3)
t, minutes

     0
     3
     6
     9
    12
    15
    18
    21
    24
    27
    30
    33
    36
    39
    42
    45
    48
    51
    54
    57
    60
    63
Fluoride Concentration
Measured, mg/L
0.20
0.20
0.20
0.20
0.29
0.67
0.94
1.04
1.44
1.55
1.52
1.73
1.93
1.85
1.92
2.02
1.97
1.84
2.06
2.05
2.10
2.14
Tracer, mg/L
0
0
0
0
0.09
0.47
0.74
0.84
1.24
' 1.35
1.32
1.53
1.73
1.65
1.72
1.82
1.77
1.64
1.86
1.85
1.90
1.94
Normalized, C/Co
0
0
0
0
0.045
0.24
0.37
0.42
0.62
0.68
0.66
0.76
0.86
0.82
0.86
0.91
0.88
0.82
0.93
0.92
0.95
0.96
Notes:
     1.
     2.
     3.
Measured cone. = Tracer cone.  + Baseline cone.
Baseline cone. =0.2 mg/L, fluoride dose =2.0  mg/L
Tracer cone. = Measured cone.  - Baseline cone.

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     The steps  in evaluating  the  raw data  shown  in  the  first and  second
columns of  Table  C-l  are  as follows  for the  graphical  method  of  analysis.
First,  the baseline fluoride concentration,  0.2 mg/L, is  subtracted  from the
measured concentration to  give  the fluoride concentration  resulting  from the
tracer  study addition alone.  For  example,  at elapsed time =  39  minutes, the
tracer  fluoride  concentration,  C, is obtained as follows:
                    C  = C         - C
                         measured    baseline
                      = 1.85 mg/L - 0.2 mg/L
                      = 1.65 mg/L
This calculation was  repeated  at each time interval  to obtain the data shown
in the  third  column of Table C-l.   As indicated, the  fluoride concentration
rises from 0 mg/L at  t  = 0 minutes to the applied fluoride dosage of 2 mg/L,
at t =  63  minutes.
     The next step is to normalize  or develop dimensionless concentrations by
dividing the tracer concentrations in the second column  of Table C-l  by the
applied fluoride  dosage,  Co = 2 mg/L.   For  time  =  39 minutes,  C/Co  is cal-
culated as follows:
                    C/Co = (1.65 mg/L)/(2.0 mg/L)
                         = 0.82
The resulting normalized data,  presented in the fourth column of Table C-l, is
the basis- for completing the determination of TIQ.
     In order to  determine  T    by the graphical  method,  a plot  of  C/Co vs.
time should be generated using  the data in Table  C-l.  A  smooth  curve should
be drawn through the data as shown on Figure C-l.
     T    is  read directly  from the  graph  at a  dimensionless concentration
(C/Co)  corresponding to the time for which 10 percent of the tracer has passed
at the effluent end of  the contact basin  (TIQ).   For step-dose method tracer
studies, this normalized concentration is C/Co = 0.10 (Levenspiel, 1972).
     T    should  be read  directly  from  Figure C-l  at C/Co  =  0.1  by  first
drawing a horizontal  line  (C/Co = 0.1) from the  Y-axis  (t = 0)  to its inter-
section with  the  smooth  curve  drawn through the  data.   At this point  of
intersection, the time  read  from the  X-axis  is TIQ and may  be found  by
                                     C - 3

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                     RGURE 0-1
                 C/Co vs. Time
               Graphical Analysis for T10
o
            10
20    30     40     50

   TIME (MINUTES)

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extending  a vertical  line downward  to  the  X-axis.   These  steps  have been
performed  as  illustrated  on Figure  C-l,  resulting in  a value  for  T   of
approximately 13 minutes.
     Plant Flow Dependency of T
     As previously stated,  tests should be conducted  for at  least four plant
flows.  The TIQ detention time should be determined by the above procedure for
each of the tested plant  flows.  The  detention times  should  then be plotted
versus plant flow.  For the  example presented in the previous section, tracer
studies were  conducted at  additional  plant  flows  of 1.1, 4.2,  and 5.6 MGD.
The T   values at the various plant flows are:
               Plant Flow          T
                1.1                20
                2.5                13
                4.2                 7
                5.6                 4

T   data  for  these tracer studies  were  plotted as  a  function of  the plant
flow, Q,  as shown on Figure C-2.
C.2  Determination of T   Without Conducting a Tracer Study
     In  some  situations,  conducting  tracer  studies  for  determining  the
disinfectant contact time, T10/ may be impractical or prohibitively expensive.
The limitations may  include  a lack of funds,  manpower  or equipment necessary
to conduct the study.  For  these cases,  the Primacy Agency  may allow the use
of standard fractions representing the ratio  of T   to T, and the theoretical
detention  time,   to  determine  the   detention  time,  T   ,  to  be  used  for
calculating CT values.   This  method for finding  T    involves  multiplying the
theoretical detention time by the fraction, T  /T, that  is  representative of
the particular contact basin configuration for which T   is desired.
      Tracer studies conducted by Marske and Boyle (1973)  and Hudson (1975) on
chlorine contact  chambers and flocculators/settlirg basins, respectively, were
used as a basis in  determining representative T10/T values  for various basin
configurations. Marske and  Boyle (1973)  performed  tracer studies on  15 dis-
tinctly different types  of  full-scale chlorine contact chambers  to  evaluate
design characteristics that affect  the actual  detention  time.   Hudson (1975)
                                       - 9

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  35
  30
  25
                   RGURE C-2

           Detention Time vs. Flow
CO
LU
  20
O  15
   10
        AVERAGE
  MAXIMUM

EXTRAPOLATION
                                  I
              23456

                 PLANT FLOW (MGD)
              8

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conducted 16 tracer  tests on several flocculation  and settling basins at six
water  treatment  plants  to identify  the effect  of flocculator  baffling and
settling basin inlet and outlet design characteristics on the actual detention
time.
     Impact of Design Characteristics
     The design characteristics evaluated include:  length-to-width ratio, the
degree of baffling within the contact basins, and the effect of inlet baffling
and outlet weir  configuration.  These physical  characteristics  of the contact
basins affect their hydraulic efficiencies  in terms of dead space, plug flow,
and mixed flow proportions.   The dead space  zone of a basin  is  basin volume
through which  no  flow occurs.   The remaining volume where  flow occurs  is
comprised of  plug flow  and  mixed flow  zones.  The  plug  flow  zone  is  the
portion of the remaining  volume  in which no mixing occurs in the direction of
flow.  The mixed flow zone  is  characterized by  complete mixing  in  the flow
direction and  is the complement  to the plug  flow  zone.   All  of these zones
were identified in the studies for each  contact basin.  Comparisons were then
made between the basin  configurations  and the observed flow  conditions and
design characteristics.
     The ratio  T10/T was calculated from the data presented in the studies and
compared  to  its  associated  hydraulic  flow  characteristics.    Both  studies
resulted in T10/T  values which  ranged  from 0.3  to 0.7.   The  results  of the
studies indicate a  correlation between  T   /T and the  contact  basin  baffling
conditions,  particularly  at  the  inlet and outlet to the  basin.   As the basin
baffling conditions  improved, higher T  /T  values were  observed, with  the
outlet conditions generally having a greater impact than the inlet conditions.
     As discovered from the results of the  tracer studies performed by Marske
and Boyle (1973)  and Hudson (1975) , the effectiveness of baffling in achieving
a high T10/T fraction  is more related to  the quality of the  baffling design
than the nature  and function of  the contact basin in which it  is utilized.
For this  reason,  T  /T values  may be  defined for  three levels  of  baffling
conditions rather  than   for  particular  types  of   contact  basins.   General
guidelines were developed relating the T  /T  values from  these  studies to the
respective  baffling  characteristics.   These   guidelines   can  be  used  to
determine the T  values for specific basins.
                                    C - 10

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     Baffling Classifications
     The  purpose  of  baffling is  to maximize  utilization of  basin  volume,
increase the plug flow zone in the basin, and minimize  short  circuiting.  Some
form of  baffling at  the inlet  and  outlet of  the basins is  used to  evenly
distribute flow across the basin.  Additional baffling  may be provided within
the interior of the  basin (intra-basin)  in circumstances requiring a  greater
degree of flow distribution or redistribution.  Ideal baffling design  reduces
the inlet and  outlet flow velocities, distributes the  water as uniformly  as
practical over the cross section of the basin, minimizes mixing with the water
already in the basin, and prevents entering water  from short  circuiting to the
basin outlet as the result of wind or density current effects.  Three  general
classifications of baffling conditions  poor,  average, and  superior   were
developed to categorize the results of the tracer  studies for  use in determin-
ing T    from the  theoretical detention time of a specific basin.   The T  /T
fractions associated with each degree of  baffling  are  summarized in Table  C-2.
Factors representing the ratio between T    and  the theoretical detention  time
for plug flow  in  pipelines and flow in  a completely  mixed chamber have  been
included  in  Table C-2  for comparative  purposes.   However,  in  practice the
theoretical T  /T  values of  1.0 for plug  flow and  0.1 for mixed  flow are
seldom achieved because  of  the  potential effect of dead  space, which  reduces
their actual values  by a proportional amount.  Conversely,  the T  /T  values
shown for the intermediate baffling  conditions  already  incorporate the  effect
of the  dead space zone,  as well  as the plug  flow zone, because they  were
derived empirically rather than from theory.
     As indicated in Table C-2, poor baffling conditions  consist of an  unbaf-
fled inlet  and outlet with  no intra-basin baffling.   Average  baffling  con-
ditions consist of intra-basin baffling and either a baffled inlet or  outlet.
Superior baffling conditions  consist of  at least  a baffled inlet  and  outlet,
and possibly some intra-basin baffling to redistribute the flow throughout the
basin's cross-section.
     The  three  basic types  of basin inlet baffling  configurations  are:   a
target-baffled pipe inlet, an overflow weir entrance, and a baffled submerged
orifice  or  port  inlet.   Typical intra-basin  baffling  structures  include:
diffuser  (perforated) walls;  launders; cross,  longitudinal,  or maze baffling
                                    C - 11

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to  cause  horizontal or  vertical  serpentine flow;  and longitudinal  divider
walls,  which prevent  mixing by  increasing  the  length-to-width ratio of  the
basin(s).   Commonly used baffled  outlet structures  include  free-discharging
weir, e.g.,  sharpcrested and V-notch,  and  submerged  ports or weirs.   Weirs
that do not  span the  width of  the  contact basin,  such as Cipolleti  weirs,
should  not be considered baffling as  their use may substantially increase weir
overflow rates  and the  dead space zone of the basin.
     Examples of Baffling
     Examples of these  levels  of baffling conditions for  rectangular  and
circular  basins are  explained  and   illustrated  in the  following  section.
Typical uses  of  various  forms  of  baffled and unbaffled inlet  and  outlet
structures are  also illustrated.
     The plan and  section of a  rectangular contact basin with poor  baffling
conditions, which can be  attributed  to the unbaffled inlet and outlet pipes,
is illustrated on Figure  C-3.  The flow pattern shown  in the plan view indi-
cates straight-through flow with dead space occurring  in the  regions between
the individual  pipe inlets and  outlets.  The section view  reveals additional
dead space from a vertical perspective in  the  upper inlet and lower  outlet
corners of the  contact basin.   Vertical mixing  also occurs as  bottom density
currents induce a counter-clockwise flow in the upper water layers.
     The inlet  flow distribution is   markedly  improved by the  addition  of an
inlet diffuser  wall and intra-basin baffling as shown on Figure C-4.  However,
only average baffling  conditions are  achieved for the basin as a whole because
of the  inadequate outlet structure  a Cipolleti weir.   The width  of  the weir
is short  in  comparison with  the width  of  the  contact  basin.  Consequently,
dead space exists in the corners of   the  contact basin, as shown  by  the plan
view.  In  addition,  the  small weir  width  causes  a  high weir  overflow  rate,
which results in short circuiting in  the center of the contact basin.
     Superior baffling  conditions are exemplified  by  the flow   pattern  and
physical characteristics of the  contact basin  shown  on  Figure C-5. The  inlet
to the  basin consists  of submerged,  target-baffled  ports.  This inlet  design
serves  to reduce the velocity of the  incoming water and distribute  it  uniform-
ly throughout  the  basin's  cross-section.   The  outlet  structure  is  a  sharp-
crested weir which  extends for  the entire  width of the contact basin.   This
                                    C - 12

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               PLAN
           (
  /\.
77.
      ,

                             f,
                                   3
                                   3
>

             SECTION
FIGURE C-3 POOR BAFFLING CONDITIONS --
          RECTANGULAR CONTACT BASIN

-------
               I  I
                PLAN

                                               r
             SECTION
FIGURE C-4  AVERAGE BAFFLING CONDITIONS
            RECTANGULAR CONTACT BASIN

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X
171
Vf
^y
 \

;
v
^

                  B
                         /
                  ^
                   PLAN
/I
                                        /
                                         X
                                        >
           X
          /
                 n-*-
                          /
                          X
                              r\
                                    '
                                   xx/
                                           X
                  SECTION
   FIGURE C-5  SUPERIOR BAFFLING CONDITIONS

              RECTANGULAR CONTACT BASIN

-------
type of outlet structure will reduce  short  circuiting and decrease the  dead
space fraction of the basin,  although  the  overflow weir does create some  dead
space  at the  lower corners  of  the  effluent  end.   These  inlet and  outlet
structures  are by  themselves  sufficient  to  attain  superior  baffling  con-
ditions; however, maze-type intra-basin baffling was included as an example of
how this type of baffling aids in flow redistribution within a contact  basin.
     The  plan and  section of  a circular  contact basin  with  poor baffling
conditions, which can be attributed to flow short  circuiting from the center
feed well directly to  the effluent  trough is  shown  on  Figure C-6.  Short
circuiting occurs in spite of the outlet weir configuration because the center
feed inlet is  not baffled.  The inlet flow distribution is  improved  somewhat
on Figure C-7  by  the addition  of an annular ring  baffle  at the  inlet which
causes  the inlet  flow to be  distributed throughout a greater portion of  the
basin's  available volume.   However, the baffling conditions in  this  contact
basin are  only average  because the  inlet center  feed arrangement does  not
entirely prevent short circuiting through the upper levels  of the basin.
     Superior baffling conditions are attained in the contact basin configura-
tion shown on Figure C-8 through the addition of a perforated inlet baffle and
submerged orifice outlet ports.   As indicated by the flow pattern, more of the
basin's  volume  is utilized due  to uniform  flow  distribution created by  the
perforated baffle.  Short  circuiting is also minimized because only  a small
portion  of flow  passes  directly  through the perforated baffle wall from  the
inlet to the outlet ports.

Additional Considerations
     Flocculation  basins  and  ozone  contactors  represent  water treatment
processes with slightly  different characteristics  from  those  presented  in
Figures C-3  through C-8  because  of  the  additional  effects  of  mechanical
agitation and  mixing from  ozone addition,  respectively.   Studies by  Hudson
(1975)  indicated that a single-compartment flocculator  had a  T   /T value  less
than 0.3, corresponding  to a  dead  space 'zone  of about 20 percent and a  very
high mixed  flow  zone of  greater than  90  percent.   In this  study two four-
compartment flocculators, one  with and the  other without mechanical agitation,
exhibited  Tin/T  va^-ues  ^n  *-he  range of  0.5  to  0.7.    This  observation
                                    C - 13

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              PLAN
             SECTION
FIGURE C-6  POOR BAFFLING CONDITIONS
           CIRCULAR CONTACT BASIN

-------
                PLAN
                               i^
                              /fZ"
   /////////////////// / / / / s
               SECTION
FIGURE C-7 AVERAGE BAFFLING CONDITIONS
          CIRCULAR CONTACT BASIN

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                PLAN
              SECTION
FIGURE C-8  SUPERIOR BAFFLING CONDITIONS
            CIRCULAR CONTACT BASIN

-------
indicates that  not  only will compartmentation  result  in higher T10/T values
through  better  flow  distribution,  but  also that  the  effects  of  agitation
intensity on T  /T  are  reduced  where sufficient baffling exists.  Therefore,
regardless of  the  extent  of agitation,  baffled (two  or more  compartments)
flocculation  basins  should  be   considered  to  possess  average  baffling
conditions (T  /T = 0.5), whereas unbaffled  (single  compartment) flocculation
basins are characteristic of poor  baffling conditions (TIO/T =  0.3).
     Similarly,  multiple  stage  ozone  contactors are  baffled  contact basins
which show characteristics of average baffling conditions.   Single  stage ozone
contactors should be  considered as being poorly baffled.   However,  circular,
turbine ozone contactors  may  exhibit flow distribution  characteristics which
approach those of completely mixed basins, with a T10/T of 0.1,  as  a  result  of
the intense mixing.
     In  many   cases,  settling  basins  are   directly  connected   to  the
flocculators. Data from Hudson  (1975) indicates  that poor baffling conditions
at the flocculator/settling basin interface  can  result  in backmixing from the
settling basin to the flocculator.  Therefore, settling basins  that have inte-
grated flocculators without  effective inlet baffling should be  considered  as
poorly baffled,  with a  T  /T of 0.3,  regardless of  the  outlet  conditions,
unless intra-basin baffling is  employed  to  redistribute  flow.   If  intra-basin
and  outlet baffling  is  utilized,   then the  baffling  conditions  should  be
considered average with a T1O/T of 0.5.
     Filters are special treatment units  because their  design  and  function  is
dependent on flow distribution that is completely uniform.   Except  for  a small
portion of flow which short circuits  the  filter  media by channeling  along the
walls of the filter,  filter media baffling  provides  a  high  percentage  of  flow
uniformity and can be considered  superior baffling conditions  for  the  purpose
of determining T  .   As such, the  T   value can be obtained  by  subtracting the
volume of  the filter media,  support gravel, and underdrains  from the total
volume and calculating the theoretical detention time by dividing  this volume
by  the  flow  through the  filter.   The   theoretical  detention  tine  is  then
multiplied by a factor of 0.7,  corresponding to superior baffling  conditions,
to determine the T   value.
                                    C - 14

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Conclusions
     The recommended T10/T  values and examples  are  presented as a  guideline
for use  by the  Primacy Agency  in determining  T   values  in site  specific
conditions and when  tracer  studies cannot  be performed because of  practical
considerations.   Selection  of  T10/T values in  the  absence of tracer  studies
was restricted to a  qualitative  assessment based on currently available  data
for  the  relationship  between contact  basin  baffling conditions  and their
associated T10/T values.  Conditions which  are  combinations or variations  of
the above examples may exist and warrant the  use  of  intermediate T   /T values
such as 0.4 or 0.6.  As more  data on  tracer studies  become available,  specif-
ically correlations between other physical characteristics of contact basins
and the  flow  distribution  efficiency parameters, further refinements  to  the
T  /T fractions and definitions of baffling conditions may be appropriate.

References
Hudson, H. E. ,  Jr..  "Residence  Times in Pretreatment",  J.  AWWA,  pp.  45-52,
     January,  1975.
Hudson,  H.  E. ,  Jr..  Water Clarification  Processes;   Practical  Design  and
     Evaluation,  Van Nostrand Reinhold Company, New York,  1981.
Levenspiel, 0..  Chemical  Reaction Engineering,  John  Wiley  Sons,  New York,
     1972.
Marske, D. M.  and Boyle, J.  D.. "Chlorine Contact  Chamber Design -  A Field
     Evaluation", Water and Sewage Works, pp. 70-77,  January, 1973.
Thirumurthi,   D..  "A  Break-through in  the  Tracer  Studies  of  Sedimentation
     Tanks",  J. WPCF, pp.  R405-R418, November, 1969.

-------
       APPENDIX E

 INACTIVATIONS ACHIEVED
3Y VARIOUS DISINFECTANTS

-------
          TABLE E-1
    CT VALUES FOR 1NACTIVATION
OF CIARDIA CYSTS BY FREE CHLORINE
           AT 0.5 C

CHLORINE
CONCENTRATION 
(ng/L>
o0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3

CHLORINE
rnurPiiTPATtfm *
IUNWCN 1 KA 1 1 UH *
(ag/D
<0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8-
3

CHLORINE
rnumiTV AT I ny
I WHICH I KM I I UH
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3


0.5
23
24
24
25
25
26
26
27
28
28
29

30
30


0.5
40
40
41
42
43
44
46
47
48
50
50
51
52
53


0.5
65
68
70
73
75
77
80
82
83
85
87
Of
91
92
PH6
Log Inactivations
1.0 1.5 2.0 2.5 3.0
46 69 91 114 137
47 71 94 118 141
48 73 97 121 145
49 74 99 123 148
51 76 101 127 152
52 78 103 129 155
52 79 105 131 157
54 81 108 135 162
55 83 110 138 165
56 85 113 141 169
57 86 115 143 172
SB 88 117 146 175
59 89 119 148 178
60 91 121 151 181
pH7.5
Leg Inactivations
1.0 1.5 2.0 2.5 3.0
79 119 158 198 237
80 ltd lav IT* ti'j
82 123 164 205 246
84 127 169 211 253
86 130 173 216 259
89 133 177 222 266
91 137 182 228 273
93 140 186 233 279
95 143 191 238 286
99 149 198 248 297
99 149 199 248 298
101 152 203 253 304
103 155 207 258 310
105 158 211 263 316
pN-9.0
Leg Inactivations
1.0 1.5 2.0 2.5 3.0
130 195 260 325 390
136 204 271 339 407
141 211 281 352 422
146 219 291 364 437
ISO 226 301 376 451
155 232 309 387 464
159 239 318 398 477
163 245 326 408 489
167 250 333 417 500
170 256 341 426 511
174 261 348 435 522
178 267 355 444 533
181 272 362 453 5- T
184 276 368 460 552


0.5
27
28
29
29
30
31
32
32
33
T/
34
35
36
36


0.5
46
io
49
51
52
54
55
56
58
59
60
61
63
64

















Log
1.0
54
56
57
59
60
61
63
64
66
*7
68
70
71
72

Log
1.0
92
;.
98
101
104
107
110
113
115
118
120
123
125
127

















pH6.5
p7.0
Inactivations
1.5
' 82
84
86
88
90
92
95
97
99
101
103
105
107
109

2.0
109
112
115
117
120
123
126
129
131
134
137
139
142
145
pH*8.0
2.5
136
140
143
147
150
153
158
161
164
168
171
174
178
181

3.0
163
168
172
176
180
184
189
193
197
201
205
209
213
217

0.5
33
33
34
35
36
37
38
39
J9
40
41
42
43
44

Inactivations
1.5
139
1*3
148
152
157
161
165
169
173
177
181
184
188
191
















2.0
185
191
197
203
209
214
219
225
231
235
241
245
250
255
















2.5
231
238
246
253
261
268
274
282
288
294
301
307
313
318
















3.0
277
286
295
304
313
321
329
338
346
353
361
368
375
382
















Note: CTOQ {
0.5
55
57
42
44
46
48
SO
68
70
71
73
74
75
77
















109
1.0
65
67
68
70
72
74
75
77
79
81
82
84
86
87

log
1.0
110
114
85
88
92
96
99
136
139
142
145
148
151
153
















Inactivations
1.5
98
100
103
105
108
111
113
116
118
121
124
126
129
131
pi
2.0
130
133
137
140
143
147
151
154
157
161
165
168
171
174
H=8.s
2.5 3.0
163 195
167 200
171 205
175 210
179 215
184 221
188 226
193 231
197 236
202 242
206 247
210 252
214 257
218 261

Inactivations
1.5
165
171
127
133
138
144
149
204
209
213
218
222
226
230
















=CT for 3-loq
2.0
219
228
169
177
184
191
198
271
278
284
290
296
301
307
















2.5 3.0
274 J29
285 342
212 254
221 265
230 276
239 287
248 297
339 407
348 417
355 426
363 435
370 444
377 452
383 460
















inactivatii

-------
          TABLE E-2
    CT VALUES FOR IMACT I VAT I ON
OF 5IAROIA CTSTS BY FREE CHLORINE
           AT 5 C

CHLORINE
CONCENTRATION
(ng/L)
<0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3

CHLORINE
CONCENTRATION 
(ng/L)
<-0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2*6
2.8
3

CHLORINE
CONCENTRATION
(9/L)
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3


O.S
16
17
17
18
18
18
19
19
19
20
20
20
21
21


O.S
28
29
29
30
31
31
32
33
33
34
35
36
36
37



0.5
47
49
SO
52
53
55
56
SB
59
60
61
63
64
65

Log
1.0
32
33
34
35
36
36
37
38
39
39
40
41
41
42

Log
1.0
55
57
58
60
61
62
64
65
67
68
70
71
72
74

Log

1.0
93
97
100
104
107
110
112
115
118
120
123
125
127
130
pH6
Inactivations
1.5 2.0 2.5
49 65 81
SO 67 83
52 69 86
53 70 88
54 71 89
55 73 91
56 74 93
57 76 95
58 77 97
59 79 98
60 80 100
61 81 102
62 S3 103
63 84 105
pN>7.5
Inactivations
1.5 2.0 2.5
83 111 138
86 114 143
88 117 146
90 119 149
92 122 153
94 125 156
96 128 160
98 131 163
100 133 167
102 136 170
IDS 139 174
107 142 178
109 US 181
111 147 184
pH9.0
Inactivations

1.5 2.0 2.S
140 186 233
146 194 243
1S1 201 251
1S6 208 260
160 213 267
16S 219 274
169 225 281
173 230 288
177 235 294
181 241 301
184 245 307
IBS 2SO 313
191 255 318
195 259 J24



pH-6.5


Log Inactivations
3.0
97
100
103
105
107
109
111
114
116
118
120
122
124
126

0.5
20
20
20
21
21
22
22
23
23
23
24
24
25
25

1.0 1.5
39 59
40 60
41 61
42 63
42 64
43 65
44 66
45 68
46 69
47 70
48 72
49 73
49 74
SO 76

2.0 2.5
78 98
80 100
81 102
S3 104
85 106
87 108
88 110
90 113
92 115
93 117
95 119
97 122
99 123
101 126
pH8.0
3.0
117
120
122
125
127
130
132
135
133
140
143
146
148
151

0.5
23
24
24
25
25
26
26
27
28
28
29
29
30
30

Log Inactivations
3.0
166
171
175
179
183
187
192
196
200
204
209
213
217
221



3.0
279
291
301
312
320
329
337
345
353
361
368
375
382
339

33
34
35
36
37
38
39
40
41
41
42
43
44
45

















AX 04
68 102
70 105
72 108
74 111
76 114
77 116
79 119
81 122
83 124
84 127
86 129
88 132
89 134

















13? 165
136 170
140 175
144 180
147 184
151 189
155 193
159 198
162 203
165 207
169 211
172 215
175 219
179 223
















3>%
.0
198
204
210
216
221
227
232
238
243
248.
253
258
263
268
















fJote: CTQQ =

O.S
39
41
42
43
45
46
47
48
49
50
51
52
53
54

















pH*7.0

Log Inactivations
1.0
46
48
49
50
51
52
53
54
55
56
57
58
59
61

Log

1.0
79
C i
84
87
89
91
94
96
98
100
102
104
106
108
















1.5 2.0
70 93
72 95
73 97
75 99
76 101
78 103
79 105
81 108
83 r.O
85 113
86 115
88 117
89 119
91 121
pH*8.5
2-5 3.0
1 '6 139
19 uj
122 U6
124 U9
127 152
129 155
132 15g
135 162
138 165
141 ;:?
1*3 172
146 175
148 178
152 182

Inactivations

1.5 2.0
118 157
.;; 163
126 163
130 173
134 178
137 183
141 187
144 191
147 196
150 200
153 204
156 208
159 212
162 216

















2.S 3.0
197 236
203 2(4
210 252
217 260
223 267
228 274
234 281
239 287
245 274
2SO 300
255 304
260 312
265 318
270 324
















CT for 3-Toq inactivatif

-------
                                                        TABLE E-3
                                                   CT VALUES FOR INACTIVATIOH
                                               OF GIAROIA CYSTS BY FREE CHLORINE
                                                         AT 10 C
f>H6
CHLORINE
CONCENTRATION
(ng/L)
<*0.
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
Log Inactivations
0.5
12
13
13
13
13
U
14
U
IS
15
15
15
16
16
1.0
24
25
26
26
27
27
28
29
29
30
30
31
31
32
1.5
37
38
39
40
40
41
42
43
44
45
45
46
47
48
2.0
49
50
52
S3
S3
55
55
57
58
59
60
61
62
63
2.5
61
63
65
66
67
68
69
72
73
74
75
77
78
79
3.0
73
75
78
79
80
82
83
86

22
23
23
24
25
25
26
26
27
27
28
1.0
42
43
n
45
46
47
48
49
50
51
52
S3
54
55
1.5
63
64
66
67
69
70
72
74
75
77
79
80
82
83
2.0
83
85
87
89
91
93
96
98
100
102
105
107
109
111
2.5
104
107
109
112
114
117
120
123
125
128
131
133
136
138
3.0
125
128
131
134
137
140
144
147
ISO
153
157
160
163
166
0.5
25
26
26
27
28
28
29
30
30
31
32
32
33
34
pH8.0
Log Inactivations
1.0
50
51
53
54
55
57
58
60
61
62
63
65
66
67
1.5
75
77
79
81
83
85
87
90
91
93
95
97
. 9*
101
2.0
99
102
105
108
111
113
116
119
121
124
127
129
131
134
2.5
124
128
132
135
138
142
145
149
152
155
158
162
164
168
3.0
149
153
158
162
166
170
174
179
182
186
190
194
197
201
0 S
30
3i
32
33
33
34
35
36
37
38
38
39
40
41
pH8.5
Log Inactivations -
1.0
59
6.
63
65
67
69
70
72
74
75
77
78
80
81
1.5
89
TC
95
98
100
103
106
108
111
113
115
117
120
122
2.0
118
lta
126
130
133
137
141
143
147
150
153
156
159
162
2.5
us
>
-------
                                                       TABU E-4
                                                  CT VALUES FOR 1NACTIVATION
                                              OF GIARDIA CYSTS BY FREE CHLORINE
                                                        AT 15 C

CHLORINE
CONCENTRATION
Cg/L>
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3

CHLORINE
CONCENTRATION
(a/i)
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
" 3



pH6
pU6.5
Log Inactivations
0.5







10
10
10
10
10
10
11

1.0
16
17
17
18
18
18
19
19
19
20
20
20
21
21

1.5
25
25
26
27
27
28
28
2?
29
30
30
31
31
32

2.0
33
33
35
35
36
37
37
38
39
W
40
41
41
42
pH-7.5
2.5
41
42
43
44
45
46
47
48
48
49
50
51
52
53

3.0
49
50
52
53
54
55
56
57
58
59
60
61
62
63

O.S
10
10
10
11
11
11
11
11
12
12
12
12
12
13

Log Inactivations
O.S
14
14
IS
IS
15
16
16
16
17
17
18
18
IB
19
1.0
28
?9
29
30
31
31
32
33
33
34
35
36
36
37
1.5
42
43
44
45
46
47
48
49
SO
51
53
54
55
56
2.0
55
57
59
60
61
63
64
65
67
68
70
71
73
74
2.5
69
72
73
75
77
78
80
82
83
85
88
89
91
93
3.0
83
86
88
90
92
94
96
98
100
102
105
107
109
111
O.S
17
17
i
18
19
19
19
20
20
21
21
22
22
22
Log Inactivations
1.0
20
20
20
21
21
22
22
23
23
23
24
24
25
25

1.5
30
30
31
32
32
33
33
34
35
35
36
37
37
38

2.0
39
40
41
42
43
43
44
45
46
47
48
49
49
51
pd-a.O
2.5
49
50
51
S3
53
54
55
57
58
58
60
61
62
63

3.0
59
60
61
63
64
65
66
68
69
70
72
73
74
76

0.5
12
12
12
13
13
13
13
14
14
14
14
IS
IS
15

Log Inactivations
1.0
33
34

36
37
38
39
40
41
41
42
43
44
45
1.5
50
51
S3
54
56
57
58
60
61
62
64
65
66
67
2.0
66
68
70
72
74
76
77
79
81
83
85
86
88
89
2.5
83
85
88
90
93
95
97
99
102
103
106
108
110
112
3.0
99
102
105
108
111
114
116
119
122
124
127 .
129
132
134
O.S
20
20
21
22
22
23
24
24
25
25
26
26
27
27
PU7.0
Log Inactivations
1.0
23
24
24
25
25
26
26
27
28
28
29
29
30
30

1.5
35
36
37
38
38
39
40
41
42
43
43
44
45
46

2.0
47
48
49
SO
51
52
53
54
5K
57
57
59
59
61
PH8.5
2.5
58
60
61
63
63
5
66
68
"0
71
72
73
74
76

3.0
Tn
fw
75
ft
7
I)
ye
13
7A
fQ
78
10
70
tr
8'
*1

84

89
91

Log Inactivations
1.0
39
41
42
43
45
46
47
48
49
50
51
52
S3
54
1.5
59
61
63
65
67
69
71
72
74
75
77
78
80
81
2.0
79
81
84
87
89
91
94
96
98
100
102
104
106
103
2.5
98
102
105
108
112
114
118
120
123
125
128
130
133
135
3.0
118
122
126
130
134
137
141
144
U7
ISO
153
154
159
162
                           ptW.O

   CHLORINE        Log Inactivations
CONCENTRATION	
      (g/L)   O.S   1.0   1.5   2.0   2.5   3.0
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
23
24
25
26
27
28
28
29
30
30
31
31
32
33
47
49
SO
52
53
SS
56
58
59
60
61
63
64
65
70
73
76
78
80
83
85
87
89
91
92
94
94
98
93
97
101
104
107
110
113
IIS
118
121
123
125
12'
130
117
122
126
130
133
138
141
144
148
151
153
157
159
163
140
146
151
156
160
165
169
173
177
181
184
188
191
195
                                                        Note:   CTgg  g=  CT for  3-1 og  inactivaticn

