# Presentation: 447613

## The Surface Water Treatment Rule

## Summary of Workshop

- History
- The Rule
- Structure
- Filtered and Unfiltered
- Video
- CT Workshops

**Notes:**
This presentation begins with a short history of the development of the Surface Water
Treatment Rule and develops the logic for its construction.

Then the SWTR itself is covered generally in the same order as it is found in the CFR.

Nearly equal emphasis is placed upon filtered and unfiltered surface water systems and 
how the Rule is structured to ensure the provision of reasonably safe water from each. 
Some discussion will be provided in terms of the public health protection short 
comings of the SWTR.

A separate video has been developed that expands upon methods and 
experiences of systems  that meet the filtration avoidance criteria of the rule.
Both large and small unfiltered surface water systems are used as examples.

## History

- National Interim Primary Drinking Water Regulation (NIPDWR)
- Turbidity MCL
- Point of Entry
- No Filtration Required
- No Disinfection Required

**Notes:**
The 1976 NIPDWRs addressed the safety of surface water as follows:
1 NTU as determined by a monthly average except that five or fewer NTU 
may be allowed if the supplier can demonstrate to the State that the higher turbidity
does not:
Interfere with disinfection
Prevent maintenance of an effective residual
Interfere with microbial determinations
5 NTU based on an average for two consecutive days
Section 141.122 Turbidity sampling and analytical requirements
Samples must be collected at a representative entry point
At least once per day
States can give reduced sampling frequency to noncommunity systems if
they practice full-time disinfection and 
maintain a residual in the distribution system
When a sample is > the MCL, resample as soon as practicable but within 1 hour
 The repeat sample determines whether the MCL has been exceeded or
 if the two-day average exceeds 5 NTU

## History (cont.)

- Waterborne Disease
- Giardiasis
- Cryptosporidiosis
- Unfiltered Surface Water Sources

**Notes:**
After passage of the SDWA and promulgation of the NIPDWRs it soon became apparent 
that existing regulations did not provide adequate protection for public health.  
Occurrence of water borne outbreaks of Giardia, mostly at unfiltered systems, 
provided ample evidence that this was the case.

Cryptosporidiosis had not yet become recognized as a public health issue of 
drinking water.

Water borne outbreaks of disease occurred at both filtered and unfiltered 
systems pointing out that more protection was needed by both filtered
and unfiltered systems.

## History (cont.)

- Filtered Water Sources
- Usually in Compliance

**Notes:**
Filtered systems, even small ones, were usually in compliance with the NIPDWRs.  
In part because only one turbidity sample had to be collected each day at a 
representative entry point.  

For small systems that operated a limited number of hours each day that meant they 
would usually arrive at the plant and collect the daily turbidity sample from the 
clearwell, prior to starting the plant.  This allowed the filtered water overnight settling 
in the clearwell and virtually ensured water that would meet the 1 NTU monthly 
standard, even though filtered water entering the clearwell might often have relatively
high turbidity readings.

## Need for Regulation

- Vulnerability
- Coliform Monitoring Weaknesses
- Bacteria
- Viruses
- Cysts
- Alternative Monitoring Weaknesses
- Cysts
- Poor Method
- Discontinuous Occurrence of Organisms

**Notes:**
Some of the issues include:
Surface water systems are typically vulnerable to various types of contaminants simply by
virtue of them being open to collect runoff, wind blown contaminants, spills,  and etc.

The turbidity monitoring was designed to ensure some level of water clarity and treatment.
It did not, however, provide an adequate measure of either treatment (in the case of filtered
systems) or of the effectiveness of the disinfection process.

Coliform monitoring was relatively effective for determining the risks of bacteria and some 
viruses.  However, it did not work well for Giardia lamblia because Giardia is more resistant
to disinfectants than are coliforms.  Coliform free water could well harbor viable cysts of 
pathogenic protozoa.

Some systems and States attempted to assess risks from Giardia by filtering hundred of 
gallons of water through wound filters, then examining the filters for cysts.  This process 
proved to be very inaccurate and, ultimately, public health officials recognized cysts occur 
discontinuously, therefore, treatment should be in place to address them when they are
present.

## History (cont.)

- Advance Notice of Proposed Rulemaking (October 5, 1983)
- Discussion Of:
- Turbidity
*Giardia lamblia*
- Viruses
*Legionella*
- Heterotrophic Plate Count (HPC)

**Notes:**
EPA published an Advanced Notice of Proposed Rulemaking on October 5, 1983.  
This contained a discussion of many of the issues associated with health risks from 
the above bulleted contaminants typically found in surface water sources.

## History (cont.) -- 1986 Amendments

- Section 1412(b)(7)(C)(i) of the 1986 Amendments to the SDWA
- .....propose and promulgate a NPDWR Specifying Criteria Under Which “Filtration” Is Required As a Treatment Technique for PWSs Supplied by Surface Water Sources
- The Administrator Shall Consider:
- Source Water Quality
- Watershed Management
- Treatment Practices Including Disinfection, Length of Storage, etc.

**Notes:**
Subsequently Congress passed the 1986 Amendments to the SDWA.  Included in the
1986 Amendments was the requirement for EPA to address surface water as a drinking
water health issue.  The Act still left open the opportunity for surface water systems
to remain unfiltered should they meet the criteria under which filtration would not be
required.  