-------
          TABLE E-5
    CT VALUES  FOR  INACTIVATION
OF GIAROIA CYSTS BY  FREE CHLORINE
           AT  20 C

CHLORINE
rfiuraiTRATlOM ' -
UUMVCN 1 KM 1 * IM
<0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3

CHLORINE
CONCENTRATION -
008/L)
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3

CHLORINE
CONCENTRATION
(9/L)
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
pH6
Log Inactivations
0.5 1.0 1.5 2.0 2.5 3.0
6 12 18 24 30 36
6 13 19 25 32 38
7 13 20 26 33 39
7 13 20 26 33 39
7 13 20 27 33 40
7 14 21 27 34 41
7 14 21 28 35 42
7 14 22 29 36 43
7 15 22 29 37 44
7 IS 22 29 37 44
8 15 23 30 38 45
8 IS 23 31 38 46
8 16 24 31 39 47
8 16 24 31 39 47
pH7.5
Log Inactivations
0.5 1.0 1.5 2.0 2.5 3.0
10 21 31 41 52 62
11 21 32 43 53 6*
11 22 33 44 55 66
11 22 34 45 56 67
12 23 35 46 58 69
12 23 35 47 58 70
12 24 36 48 60 72
12 25 37 49 62 74
13 25 38 50 63 75
13 26 39 51 64 77
13 26 39 52 65 78
13 27 40 53 67 80
14 27 41 54 68 81
14 28 42 55 69 83
pH9.0
Log Inactivations


18 35 53 70 88 105
18 36 55 73 91 109
19 38 57 75 94 113
20 39 59 78 98 117
20 40 60 80 100 120
21 41 62 82 103 123
21 42 63 W 105 126
22 43 65 86 108 129
22 44 66 88 110 132
23 45 68 90 113 135
23 46 69 92 115 138
24 47 71 94 118 141
24 48 72 95 119 143
24 49 73 97 122 146
pH6.5

O.S
7












10
Log
1.0
15
15
15
16
16
16
17
17
17
18
18
18
19
19
Inactivations
1.5
22
23
23
24
24
25
25
26
76
27
27
28
28
29
2.0
29
30
31
31
32
33
33
34
35
35
36
37
37
38
2.5
37
38
38
39
40
41
42
43
43
44
45
46
47
48
3.0
44
45
46
47
48
49
50
51
52
53
54
55
56
57
Log
O.S 1
9
9
9
9
10
10
10
10
10
11
11
11
11
11
.0
17
18
18
19
19
19
20
20
21
21
22
22
22
23
pH7.0

Inactivations
1.5
26
27
28
28
29
29
30
31
31
-;
33
33
34
34
pH*8.0

0.5
12
ij
13
14
14
14
15
15
IS
16
16
16
17
17

















Log
1.0
25
ia
26
27
28
28
29
30
30
31
32
32
33
34

















Inactivations
1.5
37
ji
40
41
42
43
44
45
46
" 47
48
49
50
51















Note

2.0
49
J 1
53
54
55
57
S3
59
61
62
63
65
66
67















:

2.5
62
o.
66
68
69
71
73
74
76
78
79
81
83
84















CTog
5 "
3.0
74
r*
79
81
83
85
87
39
91
93
95
97
99
101















q =
 
L09
O.S 1
15
15
16
16
17
17
18
18
18
19
19
20
20
20















CT for

.0
30
31
32
33
33
34
35
36
37
33
33
39
40
41















2.0
35
36
37
37
38
39
39
41
41
i;
43
44
45
45
pH=8.5
2.5 3.0
43 S2
45 54
46 55
47 56
48 57
48 53
49 59
51 61
52 62
53 63
54 65
55 66
56 67
57 63

Inactivations*
1.5
45
46
48
49
50
52
53
54
55
57
58
59
60
61















3-log


2.0
59
61
63
65
67
69
70
72
73
75
77
78
79
81















2.5 3.0
74 89
77 92
79 95
32 98
33 100
86 103
88 105
90 108
92 110
94 113
96 115
98 117
99 119
102 122















Inactivatio



-------
                                                     TABU E-6

                                                CT VALUES FOR IN ACTIVATION

                                            OF CIAROIA CYSTS BY FREE CHLORINE

                                                      AT 25 C
CHLORINE
CONCENTRATION
(g/D
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3



pH6



Log Inactivation*
0.5 1.0 1.5
4
4
4
4
5
5
5
12
13
13
13
14
14
14
5 10 15
5 10 15
5 10 15
5 10 15
5 10 16
5 10 16
5 11

16

2.0
16
17
17
17
18
18
19
19
19
20
20
21
21
21
pH.7.5
2.5
20
21
22
22
23
23
23
24
24
25
25
26
26
27

3.0
24
25
26
26
27
27
28
29
29
30
30
31
31
32

0.5
5
5
5
5
5
6
6
6
6
6
6
6
6
6



pH6.S



Log Inactivations
1.0
10
10
10
10
11
11
11
11
12
^
12
12
12
13

1.5
15
15
16
16
16
17
17
17
18
18
18
19
19
19

2.0
19
20
21
21
21
22
22
23
23
23
24
25
25
25
pH8.0
2.5
24
25
26
26
27
28
28
28
29
29
30
31
31
32

3.0
29
30
31
31
32
33
33
34
35
35
36
37
37
38

0.5
6
6
6
6
6
7
7
7
7
7
7
7
8
8



PH"7.0


log Inaeti vat ions
1.0
12
12
12
12
13
13
13
14
14
14
14
15
15
15

1.5
18
18
19
19
19
20
20
21
21
21
22
22
23
23

2.0
23
24
25
25
25
26
27
27
27
28
29
29
30
31
PN.5
2.5
29
30
31
31
32
33
33
34
34
35
36
37
38
38

3.0

3j
37
37
jj
3;
(g
41
(I
<;
(3
U
ii
W

CHLORINE
                 Log {Motivations
                                                   Leg Inaotivations
                                                                                     Log Inactivations
IKAI IUH
B/L)
"0.4
0.6
:.;
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
-2.8
3
0.5
7
7
7





8
9
9
9
9
9
1.0
14
14
15
IS
15
16
16
16
17
17
17
18
18
18

21
22
22
23
23
24
24
25
25
26
26
27
27
28

28
29
29
30
31
31
32
33
33
34
35
35
36
37

35
36
37
38
38
39
40
41
42
43
43
44
45
46

42
43
44
45
46
47
48
49
SO
51
52
53
54
55
0.5





10
10
10
10
10
11
11
11
11
1.0
17
17
18
18
18
19
19
20
20
21
21
22
22
22
1.5
25
26
27
27
28
29
29
30
31
31
32
33
33
34
2.0
33
34
35
36
37
38
39
40
41
41
42
43
44
45
2.5
42
43
44
45
46
48
48
50
51
52
S3
54
55
56
3.0
SO
jl
S3
54
55
57
58
60
61
62
63
65
66
67
O.S
10
IU
11
11
11
12
12
12
12
13
13
13
13
14
1.0
20
in
21
22
22
23
23
24
25
25
26
26
27
27
1.5
30
ii
32
33
34
35
35
36
37
33
39
3?
40
41
2.0
39
< i
42
43
45
46
47
48
49
50
51
52
53
54
2.5
49
3i
53
54
56
58
58
60
62
63
64
65
67
68
3.0
59
61
a
65
a
69
70
72
74
75
77
78
80
81
                          pH9.0



 CHLORINE          Log Inaetivations
MIMIIUI '
(g/D

-------
                                   TABLE E-7
                                CT VALUES FOR
                 INACTIVATION OF VIRUSES BY FREE CHLORINE(1'2*
                                           Log Inactivatlon
Temperature (C)

        0.5

         5

        10

        15

        20

        25
2.0
PH
6-9 (3)
6
4
3
2
1
1


10
45
30
22
15
11
7
3.0
PH
6-9(3)
9
6
4
3
2
1


10
66
44
33
22
16
11
4.0
pH
6-9 (3)
12
8
6
4
3
2


10
90
60
45
30
22
15
Notes:

    .1.
     2.
Data adapted from Sobsey  (1988) for inactivation of Hepatitus A
Virus (HAV) at pH = 6, 7, 8, 9, and 10 and temperature = 5 C.  CT
values include a safety factor of 3.

CT values adjusted to other temperatures by doubling CT for each
10 C drop in temperature.

-------
          TABLE E-8

        CT VALUES FOR
INACTIVATION OF GIARDIA CYSTS
 BY CHLORINE DIOXIDE pH 6-9
Temperature (C)
Inactivation
0.5
1
1.5
2
2.5
3
log
log
log
log
log
log
0.5
10
20
30
40
50
60
5
7
13
20
27
33
40
10
5
10
15
20
25
30
15
3.3
5
10
13
17
20
20
3
5
7.5
10
13
15
25
1.
3.
5.
6.
8.
10

7
3
0
7
3


-------
2.
                              TABLE E-9

                            CT VALUES FOR
                       INACTIVATION OF VIRUSES
                     BY CHLORINE DIOXIDE pH 6-9
                                           (1,2)
Source: Sobsey 1988
Temperature (C)
Removal 0.5 5 10 15 20
2 log 8.4 5.6 4.2 2.8 2.1
3 log 25.6 17.1 12.8 8.6 6.4
4 log 50.3 33.5 25.1 16.8 12.6
Notes:
1. Data adapted from Sobsey (1988) for inactivation of Hepatit

_25
1.4
4.3
8.4
us A Vin
(HAV) at pH  6.0 and temperature = 5 C.  CT values include a safety
factor of 3.

CT values adjusted to other temperatures by doubling CT for each 10 C
drop in temperature.

-------
         TABLE E-10

        CT VALUES FOR
INACTIVATION OF GIARDIA CYSTS
      BY OZONE pH 6-9
Temperature (c)
Inactivation 0 . 5
0.5 log
1 log
1.5 log
2 log
2.5 log
3 log
0.48
0.97
1.5
1.9
2.4
2.9
5
0.32
0.63
0.95
1.3
1.6
1.9
10
0.23
0.48
0.72
0.95
1.2
1.4
15
0.16
0.32
0.48
0.63
0.79
0.95
20
0.12
0.24
0.36
0.48
0.60
0.72
25
0.08
0.16
0.24
0.32
0.40
0.48

-------
                                  TABLE E-ll
                                CT VALUES FOR
                     INACTIVATION OF VIRUSES BY OZONE  '
Temperature (C)
Inactivation 0 . 5
2 log 0.9
3 log 1.4
4 log 1.8
5 10 15 20 25
0.6 0.5 0.3 0.25 0.15
0.9 0.8 0.5 0.4 0.25
1.2 1.0 0.6 0.5 0.3
Notes:
     1.   Data adapted from Roy (1982) for inactivation of poliovirus for
          pH = 7.2 and temperature = 5 C.  CT values include a safety
          factor of 3.

     2.   CT values adjusted to other temperatures by doubling CT for each
          10 C drop in temperature.

-------
         TABLE E-12

        CT VALUES FOR
INACTIVATION OF GIARDIA CYSTS
    BY CHLORAMINE pH 6-9
Temperature (C)
Inactivation 0.5
0.5 log
1 log
1.5 log
2 log
2.5 log
3 log
690
1,295
1,900
2,590
3,154
3,800
5
363
737
1,100
1,435
1,826
2,200
10
337
675
925
1,349
1,536
1,850
15
250
505
750
1,009
1,245
1,500
20
181
366
550
738
913
1,100
25
130
260
375
532
623
750

-------
                                  TABLE E-13

                                CT VALUES FOR
                 INACTIVATION OF VIRUSES BY CHLORAMINE  '2'3'
Temperature (C)
Inactivation 0 . 5
2
3
4
log 1,243
log 2,063
log 2,883
5
857
1,423
1,988
10
643
1,067
1,491
15
428
712
994
20 25
321 214
534 356
746 497
Notes:
     1.   Data from Sobsey (1988)  for inactivation of Hepatitus A Virus (HAV)
          for pH = 8.0 and temperature = 5 C, and assumed to apply for pHs in
          the range of 6.0 to 10.0.

     2.   CT values adjusted to other temperatures by doubling CT for each
          10 C drop in temperature.

     3.   This table of CT values applies for systems using combined chlorine
          where chlorine is added prior to ammonia in the treatment sequence.
          CT values in this table should not be used for estimating the
          adequacy of disinfection in systems applying preformed chloramines
          or ammonia ahead of chlorine.

-------
                                 TABLE E-14

                               CT VALUES FOR
                    INACTIVATION OF VIRUSES BY UV  {*'


                        	Log Inactivation
Notes:
    1.   Data adapted from Sobsey (1988) for UV inactivation of Hepatitus A
         Virus (HAV).  Units of CT values are mW-sec/cm.  CT values include
         a saftey factor of 3.

    2.   For UV inactivation, CT values are independent of temperature.
         Dependencies of pH on UV inactivation are related to changes to
         the viruses and not the UV intensity.

    3.   CT values based on UV inactivation of Coxsackie B-5 (Sobsey 1988)
         and UV inactivation of Poliovirus type 1 and Simian Rotavirus Chang
         et al. (1985) are lower from those indicated in this Table.

-------
    APPENDIX P
BASIS FOR CT VALUES

-------
                                  APPENDIX F
                              BASIS OF CT VALUES

F.I  Inactivation of Giardia Cysts

     F.I.I  Free Chlorine
     The CT values for free  chlorine  in Tables E-l  through  E-6 are based on a
statistical analysis  (Clark  et al.,  1988;  attached to this  appendix),  which
considered  both  animal  infectivity  studies  (Hibler   et  al.,   1987)   and
ex cyst at ion studies  (Jarroll et al.,  1981;  Rice  et al.,  1982; Rubin et  al. ,
1988).  A  multiplicative model was selected  to  best represent the  chemical
reactions during the inactivation process.   This model was  applied to each of
the  data  sets,  listed   above,  and  in  various  combinations.   The  animal
infectivity data  were  included in  all  the combinations  studied.   The  animal
infectivity data was considered essential for inclusion in all the  analysis of
combined data  sets  because  it included many more data points  than the  other
data  sets,  all of  which represented inactivation levels  at  99.99  percent.
Because  of  limitations   with the  excystation  methodology,  only data  for
achieving less than 99.9 percent inactivation was available from such  studies.
     Statistical analysis supported the choice of combining the Hibler  et al.
and the Jarroll et al.  data  (and excluding the Rice et al. (1981) and  Rubin et
al.  (1987)  data) , to form  the best  fit  model for predicting CT values  for
different levels  of  inactivation.   As a conservative regulatory strategy the
authors recommended  that CT  values for different* levels of  inactivation be
determined by applying first order kinetics to the 99 percent upper confidence
interval of the CT      values predicted by the model.
                  77* 99
     The model  was  applied  using the above  strategy,  as  a  safety  factor, to
determine the CT values ranging from  0.5-log to 3-log inactivation at 0.5 and
5 C.  CT values for temperatures above 5 C  were estimated  assuming a twofold
decrease for every 10 C.  CT values .for temperatures at  0.5 C were estimated
assuming a 1.5  times increase  to CT values at 5 C.  This  general principle is
supported by Hoff (1986).
                                      F-l

-------
     Application of the model to pHs  above 8,  up to 9, was considered reason-
able because the model is substantially sensitive to pH  (e.g., CTs at pH 9 are
over three times greater than CTs  at  pH 6 and over two times greater than CTs
at pH 7).  At a pH  of 9, approximately four percent  of the hypochlorous acid
fraction of  free chlorine  is still  present.   Recent  data indicate  that  in
terms of HOC1 residuals  (versus  total free chlorine  residuals including HOC1
and  OC1~)  the CT  products  required  for inactivation  of Giardia  muris  and
Giardia lamblia cysts decrease with increasing pH from  7  to  9 (Leahy et al.,
1987; Rubin et al.,  1988b).   However,  with increasing pH, the fraction of free
chlorine existing as the weaker oxidant species (OC1 ) increases.  In terms of
total free chlorine residuals  (i.e.,  HOC1 and  OCl")  the CT products required
for inactivation of Giardia muris  cysts increase  with increasing pH from 7 to
9 but less than by  a  factor of 2 at concentrations of less than 5.0 mg/L (see
Table F-l).  Also,  the significance of pH on  the  value of CT products achiev-
ing  99 percent  inactivation appears  to decrease with  decreasing temperature
and free chlorine concentration.   The relative effects of pH, temperature, and
chlorine concentration, on  inactivation of Giardia muris  cysts  appears to be
the same for Giardia lamblia cysts  (Rubin et al., 1988b), although not as much
data  for  Giardia lamblia  cysts for  high pH  and  temperature values  as  for
Giardia muris cysts is yet available.

     F.I.2  Ozone and Chlorine Dioxide
     The CT values  for ozone in  Table E-10 are based on disinfection studies
using in vitro excystation  of Giardia lamblia (Wickramanayake, G. B., et al.,
1985).  CT   values at 5 C and pH 7 for ozone ranged from 0.46 to 0.64  (disin-
fectant concentrations ranging from 0.11 to 0.48 mg/L).  No CT values were
available for other pHs.   The highest CTgg value,  0.64, was  used  as a basis
for extrapolation to obtain the CT values at  5~C, assuming first order kinet-
ics  and  applying a safety  factor  of 2,  e.g.,  (.64)  X 3/2  X 2 =  1.9).   CT
values for temperatures  above  5  C were estimated assuming a twofold decrease
for every 10~C.   CT values for temperatures at 0.5 C were estimated assuming a
1.5 times increase to CT values at 5 C.
     The CT values for chlorine dioxide in Table E-8 are based on disinfection
studies using _in vitro excystation of Giardia muris CTgg values  at 5 C and
                                      F-2

-------
                      TABLE F-l

           CT VALUES TO ACHIEVE 99 PERCENT
INACTIVATION OF GIARDIA MURIS CYSTS BY FREE CHLORINE
H
7
8
9
Temperature
(C)
1
15
1
15
1
15
(Source: Rubin
0.2-0.5
500
200
510
440
310
, et al., 1988b)
Concentration (mg/L)
0.5-1.0
760
290
820
220
1,100
420
1.0-2.0
1,460
360
1,580
1,300
620
2.0-5.0
1,200
290
1,300
320
2,200
.760

-------
pH 7 ranged from 7.2 to  17.6  (disinfectant concentrations ranging from 0.1 to

5.5 mg/L).   The  highest  CT     value,   17.6,  was  used   as   a  basis  for

extrapolation to obtain the values in Table E-8, assuming first order kinetics

and a safety factor of 1.5 , i.e.,

            CT   Q = 1 x CTQQ x 1-5 or 3 x 17.6 x 1.5 = 40
              yy. y   ^T     y y          TT
     A  lower safety  factor  is  used  for  chlorine dioxide  than  for  ozone,

because  the  data  was generated  using  Giardia muris  cysts  which are  more

resistant  than  Giardia  lambia  cysts.   CT  values  at other  temperatures  were

estimated, based on the same rule of thumb multipliers assumed for ozone.
          A larger safety factor was applied to the ozone and chlorine dioxide

data than to the chlorine data because:
     a.   Less data  were available  for ozone  and chlorine dioxide  than for
          chlorine;

     b.   Data  available  for  ozone  and  chlorine  dioxide,  because of the
          limitations of  the excystation procedure,  only reflected  up  to or
          slightly beyond  99 percent inactivation.   Data for chlorine,  based
          on  animal  infectivity studies  rather than excystation procedures,
          reflected  inactivation  of 99.99 percent.   Extrapolation  of data to
          achieve  CT values  for  99.9 percent  inactivation  with ozone and
          chlorine  dioxide,  involved  greater  uncertainty  than the  direct
          determination  of  CT  values  for  99.9  percent  inactivation  using
          chlorine.

     c.   The CT values for ozone and  chlorine dioxide to achieve 99.9 percent
         -inactivation are feasible  to achieve; and

     d.   Use  of ozone  and  chlorine  dioxide is  likely to occur  within the
          plant  rather  than in  the distribution  system (versus chlorine and
          chloramines  which  are the  likely  disinfectants  for  use in the
          distribution  system).  Contact  time measurements  within  the  plant
          will involve greater uncertainty than measurement of contact time in
          pipelines.

          EPA recognizes that  the CT values  for ozone and chlorine dioxide are
          based  on limited data.   Therefore, EPA encourages the generation of
          additional  data  in accordance  with   the protocols  provided  in
          Appendix  G to determine  conditions  other than  the  specified CT
          values,  for providing effective disinfection at a particular system.
                                       F-3

-------
     F.I.3 Chloramines
     The CT  values for  chloramines in Table E-12  are based  on  disinfection
studies using preformed  chloramines and in  vitro excystation of Giardia muris
(Rubin,  1988).   Table F-2  summarizes CT  values  for  achieving  99 percent
inactivation  of Giardia muris  cysts.  The highest CT  values for  achieving
99 percent inactivation at 1 C (2,500) and 5 C (1,430)  were each multiplied by
1.5  (i.e., first order kinetics were assumed)  to estimate the CT   g values at
0.5 C and 5 C, respectively, in Table E-12.   The CT   value of 970 at 15 C was
multiplied by 1.5 to estimate the  CT     value.   The highest CT   value of
                                      yy  "                        yy
1,500 at 15 C and pH 6 was not used because  it appeared anomalous to the other
data.  Interesting to note  is  that  among the data in  Table  F-2 the  CT values
in the lower  residual  concentration range  (<2 mg/L) are higher than those in
the higher residual concentration range  (2-10 mg/L).   This  is  opposite to the
relationship  between  these  variables   which  exists  for  free   chlorine,
indicating that  for  chloramines,  within residual concentrations  practiced by
water utilities  (less  than 10 mg/L),  residual concentration may  have  greater
influence than contact time  on the  inactivation of Giardia  cysts.   No safety
factor was applied to these data since chloramination,  conducted in the field,
is  more  effective  than using  preformed chloramines.  Also,  Giardia  muris
appears  to  be  more  resistant  than  Giardia  lamblia  to chloramines  (Rubin,
1988b).

F.2  Inactivation of Viruses

     F.2.1 Free Chlorine
     CT  values for  free chlorine  are based  on data by  Sobsey  (1988)  for
inactivation of Hepatitus A  virus  (HAV),  Strain HM175, at pH  6,7,8,9  and 10,
chlorine concentrations of 0.5 to 0.2, and  a  temperature of 5  C,  as contained
in Table F-3.  The highest CT value for the pH range  6-9 for  achieving 2, 3,
and  4-log  inactivation  of  HAV were  multiplied by a  safety  factor of  3  to
obtain the CT values  listed in Table  E-7.  (e.g.,  the CT value for  achieving
4-log    inactivation    at    pHs    6-9   was    determined   by    multiplying
2.55 X 3 = 7.6 = 8).   The CT values at pH  10  were significantly higher  than
those for pHs  6-9 and  are  considered separately.  The CT values  in  Table E-7
for pH 10 also include a safety factor of 3.  CT values  at  temperatures other
                                      F-4

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                                   TABLE F-2

                           CT VALUES FOR 99 PERCENT
            INACTIVATION OF GIARDIA MURIS CYSTS BY MONOCHLORAMINE*
H

6
(Source:
Temperature
(C)
15
5
1
15
5
1
15
5
1
15
5
1
Rubin, 1988)
Monochloramine
<0.2
1,500
>1,500'
>1,500
>970
>970
2,500
1,000
>1,000
>1,000
890
>890
>890
Concentration (mg/L)
2.0-10.0
880
>880
>880
970
1,400
>1,400
530
1,430^
1,880
560
>560
>560
 *CT values with  ">"  signs  are  extrapolated from the known data.

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                   TABLE F-3

CT VALUES FOR INACTIVATION OF HEPATITUS A VIRUS
                 BY FREE CHLORINE

LOG INACTIVATION

2
3
4
(Source: Sobsey 1988)
PH
6 2. * 1 12
1.18 0.70 1.00 1.25 19.3
1.75 1.07 1.51 1.9 14.6
2.33 1.43 2.03 2.55 9.8

-------
 than 5 C were determined  assuming a two fold  decrease  for  every 10 C increase.
 CT values for inactivating  viruses in general are based on HAV data since they
 give higher CT values  than those  for inactivation of polio  and rotaviruses
 under similar conditions  of pH  and temperature (Hoff,  1986).

     F.2.2 Chlorine Dioxide
     Data by  Sobsey  (1988)  for inactivation  of Hepatitus A  virus,  strain Hm
 175, by chlorine dioxide  concentrations of  0.14 to  0.5 mg/1 at 5 C is shown in
 Table F-4.  The CT values in Table E-9 for  pHs 6-9  were determined by applying
 a safety  factor of 2 to the above average  CT values at pH  6.   This safety
 factor is  lower than that  used  to determine CT values  for  chlorine because
 chlorine, dioxide appears  to be  significantly more effective at higher pHs and
 most waters are assumed to  have a  higher pH than 6.
     CT values at temperatures  other than  5 C in Table E-9 were determined by
 applying a  twofold  decrease for  every 10  C  increase.  The data  for  pH 9 was
 not considered because it is very  limited and other viruses are more resistant
 to chlorine dioxide than  Hepatitus A is at pH 9.  According to Hoff (1986) at
 a pH of  9  and  a temperature  of  21 C,  a CT   of  0.35  provides   a  2-log
 inactivation of  poliovirus 1.   Applying the same  safety factor  and  rule of
 thumb multipliers  to  this  data  results in  a CT  of 2.8 for a  4-log virus
 inactivation  at 0.5~C,   in contrast  to  a  CT  of 50.3  resulting  from  the
 Hepatitus A data at  pH  6.  Therefore,  in  order  to assure  inactivation of
 Hepatitus A, the higher CT  values are  needed.  Systems with high pHs may wish
 to demonstrate the effectiveness  of chlorine  dioxide at lower CT values bases
 on the protocol  in  Appendix G.   Chlorine  dioxide  is  much more  effective for
 inactivating rotavirus and  polio virus than  it is  for inactivating  HAV (Hoff
 1986) .

     F.2.3 Chloramines
     The  CT values in Table E-13 at 5 C were based directly on data by Sobsey
 (1988)  using preformed chloramines at pH 8.   No safety  factor was applied to
 the  laboratory data  since  chloramination  in   the field,  where some  transient
presence  of free  chlorine  would occur, is assumed more  effective  than  pre-
 formed  chloramines.
                                      F-5

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                                TABLE F-4
             CT VALUES FOR INACTIVATION OF HEPATITUS A VIRUS
                   BY CHLORINE DIOXIDE (SOBSEY 1988)
          Log Inactivation

pH6              2

                 3

                 4

pH9           >2.5

              >3.6
        CT
3.78, 2.97, 1.8, 2.59

9.3, 9.57, 7.92, 7.4

17.6, 19.47, 15.48, 14.43

<0.165

<0.165
Avg. CT

 2.79

 8.55

16.75

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     HAV is  less  resistant to  preformed chloranrnes than are  other  viruses.
For example, CTs of  3,800-6,500 were needed for 2-log  inactivation  of Simian
Rotavirus at pH = 8.0 and temperature = 5 C (Herman and Hoff, 1984) .   However,
these same  viruses  are very  sensitive to  free  chlorine.  CT  values  ranging
from less than 0.025 to 2.16  were required to achieve 99 percent inactivation
of rotavirus by  free chlorine  at pH  = 6-10 and  temperature  = 4-5 C (Hoff,
1986).   HAV is  more resistant to free chlorine than are rotaviruses.
     The CT  values  in Table  E-13 apply  for  systems using  combined  chlorine
where chlorine  is added  prior  to  ammonia in  the treatment  sequence.   This
should provide  sufficient contact with  free chlorine to assure inactivation of
rotaviruses.  CT  values  Table   E-13  should not  be  used for  estimating  the
adequacy of disinfection  in systems  applying preformed chloramines  or ammonia
ahead of chlorine,  since CT  values  based on HAV  inactivation with  preformed
chloramines  may  not  be  adequate  for  destroying  rotaviruses.   In  systems
applying preformed chloramines,  it is recommended that inactivation studies as
outlined in Appendix G be performed with Bacterio-phage  MS2 as the  indicator
virus to determine sufficient CT values.  Also, the protocol in Appendix G can
be used  by systems applying  chlorine  ahead  of ammonia  to  demonstrate lower
CT's than those indicated in Table E-13.

     F.2.4  Ozone
     No  laboratory  CT  values  based  on inactivation  of HAV virus  are  yet
available for ozone.   Based on  data  from Roy (1982), a  mean  CT  value of 0.2
achieved 2-log inactivation of  poliovirus 1 at 5 C and pH 7.2.  Much  lower CT
values are needed to achieve a  2-log  inactivation of  rotavirus  (Vaughn, 1985).
No CT values were  available for achieving  greater than  a 2-log  inactivation.
The CT  values in  Table  E-ll  for  achieving  2-log  inactivation  at  5  C was
determined by applying a  safety factor of  3  to the data from Roy (1982) .  CT
values for  3  and 4-log inactivation were determined  by  applying first order
kinetics and assuming  the same safety factor of  3.   CT  values were  adjusted
for temperatures other than 5 C by applying a  two  fold  decrease for every  10 C
increase.  Based on  the  available data,  CT values for ozone  disinfection are
not strongly dependent on pH.   Therefore, data  obtained at pH  = 7.2  is assumed
                                       F-6

-------
to apply for pHs in the range of 6.0 to 9.0.  However,  it should  be noted that

the maintenance of an ozone residual is affected by pH.


References

American Water  Works Association.   Water  Chlorination  Principles  and Prac-
tices, 1973.

Hibler, C. P.; C. M. Hancock; L. M. Perger; J. G. Wegrzn; K.  D. Swabby  Inacti-
vation of Giardia cysts with Chlorine at 0.5 C to  5.0 C American Water Works
Association Research Foundation, In press, 1987.

Hoff,  J.  C.  Inactivation  of  Microbial  Agents by  Chemical Disinfectants,
EPA/600/52-86/067,  U.S.  Environmental  Protection  Agency,  Water  Engineering
Research Laboratory, Cincinnati, Ohio, September, 1986.

Jarroll,  E.  L.;  A.  K. Binham; E.  A.   Meyer Effect of  Chlorine on  Giardia
lamblia Cyst Viability.  Appl. Environ. Microbiol., 41:483-487,  1981.

Leahy, J.  G.; Rubin, A. J.; Sproul, O. J.  Inactivation of Giardia muris Cysts
by Free Chlorine.  Appl. Environ. Microbiol., July  1987.

Liu, O. C.;  Seraichekas,  H. R. ;  Akin, E. W.;  Brashear, D.  A.;   Katz, E.  L.;
Hill, Jr., W. L.  Relative Resistance of Twenty Human Viruses to Free Chlorine
in Potomac Water.  1971.

Payment, P.;  Trudel, M.;   Plante,  P.  Elimination  of  Viruses  and  Indicator
Bacteria  at Each Step  of  Treatment  During Preparation of Drinking Water  at
Seven Water Treatment Plants.  Appl. Environ. Microbiol., 49:1418, 1985.

Regli, S.   USEPA Disinfection Regulations.  Presented at AWWA Seminar Proceed-
ings:   Assurance of Adequate Disinfection,  or CT or  Not CT.   Kansas City,
Missouri,  June 14, 1987.

Rubin, A. J.  "CT Products  for the Inactivation  of  Giardia Cysts by Chlorine,
Chloramine,  Iodine,  Ozone  and Chlorine  Dioxide" submitted for publication in
J. AWWA, December, 1988b.

Rubin,  A.  J.  Factors  Affecting the  Inactivation  of Giardia Cysts  by  Mono-
chloramine  and Comparison  with other  Disinfectants.   Water  Engineering  Re-
search Laboratory, Cincinnati, OH March  1988a.

Sobsey, M D. Detection  and  Chlorine Disinfection of  Hepatitus A  in Water.
CR-813-024.  EPA Quarterly Report.   Dec.,  1988.

Wickramanayake,  G.  B.;  A.  J.  Rubin;  Sproul, 0.  J.   Effects  of Ozone  and
Storage Temperature  on Giardia  Cysts.  J.AWWA,  77(8):74-77, 1985.
                                       F-7

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           INACTIVATION OF GIARDIA LAMBLIA BY FREE CHLORINE:

                          A MATHEMATICAL MODEL

                       Robert M. Clark, Director
                    Drinking Water Research Division
                 Risk Reduction Engineering Laboratory
                          Cincinnati, OH 45268

                               Stig Regli
                     USEPA-Office of Drinking Water
                    Criteria and Standards Division
                         Washington, DC  20460

                            Dennis A. Black
                       Instructor in Mathematics
                          University of Nevada
                           Las Vegas, Nevada


                              INTRODUCTION

Amendments to the Safe Drinking Water Act (PL93-523) highlight the
continuing problem of waterborne disease and mandate EPA to promulgate
(a) criteria by which filtration will be required for surface water
supplies and (b) disinfection requirements for all water supplies in
the United States.  EPA's Office of Drinking Water is proposing to use
the C*t (Concentration times Time - disinfectant residual concentration
in mg/L multiplied by the disinfectant concentration contact time in
minutes) concept for determining the inactivation of Giardla lamblia
cysts, one of the most resistant pathogens, likely to be present in
surface waters*

Among individual agents, Giardia ranks number one as a cause of water-
borne illnesses and number four as a cause of waterborne outbreaks,
even though it was first identified as a causative agent in the mid-
19601 s.l  The Office of Drinking Water is developing criteria under
which utilities using surface water would be required to meet source
water quality conditions, maintain a protected watershed and achieve
C*t values which provide a 99.9% inactivation of Giardla lamblia cysts,
In order to avoid filtration.  If, for example, a utility in addition
to meeting other requirements, can demonstrate that through effective
disinfection, manifested by a sufficient C't value, it can reduce
Giardla levels by 99.9Z, then it would not be required to filter.

In this paper a mathematical model is developed based on the C*t con-
cept, for inactivation of G_. lamblia cysts by free chlorine.  The model
is applied first to inactivation data from animal infectivity studies.
A procedure is then developed to select the best combination of data
sets available assuming that the animal infectivity data is included in
each combination.  The model is then applied to the "best" data set to
calculate the model parameters.  A regulatory strategy is proposed for
applying this model for the determination of C't values under the
surface water treatment rule (SWTR).

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THE Ct CONCEPT

The C*t concept Chat is in current use is an empirical equation stemming
from the early work of Watson and is expressed as:2

     K - Ct                                                        (1)

where

     K * constant for a specific microorganism exposed under specific
       conditions

     C  disinfectant concentration

     n - constant, also called the "coefficient of dilution"

     t - the contact time required for a fixed percent inactivation

It is based on the van't Hoff equation used for determining the nature
of chemical reactions in which the value n determines the order of the
chemical reaction*3*

The application of this equation to disinfection studies requires
multiple experiments where the effectiveness of several variables, such
as pH, temperature, and the disinfectant concentration are examined to
determine how they affect the inactivation of microbial pathogens*  The
disinfection concentration (C) and time (t) necessary to attain a
specific degree of inactivation (e.g. 99Z) are plotted on double log-
arithmic paper*  Such a plot results in a straight line with slope
n.5'6  Figure 1 Illustrates data plotted In this manner and also the
significance of the value of n in extrapolation of disinfection data.?
When n equals 1, the C*t value remains constant regardless of the
disinfectant concentration used, i.e., disinfectant concentration and
exposure time are of equal importance in determining the inactivation
rate, or the C*t product, K.  If n is greater than U disinfectant
concentration is the dominant factor in determining the inactivation
rate while if n Is less than 1, exposure time is more important than
disinfectant concentration*  Thus, the value of n is a very important
factor in determining the degree to which extrapolation of data from
disinfection experiments is valid*  In addition, Morris pointed out
that the evaluation of n is valid only if the original experimental
data follow Chick's Law (i.e., the rate of organism distruction is
directly proportional to the number of living organisms remaining at
any specified time) which is normally not the case.**

FACTORS AFFECTING C't

The destruction of pathogens by chlorlnation is dependent on a number
of factors, including water temperature, pH, disinfectant contact time,
degree of mixing, presence of interfering substances (which may be
related to turbidity), and concentrations of chlorine available*7 The pH
especially, has a significant effect on inactivation efficiency because
it determines the species of chlorine found in solution*

The impact of temperature on disinfection efficiency is also signifi-
cant.  For example, Clarke determined that in order to maintain the
same level of virus destruction by chlorine, contact time must be in-
creased two to three times when the temperature is lowered 1CTC.9
Disinfection by chlorination can inactivate Giardia cysts, but only

-------
under rigorous conditions.  Most recently, Hoff e_ jl^. concluded that
these cysts are among the most resistant pathogens known, and  that in-
activation by disinfection at low temperatures is especially difficult.10

Using in vitro excystation, Jarroll  .al.. have shown that 99.8 percent
of G. lamblia cysts can be killed by exposure to 2.5 mg/L of chlorine
for 10 minutes at 15C at pH 6, or after 60 minutes at pH 7 or 8.11
At 5*C, exposure to 2 mg/L of chlorine killed 99.8 percent of  all cysts
at pH 6 and 7 after 60 minutes.11  While it required 8 mg/L to kill  the
same percentage of cysts at pH 6 and 7 after 10 minutes, it required 8
mg/L to inactivate cysts to the same level at pH 8 after 30 minutes.
Inactivation rates decreased at lower  temperatures and at higher pHs as
indicated by the higher C*t values.  Figures 2 and 3 summarize the data
developed by Jarroll et al  It should be noted that the nature of the
excystation method limits the ability  to measure percent survival at
high inactivation levels.  The assay involves microscopic observation
of the cysts.  Therefore, to detect one viable cyst in 1000 (99.9%
inactivation), several thousand cysts  must be observed to count enough
viable cysts for statistical confidence at this level.  Since  this has
not been done, no data for achieving 99.9% or higher inactivation
levels is available from studies involving excystation procedures.

Quantification of the combined effects of pH, temperature and  disinfect-
ant concentrations require special techniques which take into  account
.the interaction of these variables so  they can be described by a single  
value.  In the following section, cyst inactivation data from  animal
infectivity studies conducted by Hibler, e  al^ are described.12 The
Hibler data are unique, in that unlike data  from excystation studies,
they indicate the disinfectant conditions necessary to achieve greater
than 99.9 percent inactivation of (. lamblia cysts.  These  data  could
be combined with excystation data for  . lamblia by Rice,  et al.,
Jarroll, e al. and Rubin e al. to  show  the combined  effects  of
chlorine concentration, pH and temperature on different  levels of
inactivation of . lamblia cysts.1*121314

ANIMAL INFECTIVITY DATA

Hibler acquired O^ lamblia isolates  from  several human sources and
maintained them by passage in mongolian gerbils.12  Cysts  obtained  from
 these animals were used to develop  C-t values for 99.99  percent  in-
 activation of G. lamblia  cysts with  chlorine at  temperatures  of  0.5, 2.5
 and  5.0C and at pH values of 6, 7  and 8.

 In  these experiments  clean G. lamblia  cysts  at  a concentration of  1.02
 x 10^ cysts/mL were exposed to selected  chlorine concentrations  at
 appropriate  pH and temperature.   At  specified time  intervals  for each
 temperature  and pH condition, chlorine activity was  stopped by the
 addition of  sodium thiosulfate.   The treated cyst  suspension was centri-
 fuged,  the supernatant  poured off  and  the cysts  resuspended in a small
 volume of buffer.  Each of 5 gerbils,  per test  run,  was  fed 5  x  10*  of
 the  concentrated chlorine exposed  cysts.   Equal numbers  of positive
 control animals were  each orally inoculated with 50  unchlorinated  cysts
 maintained and buffered  at  the  same temperature and  pH as the chlorine
 exposed cysts.   Infectivity studies  with unchlorinated cysts showed
 that approximately 5  cysts usually constituted an infective dose.
 Table  1 shows  a distribution  of  the number of animals infected by
 chlorine  exposed cysts.

-------
In order to analyze these data the following assumptions were made.
If all five animals were infected, then it can be assumed that the C*t
of the test run produced less than 99.99Z inactivation.  If no animals
were infected, then the C*t had produced greater than 99.99Z inactivation,
and if 1-4 animals were infected, the C*t produced 99.992 inactivation.

The limitation of this experiment is that it is only appropriate to
assign a specific level of inactivation (i.e. 99.992) to the case of
1-4 animals infected.

MODEL DEVELOPMENT

Statistical analysis was performed on the infectivity and excystation
data sets to determine the effects of inactivation level, temperature,
pH, and concentration of disinfectant on time to inactivation.15  A
multiplicative model was selected to best represent the chemical re-
actions during the inactivation process:

       t    - R Ia Cb pHc tempd                                   (2)
where
       t    * time to inactivation in minutes

       I     inactivation level

       C    - concentration of disinfectant in mg/L

       pH    pH at which experiment was conducted

       temp * temperature at which experiment was conducted

       R, a, b, c, d  model parameters.

A log transformation of equation 2 yields: LOG}()(t) - LOG}Q(R) +

    aLOGujd) * t> LOGio(C) + cLOGjo(pH) + dLOGjo 
-------
 differences.   Significance of  the  indicator random variable  (Z)  would
 support  the hypothesis  of different regression surfaces,  i.e.,  incom-
 patibility of  the data  sets  chosen.  The indicator random variable was
 created  in such  a way as to  always differentiate between  the Hibler
 data and other data  sets considered. l1*^, 13, 14  Table 2  contains the
 data set combinations and regression diagnostics.

 As  can be seen from  from Table 2 the indicator random variable  combining
 the Hibler, e al^. and  Jarrol, et_  al^. data bases was not  significant.
 All other data bases considered had a significant indicator  random
 variable at the  0.05 level of  significance.  A formal test for  differ-
 ences of intercept and/or slope between the Hibler, et_ al. and  Jarroll
 et  al. data sets was conducted using the BMDP PIR procedure  in  the BMDP
 statistical programming language.   Test results indicated no difference
 between  the data sets.  Thus,  statistical analysis supports  the  choice
 of  the Hibler  et al. and Jarroll et al. data as the data  base for
 Giarida  cyst modeling procedures.

      The resulting regression  equation is

      t - 0.12  1-0-27 c-0.81  pH2.54 Cenp-0-15                      (5)

      Equation  5  multiplied by  C yields

      Ct   0.12 1-0-27 CO-19  pH2-54 temp-0-15                      (6)
which is the Ct equation utilized.   It can be shown that  equation 6  is
equivalent to the Watson equation (Appendix A).   The Confidence inter-
vals for parameter estimated of equation 6 are:

       R; ( 0.0384,  0.4096)
       a; (-0.2321, -0.3031)
     1+b; ( 0.0792,  0.2977)
       c; ( 1.9756,  3.1117)
       d: (-0.0724, -0.2192)

The confidence intervals were calculated using the Bonferroni  met hod. 16

REGULATORY APPLICATION

There are many uncertainties regarding the various data sets that might
be utilitzed for calculating C*t values.  The random variable  analysis
shows the statistical incompatibility  among these data sets.   More work
needs to be done to define the impact  of strain  variation,  and in. vivo
versus in vitro techniques on Ct values.   In order to provide conser-
vative estimates for C*t values the  authors suggest the approach illus-
trated in Figure 4.

In Figure 4 the 99Z confidence interval at the 4 log inactivation level
is calculated.  First order kinetics are then assumed so  that  the in-
activation "line" goes through 1 at  C*t -  0 and  a C*t value equal to  the
upper 99Z confidence interval at 4 logs of inactivation (Appendix B) .
As can be seen the inactivation line bounds higher C*t values  then all
of the mean C*t values from equation 6 as  well as all of  the Jarroll,
t_ ja.1. data points (at inactivation  levels of 0.1 and 0.015) and the
Hibler e_t .1.  data points (at inactivation level of 0.0001).   Conser-
vative C*t values, for a specified level of inactivation, can  be obtained

-------
from the inactivation line prescribed by the disinfection conditions.
For the example indicated in Figure 4, the appropriate C't for achieving
99.9Z inactivation would be 160.  This approach (assumption of first
order kinetics) also provides the basis for establishing credits for
sequential disinfection steps.

SUMMARY AND CONCLUSIONS

Amendments to the Safe Drinking Water Act clearly require that all
surface water suppliers in the U.S. to filter and/or disinfect to pro-
tect the health of their customers.  G^ lamblia has been identified as
one of the leading causes of waterborne disease outbreaks in the U.S.
G. lamblia cysts are also one of the most resistant organisms to
disinfection by free chlorine.  EPA's Office of Drinking Water has
adopted the C*t concept to quantify the inactivation of . lamblia
cysts by disinfection.  If a utility can assure that a large enough C*t
can be maintained to ensure adequate disinfection then, depending upon
site specific factors, it may not be required to install filtration.
Similarly, the C*t concept can be applied to filtered systems for
determining appropriate levels of protection.

In this paper, an equation has been developed that can be used to
predict C*t values for inactivation of G. lamblia by free chlorine based
on the interaction of disinfectant concentration, temperature and, and
inactivation level.  The parameters for this equation have been derived
from a set of animal infectivity data (Hibler, e al.)12 and excyscation
data (Jarroll, e al.)11  The equation can be used to predict C't values
for achieving 0.5 to 4 logs of inactivation and, within  temperature
ranges of 0.5-5*C, chlorine concentration ranges up to 4 mg/L, and at pH
levels of 6 to 8.  While the model was not based on pH values above 8,
the model is still considered applicable to pH levels of 9 for reasons
discussed elsewhere.17 The equation shows the effect of  disproportionate
increases of C't versus inactivation  levels.  Using 99 confidence inter-
vals at the 4 log inactivation levels and applying first order kinetics
to these end points  a conservative regulatory strategy for defining  C-t
at various levels of inactivation has been proposed.  This approach
represents an alternative to  the regulatory strategy previously proposed.1

REFERENCES

1.    Craun, G.F.   "Waterborne Outbreaks  from Giardia" in Giardia  and
      giardiasis.  Editor:  Erlandson  Plenum Publishing Corporation  (In
      press).

2.    Watson, H.  E.   A note on the variation of the rate  of disinfection
      with change in the  concentration of  the disinfectant. J. Hyg.
      8^:536-592,  1908.

3.    Berg, G.,  S.  L. Chang, .and  E. K. Harris.  Devitalization of  micro-
      organisms  by iodine 1.   dynamics of  the devitalization  of  entero-
      viruses by elemental  iodine.  Virol. ^2:469-481,  1964.

4.    Fair, G.  M.,  J. C.  Geyer,  and D. A.  Okun.   Water  and  Wastewater
      Engineering.   Vol.  2.   Water purification and wastewater treatment
      and disposal.   John Wiley  and  Sons,  Inc., New York, NY, 1968.

 5.    Fair, G.  M.,  J. C.  Morris,  and  S.  L.  Chang.  The dynamics of
      water chlorination.  J.  New Eng. Water Works Assoc. 61:285-301,
      1947.

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 6.   Fair, G. M., J. C. Morris, S. L. Chang, II Weil, and R. P. Burden.
      1948.  The behavior of chlorine as a water disinfectant.  J. Am.
      Water Works Assoc. 40:1051-1061.

 7.   Hoff, J. C., "Inactivation of Microbial Agents by Chemical Disin-
      fectants" EPA/600/2-86-067, 1986.

. 8.   Morris, J. C., "Disinfectant Chemistry and Biocidal Activities" in
      Proceedings of the National Specialty Conference on Disinfection,
      American Society of Civil Engineers, New York, NY, 1970.

 9.   Clarke, N. A., G. Berg, P. W. Kabler, and L. L. Chang.  "Human
      Enteric Viruses in Water: Source, Survival, and Removability".
      International Conference on Water Pollution Research, Landar,
      September, 1962.

10.   Hoff, J. C., E. W. Rice, and F. W. Schaefer III, "Disinfection
      and the Control of Waterborne Giardiasis", In proceedings of the
      1984 Specialty Conference, Environmental Engineering Division,
      ASCE, June 1984.

11.   Jarroll, E.L., Bingham, A.K., and Meyer, S.A.  "Effect of Chlorine
      on Giardia Lamblia Cyst Viability".  Applied and Environmental
      Microbiology. Vol. 41, pp. 483-487, February, 1981.

12.   Hibler, C. P., Hancock, C. M., Perger, L. M., Wegrzn, J. G. and
      Swabby, K. D., Inactivation of Giardia Cysts with Chlorine at
      0.5*C to 5.0C.t  American Water Works Association Research Found-
      ation, 6666 West Quincy

13.   Rice, E. W., Hoff, J. C., and Schaefer III, F.W.  "Inacti-
      vation of Giardia Cysts by Chlorine", Applied and Environmental
      Microbiology. Vol. 41, pp 250-251, January 1982.

14.   Rubin, A., Internal Report of Progress, Through June  1, 1988,
      EPA Project CR812238.

15.   Clark, R.M., Read, E.J. and Hoff, J. C.   "Inactivation of Giardia
      Lamblia by Chlorine:  A Mathematical and  Statistical  Analysis", Ac-
      cepted for publication by the Journal of  Environmental Engineering.

16.   Neter, J. and Wasserman, W.  Applied Linear  Statistical Models,
      Irwin:  Homewood, IL, 1974.

17.   Regli, S.   "EPA Disinfection Regulations", in Seminar Proceedings
      Assurance of Adequate Disinfection or C*t or not  C*t,  pp. 1-7,
      American Water Works Association Annual Meeting  1987.

-------
                               APPENDIX - A






     Equation 6 can be shown  to be  equivalent to equation (1)  by divid-




ing equation 6 by C*"* which  yields:




     C-bt - RI pflc tempd                                      (A-l)




     Assuming a constant pfl * pS, temp - temp and I    I yields




     K -~Ria~~pHb tempc" Id                                      (A-2)




therefore




     C-* - K                                                   (A-3)




where




    b  n in equation 1

-------
                              APPENDIX - B
A general relationship that relates C*t values at different inactiva-
tion levels is:
     In (Ni/N0)

     In (Nj/N0)
(B-l)
where N^ is the number of organism left at time  tj_  and Nj  is the number
of organisms left at time tj.  Table B-l summarizes  the multiplication
factors to be applied, assuming first order kinetics, to convert a
value of Ki to an equivalent value of Kj.


   TABLE B-l.  MULTIPLICATION FACTORS TO CONVERT C't VALUES FROM ONE

             INACTIVATION LEVEL K TO INACTIVATION  LEVEL Kj
From to Inactivation
Inactivation Level j
Level i

90
99
99.9
99.99
Multiplier for Ki


90
^
1/2
1/3
1/4

99
2.0
-
2/3
1/2

99.9
3.0
1 1/2
-
3/4

99.99
4.0
2.0
1 1/3


-------
TABLE 1.  DISTRIBUTION OF ANIMALS INFECTED BY CHLORINE EXPOSED CYSTS
# of Infected Animals
pH
6
6
6
7
7
7
8
8
8
Temp
0.5
2.5
5
0.5
2.5
5
0.5
2.5
5
0
58
54
23
35
62
61
36
68
45
1
15
7
10
7
6
7
10
12
9
2
5
4
6
5
4
4
8
4
3
3
3
3
5
1
4
4
3
3
2
4
2
1
5
1
0
0
1
2
1
5
5
7
15
25
4 "
12
2
6
6

-------
TABLE 2.  REGRESSION DIAGNOSTICS FOR DATA SET COMBINATIONS
Data Sets considered
Hibler,
Hibler,
Hibler,
Hibler,
Hibler,
Hibler,
Hibler,
Hibler,
pTI -^- M -*-? ^ y
Hibler,
Hibler,
Hibler,
Hibler,
Hibler,
Rice, Jarroll, Rubin
Rice, Jarroll, Rubin, ^
Rice , Rubin
Rice, Rubin, Z
Jarroll, Rubin
Jarroll, Rubin, Z
Rice, Jarroll
Rice, Jarroll, Z
Rubin
7
Rice
Ricef Z
Jarroll
Jarroll, Z 	 	
R-sauare
0.6801
0.7316
0.6649
0.7899
0.6424
0.6879
0.8619
0.865
0.6483
0.7593
0.8548
0.8678
0.8452
0.8459
Variables
intercept, temp
not significant
intercept, temp
not significant
intercept, tenp
not significant
intercept
not significant
intercept, tenp
not significant
intercept, temp
not significant
all variables
significant
all variables
significant
temp
not significant
intercept
not significant
all variables
significant
all variables
significant
all variables
significant
Z not
sienificanc
Plots
non normal data
non constant var
non normal data
"non constant var
non normal data
non constant var
non normal data
non constant var
non normal data -
non constant var
non normal data
non constant var
non normal data
non constant var
non normal data
non constant var
non normal data
non constant var
non normal data
constant var
non normal data
constant var
non normal data
constant var
non normal data
constant var
non normal data
constant var

-------
z
2:
111
5
O)
O)
    10000E
     ioooa
100 =
           I  I I IMIIll	I I I I HH
                      I I I I Mill	I I I I 11Jl
                                                  10000
                                                  1000
                                            100
        0.01
                   1       10      100
             DISINFECTANT CONG. (MG/L)
1000
  FIGURE 1. EFFECT OF n VALUE ON Ot VALUES AT
           DIFFERENT DISINFECTANT CONCENTRATIONS
           (Ot VALUES GIVEN IN PARENTHESES)

-------
      too
        0 10
            CONTACT TIME (tawt)
 FIGURE 2.  INACTIVATION OF G. LAMBLIA CYSTS BY
            FREE RESIDUAL CHLORINE AT 5C
      lOOi
          0Mt
             OM7
                          OH
<
>
>
C


K

>
     I
     O
     K
     01
      10
      0.2
                              CMLOHIMg COMCENTSATIOMS
                                     O 3.0 aig/l
                                      2.5 mg/l
        '0 30   o 010    0 0 10 30  0

            CONTACT TIME
FIGURE 3. INACTIVATION OF G. LAMBLIA CYSTS BY
      TOTT OTQinilA!
                              OOIMC  AT

-------
 I
 N
 A
 C
 T
 I
 V
 A
 T
 I
O
N

L
E
V
E
L
 1.0000
0.1000 =
CI-PRED.

ACTUAL Ct

99% CONF. INTERVAL
0.0100 =


0.0010


0.0001


0.0000
        20  40 60 80 100 120 140 160 180 200 220 240 260 280

                       Ct VALUES


  FIGURE 4. 99% CONFIDENCE LEVELS USING HIBLER-

           JARROLL EQUATION FOR CHLORINE - 2 mg/l;

           PH-7; TEMPERATURE * 5 C

-------
 Tables 6-7 and 6-8 present a format which  the  utility can use as a daily data
 log and to submit monthly reports to the Primacy Agency.
      Recommended Reporting Not  Required by the  SWTR
      The Primacy Agency  may  also want filtered  water systems to  report some
 information associated with recommendations made in this  manual  which  are not
 requirements of  the  SWTR.  EPA  recommends that  filtered water systems:
             \
      1.    Report   the   percent  inactivation  of  Giardia  cysts  and   enteric
           viruses,  recommended by the Primacy Agency.
                 \
      2.    Report point  of  application for all disinfectants used.
                    \
                     \
      3.    Report the daily CT(s)  used to calculate the percent inactivation of
           Giardia  cysts-and viruses.
                         \
      4.    If  more  than one  disinfectant is used,  report the CT(s) and  inac-
           tivation (s)  achieved  for  each  disinfectant and  the total  percent
           inactivation  achieved.
      5.    Report  the percent inactivation  determined  prior to  filtration and
           the data  used to make this  determination.
      6.    Note any difference between the  measured CT(s) and the  CT required
           to  meet   the overall  minimum  treatment  performance   requirement
           specified by  the Primacy Agency.
                                         \
Tables 6-3 and 6-4  can  be  used  to maintain^ the records necessary for numbers 2
through 6.
     This  information  can  be  used  to  determine  the  disinfection   level
maintained  by the  system to  assure that the  overall  removal/inactivation
required is maintained.
     The  Primacy  Agency  may  make  provisions   to  minimize   the  reporting
requirements  for  systems  with  reservoirs,  large  amounts of  storage  or long
transmission  mains which  provide a  long  disinfectant  contact time.   Since
these systems  typically provide  inactivation in  excess of  that  needed, the
Primacy  Agency may require  the  system  only  to  report  the  minimum daily
residual at the end of  the disinfectant  contact  time.   The CT maintained can
then be estimated based on this residual  and the contact  time under the system
design flow.  This method  of CT determination will eliminate the need for the
system to determine the contact time under maximum flow conditions  each day.
                                     6-3

-------
        APPENDIX G

PROTOCOL FOR DEMONSTRATING
  EFFECTIVE DISINFECTION

-------
                           LIST OF APPENDICES


G-l  Determining  Chloramine Inactivation  of  Giardia for  the  Surface
     Water Treatment Rule

G-2  Determining Chloramine Inactivation of Virus  for the  Surface  Water
     Treatment Rule

G-3  Determining Chlorine Dioxide Inactivation

G-4  Determining Ozone Inactivation

-------
                                                   02/06/89
DETERMINING CHLORAMINE INACTIVATION OF GIARDIA

     FOR THE SURFACE WATER TREATMENT RULE
       Microbiological Treatment Branch
    Risk Reduction Engineering Laboratory

                     and

      Parasitology and Immunology Branch
 Environmental Monitoring Systems Laboratory
     U.S. Environmental Protection Agency
       26 West Martin Luther King Drive
           Cincinnati, Ohio  45268

-------
                              TABLE OF CONTENTS






  I.   Materials	3




 II.   Reagents	4




III.   Giardia muris Assay	7




 IV.   Disinfection Procedures for Giardia	10




  V.   Procedure for Determining Inactivation	12




 VI.   Bibliography	13




VII.   Technical Contacts	14




  Appendix




      A.  Use of the Hemocytometer	15




      B.  Preparation and Loading  of Chamber  Slides	20

-------
     The Surface Water Treatment Rule  requires 99.9% or greater removal/
Inactivation of Giardla.   The following protocol may be used to determine
the percentage  of Giardia  inactivation  obtained by  a  treatment  plant
using chloramine disinfection.

I.  MATERIALS

    A.  Materials for Disinfection

         1.  Stock chlorine solution
         2.  Stock ammonia solution
         3.  Stirring device
         4.  Incubator  or  water  bath  for  temperatures  below  ambient
         5.  Water from treatment plant
         6.  Giardia muris cysts
         7.  Assorted glassware
         8.  Assorted pipettes
         9.  Reagents and instruments for determining disinfectant residual
        10.  Sterile sodium thiosulfate solution
        11.  Vacuum filter device,  for 47mm diameter filters
        12.  1.0  urn   pore  size  polycarbonate  filters,  47  mm  diameter
        13.  Vacuum source
        14.  Crushed ice  and ice bucket
        15.  Timer

    B.  Materials for Excystation

         1.  Exposed and  control Giardia muris cysts
         2.  Reducing solution
         3.  0.1 M sodium bicarbonate
         4.  Trypsin-Tryode's solution
         5.  15 ml conical screw cap centrifuge tubes
         6.  Water bath,  37C
         7.  Warm air incubator or slide warming tray, 37C
        - 8.  Aspirator flask
         9.  Vacuum source
        10.  Assorted pipettes
        11.  Vortex mixer
        12.  Centrifuge with swinging bucket rotor
        13.  Chamber slides
        14.  Phase contrast microscope
        15.  Differential cell counter
        16.  Timer

-------
II.   REAGENTS
     A.   Reducing Solution

               Ingredient        	Amount
               glutathione (reduced form)                    0.2 g
               L-cysteine-HCl                                0.2 g
               IX Hanks balanced salt solution              20.0 ml

               Dissolve the dry ingredients  in  the  IX Hanks balanced salt
               solution and  warm  to  37 C before  use in  the  experiment.
               Prepare fresh, within 1 hour of use.

     B.   Sodium Bicarbonate Solution, 0.1 M

               Ingredient	Amount
               Sodium bicarbonate                            0.42 g

               Dissolve the  salt  in 10 to 15 ml  distilled water.   Adjust
               the volume  to  50  ml with  additional distilled  water  and
               warm to 37C  before  use in the experiment.   Prepare fresh,
               within 1 hour of use.

     C.   Sodium Bicarbonate Solution, 7.5%

               Ingredient	Amount
               Sodium bicarbonate                 '          7.5 g

               Dissolve the  sodium  bicarbonate in  50  ml distilled water.
               Adjust the  volume  to  100 ml   with  additional  distilled
               water.  Store at room temperature.

     D.   Sodium Thiosulfate Solution, 10%

               Ingredient	        Amount
               Sodium thiosulfate                           10.0 g

               Dissolve the  sodium  thiosulfate  in  50  ml distilled water.
               Adjust the  volume  to  100 ml   with  additional  distilled
               water.  Filter  sterilize   the  solution through  a  0.22  um
               porosity membrane  or autoclave  for  15 minutes  at 121C.
               Store at room temperature.

-------
E.  Tyrode's Solution, 20X
Ingredient
NaCl
KC1
CaCl 2
MgCl2*6H20
NaH2P04*H20
Glucose
Amount
160.0 g
4.0 g
4.0 g
2.0 g
1.0 g
20.0 g
          Dissolve the dry ingredients  in the order listed in 750 ml
          distilled water.  Adjust the volume to 1.0 liter with addi-
          tional distilled  water.   If  long  term   storage  (up  to   1
          year) is desired,  filter sterilize the  solution through  a
          0.22 urn porosity membrane.

F.  Tyrode's Solution, IX

          Ingredient	.	Amount
          20X Tyrode's solution                         5.0 ml

          Dilute 5 ml of the  20X  Tyrode's solution to  a final volume
          of 100 ml with distilled water.

G.  Trypsin-Tyrode's Solution

          Ingredient	Amount
          Trypsin, 1:100, U.S. Biochemical Co.          0.50 g
          NaHC03                                        0.15 g
          IX Tyrode's solution                        100.00 ml

          With continuous mixing on a stirplate, gradually add 100 ml
          IX Tyrode's  solution  to  the  dry  ingredients.   Continue
          stirring until the dry ingredients are completely dissolved.
          Adjust the  pH of  the  solution to 8.0  with 7.5%  NaHC03.
          Chill the trypsin Tyrode's solution to 4C.  NOTE:  Trypsin
          lots must  be  tested  for  their  excystation  efficiency.
          Prepare fresh, within 1 hour of use.

H.  Polyoxyethylene Sorbitan  Monolaurate (Tween 20)  Solution, 0.01%
    (v/v)

          Ingredient	Amount
          Tween 20                                      0.1 ml

          Add the  Tween 20  to 1.0  liter of  distilled water.   Mix
          well.

-------
I.   Vaspar
          Ingredient	Amount
          Paraffin                                     I part
          Petroleum jelly                              1 part

          Heat the two ingredients in a boiling water bath until melt-
          ing and mixing is complete.

-------
III.   GIARDIA MURIS ASSAY
      A.  Cysts
          Giardla muris cysts  may be available  from  Swabby  GERBCO,  Inc.,
          2319 East Grovers #260, Phoenix,  AZ  85022;  phone (602)  9712115,
          or from other commercial sources.   The cysts are produced in Mon-
          golian gerbils (Meriones unguiculatus).

          No commercial source of G_*  muris  cysts produced  in mice  is cur-
          rently known.  Mus musculus,  the  laboratory mouse, CF-1,  BALBc,
          and C3H/he  strains  have  been used successfully  to  produce  G_.
          muris cysts.  The method  is labor intensive and  requires a good
          animal facility.

          In order for the disinfection procedure  to  work properly, the  .
          muris cysts used must be  of high  quality.  Evaluation of a cyst
          suspension is a  subjective procedure involving aspects of morpho-
          logy and micobial contamination  as well  as excystment.  A good
          quality G_. muris cyst preparation should exhibit the  following:

          1.   Examine cyst stock suspension microscopically for the  presence
              of empty cyst walls  (ECW).   Cyst suspensions containing  equal
              to or greater than 12 ECW should not  be  used for  determining
              inactivation  at   any  required  level.   However,   if  a  99.9%
              level of disinfection  inactivation  is   required,  the  stock
              cyst suspension  must contain <0.1% ECW.

          2.   Excystation  should be  902  or greater.

          3.   The cyst  suspension should  contain  little or  no detectable
              microbial contamination.

          4.   Good G.  muris cysts are phase bright with a, defined cyst  wall,
              peritrophic space,  and agranular cytoplasm.   Cysts which are
              phase dark,  have no detectable peritrophic  space, and have a
              granular cytoplasm may be non-viable.  There should be no more
              than 4 to 5%  phase dark  cysts  in a preparation.

          Good . muris cyst  preparations  result when  the  following guide-
          lines are followed during  cyst purification  from feces:

          1.   Use  feces  collected  over a  period  of  24  hours  or  less.

          2.   The isolation of the cysts  from  the feces  should  be  done
              immediately after the  fecal material  is  collected.

          3.   Initially,  (3. muris cysts should  be  purified from the  fecal
              material by flotation  using 1.0  M sucrose.

          4.   If the (5. muris  cyst  suspension contains an undesirable den-
              sity of  contaminants after the  first sucrose float,  further
              purification  is  necessary.  Two  methods  for further purifica-
              tion are suggested.

-------
        a.  Cysts may be reconcentrated over a layer of 0.85 M sucrose
            in a 50  ml  conical centrifuge  tube.   If this second ex-
            posure to sucrose  is not done  quickly,  high cyst losses
            can occur due  to  their increased  bouyant density in the
            hyperosmotic sucrose medium.  The cysts must be thoroughly
            washed free  of the sucrose  immediately after collection
            of the interface.
        b.  Cysts can be separated from dissimilar sized contaminants
            by sedimentation at unit gravity, which will not adversely
            affect cyst  bouyant density,  morphology, or viability.

B.  Maintenance of Cysts

    1.  Preparation of stock suspension

        Determine the suspension density of the (5.  muris cyst prepara-
        tion using a heraocytometer (see Appendix A).  Adjust the cyst
        suspension density with  distilled'water to approximately 3-5
        x 106 cysts/ml.

    2.  Storage

        Store cysts  in   distilled  water  in  a refrigerator  at  4C.
        Cysts should not be used for disinfection  experiments if they
        are more than  2 weeks  old (from time  of  feces deposition).

C.  Excystation Assay

    A number of G_. muris  excystation procedures have  been described in
    the scientific literature (see Bibliography, Section VI).  Any of
    these procedures may be  used provided 90% or greater excystation
    of control,  undisinfected  G.   muris   cysts  is obtained.   The
    following protocol is used  to evaluate the suitability of cysts in
    the stock suspension, and to determine  excystation in control and
    disinfected cysts.

    1.  For evaluating a cyst  suspension  or for running an unexposed
        control, transfer  5  x  10^  G.  muris   cysts  from the  stock
        preparation to a 15 ml conical screw cap centrifuge tube.  An
        unexposed control should be processed  at the  same time as the
        disinfectant exposed cysts.

    2.  Reduce the volume  of .  muris cyst  suspension in each  15 ml
        centrifuge tube  to 0.5 ml  or  less  by centrifugation at 400 x
        g for 2 minutes.   Aspirate and discard the supernatant  to no
        less than 0.2 ml above the pellet.

    3.  Add 5 ml reducing  solution, prewarmed to  37C, to each tube.

    4.  Add 5  ml 0.1  M NaHC03,  prewarmed  to  37C, to  each  tube.  NOTE:
        Tightly close the  caps to prevent  the loss  of  CO2*   If the
        C02 escapes, excystation will not occur.

    5.  Mix  the  contents  of  each tube  by vortexing  and  place  in
        a 37C water bath for 30 minutes.

-------
 6.  Remove the tubes from the water  bath and  centrifuge each for
     2 minutes at 400 x g.

 7.  Aspirate and discard  the  supernatant to no less  than  0.2 ml
     above the pellet and  resuspend the pellet  in  each tube in 10
     ml trypsin-Tyrode's solution chilled to 4C.