Congress included some guidance that the Administrator should consider when
specifying criteria under which filtration would be required as a treatment technique.

## History (cont.) -- 1986 Amendments

- 1986 Amendments to the SDWA
- “Promulgate a NPDWR Requiring Disinfection As a Treatment Technique for PWSs and Specifying Criteria by Which Variances Can Be Granted.”
- National Primary Drinking Water Regulations (NPDWRs) for 83 Contaminants

**Notes:**
The Amendments also addressed disinfection of PWSs but again left open the 
opportunity for some to remain undisinfected should the proper criteria, to be
established by EPA, be met.  

Congress also demanded more action from EPA on other fronts including regulation 
of VOCs, SOCs and IOCs. 

## Brainstorming Session

*Given the Conditions and Risks Associated With Surface Water in 1986, How Would Your Craft Regulations to Reduce the Risks?*

**Notes:**
Break up the class into groups of 6 – 10 persons and have them craft a regulation for surface
 water systems based upon the the material covered in the previous slides and the 
next slide.

About 20 – 25 minutes should be allowed for this workshop.  Then each group 
should have a few minutes to present their regulation and to explain the logic 
they used in establishing the requirements.

## Questions and Considerations

- MCLs or Treatment Techniques or Both?
- Should All Surface Sources be Filtered?
- Should All Surface Sources be Disinfected?
- What Technologies Should be Allowed For Filtration?
- For Disinfection?
- What Monitoring Should be Required?

**Notes:**
These questions should be considered by participants when devising their
strategies for regulating surface water systems.

## History (cont.)

- Journal AWWA, March 1986
*Variance Analyses and Criteria for Treatment Regulations*
*Appiah Amirtharajah*

**Notes:**
In March of 1986 an article by Appiah Amirtharajah entitled Variance Analyses and 
Criteria for Treatment Regulations appeared in the JAWWA and presented:
Rationale for mandatory treatment
Rationale for filtration and disinfection of surface water
Benefit-cost implications of a filtration treatment regulation.
Performance capabilities of treatment technologies.
Percentage removal of target organisms
Virus and Giardia inactivation by disinfection
Removals by filtration-disinfection and storage-disinfection sequences
The multiple barrier concept
Conventional filtration as a “standard of the industry” for surface water treatment.
Criteria for granting variances
Watershed control
Waterborne disease outbreak history
Source  and Finished water monitoring
Control of disinfection practices
Distribution system monitoring

## History (cont.)

- Thursday June 29, 1989
- 40 CFR Parts 141 and 142
*Drinking Water; National Primary Drinking Water Regulations; Filtration, Disinfection; Turbidity, *Giardia lamblia*, Viruses, *Legionella*, and Heterotrophic Bacteria; Final Rule *

**Notes:**
On Thursday June 29, 1989 the Surface Water Treatment Rule (SWTR) was
published in the federal register.

## Part 141—National Primary Drinking Water Regulations

- 141.2
- 141.13
- 141.22
- 141.32
- 141.52

- Definitions
- Maximum Contaminant Level (MCL) for Turbidity
- Turbidity Sampling and Analytical Requirements
- Public Notification
- Maximum Contaminant Level Goals (MCLGs) for Microbiological Contaminants

**Notes:**
Additions and modifications were made to several existing sections of 40 CFR 
Part 141 including those listed above.
We will go through these changes and additions in they order the occur in the CFR.

## Part 141—National Primary Drinking Water Regulations (cont.)

- A New Subpart H - Filtration and Disinfection
- 141.70 General Requirements
- 141.71 Criteria for Avoiding Filtration
- 141.72 Disinfection
- 141.73 Filtration
- 141.74 Analytical and Monitoring Requirements
- 141.75 Reporting and Recordkeeping Requirements

**Notes:**
A new Subpart H entitled Filtration and Disinfection was added to 40 CFR Part
141.  It included the sections listed on the above slide.

The bulk of the substantive parts of the SWTR are contained in subpart H.  With 
the Interim Enhanced Surface Water Treatment Rule, promulgated in December
of 1998, another new definition was subsequently included.  It defined subpart
H systems as those that use surface water or ground water under the direct
influence of surface water.

## Part 141—National Primary Drinking Water Regulations (cont.)

- 141.2 Definitions
- Coagulation
- Conventional Filtration Treatment
- CT or CTcalc
- Diatomaceous Earth Filtration
- Direct Filtration
- Disinfection Contact Time
- Disinfection
- Filtration

**Notes:**
These new definitions were added to part 141.2 Definitions.

These definitions are critical for implementation of the SWTR.  The instructor should
refer to the rule and have an understanding of each.

## Part 141—National Primary Drinking Water Regulations (cont.)

- 141.2 Definitions
- Flocculation
- Ground Water Under the Direct Influence of Surface Water
*Legionella*
- Point of Disinfectant Application
- Residual Disinfectant Concentration
- Sedimentation
- Slow Sand Filtration

**Notes:**
These definitions are critical for implementation of the SWTR.  The instructor should
refer to the rule and have an understanding of each.

## Part 141—National Primary Drinking Water Regulations (cont.)

- 141.2 Definitions
- Surface Water
- Waterborne Disease Outbreak
- Virus

**Notes:**
These definitions are critical for implementation of the SWTR.  The instructor should
refer to the rule and have an understanding of each.