 8.  Centrifuge the tubes for 2 minutes at 400 x g.

 9.  Aspirate and discard  the  supernatant to no less  than  0.2 ml
     above the pellet.

10.  Add 0.3 ml  trypsin-Tyrode's  solution, prewarmed  to  37"C,  to
     each tube.   Resuspend the G.  muris cysts by low speed vortex-
     ing.

11.  Prepare  a   chamber  slide  for each  tube  (see  Appendix  8).

12.  Seal the coverslip  on each chamber  slide  with  melted  vaspar
     and incubate at  37C  for  30  minutes in an  incubator or  on a
     slide warmer.

13.  After incubation, place a  chamber slide  on the  stage of  an
     upright phase contrast microscope.  Focus on the slide  with a
     low power objective.   Use  a  total  magnification of 400X  or
     more for the actual quantitation.  NOTE:   Be  careful to  keep
     the objectives out of the vaspar.

14.  While scanning the slide and  using a differential cell coun-
     ter, enumerate the number of  empty cyst walls  (ECW), partial-
     ly excysted  trophozoites  (PET), and intact cysts (1C) observed
     (see Section V for a  further  description of  these  forms  and
     the method  for  calculating  percentage excystation).   If  the
     percentage excystation in the stock  suspension  is not  90%  or
     greater, do   not  continue with  the  disinfection  experiment.

-------
                                                                        10
IV.   DISINFECTION PROCEDURES FOR GIARDIA

     A.  The treatment plant water to be used  should be  the water influent
         into the chloratnine  disinfection  unit process used  in the plant.
         If chloraraine disinfection is performed at more  than one point in
         the treatment  process,  e.g.,  prefiltration  and postfiltration,
         the procedure  should  simulate  as  closely  as  possible  actual
         treatment practice.

     B.  Prepare stock  ammonia and chlorine solutions  to be added to the
         treatment plant water to achieve the same  stoichiometric relation-
         ship between  chlorine  and  ammonia  that  is  used   in  the  water
         treatment plant.  These  solutions  should  be  concentrated enough
         so that no more  than 2 ml of each solution will be added to the
         treatment plant water being  disinfected.

     C.  Determine the contact time by the methods  described in  the Surface
         Water Treatment  Rule  and/or   the  associated   Guidance  Manual.

     D.  Rinse a  600  ml  beaker  with treatment plant  water  to remove any
         extraneous material  that  may  cause  disinfectant  demand.   Then
         add 400 ml treatment  plant water  to the beaker.

     E.  Mix the contents of  the beaker  short  of producing a vortex in the
         center and  continue  until  the  conclusion  of  the  experiment.

     F.  Equilibrate the 600 ml beaker and its  contents as well  as  the dis-
         infectant reagents to the desired  experimental  temperature.

     G.  Adjust the stock (I.  muris cyst  suspension with distilled water so
         that the concentration is 2-5 x 10 cysts/ml.

     H.  Add 0.5 ml of  the adjusted cyst suspension to the contents of the
         600 ml beaker.

     I.  Add the  disinfectant reagents  to  the beaker  using  the same rea-
         gents, the  same sequence  of addition of  reagents, and the same
         time interval  between addition of reagents  that is used in the
         disinfection procedure in  the treatment plant.

     J.  Just prior to  the  end of the exposure time,  remove  a  sample ade-
         quate for  determination of  the disinfectant  residual  concentra-
         tion.  Use methods prescribed in  the  Surface  Water Treatment Rule
         for the determination of  combined chlorine.   This residual should
         be the  same (20%)  as  residual  present  in  the  treatment plant
         operation.

     K.  At the end of the exposure time, add 1.0 ml 10% sodium thiosulfate
         solution  to  the  contents  of  the 600 ml beaker.

     L.  Concentrate  the G.  muris cysts  in  the  beaker by  filtering the
         entire contents  through  a  1.0 urn porosity 47  mm diameter  polycar-
         bonate filter.

-------
                                                                   11
M.  Place the filter, cyst  side  up,  on the side of a  150 ml beaker.
    Add 10 ml 0.01% Tween 20 solution to the beaker.   Using a Pasteur
    pipette, wash the G. muris  cysts from the surface  of the filter
    by aspirating and expelling the  0.01% Tween  20 solution over the
    surface of the filter.

N.  Transfer the  contents  of the  150  ml beaker to an  appropriately
    labeled 15 ml screw cap conical centrifuge tube.

0.  Keep  the  tube  on  crushed  ice  until  the excystation assay  is
    performed (see Section III, C) on  the  disinfectant  exposed  cysts
    and on an unexposed  control  preparation obtained from the  stock
    cyst suspension.

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                                                                       12
V.  PROCEDURE FOR DETERMINING INACTIVATION

    A.  Giardia muris Excystation Quantitation Procedure

        The percentage excystation is calculated  using  the  following for-
        mula:

                 % excystation  -    ECW +  PET    v  100
                                  ECW + PET + 1C

    where        ECW is the number of empty cyst  walls,

                 PET is the number of partially excysted trophozoites, and

                 1C is the number of intact cysts.

        An ECW is defined as a  cyst  wall which is  open at  one  end  and  is
        completely devoid  of a  trophozoite.   A  PET  is a cyst which has
        started  the excystation  process and progressed  to the  point where
        the  trophozoite  has either  started to  emerge  or has  completely
        emerged  and  is  still  attached  to the  cyst wall.   An  1C is a
        trophozoite which  is  completely   surrounded with  a  cyst wall
        showing  no evidence of  emergence.   For  the  control,  generally  100
        forms are counted  to determine  the percent  excystation.

        The  number  of cysts that  must be  observed  and  classified (ECW,
        PET,  1C)  in  the disinfected sample is  dependent on the  level  of
        inactivation  desired  and on the  excystation percentage  obtained
        in the control.

              For 0.5,  1  and  2  Iog10  reductions,  (68%, 90% and  99% inacti-
              vation,  respectively),  the  minimum  number  of  cysts to  be
              observed  and  classified is determined by dividing 100 by  the
              percentage  excystation (expressed as  a decimal)  obtained  in
              the control.

              For a  3  log^ reduction  (99.9%  inactivation) the  minimum
              number  of cysts to be  observed  and classified is determined
              by  dividing 1,000  by   the percentage  excystation (expressed
              as  a decimal)  obtained in the control.

     B.  Determining  Inactivation

        The  amount of inactivation is determined  by comparing the percent-
        age  excystation of the exposed cyst preparation  to the percentage
        excystation in the  control  preparation  using  the  following  for-
        mula:

     % inactivation =  100% - [(exposed % excysted/control % excysted) x 100]

         If the percentage excystation in the exposed preparation is zero,
         i.e., only  1C (no ECW or PET) are  observed and counted, use <1 as
         the  value for "exposed % excysted" in the  formula for  calculating
         % inactivation.

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                                                                        13
VI.  BIBLIOGRAPHY

     American Public Health Association;  American Water Works  Association;
     Water Polution Control Federation.   Standard Methods  for  the  Examina-
     tion of Water and Wastewater,  16th ed.  (1985).

     Belosevic, M. &  G.M.  Faubert.  Giardia  muris;   correlation  between
     oral dosage, course of infection, and trophozoite distribution in  the
     mouse small intestine.  Exp. Parasitol.,  56:93  (1983).

     Erlandsen, L.S.  and   E.A.  Meyer*    Giardia and  Giardiasis.    Plenum
     Press, New York, (1984).

     Faubert, G.M. et  al.   Comparative  studies  on  the pattern of  infec-
     tion with Giardia  spp.  in Mongolian gerbils.  J.  Parasitol.,  69:802
     (1983).

     Feely, D.E.  A  simplifed  method for in vitro excystation of  Giardia
     muris.  J. Parasitol., 72:474-475 (1986).

     Feely, D.E.  Induction of excystation of Giardia muris by C02  62nd
     Annual Meeting of  the American  Society of  Parasitologists,  Lincoln,
     Nebraska, Abstract No. 91  (1987).

     Gonzalez-Castro, J.,  Bermejo-Vicedo, M.T.  and  Palacios-Gonzalez,   F.
     Desenquistamiento y cultivo de Giardia  muris.   Rev. Iber. Parasitol.,
     46:21-25 (1986).

     Melvin, D.M. and M.M.  Brooke.  Laboratory  Procedures for the Diagnosis
     of Intestinal Parasites.   3rd  ed., HHS  Publication No.  (CDC)  82-8282
     (1982).

     Miale, J.B.  Laboratory Medicine Hematology,  3rd  ed.  C.  V.  Mosby
     Company, St. Louis, Missouri (1967).

     Roberts-Thomson, I.C.  et  al.    Giardiasis   in  the mouse:  an  animal
     model.  Gastroenterol.,  71:57  (1976).

     Sauch, J.F.  Purification of  Giardia muris cysts  by velocity sedi-
     mentation.  Appl. Environ. Microbiol.,  48:454 (1984).

     Sauch, J.F.  A  new method for excystation  of  Giardia.  Advances  in
     Giardia Research.  University  of Calgary, Calgary, Canada (In  Press).

     Schaefer, III,  F.W.,  Rice, E.W.,  &  Hoff,  J.C.   Factors  promoting
     In vitro excystation  of Giardia muris cysts.  Trans.  Roy. Soc. Trop.
     Med. Hyg., 78:795 (1984).

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                                                                         14
VII.  TECHNICAL CONTACTS:

      A.  Eugene W. Rice
          Microbiological Treatment Branch
          Risk Reduction Engineering Laboratory
          U.S. Environmental Protection Agency
          26 West Martin Luther King Drive
          Cincinnati, Ohio  45268

          Phone: (513) 569-7233

      B.  Frank W. Schaefer, III
          Parasitology and Immunology Branch
          Environmental Monitoring Systems Laboratory
          U.S. Environmental Protection Agency
          26 West Martin Luther King Drive
          Cincinnati, Ohio  45268

          Phone: (513) 569-7222

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                                                                        15
                  Appendix A:  Use of the Hemocytoraeter

Suspension Density Determination Using the Improved Neubauer (Bright-line)
Hemocytoraeter

     The heraocytometer consists of two chambers separated by a transverse
trench and bordered  bilaterally by longitudinal  trenches.   Each chamber
is ruled  and consists  of  nine  squares, each  1  x  1  x 0.1  mm with a
volume of 0.1 nmv*.   Each  square  mm  is  bordered by  a  triple line.  The
center line  of   the  three  is the  boundary  line  of  the  square.   (See
Figure 1).

     According to the U. S.  Bureau  of Standards' requirements, the  cover
glass must be  free  of  visible defects  and must be  optically  plane  on
both sides  within  plus  or  minus  0.002   mm.   ONLY HEMOCYTOMETER COVER
GLASSES MAY BE USED.  ORDINARY COVER GLASSES AND SCRATCHED HEMOCYTOMETERS
ARE UNACCEPTABLE, as they introduce errors into the volume relationships.

     The suspension  to be  counted must  be evenly distributed  and free of
large debris, so that the  chamber  floods properly.   The suspension  to be
counted should contain  0.01Z Tween 20 solution  to  prevent  Giardia  cysts
from sticking and causing  improper  hemocytometer  chamber flooding.   Cyst
suspensions should be adjusted so that there are a total  of 60  to  100 cysts
in the four  corner  counting  squares.  Counts  are statistically accurate
in this range.  If the  suspension is  too numerous to be counted, then it
must be diluted sufficiently to bring it into this range.  In some cases,
the suspension will be too dilute after concentration to give a statisti-
cally reliable count in the 60-100 cyst range.  There is nothing that can
be done about this situation other than to record the result as question-
able.

     To use the hemocytometer:

     1.  Dilute or concentrate the suspension as required.

     2.  Apply a clean  cover glass  to the  hemocytoraeter  and  load  the
         hemocytometer chamber with 8-10 pi  of vortexed suspension  per
         chamber.  If  this  operation has  been  properly  executed,  the
         liquid should amply  fill  the entire chamber without bubbles or
         overflowing into the surrounding moats.  Repeat this step with a
         clean,  dry  hemocytometer  and cover  glass,  if  loading  has been
         incorrectly done.   See   step (1)  below  for  the  hemocytometer
         cleaning procedure.

     3.  Do not attempt to adjust the cover glass, apply clips, or in any
         way disturb  the  chamber after  it  has  been filled.   Allow  the
         Giardia cysts  to  settle  30  to 60 seconds before  starting  the
         count.

     4.  The Giardia cysts may be counted using a magnification 200-600X.

     5.  Move the  chamber  so  the  ruled  area is  centered underneath it.

     6.  Then, locate the objective close to the cover glass while watch-
         ing it   from the  side of  rather  than through  the  microscope.

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                                                                   16
 7.   Focus  up  from   the  coverslip  until  the hemocytoraeter  ruling
     appears.

 8.   At each  of the  four corners  of the chamber is  a  1 tmn^ divided
     into 16  squares  in which  Giardia  cysts are to  be  counted (see
     Figure 1).  Beginning  with the top  row of four squares,  count
     with a hand tally  counter  in  the directions  indicated in Figure
     2.  Avoid  counting Giardia cysts  twice by counting  only those
     touching the top and left boundary  lines and none of those touch-
     ing the lower and right boundary lines.  Count each square mm in
     this fashion.

 9.   The formula for  determining the number  of Giardia  cysts per ml
     suspension is:

        # of cysts counted      10     dilution factor    1,000 mm  _
        # of sq. mm counted   1 mm            1           1 ml

                                 # cysts/ml

10.   Record  the result  on   a  data  sheet  similar  to that  shown in
     Figure 3.

11.   A total of six different hemocytometer  chambers must be loaded,
     counted, and then  averaged for each Giardia  cyst suspension to
     achieve optimal counting accuracy.

12.   After each use,  the heraocytometer  and  coverslip must be cleaned
     immediately to prevent  the cysts and debris from drying on it.
     Since this apparatus is precisely  machined,  abrasives eannot be
     used to  clean  it as they  will disturb  the flooding  and volume
     relationships.

     a.  Rinse  the hemocytoraeter   and  cover  glass  first  with  tap
         water, then 70% ethanol, and finally with acetone.

     b.  Dry  and  polish the hemocytometer  chamber  and  cover  glass
         with lens paper.  Store it in a secure place.

13.   A number of factors are known to introduce errors into heraocyto-
     meter counts.   These include:

     a.  Inadequate  suspension  mixing  before flooding  the  chamber.

     b.  Irregular  filling   of   the  chamber,  trapped   air  bubbles,
         dust, or oil on the chamber or coverslip.

     c.  Chamber coverslip not  flat.

     d.  Inaccurately ruled  chamber.

     e.  The  enumeration procedure.   Too many  or  too  few Giardia
         cysts per square, skipping or recounting some Giardia cysts.

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                                                               17
f.  Total  number  of  Giardia  cysts  counted   is   too   low   to
    give statistical confidence in result.

g.  Error in recording tally.

h.  Calculation  error;  failure  to   consider  dilution   factor,
    or area counted.

i.  Inadequate cleaning  and removal  of  cysts from the previous
    count.

j.  Allowing filled chamber to sit too long so  that chamber sus-
    pension dries and concentrates.

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                                                                        18
                                         I mm.










*





I/9MM. /





ji











"A!











E







s



c






i
<


i













<


f
*






..  0pth of Chamber  O.I mm.
JL



AssJ&g
    Figure 1.   Hemocytoraeter platform ruling.  Squares 1, 2, 3, and 4 are
               used to count Giardia cysts.  (From Miale, 1967)
Figure 2.   Manner of counting Giardia cysts  in  1 square mra.  Dark cysts
           are counted and light cysts are omitted.   (After Miale, 1967)

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                                                                       19
Date




















Person
Counting




















Count
1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
f Cells
Counted




















l2
Counted




















Dilution
Factor




















Lcjp-




















Remarks




















t cysts/ml _ I of cysts counted  x  10  x dilution factor x 1,000 mm3
             t of sq. mm counted   1 mm          1             1 ml
         Figure 3.   Hemocytometer Data Sheet for Giardia Cysts.

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                                                                       20
    Appendix B.  Preparation  and Loading  of Excystation  Chamber Slides

1.  Using tape which is sticky on both sides, cut strips approximately 12
    x 3 mm.

2.  Apply a  strip  of  the  tape  to one  side of  a  22 x  22 mm coverslip.

3.  Apply a  second  strip of  tape  to the opposite edge  but same side of
    the coverslip.

4.  Handling the coverslip by the edges only, attach the coverslip to the
    center of a 3 x 1  inch glass  slide by placing  the  taped sides of the
    coverslip down along the long edge of the glass slide.

5.  Make sure the coverslip is  securely attached to  the slide by lightly
    pressing down on the edges  of  the  coverslip with your fingers.  Care
    should be taken to keep finger prints off the center of  the coverslip.

6.  To  load  the chamber  slide, place  a  Pasteur  or  microliter pipette
    containing at least 0.2 ml of the Giardia cyst suspension about 2 ran
    from an untaped edge of the coverslip.   Slowly allow the cyst suspen-
    sion to  flow toward the coverslip.   As it  touches  the coverslip it
    will be wicked or drawn rapidly under the coverslip  by adhesive forces.
    Only expell enough of  the   cyst  suspension to  completely  fill the
    chamber formed by the tape,  slide, and coverslip.

7.  Wipe away any excess cyst suspension which is not under the  coverslip
    with an  absorbant   paper  towel,   but  be careful  not  to pull  cyst
    suspension from under the coverslip.

8.  Seal all sides of the coverslip with vaspar to prevent  the slide from
    drying out during the incubation.

    NOTE:  Prepared excystation chamber slides may be commercially avail-
           able from Spiral Systems,  Inc.,  6740 Clough Pike, Cincinnati,
           Ohio  45244, (513) 231-1211 or 232-3122, or  from other sources.

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                                                    02/06/89
DETERMINING CHLORAMINE INACTIVATION OF VIRUS

      FOR THE SURFACE WATER TREATMENT RULE
        Microbiological Treatment Branch
     Risk Reduction Engineering Laboratory

                      and

       Parasitology and Immunology Branch
  Environmental Monitoring Systems Laboratory
      U.S. Environmental Protection Agency
        26 West Martin Luther King Drive
            Cincinnati, Ohio  45268

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                              TABLE OF CONTENTS









  I.  Materials	 3




 II.  Reagents and Media	4




III.  MS2 Bacteriophage Assay	6




 IV.  Disinfection Procedure	8




  V.  Procedure for Determining Inactivation	9




 VI.  Bibliography	10




VII.  Technical Contacts	11

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     The Surface Water Treatment Rule requires 99.99% or greater removal/
inactivation of viruses.   The following protocol may be used to determine
the percentage of virus inactivation obtained by a treatment plant using
chloramine disinfection.

I.  MATERIALS

    A.  Materials for Disinfection

         I*  Stock chlorine solution
         2.  Stock ammonia solution
         3.  Stirring device
         4.  Incubator or  water bath  for  less  than  ambient temperature
         5.  Water from treatment plant
         6.  MS2 bacteriophage
         7.  Assorted glassware
         8.  Assorted pipettes
         9.  Aqueous, sterile sodium thiosulfate solution
        10.  Refrigerator
        11.  Vortex mixer
        12.  Timer

    B.  Materials for MS2  Assay

         1.  MS2 bacteriophage and its Escherichia coli host
         2.  Assorted glassware
         3.  Assorted pipettes
         4.  Incubator, 37C
         5.  Refrigerator
         6.  Petri dishes, 100 x 15 ram, sterile
         7.  Vortex mixer
         8.  Water bath, 45C
         9.  Sterile rubber spatula
        10.  EDTA, disodium salt
        11.  Lysozyme, crystallized from egg white
        12.  Centrifuge with swinging bucket rotor

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II.   REAGENTS AND MEDIA

     A.   Tryptone-Yeast Extract (TYE) Broth

               Ingredient _ Amount
               Bacto tryptone                               10.0 g
               Yeast extract                                 1.0 g
               Glucose                                       1.0 g
               NaCl                                          8.0 g
               1.0 M CaCl2                                   2.0 ml

               Dissolve in distilled water to a total volume of 1.0 liter,
               then add 0.3 ml of 6.0 M NaOH.  This  medium should be steri-
               lized either  by autoclaving  for  15 minutes  at 121C  or
               filtration through  a 0.22  yra porosity  membrane  and  then
               stored at  approximately  48C.   It  is  used  in preparing
               bacterial host suspensions for viral assays.

     B.   Tryptone-Yeast Extract (TYE) Agar

               Ingredient _ Amount
               TYE broth                                     1.0 liter
               Agar                                         15.0 g

               The agar  should be added to  the  broth prior to steriliza-
               tion.  The medium  should be  sterilized  by autoclaving for
               15 minutes at  121C.   This  medium is used  to prepare slant
               tubes for  maintenance  of bacterial  stock  cultures.   The
               prepared slant  tubes  should be stored at approximately 4C.

     C.   Bottom Agar for Bacteriophage  Assay
Ingredient
Bacto tryptone
Agar
NaCl
KC1
1.0 M CaCl2
Amount
10.0 g
15.0 g
2.5 g
2.5 g
1.0 ml
               Dissolve the  ingredients  in  distilled water  to  a  total
               volume of  1  liter.   The  medium  should be  sterilized by
               autoclaving for  15 minutes at  121C.   After  autoclaving and
               cooling, store  at 4C.   Immediately  prior  to use,  liquefy
               the medium  by heating.  Add approximately  15 ml of  lique-
               fied agar  into  each Petri dish.   This bottom layer  serves
               as an anchoring  substrate  for  the  top agar  layer.

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D.  Top Agar for Bacteriophage Assay

          Ingredient	Amount
          Bacto tryptone                                10.0 g
          Agar                                          8.0 g
          NaCl                                          8.0 g
          Yeast extract                                 1.0 g
          Glucose                                       1.0 g
          1.0 M CaCl2                                   1.0 ml

          Dissolve the  ingredients  in distilled  water  to  a total
          volume of  1  liter.  This  medium  should  be  sterilized by
          autoclaving 15  minutes  at  121C.  After cooling,  store at
          4C until  needed  in  bacteriophage  assays.   Immediately
          prior to use  in assays, liquefy the medium  by  heating and
          then cool  to  and  maintain  at  a  temperature  of  45C.

E.  Salt Diluent for Bacteriophage Assay

          Ingredient	Amount
          NaCl                                          8.5 g
          1.0 M CaCl2                                   2.0 ml

          Dissolve in distilled water  to a  total volume  of 1 liter.
          This diluent  should be  sterilized  either  by  autoclaving
          for 15 minutes  at  121C  or  filtration  through a  0.22 um
          porosity membrane.  Store at room temperature.

F.  CaCl2, 1.0 M

          Ingredient	Amount
          CaCl2                                         11-1 g

          Dissolve in distilled water  to a  total  volume  of  100  ml.
          Autoclave 15  minutes at   121C  or  filter   sterilize  the
          solution through  a 0.22  urn porosity  membrane.  Store at
          room temperature.

G.  Sodium Thiosulfate, 10Z and 1Z

          Ingredient	Amount
          Sodium thiosulfate                            10.0 g

          Dissolve the  sodium  thiosulfate  in 50 ml  distilled water.
          Adjust the  volume  to   100   ml  with  additional  distilled
          water.  Filter  sterilize  the  solution through  a  0.22 um
          porosity membrane or autoclave  15  minutes  at 121C.  Store
          at room temperature. Prepare 1% sodium thiosulfate solution
          by aseptically adding 1  ml of sterile 10% sodium thiosulfate
          solution to 9 ml of sterile distilled water.

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III.  MS2 BACTERIOPHAGE ASSAY

     A.  Microorganisms

         1.  MS2  bacteriophage:   catalog number  15597-B1,  American Type
             Culture Collection, 12301 Parklawn Drive, Rockville, MD  20852

         2.  Bacterial  host:   Escherichia  coli,  catalog  number  15597,
             American Type Culture Collection.

     B.  Growth and Maintenance of Microorganisms

         1.  Preparation of bacterial host stock cultures

             Inoculate host  bacteria onto TYE  agar slant tubes,  incubate
             24 hours at 37C to allow bacterial growth,  and  then refriger-
             ate at  4C.    At  monthly  intervals  the  cultured  bacterial
             hosts should be  transferred  to  a new  TYE  agar slant.

         2.  Preparation of bacteriophage stock suspension

             Melt top agar  and maintain at 45C.   Add 3 ml  of  the agar  to
             a 13 x  100  mm test tube contained in a rack in a 45C water
             bath.  Add  0.5  to  1.0  ml  of  the  bacteriophage   suspension
             diluted so  that  the host  bacterial  "lawn"  will show  nearly
             complete lysis after overnight  incubation.   Add 0.1  to 0.2  ml
             of a TYE  broth  culture of  the  host  bacteria  that has been
             incubated overnight.  Mix  gently and  pour the contents on the
             surface of  bottom agar contained in a  Petri  dish that has
             been prepared  previously.   Rock the  Petri dish to  spread the
             added material evenly  over the agar  surface.  After  the top
             agar solidifies  (about  15 minutes),  invert the  Petri dish
             and incubate  overnight at 37C.   Repeat the above  procedure
             so that a minimum of 5 but  no  more  than 10  Petri dishes are
             prepared.

             Following this incubation  and using a sterile rubber spatula,
             gently scrape  the top  and  bottom agar  layers  into a  large
             beaker.  Add  to  this  pool of  agar  layers an  amount of TYE
             broth sufficient  to  yield a total volume of 80 ml.   To this
             mixture add  0.4  g  of  EDTA  (disodium  salt)  and 0.052  g   of
             lysozyme (crystallized  from egg white).  Incubate this mixture
             at room temperature for 2  hours with  continuous mixing.  Then
             centrifuge the mixture for 15 minutes at 3,000 x g.   Carefully
             remove the upper fluid  layer.   This fluid layer constitutes a
             viral stock  suspension  for  use   in   subsequent  testing and
             assays.  The  viral  stock  suspension  may  be   divided into
             aliquots and stored either frozen  or  at 4C.

     C.  Performance of Bacteriophage Assay

         A  two-week supply  of Petri dishes  may be poured  with  bottom agar
         ahead of tine and  refrigerated inverted  at 4C.   If stored in a
         refrigerator, allow agar plates to  equilibrate to room  temperature

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before use.  Eighteen  hours prior  to  beginning  a bacteriophage
assay, prepare a bacterial host suspension by inoculating 5 ml of
TYE broth with a  small amount of bacteria  taken  directly from a
slant tube culture.  Incubate the broth containing this bacterial
inoculum overnight (approximately  18 hours) at  37C i^jnediately
prior to use  in bacteriophage  assays as described  below.   This
type of broth  culture  should be prepared freshly for each day's
bacteriophage assays.  If  necessary, a volume greater  than 5 ml
can be prepared in a similar manner.

On the day  of  assay,  melt  a sufficient  amount  of top  agar  and
maintain at 45C in a water bath.  Place test tubes (13 x 100 mm)
in a rack in the same water bath and allow to warm, then add 3 ml
of top agar  to each tube.   Inoculate  the  test  tubes  containing
top agar with  the bacteriophage  samples  (0.5 to 1.0 ml of  the
sample/tube) plus 0.1  to  0.2 ml of  the overnight bacterial host
suspension.  Dilute the bacteriophage samples from  10"*  to 10~^
in salt diluent prior  to  inoculation and assay  each dilution in
triplicate.  In addition, assay  the  uninoculated  salt diluent as
a negative control.  Agitate  :he test tubes containing top  agar,
bacteriophage inoculum, and bacterial host suspension gently on a
vortex mixer,  and  pour  the  contents  of  each  onto a  hardened
bottom agar  layer  contained  in  an  appropriately  numbered  dish.
Quickly rock the  Petri  dishes to spread the  added material evenly,
and place on a flat surface  at  room temperature  while  the agar
present in the added  material solidifies (approximately  15 min-
utes).  Invert and incubate  the  dishes at 37C overnight (approxi-
mately 18  hours).   The  focal  areas  of  viral   infection  which
develop during this incubation are  referred to  as "plaques" and,
if possible, should be  enumerated immediatly after the incubation.
If necessary, the  incubated  Petri  dishes  can -be  refrigerated at
4C overnight  prior  to plaque enumeration.   As  a general  rule,
count only those plates that contain between  20  and  200 plaques.

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IV.   DISINFECTION PROCEDURE

     A.  The treatment plant water to be used should be the water influent
         into the chloramine  disinfection  unit process used in the plant.
         If chloramine disinfection is performed at more than one point in
         the treatment process, e.g. prefiltration and postfiltration, the
         procedure should simulate as closely as possible actual treatment
         practice.

     B.  Prepare stock ammonia and chlorine solutions to  be  added to the
         treatment plant water to achieve the same stoichloraetric relation-
         ship between  chlorine  and ammonia that  is  used  in the  water
         treatment plant.  These  solutions  should  be  concentrated enough
         so that no more  than 2 ml of each  solution  will be added to the
         treatment plant water being disinfected.

     C.  Determine the contact time by  the  methods described in  the Surface
         Water Treatment  Rule  and/or   the  associated  Guidance  Manual.

     D.  Rinse two 600 ml beakers with treatment plant water to remove any
         extraneous material  that may cause  disinfectant demand.  Then add
         400 ml  treatment plant  water  to  the  beaker.   The  first beaker
         will be  seeded  with  MS2 before the  contents  are chloraminated.
         The second beaker  will  be  an  indigenous virus  control  and will
         be chloraminated without addition of extraneous phage.

     E.  Mix the contents of  the  beaker  short of producing  a vortex in the
         center and  continue  until  the  conclusion  of   the   experiment.

     F.  Equilibrate the  600  ml beakers and their contents as  well as the
         disinfectant reagents  to  the  desired  experimental   temperature.

     G.  Dilute the stock MS2  bacteriophage  so  that the bacteriophage con-
         centration is 1  to 5  x 108 PFU/ml.

     H.  Add 1.0 ml of the diluted MS2  bacteriophage to the contents of the
         first 600 ml beaker.

     I.  Remove a 10 ml sample  from the  contents of the first beaker after
         2 minutes  of mixing.  Assay the  MS2  bacteriophage concentration
         in this  sample within 4 hours  and  record  the results as PFU/ml.
         This value is the initial MS2 concentration.

     J.  Remove  a 10 ml  sample  from  the  contents  of  the second beaker
         after 2  minutes  of  mixing.   Assay the  indigenous bacteriophage
         concentration in this sample  within 4 hours (at the same time as
         you assay  the  sample  from  the  first  beaker)  and  record  the
         results as PFU/ml.   This value  is the  initial unseeded concentra-
         tion.

     K.  Add  the  disinfectant  reagents  to  the contents  of  both beakers
         using the  same  sequence, time,  and concentrations as  are used in
         the actual treatment  plant operations.

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    L.  Just prior to the end of the contact time,  remove  a volume of sam-
        ple adequate for determination  of  the disinfectant  residual con-
        centration from  both  beakers.   Use  methods  prescribed in  the
        Surface Water Treatment  Rule for  the determination  of  combined
        chlorine.  This  residual  should  be  the  same  (20%)   as  the
        residual present in the treatment plant operation.

    M.  At the end  of  the  exposure time, remove a  10  ml  sample  from the
        first 600 ml beaker and  neutralise with 0.25 ml of 1.0% aqueous,
        sterile sodium  thiosulfate.  Assay  for  the  MS2  bacterionhage
        survivors and record  the results  as  PFU/ml.  This value  is  the
        exposed MS2 concentration.

    N.  At the end  of  the  exposure time, remove a  10  ml  sample  from the
        second 600 ml beaker and neutralize with 0.25 ml of 1.0% aqueous,
        sterile sodium thiosulfate.   Assay for the  indigenous  bacterio-
        phage survivors and record  the  results  as PFU/ml.  This  value is
        the exposed unseeded concentration.

V.  PROCEDURE FOR DETERMINING INACTIVATION

    A.  Calculation of Percentage Inactivation

        Use the  following  formula to calculate  the percent  inactivation
        of MS2:

        1.  %  inactivation -  100%  - [(exposed  MS2/initial  MS2) x 100]

        Using values from Section IV steps  I, J, M and N calculate initial
        MS2 and exposed MS2 as follows:

        2.  Initial MS2 (PFU/ml) = I - J.

        3.  Exposed MS2 (PFU/ml) - M - N.

        If the number of PFU/ml  in exposed MS2  is  zero, i.e., no plaques
        are produced after assay of undiluted and diluted samples, use <1
        PFU/ml as the value in the above formula.

    B.  Comparison  of  Percentage  Inactivation  to LogjQ  of  Inactivation

        68% inactivation is equivalent to 0.5 logjo inactivation
        90% inactivation is equivalent to 1 log^o inactivation
        99% inactivation is equivalent to 2 log^o inactivation
        99.9% inactivation is equivalent to 3 log^g inactivation

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                                                                        10
VI.   BIBLIOGRAPHY

     Adams, M.H.  Bacteriophages. Interscience Publishers, New York (1959).

     American Public Health Association; American Water Works Association;
     Water Pollution Control Federation. Standard Methods for the Examina-
     tion of Water and Wastewater. 16th ed. (1985).

     Grabow, W.O.K. et al.   Inactivation of hepatitus A virus, other enter-
     ic viruses and indicator  organisms in water  by  chlorination.   Water
     Sci. Technol., 17:657 (1985)

     Jacangelo, J.D.;  Olivieri, V.P.; & Kawata,  K.   Mechanism of inactiva-
     tion of microorganisms  by combined chlorine.  AWWARF  Rept.,  Denver,
     CO (1987).

     Safe Drinking Water  Committee.   The disinfection  of drinking  water.
     In:   Drinking Water and Health,   National Academy Press,  Washington,
     D.C., 2:5 (1980).

     Shah, P. & McCamish, J.  Relative  resistance of poliovirus  1 and coli-
     phages f and T2 in water.  Appl. Microbiol. 24:658 (1972).

     U.S. Environmental Protection Agency.   Guidance Manual  for Compliance
     with the  Filtration  and Disinfection Requirements  for Public  Water
     Systems Using Surface  Water Sources.   Appendix G.  U.S.  EPA,  Office
     of Water, Criteria and  Standards Division, Washington,  D.C.  (1988).

     Ward, N.R.;  Wolfe,  R.L.;  &  Olson, B.H.   Effect  of pH,  application
     technique, and chlorine-to-nitrogen ratio on disinfectant activity of
     inorganic chloramines  with   pure  culture  bacteria.    Appl.  Environ.
     Microbiol., 48:508 (1984).

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                                                                         11
VII.  TECHNICAL CONTACTS;

      A.  Donald Herman
          Microbiological  Treatment Branch
          Risk Reduction Engineering Laboratory
          U.S. Environmental Protection Agency
          26 West Martin Luther King Drive
          Cincinnati, Ohio  45268

          Phone: (513) 569-7235

      B.  Christon J. Hurst
          Microbiological  Treatment Branch
          Risk Reduction Engineering Laboratory
          U.S. Environmental Protection Agency
          26 West Martin Luther King Drive
          Cincinnati, Ohio  45268

          Phone:  (513) 569-7331

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               APPENDIX G 3 CHLORINE DIOXIDE INACTIVATION
     The basis  for the chlorine dioxide  CT values for  Giardia  cyst in
the manual is given  in Appendix F (pp 2-3).  The CT valves are based on
data  collected  from  five  experiments  conducted  at  five  different
chlorine dioxide  concentrations (   0.1  to 5.5 mg/L)  at pH 7 and  5 C.
The highest  single value was  used to calculate  the  CT values and  a 2
fold  safety factor  was  applied.    A  review  of data  from Hoff,  1986
indicated  that the  disinfection  efficiency  of  chlorine dioxide  for
bacteria and viruses increases approximately 2 to 3 fold as pH increases
from 7  to  9.  Data  from the  report on which  the CT values  are based
(Leahy, 1985)  indicate that  at 25  C,  G.  Muris  cyst  inactivation  CT's
were approximately 2 fold higher at pH 7 than at pH 9.  In addition, the
data  also  indicate  that  chlorine  dioxide  efficiency  increases  as
disinfectant concentration increases within the range stated.
     Because the  CT values  in  the  Manual  are very  conservative,  and
because the  data  suggest that  site  specific conditions,  i.e. water pH
and disinfectant  concentration  used,  can  have significant effects on
chlorine dioxide   effectiveness,   the  option  of  allowing the  Primacy
Agency to consider the  use of lower  CT valves by individual systems has
been provided.
     This  approval  should  be  based  on  acceptable  experimental  data
provided by the system.  The data should be collected using the protocol
provided in  Appendix G-l for determining Giardia  cyst  inactivation by
chloramine with appropriate changes  in Section IV A, B, and I to reflect
the use of chlorine dioxide rather than chloramine.

References:
Hoff,  T.C.  Inactivation of Microbial Agents By Chemical Disinfectants
EPA/600/52-86/067, U.S. Environmental  Protection Agency, Water Engineer
Research Laboratory, Cincinnati, Ohio, September, 1986.
Leahy,  J.G. Inactivation of Giandia Muris Cysts by Chlorine and Chlorine
Dioxide.  Thesis,  Department  of Civil Engineering, Ohio State  Universi-
ty, 1985.

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                     APPENDIX G-4 OZONE INACTIVATION
     The  basis  for  the  ozone  CT values  in  this  manual  is given  in
Appendix  F.   As  indicated in  Appendix F, the  ozone data base  is  very
limited.  The CT values are for Giardia cysts  derived  from one publica-
tion (Wickramanyake et al, 1985)  in which  experiments  were conducted at
one pH  (7) and two temperatures (5 C and 25 C).  Because of this limita-
tion, a large safety factor  was applied in establishing  the  CT values.
Also, the experiments were conducted  under  steady state  ozone  concen-
trations  with  ozone  continually  added during  the  contact period.   In
contrast,  as pointed out on  p. 3-14,  of this manual, steady state ozone
concentrations are  not  maintained in  field  use.   In addition  to these
factors,  the  effectiveness of ozone contactors used in  field applica-
tions may vary from each other and  from the  mixing efficiencies applied
in the laboratory experiments used to establish the CT valves.
     The net effect of all of these differences limits the applicability
of  the  CT values  to individual systems.   Therefore,  the  option  of
allowing  the Primacy  Agency  to consider the use  of lower CT  valves  by
individual systems has been provided.
     This  approval  should be  based  on   acceptable  experimental  data
provided by the system.  In general, the procedure  provided in Appendix
G-l  for determining  Giardia  cyst  inactivation by  chloramine for  de-
termining cyst viability before and after exposure to ozone can be used.
Because of the importance of  ozone transfer efficiency and the impact of
the ozone application on the contactor hydraulics,  use  of a pilot plant
of the ozonation process used is essential.  The ozone pilot unit should
have the capacity for a 1 to  10 gpm flow and should simulate the hydrau-
lics and  ozone  transfer efficiency of the full scale  unit.   the effi-
ciency of  the contactor  in activating  the cysts can be determined  from
the  viability  of cysts  in the influent and  effuent of  the  contactor,
determined  as  outlined  in Appendix G-l.   A  recommended cyst  concen-
tration for the raw water  is  1x10  cysts/gallon.   However, the influent

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concentration and  the pilot plant  flow rates  may need to  be adjusted
according to the  availability of cysts.   Additional information on the
                                    &
design of specific pilot studies can
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References:

Wickramanayake, G.B., Rubin,  A.J., and Sproul, O.J. Effects of Ozone and
Storage Temperatures on Giardia Cysts.  J.  AWWA, 77(8)-74-77,  1989

Wallis, P.M., Davies,  J.S.,  Nuthonn,  R., Bichanin-Mappin,  J.M.,  Roach,
P.D., and Van Roodseloon, A.  Removal  and  Inactivation  of  Giardia Cysts
in a  Mobile Water Treatment  Plant Under Field  Conditions:  Preliminary
Results.  In Advances in Giardia Research.  P.M. Wallis and  B.R. Hammand,
eds, Union of Calgary Press,  p.  137-144, 1989.

Wolfe, R.L.,  Stewart,  M.H.,  Liang, S.L.,  and McGuire, M.J.,  submitted
for publication, 1989.

Olivieri, V.P. and Sykora, J.L.,  Field  Evaluation  of  CT for Determining
the Adequacy  of Disinfection.  American Water Works Association Water
Quality Technology Conference.  In press, 1989.

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              APPENDIX H

SAMPLING FREQUENCY FOR TOTAL COLIFORMS
      IN THE DISTRIBUTION SYSTEM

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      APPENDIX I

 MAINTAINING REDUNDANT
DISINFECTION CAPABILITY

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                                  APPENDIX I

                       REDUNDANT DISINFECTION CAPABILITY


     In reviewing water disinfection facilities for compliance with redundancy

requirements, the following items should be checked:


  I. General

     A.   Are the capacities of all components of  both the primary system and
          the backup system equal to or greater than the required capacities?

          Some systems may have two  or  more units that provide  the  required
          dosage  rates when  all units  are  operating.   In  these cases,  an
          additional unit  is  needed  as backup, during the  downtime of  any of
          the operating units.   The  backup must have  a capacity  equal to  or
          greater than that of the largest on-line unit.

     B.   Are adequate safety precautions being followed, relative to the  type
          of disinfectant being used?

     C.   Are  redundant  components  being  exercised  or  alternated with  the
          primary components?

     D.   Are all components being properly maintained?

     E.   Are critical spare parts on hand to  repair disinfection equipment?

     F.   Are spare parts  available for  components that are indispensible for
          disinfecting the water?


 II. Disinfectant Storage
     A minimum of two storage units  capable  of being  used alternately should

be  provided.  However,  it is  not  necessary  for  both  systems to have  full

design capacity.

     A.   Chlorine
     Storage for  gaseous  chlorine   will normally  be  in  150-lb cylinders,

2,000-lb containers, or larger on-site storage vessels.
          1.   Is  there  automatic  switchover equipment  if one  cylinder  or
               container empties or becomes  inoperable?

          2.   Is  the switching  equipment  in good working  order,   (manually
               tested  on  a regularly  scheduled basis), and are spare parts on
               hand?
                                       1-1

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          3.   Are the scales adequate for at least two  cylinders or  contain-
               ers.
     B.   Hypochlorite
     Storage  of  calcium  hypochlorite  or  sodium  hypochlorite  is  normally
provided in drums or  other suitable containers.  Redundancy requirements  are
not applicable to these by themselves,  so long as the  required minimum storage
quantity is on hand at all times.
     C.   Ammonia
     Anhydrous ammonia is  usually  stored in cylinders  as  a pressurized liquid.
Aqua ammonia is usually stored as a solution  of ammonia and water  in a  hori-
zontal pressure vessel.
          1.   Is the  available storage volume divided into  two  or more usable
               units?
          2.   Is automatic  switching  equipment in operation  to change  over
               from one unit to another when one is  empty or inoperable?
          3.   Are there spare parts for the switching equipment?

III. Generation
     Ozone and  chlorine dioxide  are not  stored on-site.  Rather,   because  of
their reactivity, they are generated and used  immediately.
     To  satisfy the  redundancy  requirements   for  these  disinfectants it  is
recommended that two  generating  units,  or  two sets  of  units,  capable  of
supplying the  required feed rate be provided.    In systems where  there is  more
than one generation system,  a standby  unit should be available  for times  the
on-line units  need repair.  The backup  unit should have a capacity equal  to or
greater than the units it  may replace.
     A.   Chlorine Dioxide
     Chlorine,  sodium  chlorite,  or  sodium hypochlorite  should  be  stored  in
accordance with storage guidelines previously  described.
     B.   Ozone
     Are all generation components  present  and in working order for  both  the
primary and the redundant  units (whether using air or  oxygen)?
                                      1-2

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     C.   Common
     Is switchover and automatic start-up  equipment  installed  and operable  to
change from the primary generating unit(s)  to the redundant unit(s)?

 IV. Feed Systems
     Redundancy in feed systems requires two  separate  units, or systems,  each
capable of supplying  the  required dosage  of  disinfectant.   If more than one
unit is needed to apply the  required  feed  rate,  a third unit should be  avail-
able to replace any of the operating units during times of  malfunction.  The
replacement unit should,  therefore,  have  a capacity equal to  or greater  than
that of the  largest  unit which it  may replace-.   This  requirement  applies  to
all disinfection methods,  and is  best implemented by  housing  the primary and
redundant components  in separate rooms, enclosures, or areas, as appropriate.
     In  reviewing  these  systems  for  redundancy,   the following  components
should be checked:
     A.   Chlorine
          1.    Evaporators
          2.    Chlorinators
          3.    Injectors
     B.   Hypochlorite
          1.    Mixing tanks and mixers
          2.    Chemical feed pumps and controls
          3.    Injectors
               Dissolution equipment, including compressor and delivery piping
               systems
          Chlorine Dioxide
          1.   Chlorine feed equipment
          2.   Sodium chlorite mixing and metering equipment
          3.   Day tank and mixer
          4.   Metering pumps
          5.   If a package CIO  unit is used, two must be provided
          Chloramination
          1.   Chlorine feed equipment
                                      1-3

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          2.   Ammonia  feed  equipment,  including  applicable  equipment  for
               either:
               a.    Anhydrous ammonia (gas)
               b.    Aqua ammonia (solution)

  V. Residual Monitoring
     The best  method of  monitoring a  disinfection  facility  for continuous
operation is by continuous recording equipment.   To  improve  reliability,  it is
suggested that  duplicate  continuous monitors are present  for  backup in  the
event of monitor  failure.  However, if there is  a  failure  in the monitoring
system for  indicating that a  continuous  residual  is  being maintained,  this
would be a violation of  a monitoring requirement,  not  a treatment  requirement.
     A.    Chlorine
          1.   Does  the  facility   have  a  continuous  monitor for   chlorine
               residual  at  the  disinfection  system  site  with  an  alarm  or
               indicator to  show when the  monitor  is  not  functioning?   For
               added assurance, the provision of  a  backup monitoring unit is
               also recommended.
          2.   Is  there  instrumentation in place to automatically switch  from
               one monitor to the other if  the first one fails?
     B.    Hypochlorite
     Same as for chlorine system.
     C.    Ozone
        . 1.   Does the  facility have a continuous  ozone monitor with automa-
               tic switchover capability and alarms?
          2.   Does the  facility have a continuous ozone residual monitor  with
               automatic switchover capability and alarms?
     D.    Chlorine Dioxide
          1.   Does the  facility have a continuous chlorine  dioxide monitor
               with automatic switchover capability  and alarms?
          2.   Does the facility have  a continuous  chlorine dioxide  residual
               monitor with automatic switchover capability  and  alarms?

     E.    Chloramination
          1.   Does  the  facility   have  a  continuous  ammonia monitor  with
               automatic switchover capability and alarm?
                                      1-4

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          2.   Does  the  facility also  have a  continuous  chlorine  residual
               monitor  on-site  with  automatic  switchover  capability  and
               alarms?
 VI. Power Supply
     A permanently  installed standby generator, capable of  running  all elec-
trical  equipment at the  disinfection  station,  and  equipped for  automatic
start-up on power failure, should be on-site and functional.
     Alternatives to a standby generator, such as a feed line from a different
power source, are acceptable if they can be shown to have equal reliability.

VII. Alarms
     Indicators  and alarms,  both  local  and remote,  should  be  capable  of
promptly alerting operating and supervisory personnel of problem conditions.
     A.   Local
     Lights, buzzers, and  horns should be installed and  functioning to alert
on-site personnel to problem conditions.
     B.   Remote
     Alarm  signals  should  be relayed  to a  central  control  panel which  is
manned 24 hours  per day and whose operators  can  notify  response  personnel
immediately.
     C.   Problem Conditions
     A minimum  list of  problem conditions which  should have  indicators  and
alarms, both locally and at a 24-hour per day switchboard, are as follows:
              
          1.   Disinfectant leak
          2.   Feeder pump failure
          3.   Power outage
          4.   Generator or alternate power source on
          5.   Disinfectant residual less than setpoint value

VIII. Facility Layout
     Maximum reliability is ensured when  redundant units are  separated  from
primary units.   The  type of separation  should  be  appropriate to the  type  of
potential malfunction.   For  example,  any area within a building subject to  a
chlorine leak should have  primary  components separated  from redundant compo-
nents by an airtight enclosure, i.e., separate rooms of varying sizes.
                                      1-5

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 IX. Separate Facility
     Under certain conditions, such as location of a disinfection facility  in
an  area  of  high earthquake potential,  the most reliable  means  of providing
redundant facilities may be to  house  them in a completely separate structure
at a different site.
                                      1-6

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       APPENDIX J
WATERSHED CONTROL PROGRAM

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                                  APPENDIX J
                           WATERSHED CONTROL PROGRAM

     The following is a guideline for documenting a watershed control program.
All systems are expected to conduct the basic elements of a watershed control
program.  However, the scope of the program  should increase as the complexity
and size of the watershed/system increases.   The  program could be more or less
comprehensive than  this outline,  and will  be  determined on  a case-by-case
basis by the  utility and the Primacy Agency.  In addition  to the guidelines
below, a wellhead protection program could be the basis of a watershed control
program in many states.  All of  the elements  found below would also be part of
a local Wellhead Protection Program.
     A.   Watershed Description
          1.   Geographical location and physical features of the watershed.
          2.   Location of major  components  of the water  system in relation-
               ship to the  watershed.
          3.   Hydrology:  Annual precipitation patterns,  stream flow charac-
               teristics, etc.
          4.   Agreements and delineation  of land use/ownership.
     B.   Identification of the  Watershed  Characteristics
          and Activities Detrimental to  Water Quality
         ' 1.   Naturally Occurring:
               a.   Effect  of  precipitation,  terrain,  soil  types and land
                    cover
               b.   Animal populations  (describe)   include  a discussion of
                    the Giardia  contamination  potential,  any other microbial
                    contamination transmitted by  animals
               c.   Other  - any  other  activity  which  can  adversely  affect
                    water quality
          2.   Man-Made:
               a.   Point sources  of  contamination such  as wastewater  treat-
                    ment plant,  industrial discharges,  barnyard, feedlots, or
                    private septic systems
                                      J-l

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          b.   Nonpoint Source of Contamination:

               1)   Road construction - major highways, railroads

               2)   Pesticide usage

               3)   Logging

               4)   Grazing animals

               5)   Discharge to ground water which recharges the surface
                    source

               6)   Recreation activities

               7)   Potential for unauthorized activity in the watershed

               8)   Describe  any  other human  activity in  the  watershed
                    and its potential impact on water quality

          It should be noted that  grazing animals in  the  watershed  may
          lead to the  presence of Cryptosporidium in  the  water.   Crypto-
          sporidium is a pathogen which may result in a disease outbreak
          upon ingestion.  No information  is  available on its resistance
          to  various   disinfectants,  therefore  grazing  should  not  be
          permitted on watersheds of non-filtering systems.  The utility
          should set  priorities  to address  the impacts in B.I.  and  2.,
          considering  their  health  significance  and  the  ability  to
          control them.
C.   Control of Detrimental Activities/Events

     Depending on the  activities  occurring within the watershed,  various
     techniques  could  be  used to  eliminate or  minimize their  effect.
     Describe what  techniques are  being used  to  control the effect  of
     activities/events identified in B.I. and 2. in its yearly report.

     Example:

          Activity;   Logging in the watershed.

          Management Decision;  Logging  effects are unacceptable,  there-
          fore, do not allow logging in watershed.

          Procedure;  Buy out all logging rights within the watershed.

          Monitoring;  Periodically tour watershed to ensure  no  logging
          is conducted.
                                 J-2

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     Controlled logging may  sometimes  be more cost effective.  Measures
     should, however, be taken to:

       -  Limit access
       -  Ensure cleanup
       -  Control erosion

     Example:

          Activity;  Point sources  of discharge within the watershed.

          Management Decision;   Eliminate those  discharges  or minimize
          their impact.

          Procedures;  Actively  participate  in the  review  of  discharge
          permits to alert the reviewing agency of the potential (actual)
          impacts  of the  discharge and  lobby  for   its  elimination  or
          strict control.

          Monitoring;  Conduct special  monitoring to  ensure conditions  of
          the permit  are  met  and  to document adverse  effects on water
          quality.

D.   Monitoring

     1.   Routine:   Minimum  specifications  for  monitoring  several  raw
          water quality parameters  are listed in  Section 3.1.  Describe
          when, where  and how  these samples will be collected.   These
          results will be used to evaluate  whether  the source may  con-
          tinue to be used without  filtration.

     2.   Specific:  Routine  monitoring may not provide information about
          all parameters of interest.  For example, it may be  valuable  to
          conduct  special studies  to  measure  contaminants  suspected  of
          being  present  (Giardia,  pesticides,  fuel  products,  enteric
          viruses, etc.).   Frequent presence of either Giardia or  enteric
          viruses  in  raw water samples  prior  to   disinfection would
          indicate an  inadequate watershed control program.   Monitoring
          may  also be  useful to  assess  the  effectiveness  of specific
          control  techniques,  and  to  audit procedures  or  operational
          requirements  instituted  within the  watershed.   Utilities  are
          encouraged to conduct additional monitoring as necessary to aid
          them in controlling the quality of the  source water.

E.   Management/Operations

     1.   Management

          a.   Organizational structure
          b.   Personnel and education/certification  requirements
                                 J-3

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     2.   Operations

          a.   Describe system operations and design flexibility.

          b.   The utility should  conduct some  form of ongoing  review or
               survey in the watershed to identify and react to  potential
               impacts on water quality.  The scope of this review should
               be documented  and agreed upon by  the  utility  and  Primacy
               Agency on a case-by-case basis.

          c.   Specifically  describe operational changes which  can  be
               made  to  adjust  for changes  in  water  quality.  Example:
               Switching  to  alternate  sources;  increasing the  level  of
               disinfection;   using settling basins.   Discuss what  trig-
               gers, and who decides to make, those changes.

     3.   Annual  Report:   As part of the  watershed program,  an  annual
          report should be submitted to the Primacy Agency.  The contents
          of the report should:

          a.   Identify special  concerns that  occurred  in the  watershed
               and how they were handled (example:   herbicide usage,  new
               construction, etc.).

          b.   Summarize  other  activities  in  the  watershed  such  as
               logging, hunting, water quality monitoring, etc.

          c.   Project what  adverse activities  are expected  to occur in
               the future and describe how the utility expects to  address
               them.

F.   Agreements/Land Ownership

     The goal of a watershed management program is to achieve the  highest
     level  of  raw  water quality  practicable.    This  is  particularly
     critical to an unfiltered surface supply.

     1.   The utility will have  maximum opportunity to realize  this goal
          if  they have complete ownership  of  the watershed.  Describe
          efforts to  obtain  ownership,  such as any  special  programs  or
          budget.   When  complete  ownership of  the  watershed  is  not
          practical,  efforts  should  be  taken  to  gain  ownership  of
          critical .elements,  such as,  reservoir  or stream  shoreline,
          highly  erodable  land,   and   access   areas  to  water   system
          facilities.

     2.   Where  ownership of  land is  not  possible,  written agreements
          should  be obtained  recognizing  the  watershed  as part  of  a
          public  water  supply.   Maximum flexibility should be given  to
          the  utility to  control  land uses  which  could have  adverse
          effect on the water quality.  Describe such agreements.
                                 J-4

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3.   Describe how the  utility ensures  that the landowner  complies
     with these  agreements.
                             J-5

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  APPENDIX K
SANITARY SURVEY

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                                  APPENDIX K

                                SANITARY SURVEY


     The SWTR  requires  that an on-site  inspection  be conducted each year  as

outlined in Section 3.  It is recommended that at the onset of  determining the

classification of a source water that a detailed sanitary survey be  conducted.

In addition,  it is recommended that  a sanitary survey  such  as contained  in

this appendix  be  conducted every 3 to 5  years to ensure that the  quality  of

the water and service is maintained.  This time period is  suggested since the

time  and  effort  needed  to  conduct  the   comprehensive  survey   makes  it

impractical for it  to be conducted annually.   A periodic sanitary  survey  is

also required under the Total Coliform Rule for systems collecting less  than 5

samples/month.  The  survey must be  conducted every 5 years  for  all systems
except for protected ground water systems which disinfect.   These systems  must

conduct the survey every 10 years.
     The sanitary survey involves three phases, including planning the survey,

conducting the survey and compiling the final report of the survey,  as will  be

presented in the following pages.

     1.   Planning the Survey

          Prior to conducting or scheduling a sanitary survey,  there should  be
          a detailed  review of  the water  system's  file to prepare for the
          survey.   The review should pay particular attention to past sanitary
          survey reports  and correspondence describing previously  identified
         -problems and their solutions.  These should be  noted,  and  action/in-
          action regarding those  problems should be specifically verified  in
          the field.  Other  information to review  includes:  any other  corre-
          spondence, water system plans,  chemical and microbiological sampling
          results, operating reports, and  engineering  studies.  This  review
          will aid in the familiarization with the system's past history and
          present  conditions,  and  the agency's  past interactions with the
          system.

          The  initial phase  of the water quality  review will be carried out
          prior to conducting the survey  as well, and will  consist  of review-
          ing  the  water  system's  monitoring records.    Records   should  be
          reviewed for  compliance with all applicable microbiological,  inor-
          ganic chemical, organic chemical, and radiological contaminant MCLs,
          and also for  compliance with the monitoring requirements  for those
          contaminants.    The survey  will provide  an opportunity  to  review
          these records with the utility, and  to discuss  solutions  to any MCL
          or  monitoring   violations.    The   survey  will  also  provide  an
                                      K-l

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     opportunity to  review how and where  samples  are  collected,  and how
     field  measurements  (turbidity,  chlorine residual,  fluoride,  etc.)
     are made.  Points  to cover include:

     a.   Is the system in compliance with  all  applicable  MCLs (organic
          chemical,   inorganic  chemical,   microbiological,   and  radio-
          logical) ?

     b.   Is the system in compliance with all monitoring requirements?

     The pre-survey  file  review should  generate  a list of items to check
     in the field,   and a list of  questions about the  system.   It will
     also help the  survey or plan the format of  the  survey  and to esti-
     mate how much  time   it  may take.  . The next step  is  to make  the
     initial contact with the system management  to establish  the survey
     date(s)  and time.  Any  records,  files,  or people  that will  be
     referenced  during the  survey should be mentioned at the  outset.
     Clearly laying  out the  intent  of the  survey up  front  will greatly
     help in managing the system, and  will ensure that  the survey goes
     smoothly without a need for repeat trips.

2.   Conducting the  Survey

     The on-site  portion  of  the  survey  is  the most  important and will
     involve interviewing those in charge of managing the water system as
     well as the operators and other technical  people.   The survey will
     also review all major system  components from the  source(s)  to the
     distribution system.   A standard form  is  frequently used to ensure
     that all  major  components  and aspects of  each  system are  consis-
     tently reviewed.   However, when  in the field, it is best to have an
     open mind  and  focus  most attention  on the  specifics  of  the water
     system, using   the form only  as  a  guide.   The   surveyor  should  be
     certain to be on time when beginning  the survey.  This  consideration
    " will help get  the survey started  smoothly  with  the operator and/or
     manager.

     As the  survey  progresses,  any deficiencies that are observed should
     be brought to  the attention of the  water  system personnel,  and the
     problem and the corrective measures should be discussed.   It is far
     better  to  clarify technical details  and  solutions  while standing
     next to the problem  than it  is to do so over the telephone.  Points
     to cover include:

     a.   Is  the  operator  competent in  performing the  necessary field
          testing for operational control?

     b.   Are testing  facilities  and equipment  adequate, and do reagents
          used have  an  unexpired shelf life?

     c.   Are field  and other analytical  instruments  properly and regu-
          larly calibrated?
                                 K-2

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d.   Are records of field test results and water quality  compliance
     monitoring results being maintained?

e.   Conduct any sampling which will be part  of the  survey.

Also, detailed  notes of  the findings and  conversations  should  be
taken so that  the  report of the  survey  will be an accurate  recon-
struction of the survey.

Specific  components/features  of  the  system  to  review   and  some
pertinent questions to ask are:

A.   Source Evaluation

All of the elements for a source elevation enumerated below may also
be part of a Wellhead Protection Program.

     1.   Description:  based  on  field observations and  discussion
          with  the  operator,  a  general  characterization  of  the
          watershed should be made.   Features which  could  be  includ^-
          ed in the description are:

          a.   Area of watershed or  recharge  area.

          b.   Stream flow.

          c.   Land  usage  (wilderness,   farmland,  rural housing,
               recreational, commercial,  industrial, etc.).

          d.   Degree of access by the public to watershed.

          e.   Terrain and soil type.

          f.   Vegetation.

          g.   Other.

     2.   Sources  of  contamination   in the  watershed  or   sensitive
          areas surrounding wells or well fields should be  identi-
          fied.  Not  only should this be determined by  physically
          touring  and  observing  the watershed  and  its daily  uses,
          but the  surveyor  should also actively question  the  water
          system  manager  about  adverse and  potentially  adverse
          activities  in  the  watershed.   An  example  of   types  of
          contamination includes:

          a.   Man Made.

               1.   Point  discharges  of sewage,   stormwate'r,  and
                    other wastewater.
                            K-3

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     2.   On-site  sewage disposal systems.

     3.   Recreational   activities   (swimming,   boating,
          fishing, etc.).

     4.   Human habitation.

     5.   Pesticide usage.

     6.   Logging.

     7.   Highways or other roads  from  which there might
          be spills.

     8.   Commercial  or industrial  activity.

     9.   Solid waste or other disposal facilities.

    10.   Barnyards,  feed  lots,  turkey  and chicken farms
          and other concentrated domestic animal activity*.

    11.   Agricultural  activities  such as  grazing,  till-
          age,  etc.,  which  affects soil  erosion,  ferti-
          lizer usage, etc.

    12.   Other.

b.   Naturally Occurring.

     1.   Animal populations, both domestic and wild.

     2.   Turbidity   fluctuations   (from   precipitation,
          landslides, etc.).

     3.   Fires.

     4.   Inorganic   contaminants  from  parent  materials
          (e.g., asbestos fibers).

     5.   Algae blooms.

     6.   Other.

     This list is by  no means all inclusive.  The surveyor
     should  rely  principally  on  his  observations  and
     thorough questioning regarding the  unique properties
     of  each watershed  to  completely  describe what  may
     contaminate the  source water.
                  K-4

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3.   Source Construction.

     a.   Surface Intakes.

          1.   Is the source adequate in  quantity?

          2.   Is the best  quality  source  or location in  that
               source being used?

          3.   Is the intake protected  from icing problems  if
               appropriate?

          4.   Is  the intake  screened  to  prevent  entry  of
               debris, and  are  screens maintained?


          5.   Is animal activity controlled within  the immedi-
               ate vicinity of  the intake?

          6.   Is there a raw water  sampling tap?

     b.   Infiltration Galleries.

          1.   Is the source adequate in  quantity?

          2.   Is the best  quality source being used?

          3.   Is  the lid  over  the  gallery watertight  and
               locked?

          4.   Is the collector  in   sound  condition and main-
               tained as necessary?

          5.   Is there a raw water  sampling tap?

     c.   Springs.

          1.   Is the source adequate in  quantity?

          2.   Is there adequate  protection around  the spring
               such as fencing to control  the area  within 200
               feet?

          3.   Is the spring constructed to  best capture the
               spring flow  and exclude surface water  infiltra-
               tion?

          4.   Are  there  drains  to  divert  surface  water  from
               the  vicinity of  the spring?

          5.   Is the collection  structure  of sound  construc-
               tion with no leaks  or cracks?
                      K-5

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          6.    Is there  a  screened overflow and drain pipe?

          7.    Is the  supply  intake  located above the floor and
                screened?

          8.    Is there  a  raw water  sampling tap?

     d.   Catchment and  Cistern.

          1.    Is source adequate in quantity?

          2.    Is the  cistern of adequate size?

          3.    Is the  catchment area  protected  from potential
                contamination?

          4.    is the  catchment drain properly screened?

          5.    Is  the  catchment  area  and cistern  of  sound
                construction and in good condition?

          6.    Is catchment  constructed of approved non-toxic,
                non-leaching material?

          7.    Is the  cistern protected  from  contamination 
                manholes, vents, etc?

          8.    Is there a  raw water  tap?

     e.   Other Surface Sources.

          1.    Is the  source  adequate in quantity?

          2.    Is the best possible  source being used?

          3.    Is the  immediate  vicinity of  the  source  pro-
                tected  from contamination?

          4.    Is the  structure  in  good condition and properly
                constructed?

          5.    Is there a  raw water  sampling tap?

4.   Pumps, Pumphouses, and Controls.

     a.   Are all intake pumps,  booster pumps,  and other pumps
          of sufficient capacity?

     b.   Are all pumps and controls operational and maintained
          properly?
                       K-6

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c.   Are check  valves,  blow off valves, water meters  and
     other appurtenances operated and maintained  properly?

d.   Is  emergency power  backup with  automatic  start-up
     provided and does it work (try it)?

e.   Are  underground   compartments  and  suction   wells
     waterproof?

f.   Is the interior and exterior of the pumphouse in good
     structural condition and properly maintained?

g.   Are there  any  safety hazards  (electrical or mechan-
     ical)  in the pumphouse?

h.   Is  the  pumphouse  locked  and  otherwise   protected
     against vandalism?

i.   Are  water  production  records  maintained   at   the
     pumphouse?

Watershed Management  (controlling  contaminant  sources) :
The goal of the watershed management program  is  to ident-
ify and control contaminant sources in  the watershed  (see
Section 3.3.1 of  this  document,  "Watershed  Control Pro-
gram").  Under ideal conditions each source of contamina-
tion identified in 2 will already have  been identified by
the utility,  and  some means of  control instituted, or  a
factual  determination  made  that  its  impact   on  water
quality is insignificant.   To  assess the degree  to  which
the watershed management program  is  achieving its  goal,
the following types of inquiries could be made:

a.   If the watershed  is  not entirely owned by  the  util-
     ity, have  written agreements  been made  with  other
     land owners to control land usage to the  satisfaction
     of  the  utility?   Are  appropriate regulations  under
     the contract of state/local department  of health  in
     effect?
b.   Is the utility  making efforts to obtain as  complete
     ownership of  the watershed as  possible?  Is  effort
     directed to control critical elements?

c.   Are there means  by which the watershed  is regularly
     inspected for new  sources of contamination or  tres-
     passers where access is limited?

d.   Are there adequately  qualified  personnel employed  by
     the  utility  for  identifying  watershed  and  water
                  K-7

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               quality problems and who are given the responsibility
               to correct these problems?

          e.   Are  raw  water quality records kept  to assess trends
               and  to assess the  impact of different activities and
               contaminant control techniques in the watershed?

          f.   Has  the  system  responded  adequately  to  concerns
               expressed  about  the  source  or watershed  in  past
               sanitary surveys?

          g.   Has  the  utility  identified problems  in  its  yearly
               watershed  control  reports, and if  so,   have  these
               problems been adequately addressed?

          h.   Identify what other agencies  have  control or juris-
               diction  in the  watershed.   Does the utility actively
               interact  with  these  agencies  to  see  that .their
               policies  or   activities  are   consistent  with  the
               utility's goal of maintaining high raw water quality?
B.   Treatment Evaluation
     1.   Disinfection.
          a.   Is   the  disinfection   equipment   and  disinfectant
               appropriate  for  the application (chloramines, chlor-
               ine ,  ozone,   and  chlorine  dioxide  are  generally
               accepted disinfectants)?

          b.   Are  there back-up disinfection units on line in case
               of  failure, and are they operational?

          c.   Is  there  auxiliary power with automatic  start up in
               case of power  outage?   Is it  tested  and operated on a
               regular basis, both with and  without load?

          d.   Is  there an adequate quantity of disinfectant on hand
               and is  it properly stored  (e.g., are chlorine cylin-
               ders properly  labeled and chained)?
          e.   In  the case of  gaseous  chlorine,  is there automatic
               switch over  equipment when  cylinders expire?

          f.   Are  critical  spare  parts  on  hand to  repair disin-
               fection equipment?

          g.   Is disinfectant  feed proportional  to water flow?
                             K-8

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     h.   Are daily records kept of disinfectant residual  near
          the first customer from which to  calculate CTs?

     i.   Are production records  kept  from which to determine
          CTs?

     j.   Are CTs  acceptable  based on  the  level of treatment
          provided  (see  Surface  Water  Treatment  Rule   for
          filtered sources, and Section 3.2.2 of this guidance
          manual  for  unfiltered  sources,   to   determine   the
          appropriate CT)?

     k.   Is  a  disinfectant  residual  maintained in  the   dis-
          tribution  system,   and  are  records  kept  of  daily
          measurements?