## Conventional Treatment Process (Single Train)

**Notes:**
Over the past several decades experience has shown that water borne disease is
uncommon, even with surface water sources, when they are treated by a well
designed and properly operated “conventional” filtration plant.  Such a plant
makes use of the “multiple barrier” concept of public health protection.  Put in
its simplest form that is, establishing sequential treatment barriers designed to
remove and/or inactivate pathogenic organisms that might be in the raw water
source.

In conventional treatment those barriers typically include; 1. Coagulation/flocculation
and sedimentation, 2. Filtration, and 3. Disinfection with adequate contact time.  In 
this presentation we will address each of these barriers and explain their purpose.  
It is important to note that the SWTR was developed to ensure that conventional
treatment plants are properly operated and that other filtration technologies provide
equivalent protection to the water users.  Additionally, it is crafted to ensure that
systems that meet the criteria to avoid filtration also provide equivalent public health
protection to water users.

## Redundancy

**Prescreen     RM   Flocculation     Sedimentation    Filtration**

*Redundancy*

**Notes:**
As an aside, it is useful to note that most surface water treatment plants are built
with redundant treatment trains.  That is, side-by-side unit processes that provide the
same treatment.  The SWTR primarily addresses the quality of the combined filter
effluent (i.e. the water from all treatment trains after it is combined).  Thus, one or
more treatment trains might be making poor quality water and the problems could
 be masked by blending that water with higher quality water from the other trains.
This could result is more exposure of users to pathogens than what would occur
if all treatment trains were providing equally high quality water.

This is a weakness in the SWTR that we should be aware of and is addressed
in future rules and in training.

## Flash Mix

**Notes:**
Surface water is typically screened to take out sticks, leaves, rocks, etc.  Then the
water passes through a “flash mix” unit where coagulant chemicals are added and
coagulation takes place.   Based on research and years of practical experience,
engineers have learned the mixing intensity flash mixers must provide
to optimize coagulation.

## Example of Inline Mixer

**Notes:**
This is an example of a mechanical flash mixer.  It operates much like a kitchen
blender with the electric motor spinning an impeller that “blends” or “flash mixes” the
chemicals added just upstream.  These types of flash mixers are often designed
so the speed or mixing intensity can be adjusted to fine tune and enhance the
coagulation process.  Note that the chemicals are typically added just ahead of the 
mixer.  Some chemicals that may be damaged by the intensity of the mixing may
be added after the mixer.

Often “static mixers” are used, particularly in small plants.  These are essentially 
sections of pipe with vanes arranged within the pipe to create turbulent flow with the
correct intensity to cause coagulation to occur.

## Slide 23

**Notes:**
Turbidity particles, including pathogens, that need to be removed from surface water 
are typically colloidal in size.  That is, they are very small and have negative charges 
and, therefore, will not settle out of the suspension.  The like charges tend to keep 
the particles from clumping together.  This, their size and the fact that they are typically
hydrophilic (water loving) make them very difficult to settle out or otherwise remove.

Obviously, these problems must be overcome to remove the particles.

## Slide 24

**Notes:**
Inorganic coagulant chemicals such as alum, ferric chloride and ferrous sulfate are
typically added to aid in the removal of turbidity.  These coagulants are salts of 
aluminum or iron and the positive charges associated with them are able, when
fed at a proper dosage, to neutralize the negative charges of the colloidal particles.
This charge neutralization process allows the particles to come together and form
larger particles.

Organic polymers can also be used as coagulants and as coagulant aids.

## Slide 25

**Notes:**
When the particles are neutralized they start to come together and form a “floc.”  

## Floc Growth

**Notes:**
In the next stage of the treatment process, flocculation, the water is mixed to allow
the destabilized particles to come into contact with each other.  The flocculator 
shown above is designed to be “staged” or “tapered” and has higher mixing intensities
in the upstream units.  The mixing intensity decreases as the water passes through
each stage.  Thus larger and larger floc particles are formed in each stage and the
slower mixing allows this to happen and avoids tearing apart floc particles.

In this process floc particles are being formed that can settle out in the plant’s
sedimentation basin or “clarifier.”

## Paddle Wheel Flocculation

**Notes:**
This is a photograph of paddle wheel flocculator units.  The speed of the paddle 
wheels is slowed down as the water travels from the first unit on through the 
process.

## Sedimentation

**Notes:**
The next stage in the process is called sedimentation or clarification.  This occurs in
sedimentation basins or clarifiers.  This is where the bulk of the floc particles are 
removed by gravity.  The clean or “clarified” water then passes out of this basin and
goes on to the filters.

## Floc Settling

**Notes:**
This diagram shows how the floc particles settle and come into contact with other
floc particles.  The concentration of floc particles increases as the particles settle 
deeper and deeper into the clarifier.  The higher concentration of particles, known
as “sludge” is removed from the bottom of the clarifier.

## Sedimentation Basin

**Notes:**
In this photograph the water is traveling in the direction of the super-imposed arrow.
You can see the blanket of floc particles settle deeper into the water as the water
moves through the basin.  At the far end the photo shows the water near the surface
is clear.  This clarified water will move over collector weirs and be transferred to 
the filters for further treatment.

## Slide 31

**Notes:**
This is a drawing of a rectangular clarifier that can be used for water 
treatment.

## Flow

**Flow**

**Notes:**
This drawing shows water entering the center of a round clarifier.  As the
water and floc move outward from the center the floc settles and the
clarified water goes over the weirs.  As the water moves outward in the
basin its velocity decreases and more settling occurs.