     1.   If  gas  chlorine  is  used,  are adequate  safety   pre-
          cautions  being  followed  (e.g.,   exhaust  fan   with
          intake within six inches of the floor,  self-contained
          breathing apparatus that is regularly  tested, regular
          safety training for employees, ammonia bottles and/or
          automatic chlorine  detectors)?   Is the  system   ade-
          quate  to ensure the safety of both  the public and the
          employees in the  event of a chlorine leak?
2.   Other.
     a.    Are other  treatment  processes  appropriate  and are
          they  operated  to  produce  consistently high  water
          quality?

     b.    Are pumps,  chemical  feeders,  and  other mechanical
          equipment in good condition and properly maintained?

     c.    Are controls and  instrumentation and adequate for the
          process,  operational,  well maintained and calibrated?

     d.    Are accurate records  maintained  (volume  of  water
          treated,  amount of chemical used, etc.)?

     e.    Are adequate supplies  of chemical on hand  and pro-
          perly  stored?

     f.    Are adequate safety devices available and precautions
          observed?

     Sections of  a   sanitary  survey pertaining  to  systems
     containing   filtration  facilities have  been  omitted,  as
     this section  of  the  guidance document pertains  to non-
     filtering systems.
                       K-9

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C.   Distribution System Evaluation

     After water has been treated, water  quality must be protected
     and maintained as it flows  through  the distribution system to
     the  customer's tap.   The following  questions pertain  to  the
     water purveyor's  ability to maintain high water quality during
     storage and distribution.

     1.   Storage.

          a.   Gravity.

               1.    Are  storage  reservoirs  covered  and otherwise
                     constructed to prevent contamination?

               2.    Are  all  overflow lines,  vents,  drainlines, or
                     cleanout  pipes turned  downward and  screened?

               3.    Are all reservoirs  inspected  regularly?

               4.    Is the  storage capacity adequate  for  the  system?

               5.    Does   the  reservoir   (or  reservoirs)   provide
                     sufficient pressure throughout the  system?

               6.    Are  surface  coatings  within  the  reservoir in
                     good  repair  and acceptable   for  potable water
                     contact?

               7.    Is the hatchcover  for  the  tank watertight and
                     locked?

               8.    Can the reservoir be  isolated from the system?

               9.    Is adequate  safety  equipment (caged ladder,  OSHA
                     approved   safety  belts,  etc.)  in   place  for
                     climbing  the tank?

               10.    Is the site  fenced,   locked,  or otherwise  pro-
                     tected against vandalism?

               11.    Is  the   storage   reservoir   disinfected after
                     repairs are  made?

               12.    Is  there  a  scheduled  program  for  cleaning
                     storage  reservoir  sediments,  slime on floor and
                     side  walls.

           b.    Hydropneumatic.

                1.   Is the storage capacity adequate for the system?
                            K-10

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          2.    Are instruments,  controls, and  equipment  ade-
               quate, operational, and maintained?

          3.    Are the  interior  and  exterior  surfaces of  the
               pressure tank in good condition?

          4.    Are tank supports  structurally sound?

          5.    Does the  low pressure  cut in provide  adequate
               pressure throughout the entire system?

          6.    Is the pump cycle  rate acceptable  (not more  than
               15 cycles/hour)?

2.   Cross Connections.

     a.   Is   the  system  free  of  known uncontrolled  cross
          connections?

     b.   Does the utility  have  a cross  connection prevention
          program, including annual testing of backflow preven-
          tion devices?

     c.   Are  backflow  prevention devices  installed at   all
          appropriate  locations   (wastewater  treatment  plant,
          industrial  locations, hospitals, etc.)?

3.   Other.

     a.   Are  proper pressures  and  flows maintained  at   all
          times of the year?

     b.   Do  all construction materials meet  AWWA or equivalent
          standards?

     c.   Are all services metered and are meters read?

     d.   Are plans for the system available  and current?

     e.   Does the system have an adequate maintenance  program?

            -  Is there evidence  of leakage in the  system?

            -  Is there a pressure testing program?

            -  Is there a regular flushing program?

            -  Are valves and  hydrants  regularly exercised and
               maintained?
                      K-ll

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                 -  Are  AWWA  standards  for disinfection  followed
                    after all repairs?

                 -  Are  there  specific bacteriological criteria and
                    limits  prescribed  for  new  line  acceptance  or
                    following line repairs?

                 -  Describe the corrosion control program.

                 -  Is the system interconnected with other systems?

D.   Manageme nt/Ope ration

     1.   Is there an organization that is responsible for providing
          the  operation, maintenance,  and management of  the  water
          system?

     2.   Does  the  utility regularly summarize  both current  and
          long-term problems identified in their watershed, or other
          parts of the  system,  and define how  they  intend to solve
          the problems i.e., is their planning mechanism effective;
          do they follow through with plans?

     3.   Is  the  budget  and  financing  satisfactory  to  provide
          continuous  high  quality service,  and  allow for  future
          replacements and improvements?

     4.   Are  customers  charged  user  fees  and  are  collections
          satisfactory?

     5.   Are there  sufficient  personnel to operate  and manage the
          system?

     6.   Are personnel  (including management)  adequately trained,
          educated, and/or certified?

     7.   Are  operation  and maintenance  manuals  and manufacturers
          technical specifications readily available for the system?

     8.   Are routine preventative maintenance schedules established
          and adhered to for all components of the water system?

     9.   Are sufficient tools, supplies, and  maintenance  parts  on
          hand?

    10.   Are sufficient operation and maintenance records kept and
          readily available?

    11.   Is an  emergency plan available and  usable, and are  em-
          ployees aware of it?
                           K-12

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         12.    Are all facilities free from safety defects?

          When the survey  is  completed,   it is  always  preferable  to
          briefly summarize the  survey  with the  operator(s) and manage-
          ment.  The main findings of the survey  should be  reviewed  so  it
          is   clear that  there  are   not  misunderstandings  about   find-
          ings/conclusions.   It  is also good to thank  the utility  for
          taking  part  in the  survey,  arranging interviews with employees,
          gathering and explaining their records, etc.   The information
          and help  which the  utility can  provide  are  invaluable  to  a
          successful survey,  and every attempt should be  made to continue
          a positive relationship with the  system.

3.   Reporting the Survey

     A final  report of the survey should be completed as  soon as possible
     to formally notify  the  system and other agencies  of the findings.
     There is no  set  or necessarily  best  format for doing  so,  and the
     length of the  report will depend on the findings of the survey and
     size of  the  system.   Since the report  may be used for  future compli--
     ance  actions   and  inspections,   it should   include  as a  minimum:
     1) the date of the survey;  2)  who was  present  during the survey;
     3) the findings  of  the  survey;   4) the recommended improvements  to
     identified problems;  and 5)  the  dates  for completion of any improve-
     ments.   Any  differences  between  the  findings  discussed at the
     conclusion of  the  survey and what's  included in  the final report
     should be discussed and  clarified with the  utility prior to sending
     out the  final report.  In other words, the  utility should be  fully
     aware of the contents of the final report before receiving it.
                                K-13

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        APPENDIX L
SMALL SYSTEM CONSIDERATIONS

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                                  APPENDIX L
                          SMALL  SYSTEMS  CONSIDERATIONS

Introduction
     Under  the provisions of  the SWTR,  systems  with fewer than  500 service
connections may be eligible for an exemption.   Guidance  on the requirements
for an exemption is provided in  Section  9.  For systems which are not eligible
for  an  exemption, compliance  with the  SWTR  is  mandatory.  It  is recognized
that the  majority (approximately 75 percent)  of people in  the  United States
are served by  a relatively small number  of large  systems.  However, most water
systems in  the United States  are  small.  For small  systems,  compliance with
the various provisions of the  SDWA has  traditionally been a problem.  Records
show small  systems  have a  disproportionately  higher  incidence  of  drinking
water quality  and monitoring difficulties.  The reasons for these difficulties
can generally  be broken down into the  following three categories:
       -  Economics
       -  Treatment Technologies
       -  Operations  (lack of qualified  personnel)
     Small water  systems typically  face severe  economic  constraints.   Their
lack of operating revenues results in  significant limitations on their ability
to respond to  the requirements of the  SDWA.  These systems cannot benefit from
the economies  of scale which are available to larger systems.
     The  second difficulty  facing the  small systems  has been  the  lack  of
appropriate treatment technologies.  Although methods for removing most of the
contaminants known to occur in  drinking water  are  available,  many  of  these
technologies have only recently  been scaled down  for the smaller systems.
     The  third problem which has  traditionally  plagued small systems is the
lack of well  trained operators.  This deficiency is the  result of  many com-
bined factors.  First of all,  many of these operators are  employed  only on a
part-time basis or  if they are employed on  a  full-time  basis they have  a
myriad of additional duties.  In addition, the operator's technical background
may be  limited as well.   This  results  from  the low salary of  the  position,
which is uninviting to qualified operators.  Also, in spite of the requirement
                                       L-l

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of retaining certified operators upheld in many states,  it seems to be diffi-
cult to enforce this requirement in small systems.
     The  purpose  of this  appendix is  to provide  assistance  to the  Primacy
Agency in defining the problems and potential solutions typically  associated
with small systems.   It is  beyond the scope  of this document to  provide an
indepth  dicussion of  the  needs  of small  systems.  However,  over the  past
several years the needs of the small water systems  have  been recognized to be
of primary concern and numerous  workshops, seminars  and  committees have  been
attempting  to  more clearly define workable  solutions.   A partial  listing cf
the  papers, reports  and  proceedings  which  discuss problems  and  solutions
pertaining  to  small  systems beyond that  which is possible in this  manual is
presented in the reference list of this appendix.

Economics
     One of the most severe constraints of small systems  is the small economic
base from which  to draw funds."  Certain  treatment  and services must  be  pro-
vided for  a community  regardless  of how few people are  served.  Thus,  as the
number of connections  to  the system  decrease, the  cost per connection  in-
creases.   The  economic limitations of small  utilities makes it difficult to
provide  needed upgrading  of existing  facilities  or an  adequate  salary  to
maintain  the employment  of a qualified operator to monitor and maintain  the
system.  Adding to the severity of the economic hardships of small  systems is
the  fact  that  many of  the  small water  systems are privately  owned,  with
private ownership  increasing  as  system size decreases.   The ownership  of  the
plant presents difficulties since privately owned systems are subject  to  rate
controls by the local  public  utility  commission, are not  eligible  for  public
grants and loans,  and may find commercial  loans hard to obtain.
     Financing options for  small  systems  include; federal and state loan  and
grant  programs,   federal  revenue  sharing and  revenue  bonds  (for   municipal
systems)   and  loans through  the  United States Small Business Administration
(SBA) and use  of industrial  development  bonds or privatization (for  private
utilities).  These options  are  explained in  greater  detail  in the  "Guidance
Manual -  Institutional Alternatives for  Snail  Water Systems"  (ANWA,  1986).
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The following paragraphs will explain some existing options which may ease the
hardship of financing small water treatment facilities.
     The major  cause of small  system  difficulties  arises  from the  lack  of
funds and resources.  It is  therefore in the best interest of small utilities
to expand their economic base  and the resources available to them, to achieve
the economies of  scale available  to larger  systems.   Regionalization  is the
physical or operational union of  small systems  to  effect this  goal.   This
union can be accomplished  through  the physical interconnection of two or more
small systems or  the connection of  a smaller system to a pre-existing larger
system.  Water  supply  systems  can  also  join together  for the  purchase  of
supplies, materials, engineering services, billing and maintenance.  The union
of the  small  systems increases the  population served,  thereby dispersing the
operational costs and decreasing the cost per consumer.
     The creation of utility satellites  is another form of regionalization.  A
satellite utility  is one which taps into  the resources of an existing larger
facility without being physically connected  to, or owned by, the  larger facil-
ity.   The  larger  system may  provide any  of  the following  for  the smaller
system:
     1.   Varying levels of  technical operational, or managerial assistance on
          a contract basis.
     2.   Wholesale treated  water with or without additional services.
     3.   Assuming  ownership, operation and  maintenance  responsibility  when
         . the small  system is  physically separate with  a  separate  source.
     The  formation  of  a  satellite  offers  many  advantages  for both  the
satellite  and the  parent  utility.   These  advantages include:   an improved
economy of scale  for  satellites,   an  expanded  revenue  base for  the parent
utility, provisions of  needed resources to  satellites,  the retention of the
satellites'   local  autonomy,   improved  water  quality  management  of  the
satellite,  improved  use  of public  funds  for  publicly owned satellites.
     In order to  create a more  definite structure for the union of resources
of water   treatment  facilities,   water  districts   may   be  created.   Water
districts  are formed by county officials and provide for  the  public ownership
of the  utilities.  The  utilities in any  given district  would combine resources
and/or  physically  connect  systems so that one or two facilities  would provide
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water  for  the entire  district.  The creation  of water  districts  creates
eligibility  for public  monies,  has  the  potential  for economies  of  size,
facilitates the takeover or contract services with  publicly  owned non-commun-
ity  systems and small privately owned systems,  and  offers  a tax  advantage.
Drawbacks  include  subjection  to politics, a  strong local planning  effort is
needed for success, and competition with private enterprises.
     The centralization of utilities can be taken one step further through the
creation of county utilities  or even state  utilities.   The government  will
create a board which may then  act  to acquire, construct,  maintain and  operate
any public  water supply  within its district, the system  may provide water on
its own or purchase water from any municipal corporation.   The  board may adopt
and administer rules for the construction, maintenance, protection  and use of
public water supplies and the fixation of reasonable rates for  water supplies.
The  cost  of  construction  and/or upgrading  of  facilities  may  be defrayed
through  the issuance of bonds  and/or property assessment.  As  with  all  the
alternatives,  the  creation of government control  of the utilities  has  its
advantages  and disadvantages.  The  advantages  include:   the  creation  of
central  management,  creation  of economy  of  scale  for utilities,  eligibility
for public  grants  and  loans,  savings through centralized purchasing,  manage-
ment, consultation, planning and technical assistance, and possible  provision
for pool of trained operators.   The  disadvantages include the  subjectivity to
politics, the slow response caused by bureaucracy,  and competition  to  private
contractors.

Treatment Technologies
     The high  cost  of  available treatment technologies has limited  their  use
in  small water  supply systems.   Recently  prefabricated package plants  and
individual  treatment units have  been developed  to lessen  these costs.   At  the
present time, the treatment technologies which are available  to enable  systems
to comply with the Safe Drinking Water Act are identified  to  be the  following:
       -  Package plants
       -  Slow-sand filters
       -  Diatomaceous earth filters
       -  Cartridge filtration
     A brief discussion of each  treatment method is provided  belcw.

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     Package Plants
     Clarification and  filtration units which require minimal assembly in the
field can now  be manufactured.   To minimize required operator skill level and
operational attention,  the equipment  should be automated.  Continuous effluent
turbidity  and   disinfectant  residual   monitoring  systems  with  alarms  and
emergency shutdown  provisions are  features  that safeguard water  quality and
should be provided for  unattended plants.
     Slow-Sand Filters
     Slow-sand  filters  are applicable  to small water  supply systems.   Their
proven record  of effective removal of  turbidity and  Giardia  cysts makes them
suitable  for  application  where  operational  attention  is minimal.   Since  no
chemicals other  than a  disinfectant are needed, and no mechanical equipment is
involved, the  required operator  skill  level is the  lowest of the filtration
alternatives available  to small systems.
     Diatomaceous Earth Filters
     Diatomaceous  earth  (DE)  pressure and  vacuum  filters  can  be  used  on
relatively low turbidity  surface  waters (less than 1 to 2 NTU) for removal of
turbidity and  Giardia  cysts.   DE filters  can  effectively remove particles  as
small as 1 micron, but  would  require  coagulating chemicals and special filter
aids to provide  significant virus removal.
     Cartridge Filters
     Cartridge  filters  using microporous ceramic  filter elements with  pore
sizes as" small  as  0.2 um may  be  suitable  for producing potable water,  in
combination with disinfection,  from  raw  water supplies  containing  moderate
levels of turbidity,  algae,  protozoa and  bacteria.   The  advantage  to a small
system,  is, with the exception of  chlorination,  that no  other  chemicals are
required.  The process  is  one of  strictly physical removal of small particles
by  straining  as the water passes through the  porous membranes.   Other  than
occasional cleaning or  membrane  replacement,  operational  requirements are not
complex and do not require skilled personnel.
     Selection of a Filtration Technology
     The criteria for selection of a  filtration technology for a small commun-
ity are  essentially  the same as  those  for a larger  community.  That  is,  the
utility  must   first  screen the  complete  list of  available  alternatives  to
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 eliminate those  which are  either  not technically  suited  to the  existing
 conditions  (Table 4-1)  or not affordable by  the utility.   Remaining alterna-
 tives  should  then be  evaluated based  on both cost  (capital,  annual,  and
 life-cycle)  and  non-cost  bases  (operation and maintenance, technical require-
 ments  versus personnel available; flexibility  regarding future needs;  etc.).
 In these evaluations  it  should be noted  that even though  automated package
 plants are  cost-competitive  with slow sand filters, their operation require-
 ments  to  achieve  optimum  performance  could  be  complicated.   Also,  the
 maintenance  requirements  for  package  plants  would  be  mechanically  and
 electrically  oriented  and might  require a  maintenance  agreement  with  the
 manufacturer.
     During  the  process of installing the treatment system,  interim measures
 should be taken  to  ensure the  delivery of  a reasonably  safe water to  the
 consumers.   In   addition  to  the  available   interim  measures   listed  In
 Section 9.3,  temporary  installation  of  mobile  filtration  plants  may  be
possible.   These  trailer-mounted  units  are  sometimes available  from  state
agencies  for emergencies, but  more often  may  be  rented or  leased from  an
equipment manufacturer.
     Modification of Existing Filtration Systems
     Small treatment systems that arc already in existence should comply with
 the performance  criteria  of the  SWTR.   If the systems are not  found  to  be
performing  satisfactorily,  modifications to  the  existing  process  may  be
 required*.  Improvement in  treatment efficiency  depends on  the  type of filtra-
 tion system  in use.   Operation  of slow sand  filters could be  checked for  bed
 depth, short-circuiting, excessive hydraulic  loading, and  for the need to pre-
 treat the raw  water.  Infiltration galleries,  or sometimes, roughing  filters
 ahead of a slow sand filter may provide for better performance  by reducing  the
 solids load  on the filters.   However,  the design criteria and  costs  for this
 alternative have not yet been defined.   Site  specific studies  may be  required
before roughing  filters could be used to achieve compliance with the regula-
 tions.   Diatomaceous earth  (DE)  filters  should be checked  for appropriate
precoat and body feed application, hydraulic  loading, grade (size) of  DE  being
used, and possible need for chemical pretreatment.  Package plants would have
 to  be   checked   process-by-process,   similar  to  the  system  used  for   a
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conventional plant.   Other filtration processes would  have  to be checked for
hydraulic  loading rate, appropriateness  of the filter material  (pore size),
and possible need for additional pretreatment.
     Disinfection
     Disinfection  (CT)  requirements for  small  systems can be  met  in several
different  ways.   The  most  obvious  method of  maintaining   a  disinfectant
residual  in the  distribution system  is  to add disinfectant  at one  or  more
additional  locations.   An  alternate method is to  increase  the  disinfectant
dose at  the existing application  point(s).  The latter alternative, however,
may increase disinfectant byproducts,  including THMs, in the system.
     If it is a relatively  short distance between  the treatment system and the
first  customer,  additional   contact   time  can  be  provided  so  that  the
disinfectant dose  does not have  to be increased  beyond desirable residuals.
Two  specific  methods  of  increasing  contact   time  for  small  systems  are
1) installing a pressure  vessel or  closed  storage vessel,  baffled to provide
adequate contact  time,  or 2)  constructing a looped pipeline,  on  the finished
water line between the  filtration-disinfection  system and the first customer.
The feasibility of  either of  these methods would  depend  on system specifics
that include size, physical conditions, and cost.
     If it is not practical to provide additional  storage  time to achieve the
desired  CT, an  alternate,  more   effective  disinfectant  may be  used.   An
alternate disinfectant may provide  a sufficient CT without altering the system
configuration.

Operations
     Water  treatment facilities  need  to be operated properly  in order  to
achieve  maximum treatment  efficiencies.   There is  currently  a lack  of  well
trained operators at many small treatment plants.   The main cause  is  lack of
awareness  of the  importance  of  correct  plant operation,  lack  of  training
programs, lack of enforcement of the requirement for employment of a certified
operator and lack of funds  to employ such an operator.
     Small systems may wish to implement a circuit rider/operator program.  In
this program a  qualified,  certified,  experienced  operator works  for  several
water supply systems.   The rider  can  either directly  operate  the  plants,  or
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provide technical  assistance to  individual  plant operators, by  acting as  a
trainer through on-the-job supervision.  The latter would be  preferable since
it could create a pool of well trained operators.
     The main  cause of  inadequately trained  operators  is the  lack of  well
established  training  programs.    Until  such  training  programs  are  begun,
systems must depend on other training means, such as  seminars and  books.   One
resource which may  be helpful  in  running  the plant  is  "Basic  Management
Principles for  Small Hater  Systems  - An  AWWA Small-Systems Resource  Book",
1982.
     Host  package  plant  manufacturers'  equipment  manuals include  at  least
brief  sections  on  operating  principles,  methods  for  establishing  proper
chemical dosages, instructions for operating the equipment, and  troubleshoot-
ing guides.  An  individual who studies these basic instructions and receives
comprehensive  start-up training  should be  able  to  operate  the  equipment
satisfactorily.  These services are  vital  to the successful performance of  a
package water treatment plant and should be a requirement of the  package plant
manufacturer.  The engineer designing a package  plant facility should specify
that start-up and training services be provided  by the manufacturer,  and also
should consider requiring the  manufacturer to  visit the plant at  6-month  and
1-year intervals after start-up to  adjust the  equipment,  review  operations,
and retrain operating personnel.  Further, this  program  should be  ongoing  and
funds should be budgeted  every year for at  least  one revisit by  the  package
plant manufacturer.
     Another way for small systems to obtain qualified plant operation would
be to contract the  services  of administrative, operations,  and/or  maintenance
personnel  from a  larger neighboring  utility,  government  agencies,  service
companies or consulting firms.   These organizations could supply  assistance in
financial  and  legal  planning,  engineering, purchasing accounting  and  collec-
tion  services,  laboratory support,  licensed operators or  operator  training,
treatment  and  water quality  assurance,  regulatory  liaison, and/or  emergency
assistance.  Through the  contracting of these services  the utility  provides
for the resources  needed, improves water  quality  management  and  retains  its
autonomy.    However,  if  and when the  contract  is  terminated,  the  utility
returns to its original status.
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References

American Water Works Association.  Basic Management Principles for Small Water
Systems, 1982.

American  Water Works  Association.   Design  and Construction  of  Small Water
Systems, 1984.

Kelly,  Gidley,  Blair  and  Wolfe,  Inc.   Guidance  Manual  -  Institutional
Alternatives  for  Small  Water  Systems.   AWWA  Research  Foundation  Contract
79-84, 1986.
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            APPENDIX M

       PILOT STUDY PROTOCOL
FOR ALTERNATE FILTRATION TECHNOLOGY

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                                  APPENDIX M

     If  a  system desires  to use an alternate  filtration  technology,  then the
 system must  demonstrate  through pilot  testing that the  alternate  technology
 can  meet  the performance  criteria  for  virus  and Giardia  removal  and/or
 inactivation.  However, pilot testing for virus removal is not required if the
 water to be  disinfected has a turbidity less  than 1 NTD  and  sufficient CT is
 provided  to  achieve  4-log virus  inactivation.   Alternate technologies  may
 include  demonstrated technologies  operating  outside  the  range of  accepted
 design criteria.
     This  appendix  provides a  recommended protocol for  evaluating  alternate
 filtration methods  through  pilot  testing.    This  protocol  is  divided  into
 sections:
       -  Pilot Plant
       -  Testing Program
       -  Monitoring and analyses.

Pilot Plant
     The primary consideration  in design  of the pilot plant  is  to  adequately
simulate the  treatment  provided by the  full scale facility.  Criteria which
should be considered in the pilot plant design include but  are not  limited to
the parameters in the following list.
     Treatment Process                  Criteria
     Rapid Mix                          Number of Stages
                                        Detention Time
                                        Mixing Intensity
     Flocculation                       Number of Stages
                                        Detention Time
                                        Mixing Intensity(ies)
     Sedimentation                      Unit Type (plate,  tube, etc.)
                                        Loading Rates
     Filtration                         Media type and  size
                                        Media depth
                                        Loading Rate
                                        Operation Mode  (constant  rate,
                                          declining rate)
     Chemical Addition                  Location
                                        Dosage
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Testing Program
     In developing a pilot testing procedure or study to evaluate an alternate
filtration technology, seasonal water quality variations should be reviewed in
order  to  establish  the annual  worst case  water quality  conditions  for an
individual  source  water.  The  water quality parameters  which should  be re-
viewed include:
       -  Total and/or Fecal Coliforms
       -  Heterotrophic plate count
       -  Turbidity
       -  Temperature
       -  PH
       -  Color
       -  Chlorine demand

     As a minimum, pilot testing should  be conducted when the  source exhibits

its  worst  case  annual  conditions.   However,  it  is  preferable  to  perform

testing under all seasonal water quality conditions.

     The  design  of pilot  plant studies will depend on a variety  of  factors
including the technology being evaluated and individual site constraints.  Any

pilot study should include consideration of the following (Thompson, 1982)    :
       -  Definition of purpose of study
       -  Identification of end product of study
       -  Collection of available background information
       -  Acquisition of additional  information required
       -  Establishment of size of pilot plant and available space
       -  Determination of who will  operate pilot plant
       -  Ascertainment of how it should be operated
       -  Establishment of life of pilot plant
       -  Determination  of frequency  and location  of sample  collection and
          _ analysis
       -  Modification of pilot plant  (if required)
       -  Revision of goals and budget if necessary
       -  Preparation of design  and  construction of pilot plant based on above
       -  Recording of all pilot plant data
     1.Additional  information on the design of  specific  pilot  studies  can  be
     found  in the  following  references:
       -  Overview of Pilot  Plant Studies.   (Thompson, 1982)

       -  Water Treatment  Principles  and Design, James M. Montgomery.

       -  Al-Ani,  C.S.U.,  Filtration  of  Giardia Cysts and Other Substances:
          Volume 3.  Rapid Rate  Filtration  (EPA/600/2-85/027).
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       -  Performance of critical data analysis
       -  Reporting of Substantiated Conclusion
Monitoring Requirements
     The purpose  of  the  pilot  testing  program  is to  demonstrate that  the
alternate filtration  technology  can meet the  performance criteria  for  virus
and  Giardia  removal/inacti vat ion  outlined  in  Section 5.    The  monitoring
locations and  frequency should  therefore be  selected to  comply with  these
requirements.  For example,  filter effluent  turbidity  should  be  monitored
continuously or,  at a minimum every  four  hours.   Disinfectant  residual should
also be monitored as outlined in  Section  5.

References
     J. C.  Thompson,  "Overview  of  Pilot Plant  Studies  in  Proceedings  AWWA
Seminar on Design of Pilot-Plant  Studies," May 16, 1982.
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        APPENDIX N

PROTOCOL FOR DEMONSTRATION
  OF EFFECTIVE TREATMENT

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                               APPENDIX N

                       PROTOCOL FOR DEMONSTRATION
                         OF EFFECTIVE TREATMENT
     Based upon  the  requirements  of the SWTR, the minimum  turbidity perform-
 ance criteria for systems using conventional treatment or direct filtration is
 filtered water turbidity  less than or equal  to  0.5  NTU in 95 percent  of the
 measurements  taken  each month.   However,  at the discretion  of the  Primacy
 Agency, filtered water turbidity  levels  of less  than or equal to 1  NTU in 95
 percent of the measurements  taken every  month may be permitted  on  a case-by-
 case basis depending on  the capability  of the total system to  remove  and/or
 inactivate at least  99.9  percent  of  Giardia lamblia  cysts.    This  appendix
 presents  several approaches which could  be taken to  demonstrate  overall
 effective removal and/or  inactivation of  Giardia  cysts and when higher tur-
 bidity limits might be appropriate.

 Optimize Turbidity Removal
     Since turbidity  measures the  scattering of visible light  {wavelength -
 0.5 um) it will be particularly sensitive on an equivalent-weight basis to the
presence of particles of  this size (O'Melia,  1987).  Filtration theory indi-
 cates that on a per-weight basis,  particles between 0.1 and 2  um (depending on
 filtration rate,  media  size  and  temperature) should be  removed to a  lesser
 degree than particles that are either larger or smaller (Yao,  et  al,  1971) .
 Thus, turbidity measurements are likely to be most sensitive to particles that
 are least likely to be removed.
     Since the principal consideration for filtered  systems under the  SWTR is
 the removal of  Giardia  cysts  which are  considerably larger  than 2 um (7-12
 um), good turbidity removal  should  be  tantamont  to good Giardia cyst removal.
 Therefore, depending  on  the type of turbidity,  it may be possible  to  effec-
 tively remove Giardia cysts  without producing  extremely low  filtered water
 turbidities.
     Treatment plants that  use settling  followed by  filtration,  or  direct
            *
 filtration  are  generally  capable of  producing  a  filtered  water  with  a
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turbidity of  0.2  NTU or  less.   The most likely  cause  of  high turbidities  in
the filtered  water is incorrect coagulant dosing  (O'Melia, 1974).  Regardless
of  the  turbidity  of the raw  or finished  water, coagulant addition  at  some
point prior to  filtration is required to destabilize particles for removal in
the  filter.   Only  plants   documenting  continuous  coagulant  feed  prior  to
filtration should  be eligible for being allowed higher filtered water turbid-
ities than  the 0.5  NTU  requirement.  At plants  that  continuously feed coag-
ulant and do not  meet the  0.5 NTU  requirement,  a series of  jar tests,  and
perhaps sand  column filtration tests (in batch) should be performed to evalu-
ate the optimum coagulant dose for  turbidity removal.
     In the event  that  plants  can document continuous coagulant feed,  and,
after running  the  plant under  conditions  determined  in batch  testing  to  be
optimal for turbidity  removal, still  do not  meet the 0.5  NTU  requirement,
effective  filtration  status  might  be  appropriate.   This  would  further  be
supported if  it can be shown that the full  scale  plant  is  capable  of achieving
a  2-log  reduction  in the concentration  of  particles  between 5  and  15  urn in
size.  Where  a  full scale plant does not yet exist, appropriately scaled-down
pilot  filters  might be  used  for  such a  demonstration.   "Appropriate scale-
down" involves  the following:
       -  filtration rate of the pilot equal to  filtration rate on full scale
          unit,
       -  pilot filter diameter greater  than or  equal to 50 times the media
          diameter, (Robeck, et al  1959)
       -  media diameter,  depth,  and  size  gradation  should  be  identical to
          full  scale,
       -  coagulant dosing  identical to full scale
       -  any  mixing and  settling occurring  before  filtration  in  the full
          scale plant  should  be  reproduced  as   closely  as   possible  in  the
          pilot.   Mixing should be  of  the  same G value(s) , and  the detention
          time  for settling should  be close to the average flow detention time
          for the  projected full scale plant.
      In the case of either a  full  scale or pilot scale demonstration, removal
 of particles in the range of 5 to 15 urn in diameter should be determined using
 an electronic particle  counter that has  been calibrated with latex  spheres.
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If a light blockage device is used (e.g. HIAC) this calibration will have been
done at installation of the device.   The  calibration  should be checked before
taking measurements for the purposes of this demonstration.   Samples should be
diluted appropriately  to  ensure that  measurements do not  reflect  coincident
error.  An electrical sensing zone device (e.g. Coulter Counter or Elzone)  may
also be  used.  Appropriate dilutions,  electrolyte strength,  and  calibration
procedures should be followed  (these  are  scheduled to be outlined in the 17th
edition of Standard Methods).   when using an  electrical  sensing  zone instru-
ment, an  orifice no larger than  125  urn and  no  smaller  than 40 um  should be
used since only particles between 2%  and 40% of the orifice  are  accurately
sized and counted (Karuhn et al 1975).
     Samples  of the  filter influent  and  effluent  should be taken  5  minutes
after the backwashed  filter  is  placed in  operation, and  every 30  minutes
thereafter for  the first  3  hours  of operation, followed by  hourly  samples up
until backwash  (Wiesner et al 1987).   All samples should  show a 2-log removal.
Samples from  repeated  filter runs  may be  averaged at each  sampling  time,  but
samples should not be averaged within one filter run.
     Additional suggestions on particle counting technique (Wiesner 1985) :
     1)    If  particle  counts  are not determined  immediately upon  sampling
          (within 10  minutes)  samples should be diluted.
     2)    For  an  electrical   sensing  zone  measurement,  samples  should  be
          diluted  1:5  to  1:20 with  a "particle-free"  electrolyte  solution
          (approximately 1% NaCl)  containing 100 particles per ml  or fewer.
     3)    For a light blockage measurement,  particle free water should be used
          to dilute samples.
     4)    Dilutions should be done to produce particle concentrations as close
          to  the  tolerance for  coincident  error as possible  to  minimize
          background  counts.
     5)    Particle counts  should be determined within  8 hours of sampling.
     6)    All sampling vessels should  be washed  with laboratory  detergent,
          double rinsed  in particle  free water,  and rinsed  twice with  the
          water being sampled at the time  of sampling.
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Disinfection
     The  level  of disinfection could  also  be considered for determining when
to allow  a higher turbidity performance criterion for a system.  For example,
if a system achieves 3-log Giardia cyst inactivation through disinfection, as
determined by CT  values,  it may be appropriate to allow higher filtered water
turbidities  (i.e.,  greater than 0.5 NTU but  less  than  1 NTU in 95 percent of
the measurements  and never exceeding 5 NTU) .  As an extension of this concept,
if a  system achieves  2-log Giardia cyst  inactivation  and is  able  to demon-
strate greater  than a  1-log reduction in concentration of particles between 5
and 15 um, in accordance  with the procedure discussed in the previous section,
this could provide  a basis for allowing filtered water turbidity limits above
0.5 NTU but less  than  1 NTU in  95 percent of  the measurements.
     The  expected level of fecal contamination and Giardia cyst concentrations
in the source  water  should be considered in the  above analysis.   In many
cases, high levels  of disinfection (e.g.,  2  to  3-log inactivation of Giardia
cysts),  in  addition to  filtration  which  achieves  less than  0.5 NTU  in 95
percent of  the measurements may be appropriate,  depending  upon source water
quality.  Further guidance  on  the level  of disinfection to be provided for
various source  water conditions is provided in Section  4.4.2.
References
Coulter Electronics  600 W.  20th  Street,  Hialeah,  FL   33010-2428
Karuhn,  R.;  Davies,  R.;  Kaye,  B.  H.;  Clinch,  M.  J.  Studies  on the Coulter
Counter Part I.  Powder Company  Volume II, pp.  157-171,  1975
O'Melia,  C.  R.  The  Role of  Polyelectrolytes in Filtration  Processes,  EPA -
67012-74-032, 1974T~~~
Robeck,  G.  G.;  Woodword,  R.  L. Pilot  Plants  for  Water Treatment Research,
Journal of Sanitary  Engineering  ASCE Vol. 85;SA4; 1,  August 1959.
Wiesner,  M.  R.;  Rook, J.  J.;  Fiessinger, F. Optimizing the  Placement of GAC
Filters,  J. AWWA VOL 79,  pp. 39-49,  Dec 1987.
Wiesner,  M.  R.  "Optimum Water  Treatment  Plant Configuration  Effects  of Raw
Water  Characteristics,"  dissertation  John Hopkins  University,  Baltimore, MD,
1985.
                                       N-4

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        APPENDIX O

PROTOCOLS FOR POINT-OF-USE
          DEVICES

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             UNITED STATES
    ENVIRONMENTAL PROTECTION AGENCY
         Registration Division
     Office of Pesticide Programs
    Criteria and Standards.Division
       Office of Drinking Water
    GUIDE STANDARD AND PROTOCOL FOR
TESTING MICROBIOLOGICAL WATER PURIFIERS
         Report of Task Force
         Submitted April, 1986
          Revised April, 1987

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                                   CONTENTS



                                                                      Page

PREFACE

1.   GENERAL                                                            1

2.   PERFORMANCE REQUIREMENTS                                           6

3.   MICROBIOLOGICAL WATER PURIFIER TEST PROCEDURES                     8

APPENDIX   1   SUMMARY FOR BASIS OF STANDARDS AND                       21
  TEST WATER PARAMETERS

APPENDIX   2   LIST OF PARTICIPANTS IN TASK FORCE                       29

APPENDIX   3   RESPONSE BY REVIEW SUBCOMMITTEE TO                       31
  PUBLIC COMMENTS

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Preface
     The protocol  presented in this paper  can be applied to  demonstrate  the
effectiveness  of  new  technologies as  well  as  point-of-use  devices.   The
evaluation  presented   here   deals   with  the  removal  of  particulates   and
disinfection.    In  areas   which   pertain  to  disinfection,  the  guidelines
contained in Appendix G take precedence.

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                                  1.  GENERAL


1.1  Introduction


     The subject of microbiological purification for waters of  unknown  micro-

biological quality repeatedly presents itself to a variety of  governmental and

non-governmental agencies, consumer  groups,  manufacturers and  others.   Exam-

ples of possible application of such purification capabilities include:

       -  Backpackers and campers

       -  Non-standard military requirements

       -  Floods and other natural disasters

       -  Foreign travel and stations  (however, not  for  extreme contamination
          situations outside of the U.S.)

          Contaminated individual sources,  wells and  springs  (however, not for
          the conversion of waste water to  microbiologically potable water)

       -  Motorhomes and trailers

     Batch methods of water  purification based on chlorine and  iodine  disin-

fection or  boiling are well  known,  but many  situations and personal  choice

call for  the consideration  of water  treatment  equipment.   Federal  agencies

specifically  involved  in  responding to questions and  problems relating  to

microbiological purifier equipment include:
       -  Registration Division, Office of Pesticide Programs  (OPP),  Environ-
          mental Protection  Agency  (EPA):  registration  of  microbiological
          purifiers (using chemicals);

       -  Compliance  Monitoring  Staff,  EPA:   control  of  microbiological
          purifier device  claims  (non-registerable  products  such  as  ultra-
          violet units,  ozonators, chlorine generators, others);

       -  U.S. Army Medical Bioengineering  Research and Development Laboratory
          (USAMBRDL), U.S.  Army  Natick Research  and Development  Center  and
          other  Army and  military  agencies:   research   and  development  for
          possible field applications;

       -  Criteria and  Standards Division,  Office of Drinking Water  (ODW) ,
          EPA:  Consideration  of  point-of-use  technology as  acceptable  tech-
          nology  under  the  Primary  Drinking Water  Regulations;   consumer
          information and service;

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       -  Drinking  Water   Research,   Water  Engineering  Research  Laboratory
           (WERL), EPA;  responsible for water treatment  technology research;
       -  Microbiology  Branch,  Health Effects Research  Laboratory (HERL), EPA;
          responsible  for  study  of health effects  related  to drinking water
          filters.
     A  number of  representatives  of  the  above mentioned  agencies  provided
excellent participation in the task  force  to  develop microbiological testing
protocols for  water purifiers.  Major  participation  was  also provided by the
following:
       -  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  (microbiology)   from  the  University  of
          Arizona.
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.,  et  al.,
Nov. 22,  1965),   a  unit,   in   order  to  be  called  a  microbiological  water
purifier, must remove,  kill or inactivate all types of disease-causing micro-
organisms from the  water,  including  bacteria,  viruses  and  protozoan  cysts so
as to render the processed water safe  for drinking.  Therefore, to qualify, a
microbiological  water  purifier must  treat or  remove all types  of challenge
organisms to meet specified standards.
     1.2.2  General Guide
     The standard and protocol  will be  a general guide  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 was not feasible to
conduct full-fledged  testing for  all possible  types  of units.  Consequently,
protocol users should  include  pre-testing of  their  units  in  a  testing  rig,
including . the  sampling techniques to  be used.   Where  users  of  the  protocol
find good  reason  to alter or add to the  guide in order  to meet  specific
operational problems, to use an alternate organism or laboratory procedure, or
to  respond  to innovative  treatment  units  without  decreasing  the level  of

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 testing  or  altering the intent of  the  protocol, they should feel  free  to do
 so.   For example, the  OPP  Registration Division might  find it  necessary to
 amend  the guide  somewhat  for  different  types  of  treatment units.   Another
 example  would  be ultraviolet  (O.V.)  units,  which may have  specific  require-
 ments in addition to the guide protocol.
     1.2.3  Performance-Based
     The  standard will be  performance-based,  utilizing realistic  worst case
 challenges and  test  conditions and  use  of the standard shall result  in  water
 quality   equivalent  to  that  of   a   public  water   supply  meeting   the
 microbiological requirements and. intent of the National Primary Drinking  Hater
 Regulations.
     1.2.4  Exceptions
     A microbiological 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 units  removing  specific
 organisms to serve a definable environmental  need  (i.e., cyst  reduction  units
 which can be used on otherwise disinfected and microbiologically safe  drinking
water, such  as  a disinfected  but unfiltered surface water  containing cysts.
 Such units are not to be called microbiological water purifiers and  should not
be used as sole treatment for an untreated raw water.)
     1.2.5  Not to Cover Non-Microbiological Reduction Claims
     The treatment of water to achieve removal of a specific chemical  or  other
 non-microbiological substances from water 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 Information Exclusions
     While  the  standard recommends safe, responsible  construction of  units
 with non-toxic materials for optimum  operation,  all  such items  and  associated
 operational  considerations  are  excluded  as  being beyond  the scope  of  the
 standard.  Included in the exclusion are materials of construction,  electrical
 and safety aspects,  design  and construction  details,  operational  instructions
 and information, and mechanical performance testing.

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     1.2.7  Research Needs Excluded
     The  guide  standard  and protocol  must  represent  a  practical  testing
program and not include research recommendations.  For example, consideration
of  mutant organisms  or  differentiation  between  injured and  dead  organisms
would be  research  items at this time and not appropriate for inclusion in the
standard.
     1.2.8  Not to Consider Sabotage
     Esoteric problems  which could be presented by  a variety of hypothetical
terrorist  (or wartime)  situations,  would provide an unnecessary complication,
and are not appropriate  for inclusion in the standard.
     1.2.9  Continuity
     The  guide  standard  and  protocol will be  a living  document, subject  to
revision  and updating  with the onset of new  technology and knowledge.   It  is
recommended that the  responsible authorities  for registration  and  drinking
water quality  review potential needs  every two to  three years and  reconvene
the task  force  upon need or upon request  from  the water quality industry,  to
review and update the standard and testing protocol.

1.3  Treatment Units Coverage
     1.3.1  Universe of  Possible Treatment 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 light  ra-
diation.
     1.3.2  Coverage of  This Standard
     In view of  the  limited technical data available and in order to  expedite
the work  of the task  force,  the initial  coverage is  limited, on a  priority
basis,  to three  basic  types of  microbiological water  purifiers or  active
components with their principal means of action as follows:
     1.3.2.1  Ceramic Filtration Candles or Units  (may  or
              may not contain a chemical bacteriostatic agent)
     Filtration,  and adsorption,  and chemical  anti-microbial  activity if  a
chemical  is included.

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     1.3.2.2  Halogenated Resins and Units
     Chemical  disinfection  and  possibly  filtration.    (Note:   While  not
included in this guide standard, halogen products  for  disinfection or systems
using halogen  addition  and fine filtration  may be  tested  using many of  its
elements, i.e., test water parameters,  microbiological  challenge and  reduction
requirements, analytical techniques and other pertinent elements.)
     1.3.2.3  Ultraviolet (UV)  Units
     0V irradiation with possible add-on treatment for adsorption and filtra-
tion (not applicable to 0V units for treating potable  water  from public  water
supply systems).
     1.3.3  Application of Principles to Other Units
     While only three types of units are covered in this standard, the princi-
ples and approaches outlined should  provide  an initial guide for the testing
of any of a number of other types of units  and/or systems for the microbiolo'g-
ical purification of contaminated water.

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                         2.  PERFORMANCE REQUIREMENTS

2.1  Microbiological Water Purifier
     In order  to make  the claim  of "microbiological water  purifier,"  units
must be tested and demonstrated  to meet the microbiological reduction require-
ments  of  Table  1  according  to  the  test procedures  described in  Section 3
(Appendix O-l) for the specific  type  of unit involved.

2.2  Chemical Health Limits
     Where  silver  or some other pesticidal  chemical is used in a  unit,  that
chemical  concentration  in the effluent  water must  meet  any  National Primary
Drinking Water Maximum  Contaminant Level (MCL), additional Federal guidelines
or otherwise  be  demonstrated not  to constitute a threat  to  health  from con-
sumption or contact where no MCL exists.

2.3  Stability of Pesticidal Chemical
     Where  a pesticidal  chemical is used in the treatment unit, the stability
of the chemical for  disinfectant  effectiveness should be sufficient for the
potential shelf  life  and the projected use life of  the unit based on manufac-
turer'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
treatment capability  either  through:
     a.   Having the  unit  terminate discharge  of  treated water, or
     b.   Sounding  an alarm,  or
     c.   Providing simple,  explicit instruction for  servicing  or replacing
          units  within  the recommended use  life (measurable in  terms of volume
          throughput, specific  time frame or other appropriate  method).

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     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  disinfection is  acceptable  for short-term or
limited or  emergency use but  that  it is  not recommended  for long-term or
routine community water supply application where iodine-containing  species may
remain in the drinking water.

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              3.  MICROBIOLOGICAL WATER PURIFIER TEST PROCEDURES

3.1  Purpose
     These tests  are performed on ceramic  filtration  candles or  units,  halo-
genated resins  and  units and ultraviolet  (UV) units  in order to  substantiate
their microbiological  removal  capabilities over  the effective use life  of  the
purifier as  defined in Table  1  and,  where a pesticidal chemical  is  used,  to
determine  that said chemical  is  not  present  in  the effluent  at  excessive
levels (see Section  3.5.3.4, Appendix O).

3.2  Apparatus
     Three production units of  a type  are to  be  tested,  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-Schematic"  (p. A-2 of Standard Number 53
"Drinking  Water  Treatment  Units    Health Effects,"   National  Sanitation
Foundation).  Otherwise,  the  test rig must be designed to simulate field  use
conditions (worst case)  for the unit  to be tested.

3.3  Test Waters    Non-Microbioloaical Parameters
     In addition  to the microbiological influent challenges, the various test
waters "will be  constituted  with  chemical  and  physical  characteristics  as
follows:
     3.3.1  Test  Water #1  (General Test Water)
     This water is intended for the normal non-stressed  (non-challenge) phase
of  testing for all units and shall  have  specific characteristics  which  may
easily  be obtained by  the  adjustment of  many  public system  tap waters,  as
follows:
     a.   It shall  be free  of  any chlorine or other disinfectant  residual;
     b.   pH  6.5-8.5;
     c.   Total Organic Carbon (TOO  0.1 - 5.0 mg/L;
     d.   Turbidity 0.1-5  NTU;

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     e.   Temperature 20 C  5 C; and
     f.   Total Dissolved Solids (TDS)  50 - 500 mg/L.
     3.3.2  Test Water #2 (Challenge Test Water/Halogen Disinfection)
     This water is intended for  the  stressed  challenge phase of testing where
units involve halogen disinfectants  (halogen  resins  or other units)  and shall
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  information
          indicates that  the  low pH will be the  most severe test for virus
          reduction by iodine disinfection);
     c.   Total Organic Carbon (TOO  not less than 10 mg/L;
     d.   Turbidity not less than 30 NTU;
     e.   Temperature 4 C  1C; and
     f.   Total Dissolved Solids (TDS)  1,500 mg/L t 150 mg/L.
     3.3.3  Test Water #3 (Challenge Test Water/Ceramic Candle
            or Units With or Without Silver Impregnation)	
     This water  is  intended for the stressed challenge phase of  testing for
the indicated  units  but not  for such  units  when  impregnated with a  halogen
disinfectant (for the latter,  use Test Water 2).  It shall  have the  following
specific characteristics:
     a.   It shall be free of any chlorine or other disinfectant residual;
     b.   pH 9.0  .2;
     c.   Total Organic Carbon (TOO   not less than 10 mg/L;
     d.   Turbidity  not less than 30 NTU;
     e.   Temperature 4 C  1C; and
     f.   Total Dissolved Solids (TDS)   1,500 mg/L  150 mg/L.
     3.3.4  Test Water #4 (Challenge Test Water for Ultraviolet Units)
     This water is intended for the stressed phase of testing for UV  units and
shall have the following specific characteristics:

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     a.   Free of chlorine or other disinfectant residual;

     b.   pH 6.5 - 8.5;

     c.   Total Organic Carbon  (TOO  not less than 10 mg/L;

     d.   Turbidity  not less than 30 NTU;

     e.   Temperature 4 C  1 C;

     f.   Total Dissolved Solids  (TDS)  1,500 mg/1  150 mg/L;

     g.   Color  U.V.  absorption  (absorption  at 254  ran)    Sufficient  para-
          hydroxybenzoic acid (PHBH) to be just below the trigger point of the
          warning alarm on the U.V. unit.  (Note that Section 3.5.1.1 provides
          an alternative of adjusting the U.V. lamp electronically,  especially
          when the U.V. lamp is preceded by activated carbon treatment.)

     3.3.5  Test Water #5 (Leaching Test Water for Units 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 characteristics:

     a.   Free of chlorine or other disinfectant residual;

     b.   pH  5.0  0.2;

     c.   Total Organic Carbon  (TOO  approximately 1.0 mg/L;

     d.   Turbidity  0.1 - 5 NTU;

     e.   Temperature  20 C  5 C; and

     f.   Total Dissolved Solids  (TDS)  25 - 100 mg/L.

     3.3.6  Recommended Materials for Adjusting Test Water Characteristics

     a.   pH:  inorganic acids or bases (i.e., HC1, NaOH);

     b.   Total Organic Carbon  (TOO:  humic acids;

     c,   Turbidity:  A.C. Fine Test Dust (Park No. 1543094)

               from:     A.C. Spark Plug Division
                         General Motors Corporation
                         1300 North Dort Highway
                         Flint, Michigan 48556;

     d.   Total Dissolved Solids  (TDS):   sea  salts, Sigma Chemical  Co.,  S9883
          (St. Louis,MO)  or another equivalent source of TDS;
                                       10

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     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  time  of

its preparation and subsequent improvements should be expected.  Methods  used

for microbiological analyses should be compatible with and equal to or better

than those given below.

     3.4.1.1  Bacterial Tests

     a.   Chosen Organism:   Klebsiella terrigena (ATCC-33257).

     b.   Method of Production:  Test organism will be prepared by overnight
          growth in nutrient broth  or equivalent to  obtain the organism in the
          stationary  growth  phase  (Reference:  Asburg,  E.D.,  Methods  of
          Testing Sanitizers and Bacteriostatic Substances In:  Disinfection,
          Sterilization and  Preservation, Seymour S. Block,  ed., pp. 964-950,
          1983}.  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  phosphate  buffered
          saline.  The suspensions  should be filtered through sterile  Whatman
          Number 2  filter   paper  (or equivalent)   to  remove any  bacterial
          clumps.  New batches of organisms must be prepared daily for use  in
          challenge testing.

     c.   State of  Organism:   Organisms in  the stationary  growth  phase and
          suspended in phosphate buffered saline will be used.

     d. .  Assay Techniques:   Assay may be  by  the spread plate,  pour plate  or
          membrane filter technique on nutrient agar, M.F.C. or m-Endo medium
          (Standard Methods  for the Examination of Water and Wastewater,  16th
          edition,  1985,  APHA).   Each  sample  dilution will  be assayed  in
          triplicate.

     3.4.1.2  Virus Tests
     a.   Chosen Organisms:   Poliovirus  type  1  (LSc)  (ATCC-VR-59),  and Rota-
          virus Strain SA-11 (ATCC-VR-899)  or  WA (ATCC-VR-2018).

     b.   Method  of Production:   All stocks   should  be  grown  by  a  method
          described by Smith and Gerba (in Methods  in Environmental virology,
          pp. 15-47, 1982)  and  purified by  the procedure   of  Sharp,  et al.
          (Appl. Microbiol.,  29:94-101,  1975),  or  similar  procedure  (Herman
          and Hoff, Appl.   Environ.  Microbiol., 48:317-323,  1984),  as these
          methods will produce largely monodispersed virion particles.
                                       11

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c.   State  of the Organism:   Preparation  procedure will largely produce
     monodispersed particles.

d.   Assay  Techniques:  Poliovirus  type  1  may be grown in the BGM, MA-104
     or other cell line which  will  support the  growth of this virus.  The
     rotaviruses  are best  grown in  the  MA-104  cell line.   Since both
     viruses  can  be  assayed  on the  MA-104  cell  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  10 /mL  of each virus) .  Assays
     may  be as  plaque forming  units  (PFU) or  as immunofluorescence foci
     (IF)   (Smith  and  Gerba,   In:   Methods  in Environmental  Virology,
     PP-  15-47, 1982).  Each dilution will be assayed in triplicate.

3.4.1.3   Cyst Tests

a.   Chosen Organism

     1.   Giardia lamblia or the related organism,  Giardia muris,  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  particles may only be  used  to evaluate
          filtration efficacy.   Disinfection efficacy can  only be evalu-
          ated with  the use  of viable Giardia cysts.

b.   Method of  Production:   Giardia muris may  be  produced in laboratory
     mice  and  Giardia  lamblia may  be produced   in Mongolian  gerbils;
     inactivation results  based on  excystation measurements  correlate
     well with animal infectivity results.

c.   State  of  the  Organism:    Organisms   may  be  separated   from  fecal
   .  material by the  procedure  described by  Sauch  (Appl.  Environ.
     Microbiol.,  48:454-455,  1984)  or  by the  procedure described  by
     Bingham, et  al.  (Exp. Parasitol., 47:284-281,  1979).

d.   Assay  Techniques:  Cysts  are first reconcentrated  (500 ml., minimum
     sample size) according to  the  method of Rice,  Hoff and  Schaefer
     (Appl.  Environ.  Microbiol.,  43:250-251,   1982).   The  excystation
     method described  by Schaefer, et al.  (Trans.,  Royal Soc.  of Trop.
     Med.  &  Hyg.  78:795-800,  1984)  shall  be  used to  evaluate Giardia
     muris  cyst  viability.   For Giardia  lamblia cysts,  the  excystation
     method described by  Bingham and Meyer (Nature, 277:301-302, 1979) or
     Rice and Schaefer (J.  Clin. Microbiol.,  14:709-710,  1981)  shall be
     used.   Cyst viability  may  also  be  determined  by  an assay  method
     involving  the  counting  of trophozoites  as   well  as intact  cysts
     (Bingham, et al., Exp.  Parasitol.,  47:284-291, 1979).
                                   12

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     3.4.2  Chemical and Physical Methods

     All physical and chemical analyses shall be conducted  in accordance  with

procedures in Standard  Methods for the  Examination  of Water and Wastewater.

16th Edition, American Public Health Association,  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  the  start  of the  test  in
               accordance with the  manufacturer's  instructions  with the  test
               water without  the addition of the  test contaminant.  Measure
               the flow rate through each  unit.  The unit shall be tested  ar
               the maximum  system pressure of  60 psig static  and  flow  rate
               will not be artificially controlled.

          2.   Test waters shall  have  the defined characteristics continuously
               except for test waters  2,  3 and  4  with respect to  turbidity.
               The background non-sampling turbidity level  will be  maintained
               at  0.1-5  NTU  but  the  turbidity  shall be  increased  to  the
               challenge  level  of  not  less than  30  NTU  in  the   following
               manner:

                 -  In the "on" period(s)  prior  to  the  sampling  "on" period.

                 -  In the sampling "on" period when the  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  adequate  seasoning and  uni-
                    formity before sample collection.-)

     b.   1.   Use  appropriate techniques of  dilution and insure  continual
               mixing to prepare  a challenge  solution containing the bacterial
               contaminant.    Then  spike   test  water  continuously  with  the
               influent concentration  specified  in  Table 1.

          2.   Use  appropriate techniques to prepare  concentrated  virus  and
               Giardia suspensions.  Feed  these suspensions into the influent
               stream so  as  to achieve the influent concentrations specified
               in Table 1 in the  following manner:

                 -  In the "on" period(s)  prior  to  the  sampling  "on" period.

                 -  In the sampling "on" period when the  sample actually  will
                    be taken.   (Note:   at least  10  unit void volumes of  seeded
                    water shall pass through the unit prior to sampling  so as
                    to provide adequate seasoning and uniformity before  sample
                    collection.)
                                       13

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     c.   Purge the system  of  the  uncontaminated water with a sufficient flow
          of contaminated test water.   Start an operating cycle of 10 percent
          on, 90 percent off with a 15 to 40 minute cycle (Example:  3 minutes
          on,  27 minutes  off)  with  the 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 halogenated  resins or units  and  for
          10-1/2 days for ceramic candles or units and U.V. units.

     d.   Sampling:  Samples 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  the  investigator.   All  samples shall  be collected  in
          duplicate from the flowing water during the sampling "on" portion  of
          the  cycle and they shall be  one  "unit void volume" in quantity (or
          of  appropriate quantity  for analysis)  and  represent  worst  case
          challenge conditions.   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 be  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  microbiological  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.)

l(a).  Sampling Plan:   Halogenated Resins or Units (Non-iodine Based)
                                                       Tests
Test Point
(% of Estimated
Capacity)	

Start
  25%
  50%
After 48 hours
  stagnation
               Influent
               Background
General
Active
Agent/
Residual

   X
   X
   X
Microbiological

       X
       X
       X
  60%
  75%
After 48 hours
  stagnation
  100%
Chal-
lenge
pH -
9.0  0.2
   X
   X

   X
   X
       X
       X

       X
       X
                                        14

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Kb).  Sampling Plan:  lodinated Resins or Units
                                                       Tests
Test Point
 (% of Estimated
Capacity)

Start
  25%
  50%
After 48 hours
  stagnation
               Influent
               Background
General
Active
Agent/
Residual

   X
   X
   X
Microbiological

       X
       X
       X
  60%
  75%
After 48 hours
  stagnation
Chal-
lenge
pH -
9.0  0.2
   X
   X
       X
       X
  90%
 100%
After 48 hours
  stagnation
Chal-
lenge
pH -
5.0  0.2
   X
   X
       X
       X
    Sampling Plan:  Ceramic Candles or Units and U.V. Units
                                                       Tests
Test Point
                         Influent
                         Backoround
              Microbiolocical
Start  -
Day 3 (middle)
Day 6 (middle)
After 48 hours
  stagnation
          General
                      X
                      X
                      X
Day 7 (middle)
Day 8 (near end)
After 48 hours
  stagnation
Day 10-1/2
          Chal-
          lenge
                     X
                     X

                     X
                     X
(Note:  All days are "running days" and exclude stagnation periods.  When
the units contain silver,  a leaching test shall be conducted  as shown  in
Section 3.5.1.e and silver residual will be measured  at  each  microbiological
sampling point.)

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     e.   Leaching  Tests   for  Silverized  Units:   Where  the unit  contains
          silver,  additional tests utilizing  Test Water #5 will  be conducted
          as follows:
                                                   Tests
                                    Influent
Test Point                          Background              Silver/Residua^

Start                                   X                         X
Day 2                                                             x
After 48 hours
  stagnation                                                      v
     f.   Alternate Sampling Plans:

          1.   Since  some  laboratories may find  it  inconvenient  to test some
               units  on a  16  hour  on/8 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"/80 percent  "off"  for a propor-
                    tionally shorter operational  day

          2.   Sampling points must be appropriately  adjusted in any alternate
               sampling plan.

     g.   Application  of Test Waters:   The  application of  test waters  is
          designed to provide  information on performance under both normal and
          stressed  conditions; it  should be  the same  or equivalent  to  the
          following:

          1.   a.   Halogenated Resins or Units  (Non-iodine based) --

                    First 50%  of test period:      Test Water 1 (General)
                    Last 50% of test period:       Test Water 2 (Challenge)
                                                   (pH - 9.0  0.2)

               b.   lodinated  Resins or Units -

                    First 50%  of test period:      Test Water 1 (General)
                    Next 25% of test period:       Test Water 2 (Challenge)
                                                   (pH - 9.0  0.2)
                    Last 25% of test period:       Test Water 2 (Challenge)
                                                   (but with pH - 5.0  0.2)

          2.   Ceramic Candles or Units 

               First 6 days of testing:            Test Water 1 (General)
               Last 4-1/2 days of testing:         Test Water 3 (Challenge)
                                       16

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     3.   Ultraviolet (U.V.)  Units 

          First 6 days of testing:
          Last 4-1/2 days of testing:

h.   Analyses and monitoring:
                                        Test Water 1 (General)
                                        Test Water 4 (Challenge)
i.
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 (see Section  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  water shall be  con-
     ducted at least  once at the  start of  each  test  period  to
     determine the concentration  of  the  U.S. EPA  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 make sure that there is no signifi-
     cant change over  the test day.   Populations will be  measured
     (for example,  as dispersed in the supply tank)  at the beginning
     and end of the  test day to detect  possible  incidenral effects
     such as  proliferation,  die-off,  adsorption  to surfaces,  etc.
     Relatively stable bacterial  seed populations are  essential  to
     an acceptable  test program.

5.   When a unit contains  a  halogen  or silver,  the active  agent
     residual will  be measured in the effluent at each microbiologi-
     cal test  (sampling)  point.

6.   Silver will additionally be measured three times in  the  efflu-
     ent as specified in Section 3.5.I.e.

Neutralization  of  Disinfection Activity:  Immediately  after  col-
lection, each  test sample must be  treated  to neutralize  residual
disinfectant.   For halogen- and silver-based disinfectants  this  may
be  done  by   addition   of  thioglycollate-thiosulfate   neutralizer
solution (Chambers,  et al., J. Amer.  Water Works Assoc.,  54:208-216,
1962).  This  solution should  be  prepared daily.   All  results  are
invalid unless samples are neutralized immediately upon  collection.
                                  17

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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 set  forth in Section  3.5.1.d.2 shall be maintained.

     2.   Cleaning  of  ceramic units:   Units  should  be  cleaned  according
          to  manufacturer's  directions.   Two  cleanings  should  occur
          during  the  period  of  test   (in  order  to prove  the  unit's
          durability 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.

Jc.   Halogenated units or  U.V. units with mechanical  filtration processes
     separate from the 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 the test flow rate.
     Units with non-removable mechanical filtration components  will  be
     run  until  . flow   is below  that  considered  acceptable  for  consumer
     convenience.   (If  premature  clogging  presents  a  problem,  some
     specialized units may require a customized  test plan.)

1.   Special Provisions for Ultraviolet (U.V.) Units:

     1.   The units will be adequately challenged by the prescribed test
          waters; consequently they will be operated at normal intensity.
          However,  where  the U.V.  treatment component  is  preceded  by
          activated carbon treatment,   the output of the  U.V. lamp shall
          be adjusted  electronically,  such as by reducing the current to
          the lamp or  other appropriate means, to be just above the alarm
          point.  This option shall be  available for use under other U.V.
          configurations,  at the  choice of the persons  responsible  for
          testing,  as  an  alternative  to the use of the  U.V. absorbent,
          p-hydroxybenzoic acid.

     2.   Fail/safe:   Units will provide and will be tested for fail/safe
          warnings  in  the event of water quality  changes  or  equipment
          failures which may  interfere  with its microbiological purifica-
          tion  function.

     3.   Cleaning:    Manufacturer's  guidance with  respect  to  cleaning
          will  be followed.
                                   18

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     3.5.2  Procedure;   Non-Plumbed Units

     a.   General:  The basic procedures given in Section 3.5.1 shall  be  used
          with necessary adaptations to  allow  for the specific design  of the
          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  actual  use conditions  in  consultation with  the manufacturer,
          including flow rate and  number of people  to be served per  day.   in
          some cases variable flow  or other non-standard  conditions  may  be
          necessary to  reflect a worst-case test.

     3.5.3  Acceptance  and  Records

     3.5.3.1
     To qualify  as  a  microbiological water purifier, all  three production

units of a type must continuously  meet or exceed  the reduction  requirements of

Table 1, within allowable measurement tolerances  for not more than  ten percent

of influent/effluent sample pairs,  defined as follows:


          Virus:          one order of magnitude
          Bacteria:      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 1.  An example is given as follows:


       -  Unit:  iodinated  resin.

       -  Number of sample  pairs over the completed  test program:
          10 per unit  3  units = 30.

       -  Number  of  allowable sample  pairs where  log reduction  is  insuffi-
          cient:  10% of 30 = 3 sample pairs.

       -  Allowable minimum log reductions in these  3 pairs:

          0    Bacteria  -   5 log
          0    Virus     -   3 log
          8    Cyst      -   2-1/2  log

       -  Conclusion:   If   the  geometric  mean  of   all  reductions  meets  or
          exceeds  the   requirements  of  Table  1,  the indicated  insufficient
          sample pairs  will.be allowed.
                                       19

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     3.5.3.2  Records
     All pertinent  procedures  and data shall be recorded in a standard format
and retained for possible  review until  the  report of results has  been  com-
pletely accepted by review  authorities,  in  no case  for less than a year.
     3.5.3.3  Scaling Up  or Down
     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 representative of
others.   Where  any serious  doubt  exists, all  units of  various   sizes  may
require  testing.    A  "rule  of three"  is suggested as a matter  of  judgment.
Scaling up to three times larger  or on-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
     Where silver or some other, chemical is  used in the unit, concentrations
in the  effluent water must meet  any National  Primary  Drinking  Water Maximum
Contaminant  Level  (MCL),  additional Federal guidelines,  or otherwise must not
constitute a threat to health-where  no MCL  exists.
                                        20

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                                  APPENDIX O-l

           SUMMARY  FOR  BASIS OF STANDARDS AND  TEST WATER PARAMETERS


A-   Microbiological  Reduction Requirements

     1.   Bacteria

               Current  standards for  the microbiological  safety  of drinking
          water  are  based on  the  presence  of  colifonn  bacteria of  which
          Klebsiella  is a member.   Members  of  the  genus  Klebsiella are also
          potential pathogens  of man (Vlassof,  1977).   Klebsiella terrigena is
          designated  as  the   test   organism  since  it is  commonly found  in
          surface waters  (Izard, et  al.,  1981).