## Slide 33

**Notes:**
This is a photo of a round clarifier that has been drained.

## Slide 34

**Notes:**
This is a cross sectional drawing of a unit that allows flash mixing,
flocculation, and sedimentation to occur in a single tank.  The water is
introduced in the center of the tank where flash mixing of chemicals 
occurs.  Then the coagulated water is slowly mixed as it is forced down-
ward under the skirt shown above.  In this process the formation of floc
begins.  After passing under the skirt the water and floc is forced upwards.  Here the water moves upward and the heavier floc particles have a tendency to settle.  A sludge blanket is created that effectively removes more floc as it passes through the blanket.  The clarified water exits at the top of the basin via weirs that are located around the outer edge of the round tank.

The 4 spigots on the side of the basin are used to remove sludge to regulate the density of the sludge blanket.

## Package Plants

*Package Plants*

**Notes:**
Tube settlers or plate settlers are installed in many clarifiers.  They have been shown 
to make the settling process more efficient.

## Filtration

**Notes:**
Next the clarified water passes on to granular media filters where the finer destabilized
floc particles are removed.  In this process the particles typically adsorb or attach
to the grains of sand or anthracite in the filter.

## Filtration

**Notes:**
This is a cross sectional drawing of a granular media filter.  Water enters through the 
top, travels though the media, is collected in underdrain piping systems below, and
eventually exits the filter and passes on to the clearwell or distribution system.  As 
particles are removed in the media, loss of head occurs in the filter.

## Granular Filtration Theory

- Mechanisms of Particulate Removal
- Transport Mechanisms (Major)
- Sedimentation , Impaction, Interception, Diffusion, and Hydrodynamic Forces
- Adsorption (Major)
- Absorption (Minor)
- Straining (Minor)

**Notes:**
The fundamental system that removes particulate matter is filtration, the most common filters are composed of granular media of certain sizes and depths.  The forces that typically remove particles in granular media filters include:
Transport Mechanisms: Sedimentation--Density of particle is significantly greater than water and deviates particulate path from the water streamlines. Impaction--Inertia of particle is greater than hydrodynamic force. Interception--Particle remains in the fluid streamlines, but passes within a distance of half the particles diameter.  Diffusion--Affects only colloidal particles (<1-micron)   Dependent upon density, particle size, and flow velocity. Hydrodynamic--Not an important force with  laminar (non-turbulent) flow, but basically particles are transported out the fluid streamlines to the surface of the media.
Adsorption--collection of particulate matter on the surface or interface zone of media.  Short range surface forces.  Can only be realized if adequate destabilization has been accomplished (functions similar to coagulation).
Absorption--taking in or absorbing contaminants.  This mechanism is of little importance after the initial wetting.
Straining--Removal of particulate by passing liquid through a media with smaller pore sizes than the particles.  Relatively unimportant because most of the particles are too small to be effectively strained.

## Filtration Attachment Mechanisms

- Sedimentation

- Impaction

- Interception

- Diffusion

- Streamlines

- Hydrodynamic Forces

**Notes:**
This is a schematic of sand or anthracite grains within a granular filter bed.  The pores within the media perform very much like small sedimentation basins and the mechanisms discussed in the previous slide work to remove particles as they pass through.  

Obviously, as more and more floc particles are removed in the pores of the media, the pores become smaller and smaller.  This creates headloss through the filter and causes the velocity of the water traveling through the media to increase (assuming the filtration rate remains constant).  This increase in velocity will cause corresponding increased shear forces and will eventually lead to break though of turbidity.

## Slide 40

**Notes:**
These are cross sectional drawings of typical rapid sand (left) and dual media filters.

## Slide 41

**Notes:**
The filter on the left is known as a mixed or multi media filter.  The size of the particles decrease from the top of the media to the support gravel.  The specific gravity, however, increases.  Thus the types of media restratify themselves properly after expansion in the backwashing process.

The filter on the right is a deep bed mono media filter.  These filters can often be operated at high rates while still producing high quality water.

## Filter Backwash

**Notes:**
This drawing depicts the backwashing process.  The media is fluidized and the 
collected particles are removed and disposed of.

## Slide 43

**Notes:**
This drawing depicts the backwashing process.  The media is fluidized and the collected particles are removed and disposed of.

## Part 141—National Primary Drinking Water Regulations (cont.)

- 141.13 MCL for Turbidity
- Requirements Apply to Unfiltered Systems Until December 30, 1991
- Unless State Has Determined Filtration Is Required
- _Applies to Unfiltered Systems, Required to Filter, Until June 29, 1993 or Until Filtration Is Installed, Whichever Is Later_
- Requirements Apply to Filtered Systems Until June 29, 1993

**Notes:**
“The requirements in this section apply to unfiltered systems that the State has 
determined, in writing, pursuant to section 1412(b)(7)(C)(iii), must install filtration, 
until June 29, 1993, or until filtration is installed, whichever is later.”

Not later than 18 months after the enactment of the amendments of 1986, the 
Administrator shall adopt NPDWRs specifying criteria under which filtration is required for 
PWSs supplied by surface water. The Administrator shall consider watershed protection,
 treatment practices (e.g. disinfection and length of water storage) and other factors 
relevant to public health.  (THESE ARE NOT THE EXACT WORDS OF THE ACT)

Section 1412(b)(7)(C)(iii): Within 18 months from the time that the Administrator 
establishes the criteria and procedures under this subparagraph, a State with primary 
enforcement responsibility shall adopt any necessary regulations to implement this 
subparagraph.  Within 12 months of adoption of such regulations the State shall make 
determinations regarding filtration for all PWSs within its jurisdiction supplied by 
surface waters.

## Part 141—National Primary Drinking Water Regulations (cont.)

- 141.22 Turbidity Sampling and Analytical Requirements
- Requirements Apply to Unfiltered Systems Until December 30, 1991
- Unless State Has Determined Filtration Is Required
- _Applies to Unfiltered Systems, Required to Filter, Until June 29, 1993 or Until Filtration Is Installed, Whichever Is Later_
- Requirements Apply to Filtered Systems Until June 29, 1993

**Notes:**
“The requirements in this section apply to unfiltered systems that the State has 
determined, in writing, pursuant to section 1412(b)(7)(C)(iii), must install filtration, 
until June 29, 1993, or until filtration is installed, whichever is later.”

Not later than 18 months after the enactment of the amendments of 1986, the 
Administrator shall adopt NPDWRs specifying criteria under which filtration is required for 
PWSs supplied by surface water. The Administrator shall consider watershed protection,
 treatment practices (e.g. disinfection and length of water storage) and other factors 
relevant to public health.  (THESE ARE NOT THE EXACT WORDS OF THE ACT)

Section 1412(b)(7)(C)(iii): Within 18 months from the time that the Administrator 
establishes the criteria and procedures under this subparagraph, a State with primary 
enforcement responsibility shall adopt any necessary regulations to implement this 
subparagraph.  Within 12 months of adoption of such regulations the State shall make 
determinations regarding filtration for all PWSs within its jurisdiction supplied by 
surface waters.

## Part 141—National Primary Drinking Water Regulations (cont.)

- 141.32 Public Notification
- Adds “Occurrence of a Waterborne Disease Outbreak” As an Acute Violation
- Adds Mandatory Health Effects Language for “Microbiological Contaminants” for Violations of Subpart H

**Notes:**
Acute violations that require acute type notification include:
Any violations specified by State as posing an acute risk.
NO3 or NO4
TCR violation with fecal or E. coli in one or more of the samples
Occurrence of a waterborne disease as defined in 141.2 (in a system that is deter-
mined to be deficient in treatment).

Waterborne Disease Outbreak means the significant occurrence of an acute
 infectious illness associated with drinking water.

## 141.52 MCLGs for Microbiological Contaminants

*Part 141—National Primary Drinking Water Regulations (cont.)*

**Notes:**
Maximum contaminant level goals are established in the SWTR for these pathogens.
The MCLG must be established at a level that poses no risk to water consumers
with a margin of safety.  Because it is conceivable that one pathogen could cause
infection, the EPA established the MCLGs at zero.

Note: The Interim Enhance Surface Water Treatment Rule(IESWTR), effective 
January 1, 2002, and the Long Term 1 Enhanced Surface Water Treatment Rule
(LT1), effective January 14, 2005, establish a MCLG o f zero for Cryptosporidium.

## Subpart H—Filtration and Disinfection 

- 141.70 General Requirements
- Establish Criteria Under Which Filtration Is Required
- Establish Treatment Techniques in Lieu of MCLs for:
*Giardia lamblia*
*Legionella*
- Viruses
- HPC
- Turbidity

**Notes:**
This section provides a preface to the requirements of the rule and points out that the
rule establishes criteria under which filtration will be required of systems using
surface water or GWUDI.  It points out that treatment techniques are established, in
lieu of MCLs, for the control of the bulleted pathogens.  Treatment techniques are
established when it is not practical for controlling a contaminant or contaminants by
use of an MCL and monitoring.

Note: The IESWTR and LT1 address Cryptosporidium by requiring filtration systems
by remove 2 log and unfiltered systems to address it in their watershed protection
program.

## Subpart H—Filtration and Disinfection

- 141.70 General Requirements
- Establishes **Treatment Techniques** That Must Achieve:
- At Least 99.9 Percent Removal And/or Inactivation of *Giardia lamblia* Cysts
- At Least 99.99 Percent Removal And/Or Inactivation of Viruses
- Between a Point Where the Water Is Not Subject to Contamination by Surface Water Runoff and a Point Before the First Customer

**Notes:**
The section also outlines the minimum requirements that must be achieved for
subpart H systems to be in compliance with the SWTR’s treatment technique
requirements.  
Note: The IESWTR and LT1 address Cryptosporidium by requiring filtration systems
by remove 2 log and unfiltered systems to address it in their watershed protection
program.

## Treatment Technique Approach

- 141.70 General Requirements
- Compliance Based on
- Proper Use of **Treatment Technique** and
- 99.9 Percent *Giardia lamblia* Removal/Inactivation
- 99.99 Percent Virus Removal/Inactivation

**Notes:**
Later in the rule performance standards will be established to ensure the 3 log and 4 
log removal and/or inactivation requirements are being met.