               Experience  with  the  use  of colifonn bacteria  to  estimate the
          presence  of  enteric  bacterial  pathogens  in  drinking water  as per-
          formed over the last  75 years  indicates a high degree  of reliabil-
          ity.   Required testing of more than one bacterial pathogen appears
          unjustified  since  viral  and  Giardia  testing  will  be  required.
          Enteric viruses  and  Giardia  are known to be  more  resistant to common
          disinfectants than  enteric bacterial pathogens  and viruses are more
          resistant to removal by  treatments  such as filtration.  Thus, any
          treatment which  would give a good removal of both virus and Giardia
          pathogens would most likely reduce enteric bacteria  below levels
          considered  infectious (Jarroll, et al.,  1981; Liu, et al., 1971).

               The  concentration of  coliform bacteria  in raw sewage  is approx-
          imately  10/100 ml.   Concentrations  in  polluted stream waters have
          been found  to exceed 10 per 100 ml  (Gulp, et al., 1978, Table 10).

               Based  on the over 10 /100 ml concentrations observed in highly
          polluted  stream water and a target  effluent concentration  of less
          than 1/100  ml,  a 6  log reduction is  recommended.

     2.   Virus

               In  the United  States concentrations of enteroviruses are esti-
                                 3   4
          mated  to  range  from 10 -10 /liter in raw sewage  (Farrah and Schaub,
          1971) .    Based  on this observation  it is  estimated  that  natural
          waters  contaminated  with  raw  sewage may contain  from 10   to 10
          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  (RMCL)  of zero
          for viruses (EPA, 1985) .   Several individuals and organizations have
          developed guidelines  for  the presence of  viruses in drinking water
          and various experts have proposed standards  (WHO, 1979, 1984; Berg,
          1971;   Melnick,   1976).    It  has  generally   been    felt   that
                                        21

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     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.   Guide-
     lines suggested by the World  Health 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.

          Assuming a target effluent level of less than one  virus  in  100
     liters of water and  a concentration of 10   enteric  viruses  in  100
     liters  of  sewage-contaminated  waters,  the  water  purifier  units
     should achieve at  least 4 logs of virus  removal.

          The relative  resistance  of  enteric viruses  to different dis-
     infectants varies  greatly among  the enteric  viruses  and  even  among
     members of the same group (i.e.,  enteroviruses).   For example,  while
     f2 coliphage is one of the most resistant viruses  to  inactivation by
     chlorine it is one of the most susceptible to inactivation by ozone
     (Harakeh and Butler,  1984).   Ionic conditions and  pH  can also  affect
     the  relative  resistance  of  different  viruses  to  a  disinfectant
     (Engelbrecht,  et al., 1980).   On this  basis it  is  felt that more
     than one enteric  virus  should be  tested to  ensure  the efficacy of
     any disinfection system.   Poliovirus type 1  (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 by chlorine,  but  is  still  resistant
     enough to serve as a useful  indicator.   Rotavirus  is  selected  as  the
     second test  enteric  virus  since  it represents  another  group   of
     enteric viruses in nucleic acid composition and size.   It  is  also a
     major cause of  viral gastroenteritis  and has been  documented as  a
     cause of  water borne gastroenteritis   (Gerba,  et al.,  1985).   The
     human rotavirus or the similar Simian rotavirus may  be used  in  the
     test procedure.   A net  4-log reduction for a joint challenge  of
  "  1 x 10 /L each for poliovirus  and rotavirus is recommended.

3.   Cysts (Protozoan)

          Over the past several  years, giardiasis has  consistently been
     one of the most frequently reported waterborne diseases  transmitted
     by drinking  water in the  United States  (Craun, 1984).   EPA  has
     proposed a RMCL of zero for  Giardia (EPA, 1985).   Its  occurrence  has
     generally been  associated  with  treatment  deficiencies   including
     either inadequate  or  no  filtration.   Giardiasis  has not been  known
     to occur from  drinking  water produced  by  well-operated  filtration
     treatment plants.   De Walle,  et al.  (1984), in a study of  filtration
     treatment plant efficiencies,  cited percent removals for Giardia in
     pilot plant  tests  as  follows:

       -  Rapid filtration with coagulation-sedimentation:  96.6-99.9%;

       -  Direct  filtration with  coagulation:  95.9-99.9%.
                                  22

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               From  this  research  and from  the  lack of  Giardia  cases  in
          systems where  adequate filtration exists, a 3-log  (99.9%)  reduction
          requirement  is  considered  to  be  conservative  and  to provide  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  1/L to less
          than 10/L.   Here  a  3-log reduction would provide an  effluent of less
          than 1/100 L,  comparable to  the  recommended  virus  reduction require-
          ments .

               Either  Giardia lamblia or the related  organism, Giardia muris,
          which  is reported to be a satisfactory  test organism  (Hoff, et al.,
          1985) , may be used  as  the challenge organism.  Tests  will be con-
          ducted  with a challenge  of  10  organisms  per  liter for a  3-log
          reduction.

               Where the treatment unit or component for cysts is based on tjie
          principle  of occlusion filtration alone, testing for a 3-log reduc-
          tion of 4-6  micron  particles or  spheres  (National  Sanitation Founda-
          tion Standard  53, as an example)  is  acceptable.  Difficulties in the
          cyst  production  and  measurement  technologies by lesser-equipped
          laboratories may require  the use of such  alternative tests  where
          applicable.

B.   Microbiological Purifier Test Procedures^

     1.   Test Waters

          a.   The  general test  water  (test water #1)  is  designed for  the
               normal, non-stressed  phase  of testing with characteristics that
               may easily  be  obtained by the  adjustment of many public system
               tap waters.

          b.   Test  water #2  is  intended  for the stressed  phase  of testing
               where units  involve halogen disinfectants.

               1.    Since  the  disinfection activity  of some  halogens  falls
                     with a rising pH,  it  is  important to  stress  test  at an
                     elevated  pH.  The recommended  level of 9.0  0.2,  while
                     exceeding the recommended secondary level  (Environmental
                     Protection Agency,  1984)  is still within  a  range seen in
                     some  natural waters   (Environmental  Protection Agency,
                     1976).  However, for iodine-based units,  a second stress-
                     ful  condition  is  provided  a  pH  of  5.0  0.2  since
                     current  information   indicates   that   the  disinfection
                     activity  of iodine  falls with a low pH  (National Research
                     Council,  1980).    While  beneath the recommended  secondary

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          level (Environmental Protection Agency, 1984) a pH  of  5.0
          is not unusual in natural waters (Environmental  Protection
          Agency,  1976).

     2.   Organic matter as  total  organic carbon (TOO 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 (Culp/Wesner/Culp, 1978).

     3.   High concentrations of turbidity can  shield  microorganisms
          and  interfere  with disinfection.  While  the recommended
          level of not less than 30 NTD is in  the range of turbidi-
          ties seen in secondary wastewater effluents,  this level  is
          also  found in  many   surface  waters,  especially   during
          periods of heavy  rainfall and snow melt (Culp/Wesner/Culo,
          1978).

     4.   Studies with Giardia  cysts  have shown decreasing halogen
          disinfection activity  with  lower  temperatures   (Jarroll,
          et al.,   1980);  4  C,   a  common  low   temperature  in many
          natural waters,  is recommended for  the stress test.

     5.   The  amount of  dissolved   solids  (TDS)  may impact  the
          disinfection effectiveness of units that rely on displace-
          able or exchange  elements  by displacement of halogens  or
          resins,  or  it may interfere with  adsorptive  processes.
          While TDS  levels  of 10,000 mg/L are considered unusable
          for drinking,  many supplies with over 2,000 mg/L are used
          for  potable purposes  (Environmental  Protection  Agency,
          1984).  The recommended  level  of 1,500 mg/L represents  a
          realistic stress  challenge.

c.   Test water #3 is intended for the stressed phase of  testing  of
     ceramic  filtration  candles or  units with or  without   silver
     impregnation.

     1.   Since viruses  are typically eluted from adsorbing media  at
          high pHs (Environmental Protection Agency, 1978) it  may  be
          concluded that a  high  pH will provide the 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 mg/L  is  recom-
          mended .

     3.   Turbidity  may enhance  the  entrapment   and  removal   of
          microorganisms  but    it   also   may   stimulate  "short-
          circuiting" through  some  units.  A  turbidity   level   cf
                             24

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                30 NTU  will provide  stress  at  time  of sampling but  the
                non-sampling level  of 0.1-5  NTU will allow routine  opera-
                tion of units.

           4.   Expert opinion holds  that low water temperatures and high
                TDS would  most likely  interfere with virus  reduction  by
                adsorption; consequently, a 4 C temperature and 1,500 mg/L
                TDS are recommended.

      d.    Test water #4 is intended for the stressed phase of testing for
           ultraviolet (UV) units.

           1.   In general, high  TOC, turbidity and TDS and  low tempera-
                ture are  considered most  stressful for UV,  and the  in-
                dicated  challenge  levels  are   the   same  as   for   test
                water #2.

           2.   The pH is  not critical and may range from 6.5  to 8.5.

           3.   In order  to test the UV units  at their most  vulnerable
                stage  of operation,  a color challenge (light absorption'at
                254 nm) is to be maintained  at a  level  where UV  light
                intensity  is just above the  unit's low  intensity warning
                alarm  point.   However,  an  alternate  to  the  absorption
                challenge  is provided through adjusting the  light intensi-
                ty  output   of  the  UV  lamp  electronically  by  reducing
                current  to  the  lamp,  or  other  appropriate means,  to be
                just  above  the   alarm  point;  this  approach   would  be
                particularly necessary  where  the UV  lamp  is  preceded by
                activated  carbon  treatment.

     e.   Test  water #5 is  intended for the  stressed leaching tests of
          units containing silver.   Low  pH,  TOC,  turbidity,  and TDS and
          higher  temperature are felt  to be the characteristics associ-
          ated  with  increased   leachability.   The   recommended  pH  of
          5.0  .2, while being  beneath  the recommended secondary range
          of 6.5-8.5  (Environmental Protection  Agency,  1984)   is  still
          found in some natural waters.

2.   Test Procedures

          The plan for testing  and sampling  is  designed  to  reveal  unit
     performance  under both "normal"  and  "stressed" operating conditions.
     The stressed phase would utilize  a  set of water quality and opera-
     tions conditions to give the units a realistic worst case challenge.
     Testing plans for a  specific  model might  involve modifications  to
     the recommended plan;  more samples could  be  taken and analyzed;  more
     units could be  studied.   The  principle of  demonstrating adequate
     performance  even under  realistic worst  case conditions  should  be
     maintained and  the final selected test  procedures  should  be agreed
     as between investigators and reviewers or regulators.
                                  25

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     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.  Conse-
quently, 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.
                             26

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REFERENCES;

Berg, G.   Integrated approach to  the  problem of viruses in water.  J.  ASCE,
Sanit. Eng. Div. 97:867-882, 1971.

Culp/Wesner/Culp.  Guidance  for  planning the location of water supply  intakes
downstream from municipal wastewater treatment facilities.  EPA Report,  Office
of Drinking Water.  Washington, DC, 1978.

Craun, G. F.  1984.  Waterborne outbreaks of giardiasis:  Current status.   In:
Giardia and  giardiasis.   D. L. Erlandsen and E. A. Meyer Eds.,  Plenum  Press,
New York, pp. 243-261, 1984.

DeWalle, F.  B.;  J. Engeset;  Lawrence, W.  Removal of Giardia  lamblia cyst by
drinking  water  treatment plants.   Report  No.  EPA-600/52-84-069,  Office of
Research and Development, Cincinnati, OH, 1984.

Engelbrecht, R. S.,  et al.   Comparative inactivation of viruses by  chlorine.
Appl. Environ. Microbiol.  40:249-256, 1980.

Environmental Protection Agency.  Quality criteria for water.   Washington,  DC,
1976.

Environmental   Protection   Agency.    National   secondary   drinking    water
regulations.  EPA-570/9-76-000, Washington, DC, 1984.

Environmental Protection Agency.  National primary drinking water regulations;
synthetic organic  chemicals,  inorganic chemicals and microorganisms; Proposed
rule.  Federal Register, Nov.  13, 1985.

Farrah, S. R. ,  and S. A. Schaub.  Viruses in wastewater  sludges.  In:   Viral
Pollution of  the Environment, G. Berg,  Ed.   CRC Press, Boca  Raton, Florida.
pp. 161-163, 1983.

Gerba, C. P.; Rose, J. B.; Singh,  S.  N.   Waterborne  gastroenteritis and  viral
hepatitis.  CRC Critical Rev.  Environ. Contr.  15:213-236, 1985.

Harakeh, M.;  Butler, M.   Inactivation  of  human rotavirus,  SA-11  and  other
enteric viruses in effluent by disinfectants.  J. Hyg. Camb. 93:157-163,  1984.

Hoff, J. C.;  Rice, E. W.; Schaefer,  F.  W.   Comparison of animal infectivity
and  excystation as measures  of  Giardia muris cyst  inactivation by chlorine.
Appl. Environ. Microbiol.  50:1115-1117, 1985.

Izard, D.;  Farragut, C.;Gavini,  F.;  Kersters,  K.;  DeLey,  J.;  Leclerc,  H.
Klebsiella terrigena, a new  species  from water and  soil.   Intl.  J. Systematic
Eacteriol.  31:116-127, 1981.
                                       27

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Jakubowski, W.  Detection  of Giardia cysts  in drinking water.   In:   Giardia
and  Giardiasis,  Erlandsen,  S.  L.;  Meyer,  E.  A.  Eds.,  Plenum  Press,  NY.
pp. 263-286, 1984.

Jarroll, E. L.;  Bingham,   A.  K.;  Meyer, .E.  A.   Giardia  cyst  destruction:
Effectiveness of six  small-quantity water  disinfection  methods.   Am. J.  Trop.
Med.  29:8-11, 1980

Jarroll, E. L.; Bingham, A.  K.;  Meyer,  E. A.   Effect of chlorine on  Giardia
cyst viability.  Appl. Environ.  Microbiol.   43:483-487,  1981.

Liu, 0. C.,  et al.   Relative resistance of  20 human enteric viruses  to  free
chlorine in Potomac River water.   Proceedings of 13th Water Quality Conference
Snoeyink, V.; Griffin, V.  Eds.,  pp. 171-195,  1971.

Melnick, J. L.   Viruses   in  water.     In:    Viruses   in   Water  Berg,   G.;
Bodily, H. L.; Lennette,  E.  H.;  Melnick,  J. L.;  Metclaf T.  G., Eds.   Amer.
Public Hlth. Assoc., Washington,  OE,  pp. 3-11,  1976.

National Research Council.  The  disinfection of  drinking water,  In:  Drinking
Water and Health, Volume 2.  Washington, DC,  pp.  5-137,  1980.

National  Sanitation  Foundation.  Drinking  water  treatment  units:    Health
effects.  Standard 53.  Ann Arbor, MI,  1982.

Vlassoff, L. T.   Klebsiella.    In:     Bacterial  Indicators/Health   Hazards
Associated with Water Hoadley,  A. W.;  Dutka,  B. J., Eds. American Society for
Testing and Materials, Philadelphia,  PA. pp. 275-288,  1977.

World  Health  Organization.   Human  Viruses  in Water,  Technical   Support
Series 639, World Health Organization,  Geneva,  1979.

World Health Organization.  Guidelines  for Drinking Water Quality.  Volume 1.
Recommendations.   World Health Organization,  Geneva,  1984.
                                       28

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                                 APPENDIX 0-2

     LIST OF PARTICIPANTS;  TASK FORCE ON GUIDE STANDARD AND PROTOCOL FOR
                    TESTING MICROBIOLOGICAL WATER PURIFIERS


Stephen A. Schaub, Chairman  U.S. Army Medical Bioengineering Research and
     Development  Laboratory  (USAMBRDL),  Fort  Detrick,  Maryland 21701,  FTS:
     8/935-7207  Comm:  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 Berger, 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  Disinfectants Branch, Office of Pesticide Programs (TS-767CO,
     Environmental Protection Agency, Washington, D.C. 20460, Phone:   703/557-
     3695.

Ruth Douglas  Disinfectants 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. Clair Street, Cincinnati, Ohio
     45268, Phone:  FTS:  8/684-7870  Comm:  513/569-7870.

Ed Geldreich  Chief, Microbiological Treatment Branch, Water Engineering
     Research  Laboratory, Environmental  Protection  Agency,  26  W.   St.  Clair
     Street,  Cincinnati,  Ohio  45268,  Phone:   FTS:   8/684-7232    Comm:
     513/569-7232.

Charles Gerba  Associate Professor, Department of Microbiology and
     Immunology,   University  of  Arizona,  Tucson,   Arizona  85721,   Phone:
     602/621-6906.

John Hoff  Microbiological Treatment Branch, Water  Engineering Research
     Laboratory,  Environmental  Protection  Agency,  26 W.  St.   Clair  Street,
     Cincinnati, Ohio 45268, Phone:  FTS:  8/684-7331  Comm:  513/569-7331.

Art Kaplan  Office of Research and Development  (RD-681) Environmental
     Protection Agency, Washington, D.C. 20460, Phone:  202/382-2583.

Bala Krishnan   Office  of Research  and Development  (RD-681)  Environmental
     Protection Agency, Washington D.C. 20460, Phone:  202/382-2583.
                                        29

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John Lee ~ Disinfectants Brcinch,  Office  of  Pesticide  Programs  (TS-767C)
     Environmental  Protection   Agency,   Washington,   D.C.   20460,   Phone:
     703/557-3663.

Dorothy Portner  Disinfectants Branch,  Office  of  Pesticide Programs
     (TS-767-C),  Environmental  Protection  Agency,  Washington,  D.C.  20460,
     Phone:  703/557-0484.

Don Reasoner  Microbiological  Treatment Branch, Water  Engineering Research
     Laboratory,  Environmental  Protection  Agency,  26  W.  St.  Clair  Street,
     Cincinnati, Ohio  45268, Phone:   312/654-4000.

P. Reguanthan (Regu)  Everpure,  Inc., 660  N. Blackhawk Drive,  Westmont,
     Illinois 60559, Phone:   312/654-4000.

David Stangel  Policy and  Analysis Branch, Office of Compliance  Monitoring,
     Environmental Protection Agency, Washington, D.C.,  Phone:   202/382-7845.

Richard Tobin  Monitoring  and  Criteria  Division,  Environmental Health
     Center, Department  of  Health  and Welfare  of  Canada,  Tunney's Pasture,
     Ottawa, Ontario,  K1A OL2, Canada, Phone:  613/990-8982.
                                       30

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                                  APPENDIX O-3

    RESPONSE BY  REVIEW SUBCOMMITTEE(1)  TO PUBLIC COMMENTS ON GUIDE  STANDARD
           AND PROTOCOL FOR TESTING MICROBIOLOGICAL WATER PURIFIERS


A.   Recommendation  for the use of Giardia  lamblia  cysts  as  a replacement for
     Giardia muris cysts as the protozoan cyst test organisms.

Recommendation;

     The subcommittee  concurs  with the  recommendation and further endorses the
     use of  Giardia lamblia as the preferred cyst test for evaluation of all
     treatment units and devices.   Obviously the use  of the protozoan orga-
     nisms  of actual  health  concern in  testing is  most desirable.  Anyone
     finding  the  Giardia  lamblia  strain  feasible  for  testing  and  cost-
     effective  to work with  is  encouraged to  use same  instead  of Giardia
     muris.

B.   Substitution of 4-6 micron bead or particle tests as  an alternate option
     instead of  the  Giardia cysts for evaluating devices  that rely  strictly on
     occlusion  filtration  for  microbiological  removal:   Several  commenters
     criticized  the use of beads or  particles  (e.g.,  A.C. fine  dust)  and
     recommended only  use of live Giardia cysts for  performance tests.

Discussion;

     The  subcommittee  recognizes  and  favors  the  use of the natural  human
     parasite, Giardia  lamblia, but was  not  aware of any  convincing scientific
     data  which  would disallow  the  optional  use  of  testing  with  beads  or
     particles for units or devices using only occlusion filtration to remove
     microorganisms.   Previous development of the National  Sanitation Standard
     (NSF)  53  (1982) requirement  for cyst reduction (using 4-6  micron parti-
     cles as cyst models)  was  based on engineering  and scientific opinion and
     experimental  evidence at  that  time.   Specifically,  Logsdon     used
     radioactive  cyst  models   in the  initial phase  of  a study  of removal
     efficiencies for  diatomaceous earth filters; subsequent experiments with
     Giardia  muris  cysts   confirmed  the  efficacy  of the  diatomaceous  earth
     filters.  Further  studies by Hendricks    and DeWalle     with Giardia
     lamblia   cysts   also   showed  comparable   reduction   efficiencies   for
     diatomaceous earth filters.
     l.S.A. Schaub;     F.A.  Bell,  Jr.;     P. Berger;    C. Gerba;     J. Hoff;
     P. Regunathan;  and R. Tobin.   [Includes  additional  revision  pursuant  to
     Scientific  Advisory  Panel  review  (Federal  Insecticide, Fungicide,  and
     Rodenticide Act).]
                                        31

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     Subsequently  confirmatory parallel testing  results have been  developed
     vis-a-vis  4-6 micron  particles as  compared to  Giardia lamblia  cysts.
     Specifically,  two units  listed by  NSF  for cyst  reduction  (using  4-6
     micron particles)    have also been tested and lifted for 100% efficiency
     reduction  (using Giardia lamblia cysts) by Hibler   :

          1.   Everpure Model QC4-SC
          2.   Royal Boulton Model F303.

     Again we prefer the use of  the  human  pathogen,  Giardia  lamblia;  however,
     no experimental data has been provided regarding  the lack of  validity or
     of failure in previous tests utilizing beads or particles of 4-6  microns.
     In most cases  the bacterial or  viral  challenges to  occlusion  filters  ill
     represent  a  greater  problem  in  terms  of  microbiological reduction
     requirements  than  will  cysts.   Therefore,  without  substantiation   of
     deficiencies, the use  of  4-6 micron  beads or particles  is  considered to
     be as  feasible as the use of live cysts  for routine performance testing
     of water filtration (occlusion)  devices.

Recommendation;

     Recommend retaining the optional use  of 4-6 micron particles or beads  for
     cyst reduction testing in occlusion filtration devices only.

References;

          Logsdon, G. S., et al.  Alternative Filtration Methods  for  Removal
          of Giardia Cysts and Cyst  Models, JAWWA, 73(2)111-118,  1981.

          Logsdon, G. S.; Hendricks,  D. W., et al.  Control  of  Giardia Cysts
          by Filtration:  The Laboratory's  Rose.   Presented at the AWWA Water
          Quality Technology Conference, December, 1983.

        "  OeWalle, et al.  Removal of Giardia  lamblia Cysts by Drinking Water
          Treatment  Plants,  Grant   No. R806127,   Report  to   Drinking  Water
          Research Division, U.S. EPA (ORD/MERL),  Cincinnati,  Ohio.

     (4)
          National Sanitation Foundation,  Listing  of Drinking  Water Treatment
          Units, Standard 53.  May,  1986.

          Hibler, C. P.  An  Evaluation  of  Filters in  the Removal  of Giardia
          lamblia.  Water Technology, pp.  34-36.   July, 1984.

C.   Alternate assay techniques for  cyst tests (Jensen):   Proposed  alterations
     in cyst tests include a different method  for  separating  cysts from fecal
     material and  an  assay method involving  the  counting of  trophozoites  as
     well as intact cysts.   Both alterations have  been  used by Bingham, et  al.
     (Exp. Parasitol.,  47:284-291, 1979).
                                       32

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Recommendation;

     These alterations appear to be reasonable  laboratory procedures, support-
     ed  by a peer-reviewed article  and will  be  included  in the  Report  as
     options for possible development and use by  interested laboratories.

D.   The use  of pour plate techniques as  an option for Klebsiella terrigena
     bacteria analyses.

Recommendation;

     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 Klebsiella terrigena.
     Consequently,  it will  be  added  to  the  Report as  one  of the acceptable
     techniques.

E.   Option of using Escherichia coli in lieu of Klebsiella terrigena for the
     bacterial tests.

Discussion:

     Appendix 0-1, Section  A.I.  of  the Guide Standard and Protocol sets forth
     the basis  for  selection  of  K.   terrigena  as  the test  bacteria.   The
     selection was made  along pragmatic line emphasizing the occurrence of j^i
     terrigena  in surface  waters  and that  it  would represent  the  enteric
     bacteria.  It was also pointed out that the tests with virus and Giardia
     were expected to be more severe than the bacterial  tests.  For comprehen-
     siveness, bacterial tests were included in the  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
     tes'ting and survival characteristics (equivalent to K.  terriaena)  by the
     interested research laboratory.

Recommendation;

     The intent of the Guide Standard and  Protocol is  to provide a baseline
     program subject to  modification  when properly supported by an interested
     laboratory.  Consequently,  any laboratory could  propose  and with proper
     support  (demonstrating challenge  and  test  equivalency to  K. terrigena)
     use Escherichia coli  or  one of  the other  enteric bacteria.   This  idea
     will be included in revised working  in Section  1.2.2, "General Guide."

F.   Performance requirements  for Giardia cysts  and virus in  relation to the
     EPA-Recommended Maximum Contamination  Levels (RMCLs) of zero.

Discussion:

     The RMCLs of zero for  Giardia and  viruses  which have been proposed by EPA
     are health goals.   They are no enforceable  srandards since to assure the
                                        23

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     presence  of  "no  organisms"  would  require  an  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 test for  units  resulting
     in treated  effluent water equivalent to  that of  a  public water  supply
     meeting  the microbiological  requirements  and  intent  of  the  National
     Primary Drinking Water Regulations.

Recommendation;

     Retain recommended performance (3,og reduction) requirements for  cyst and
     virus reduction.

G.   Rotavirus and its proposed assay:  One commenter  states  that the  rota-
     virus tests are impractical because Amirtharajah  (J. AWWA, 78(3):34-49,
     1976) cites "no  satisfactory culture procedures available  for  analysis of
     these pathogens  and, therefore,  monitoring would not  be  feasible."

Discussion;

     Section 3.4.1.2, "Virus  Tests"  of  the  Report,  presents  means  for  cul-
     turing  and  assaying  rotaviruses.   This  means   for  doing the  rotavirus
     tests are available and are practical for application in  the  laboratory.
     Dr. Amirtharajah was referring to the field collection,  identification in
     the presence of a wide variety of microorganisms, and quantification as
     not being "satisfactory."  Laboratory analysis of  rotaviruses  is practi-
     cal but their field monitoring may not yet be feasible.

     Further, the selection  of both  poliovirus and rotavirus  as test viruses
     was necessitated by  the fact that the surface adsorptive properties and
     disinfection resistance of the various enteric viruses have  been shown to
     differ significantly by virus group and by strains of a  specific  virus.
     Whi-le all  enteric  viruses  and  their strains  could  not  be economically
     tested, it was determined by the  task force  that at  least two distinctly
     different virus types  should be  tested  to achieve some  idea of  the
     diversity of removal by the various  types of water purifiers.   Polio and
     rota  viruses  have  distinctly different  physical and  chemical charac-
     teristics representative  of the  viruses  of  concern.   Polioviruses  are
     small single stranded RNA viruses  with generally good adsorptive proper-
     ties  to surfaces and  filter  media while rotaviruses are over  twice as
     large,  are  double  stranded RNA  and in some  studies  have been  found to
     possess  less  potential  for adsorption onto surfaces or filter  media.
     These two viruses also  have been  demonstrated to have somewhat  different
     disinfection kinetics.

Recommendation:

     Retain the rotavirus test requirements.

H.   Definition  of  microbiological  water  purifier:  One  general comment
     requested redefinition  based  on "lack of any virus  removal "requirement:
                                       34

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     in the EPA primary drinking water  regulations, so that no virus reduction
     requirement should be  included.  Also,  it was claimed that the separation
     of purifiers  from non-purifiers would  be a "disservice  to consumers and
     other users."

Discussion;

     Viruses are recognized in  the EPA  regulations vis-a-vis a proposed recom-
     mended maximum contaminant  level of  zero.  Since virus  monitoring for
     compliance with a possible MCL is not yet  feasible, a treatment require-
     ment is necessary.  Virus  control  will  be considered in the Safe Drinking
     Water Act  filtration  and disinfection treatment regulations.   The reduc-
     tion  of  viruses  by  treatment  is discussed by Amirtharajah  (J.  AWWA,
     78:3:34-49, 1986).

     With  respect  to  consumers  and other  users,  we  feel  that  the  current
     definition is  appropriate  and necessary.  The average consumer cannot be
     expected to  know the  difference between viruses,  bacteria and cysts, or
     when  a  raw water will or will  not  contain any of  these  organisms.  In
     order to protect  the  average consumer,  the subject units either alone jar
     with  supplementary treatment,  should  be  able  to  cope  with all  of the
     specified organisms.

Recommendation;

     Retain the current definition  for  microbiological water purifier.

I.   Coverage of  units:  Several  comments related to  the  coverage  of units.
     These questions are addressed  individually  as follows:

     1.   Ultraviolet  units that are used for supplemental treatment of water
          from  public  water system  taps  would  not  be covered.   We agree that
          such  units  are   not  covered and  parenthetical  language has  been
          included  in  Section 1.3.2.3 to  clarify this point.

     2.   A special status should be given  to  units which remove Giardia and
          bacteria  but not  virus.   Specifically, the  meaning of Section 1.2.4,
           "Exceptions,"  was addressed.   The "Exceptions"  section  was specif-
           ically  developed to  relate to the problem of  public water systems
          having  disinfection  but  no filtration on  a  surface  supply.  Cysts
          alone have been  found to  survive disinfection treatment  and could be
          present  in  such  treated  waters.   In this case an  effective cyst
           filter  serves an  independent,  beneficial  purpose  and should not be
           required  to be a microbiological  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.   The  entire  treatment unit or  system  should  be tested,  not just a
           single  component.   We agree but  believe  that it  is  sufficiently
           clear without  providing additional language.
                                        35

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     4.   The protocol should be expanded to cover units  for  the  reduction of
          TCE, EDB and other chemical pollutants.  We  felt  that the  introduc-
          tion of  non-microbiological claims  to the  standard would make  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."

     Nowhere in our report have we advocated NSF (or any  other laboratory)  as
     the prime or only laboratory for implementing "the required protocol."

Recommendation;

     No action needed.

K.   Instruction   concerning effective  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.

Recommendation;

     Where a manufacturer provides a  satisfactory "other"  means of  determining
     lifetime, this should be accepted.  Appropriate words have been  added to
     Section 2.4.I.C.

L.   Ceramic  candles  should not  be  cleaned  during  testing  because   some
     consumers would  not clean  them  and this  would provide  the  "worst  case
     test."  One  comment asserted this point.

Discussion:

     There is some truth to this  proposition.   However, the  other  approach may
     also have validity.  Frequent brushing may reduce filtration  efficiency.
                                       36

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     In any event, where a manufacturer prescribes filter cleaning and how to
     do it, and provides  a  gauge to determine  lifetime,  we  feel  the testing
     program is bound to follow  the manufacturer's directions.

Recommendation;

     No change needed.

M.   Scaling up  or down.  One comment points  out that one  or  more  manufac-
     turers may  vary size of  treatment  units by increasing or decreasing the
     number of  operative  units  rather than  the size of  the operative  unit.
     The comment suggests allowing scaling based on size of operative unit.

Recommendation;

     We  agree  with  the  comment and  have  added clarifying  words  to  Sec-
     tion 3.5.3.3.

N.   Turbidity  level  of  "not  less that  30 NTU" for ceramic candles or units.
     One comment states that "Such levels are impossible to utilize in testing
     mechanical  filtration devices which  will  clog  entirely or require such
     frequent  brushing  as  to  render  the   test impossible  as  a  practical
     matter."

Discussion;

     We  recognized  the  potential  "clogging problems"  in Section 3.5.1.a(2)
     where  the   30  NTU  water is only to be applied  immediately  before and
     during each sampling event; the non-sampling turbidity  level, which will
     be applied  over 90%  of the "on" time,   is  currently  set at no less than
     10 NTU.

     Turbidity  levels  of  30 NTU are commonly  found  in surface waters during
     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.

Recommendations:

     1.   Retain sampling turbidity  level of not less than 30 NTU, and

     2.   Change non-sampling turbidity  to 0.1-5 NTU.   Appropriate wording
          changes  have  been  introduced  in   Section 3.5.1.a(2)   and  in  Appen-
          dix O-l, Section B.

O.   Chlorine  in test  water  #5.  One comment asserts that chlorine "tends to
     increase  silver ion leaching activity" and that a  high  chlorine level
     should  be  included  in  the silver  leaching test;  but no  reference  or
     evidence, however, is provided  to back  this assertion.
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Discussion;

     We have no  compelling evidence or  reason to  expect  that chlorine  will
     enhance the leaching  of  silver.   However, the prescribed low pH and TDS
     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  comments are outlined  and
     discussed as follows:

     1.   Too 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  consumers'  health  pro-
          tection.

     2.   Three units  are too many  to study; parallel  testing  of  two  units
          should be satisfactory:  For consumer  protection, the Disinfectants
          Branch, Office of Pesticide Programs, has  traditionally required the
          testing of  three units.   The  committee  recognizes  the additional
          cost involved  in testing  a  third  unit  but feels  that  this  will
          provide a minimum level of assurance to prevent  infectious disease
          and recommends retention of the 3-unit requirement.

     3.   The protocol requires  large tanks and microbiological reseeding on a
          daily  basis:   We  feel that the  tank size requirements  are  not
          extreme and  can be met 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  that 10% of the
          "on"  time.   This "spot" seeding for viruses and cysts recognized the
          expense and  difficulty of maintaining large  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 some 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 required log reduc-
          tions  without  having  to  utilize   sample  concentration  procedures
          which are time/labor  intensive  and which  may,  on their own, intro-
          duce  quantitative  errors  to the microbiological assays.   As  men-
          tioned in Part I of  this  paper, the  log  reductions for bacteria,
          virus  and  Giardia  have  been   suggested   for  public  water  system
                                       38

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treatment in a paper by Amirtharajah  (1986, JAWWA, 78:3:34-49).  The
reductions  in the  microbiological purifier  standard  are  entirely
compatible  with  the  reductions  cited  for  public  water  supply
treatment.
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