## Percentage vs. Log Reductions

**Notes:**
Most people commonly refer to the 
99.9 % removal/inactivation requirement  as “3 log removal/inactivation” and the
99.99% removal as “4 log removal/inactivation.
This is because the log removal number is based on the “negative base 10 log of the
fraction remaining.”  Thus if 1,000 cysts are in the raw water and 99.9% of them are
removed by filtration 1 cyst (1/1,000 of the raw water total) will be remaining.  The
log of 1/1,000 is -3.00, therefore the negative log is 3.00.  Thus 99.9% removal
equates to 3 log removal.  90% = 1 log, 99% = 2 log, and 99.99% = 4 log.

This proves to be a handy technique and the log removal/inactivations across 
a plant’s various treatment units are additive.  Thus the log removal at each treatment
stage can be added to the log removals of other units to determine the final log
removal/inactivation credit that will be allowed by the regulatory agency.  For example,
if a plant removes 2.5 log of Giardia lamblia cysts by sedimentation and filtration,
and inactivates 1.2 log cysts with disinfection, the primacy would credit them with
2.5 + 1.2 or 3.7 log removal and inactivation.

## Subpart H—Filtration and Disinfection

- § 141.70 General Requirements
- A System Is in Compliance With the Treatment Technique Requirements If It:
- Meets the Avoidance Criteria and Unfiltered Disinfection Requirements
- Meets the Filtration and Disinfection Requirements for Filtered Systems
- Each System Must Be Operated by Qualified Personnel

**Notes:**
This rule specifies that all subpart H systems must be operated by “qualified
personnel.”  This is EPA’s first effort to ensure that properly trained operators
are in charge of complex systems.  

After the 1996 Amendments to the the SDWA EPA has addressed formal certification
of operators by States.  All States now have a certification program that meets
EPA’s guidelines and properly certified operators are deemed “qualified” under
the SWTR.

## Surface Water Treatment Rule

*§** 141.71 Criteria For Avoiding Filtration*

## §141.71 Criteria for Avoiding Filtration

- To Avoid Filtration a System Must Meet Specific
**1.  Source Water Quality Conditions**
**2.  Site-Specific Conditions**
**Disinfection Requirements**
**Watershed Control**
**Annual On-Site Inspection**
**TCR  and TTHM Compliance**

**Notes:**
To avoid filtration a surface water system has to meet specific source water quality
conditions and other site specific conditions designed to make and keep the high
quality water safe.

## §141.71—Criteria For Avoiding Filtration

- 1.  Source Water Quality Conditions
- Fecal Coliforms  20/100 ml
- Total Coliforms  100/100 ml
- In at Least 90 Percent of the Measurements Made for the Previous 6 Months
- _If Both Are Measured, the Fecal Criterion Must Be Met_
- Turbidity Cannot Exceed 5 NTU in Any Readings on 2 Consecutive Days
- For More Than 2 Events in 12 Months or
- 5 Events in Past 10 Years
- Unusual and Unpredictable Circumstances

**Notes:**
The source water of unfiltered systems must meet specific limits for bacteriological
content and turbidity.  The bacteriological quality limits are indicators of high quality 
water and water that is of low risk in terms of contamination by pathogenic organisms.
Turbidity is an indicator of contamination, in some cases, and is also an indicator of
how efficient the disinfection process will be.  That is, turbidity can exert a chlorine
demand and can shield pathogens from the disinfectant.

An “event” is a series of consecutive days during which at least one turbidity
Measurement each day exceeds 5 NTU.

## §141.71—Criteria For Avoiding Filtration (cont.)

- 2.  Site-Specific Conditions
- Compliance With Disinfection Requirements
- Watershed Control Program
- Annual On-Site Inspection
- Can Not be Identified as a Source of Waterborne Disease Outbreak
- Compliance with TCR MCL
- Compliance with TTHM Requirements

**Notes:**
The waterborne disease issue is limited to “in current configuration.”  In other words, if
they have made improvements that will cure the problems that caused the event, 
it is possible for them to meet the avoidance criteria.

TCR compliance in 11 of past 12 months unless not caused by a treatment 
deficiency of Source water.  For example, should a backflow situation cause a coliform 
compliance problem, this would not cause the system to install filtration.

Prior to the Stage 1 DBPR, large unfiltered surface water systems were required to 
maintain compliance with the TTHM Rule as a part of the avoidance criteria.  However,
these systems must now maintain compliance with Stage 1.  When LT1 becomes
effective, small unfiltered systems will also have to meet this requirement.

## 2.  Site Specific Conditions

- Disinfection
- Disinfection Must Provide 3-Log *Giardia* and 4-Log Virus Inactivation
- Every Day of the Month Except One
- In at Least 11 of the Past 12 Months
- Unless Caused by “Unusual and Unpredictable Circumstances”
- Redundant Disinfection Components
- Auxiliary Power Including Auto Start-up and Alarm _**or**_
- Auto Shut-Off When Residual Is < 0.2 mg/l

**Notes:**
Note that Cryptosporidium is not mentioned.  No one knew enough about it at the
time the SWTR was promulgated to adequately address it in the regulation.

If the State approves automatic shut-off it must determine that shut-off will not
cause unreasonable risk to health or interfere with fire protection.  The system must 
comply with the auxiliary power/auto start/alarm requirements. 

**Notes:**
This system is set up to monitor chlorine residuals, pH, peak flows and temperature
so they can, on a daily basis at peak hourly flow, show the State they meet
the SWTR disinfection requirements.

## 2.  Site Specific Conditions

- Disinfection
- Disinfectant Residual Cannot Be < 0.2 mg/l for More Than 4 Hours
- Unless Caused by “Unusual and Unpredictable Circumstances”
- Disinfectant Residual in the Distribution System Cannot Be Undetectable in More Than 5 Percent of Monthly Samples for Any Two Consecutive Months
- HPC  500 cfu/ml Is Deemed “Detectable”
- Unless the Failure Was Not Caused by a Deficiency in Treatment of the Source Water

**Notes:**

V =    c + d + e  X  100		V can’t exceed 5%
            a + b 

Where:
A = number of disinfection residual measurements
B = number of instances where residual is not measured but HPC is measured
C = number of instances where residual is measured, but not detected and no 
	HPC is measured
D = number of instances where residual is measured but not detected and HPC 
	is > 500/ml
E = number of instances where residual is not measured and HPC is > 500/ml

## 2.  Site Specific Conditions

- Disinfection
- Formula For Calculating Compliance With Distribution System Residual Requirements

- V =  c + d + 3    X 100

- a + b

**Notes:**

V =    c + d + e  X  100		V can’t exceed 5%
            a + b 

Where:
A = number of disinfection residual measurements
B = number of instances where residual is not measured but HPC is measured
C = number of instances where residual is measured, but not detected and no 
	HPC is measured
D = number of instances where residual is measured but not detected and HPC 
	is > 500/ml
E = number of instances where residual is not measured and HPC is > 500/ml

## 2.  Site Specific Conditions

**Watershed Control**
- Must Be Maintained to Minimize Contamination by *Giardia lamblia *& Viruses
- Characterize the Watershed
- Identify Watershed Characteristics and Activities That May Have an Adverse Effect
- Monitor Occurrence of Activities That May Have an Adverse Effect
- Must Demonstrate Activities Can Be Controlled
- Ownership or Written Agreements
- Annual Report to the State Identifying Special Concerns and How They Were Handled
- For GWUDI an Approved WHP Program May be Acceptable

**Notes:**
Watershed control programs vary from system to system based on site-specific 
conditions.  All, however, must have these components.

Again, Crypto is not mentioned for reasons discussed previously, however, systems 
must now comply with the Crypto requirements of the IESWTR and LT1ESWTR 
(beginning 1/14/05).

## 2.  Site Specific Conditions

- Annual On-Site Inspection
- Subject to an Annual On-Site Inspection
- Conducted by Competent Individuals
- A Report Must Be Provided to the State and Show
- The Watershed Protection Program and Disinfection Treatment Process Are Adequately Designed and Maintained

**Notes:**
In most cases, the annual on-site inspection is conducted by personnel of the primacy
agency.

## 2.  Site Specific Conditions

- Annual On-Site Inspection
- Review Effectiveness of WCP
- Review Intake
- Review Systems Equipment Maintenance Program
- Inspect Disinfection Equipment
- Review Operating Procedures
- Review Data Records
- Identify Needed Improvements

**Notes:**
The rule specifically requires, in section §141.71, that the on-site inspection include,
at a minimum, the above items.

## 2.  Site Specific Conditions

- Must Not Have Had an Identified Waterborne Disease Outbreak in Its Current Configuration
- Must Comply With Coliform MCL for 11 of Past 12 Months
- Or Failure to Do So Was Not Caused by a Treatment Deficiency
- Must Comply With Requirements for TTHMs

**Notes:**
The waterborne disease issue is limited to “in current configuration.”  In other words, if
they have made improvements that will cure the problems that caused the event, 
it is possible that they still could meet the avoidance criteria.

TCR compliance in 11 of past 12 months unless not caused by a treatment 
deficiency of Source water.  For example, should a backflow situation cause a 
coliform compliance problem, this would not cause the system to install filtration.

Note: As of Jan. 1, 2002 large (>10,000 persons) systems must comply with the 
Stage 1 requirements subpart H to maintain filtration avoidance.  The remaining 
unfiltered systems will have to comply with the Stage 1 DBPR beginning January 14,
2005.

## Treatment Technique Violations

- Failure to Meet Any of the Avoidance Criteria And/Or
-  Failure to Install Filtration by the Required Date
- A System That Has Not Installed Filtration Is in Violation If:
- Source Water Turbidity Greater Than 5 NTU
- Identified As a Source of Waterborne Disease Outbreak

**Notes:**
“Systems that have not installed filtration” here means those that are meeting the 
avoidance criteria and checking turbidities with proper meters, before the point of 
application of disinfectant, every 4 hours or more frequently.

Again, if avoidance criteria are not met the system must install filtration.

## §141.72—Disinfection of Unfiltered Systems

- Unfiltered Must Meet Disinfection Requirements By:
- December 30, 1991
- Ground Water Under the Direct Influence of Surface Water (GWUDI)
- December 30, 1991 or
- 18 Months After State’s Determination

- unfiltered

**Notes:**
These were the dates by which the systems had to be in compliance.

## §141.74—Unfiltered Analytical and Monitoring Requirements

- Measurements Must Be Performed by State Approved Party for
- pH
- Temperature
- Turbidity
- Residual Disinfectant

**Notes:**
The SWTR is designed so that properly trained operators can perform the daily
tests that are required.  In these cases certified laboratories are not required.

## §141.74—Unfiltered Analytical and Monitoring Requirements (cont.)

- Measurements Must Be Performed by a Certified Laboratory for
- Total Coliforms
- Fecal Coliforms
- HPC
- Methods Established by Rule

**Notes:**
On the other hand, some tests have to be performed by certified laboratories.

## §141.74—Unfiltered Analytical and Monitoring Requirements (cont.)

- Fecal or Total Coliform Source Water Monitoring
- Immediately Prior to the First Point of Disinfectant Application

**Chlorine**

**Monitoring**
**Site**

**Notes:**
The source water coliform monitoring has to be done prior to the application of
chlorine.  The photo shows a sampling tap in the base of a dam on an unfiltered
systems source.  Chlorine is introduced to the raw water about 20 yards down
stream of this sampling point.

## §141.74—Unfiltered Analytical and Monitoring Requirements (cont.)

**2 Also one must be done on days when turbidity is > 1 NTU**

*§141.74—Unfiltered Analytical and Monitoring Requirements (cont.)*

**Notes:**
These are the source water coliform monitoring requirements. 

In addition, one total coliform or fecal coliform measurement must be made every day 
the system serves water to the public and the turbidity of the source water exceeds 
1NTU.  These samples count towards the weekly coliform requirement.

## §141.74—Unfiltered Analytical and Monitoring Requirements (cont.)

- Turbidity
- Same Location
- Every Four Hours (Minimum)
- Continuous Monitoring May Be Substituted If Regularly Validated Using State-approved Protocol

**Notes:**
The required turbidity samples have to be collected as representative grab samples
every four hours at the same location the coliform samples the raw water fecal or
total coliform samples are collected (i.e. immediately prior to the introduction of
disinfectant.  The State may allow systems to substitute the results from continuous 
monitoring turbidimeters.

## §141.74—Unfiltered Analytical and Monitoring Requirements (cont.)

- Total Inactivation Ratio Must Be Determined Each Day of Operation
- Based on CT99.9 Values From
- Tables 1.1 - 1.6		Chlorine
- Table 2.1		Chlorine Dioxide & Ozone
- Table 3.1		Chloramines

## §141.74—Unfiltered Analytical and Monitoring Requirements (cont.)

- Residual
- Sampling
- Point

**Notes:**
This table shows a summary of the monitoring requirements.

## §141.74—Unfiltered Analytical and Monitoring Requirements (cont.)

- Systems Using Disinfectants Other Than Chlorine Can Demonstrate to the State That Other Operational Parameters Aside From Those in Tables 2.1 and 3.1 Achieve the Minimum Inactivation Requirements
- Table for Chloramines Assumes Chlorine Is Added First — If Not
- System Must Demonstrate 99.99 Percent Virus Inactivation _IF_ Chlorine is Not Added First

**Notes:**
The rule allows systems to show that disinfectants, other than chlorine, can meet
the inactivation requirements using operational parameters other than those in 
the rule.

The tables in the rule for chloramines assume that chlorine is added ahead of 
ammonia, thus providing a short time with the added disinfection capability of
free chlorine.  If chlorine is not added first, the system must show the State it can
meet the disinfection requirements for 4 log virus inactivation.

## Disinfection Contact Time

- Based on:
**Tracer Studies**
**T****10****  = The Detention Time at Which 90% of the Water Passing Through the Unit is Retained Within the Basin**
**Baffling Factors**
**Guidelines for T****10****/T Used in Lieu of Tracer Studies **

**Notes:**
The time that the disinfectant is in contact with the water prior to the first customer
is a critical component when determining CT.  Because short circuiting is common in
many water treatment and storage basins, estimates of actual contact time must be
made.  For regulatory purposes the term T10 is used for contact time.  This is defined
as the time in minutes at which 90% of the water entering a basin is still retained in
the basin or, conversely, the time at which 10% of the water has passed through the
basin.

Baffling factors are used for some common basin configurations where studies have
determined typical T10s.  The SWTR Guidance Manual has guidelines for baffling 
factors (T10 /T).  In many cases, however, the T10 is determined based on tracer studies.

## Contact Time

**Transmission**

**Transmission**

**Distribution System**

*Contact Time*

- Storage with 0.1 Baffling Factor

**Storage**

**Chlorine Injection Point**

**Monitoring Point**
**Before 1st Customer**

**Notes:**
This schematic shows an unfiltered system that adds the disinfectant at the intake.  The
water then travels through a transmission main, then through a storage tank with 
separate inlet and outlet, then on to the first user via another transmission main.  The
transmission mains are expected to have “plug flow” and, thus, are afforded a baffling
factor of 1.0 or 100% of the calculated contact time at peak hour flow.  The storage tank
will only get a baffling factor of 0.1 or 10% of the theoretical contact time.  For the 
storage tank the volume used has to be the minimum volume, or worst case scenario.
The final elevated storage tank shown in the schematic, rides or “floats” on the line with 
common inlet/outlet.  No contact time is granted for this type of situation as produced
water may or may not go to the tank depending upon where the demand is.

**Notes:**
This slide and the following two slides can be used by the instructor to explain one way 
the results of tracer studies can be used to determine the T10  of a basin.  The
SWTR Guidance Manual has a full discussion on procedures for doing the tracer
studies and determining T10 for basins.  Other references are also referenced in the
Guidance Manual.

This procedure is too complicated to cover in speaker’s notes, therefore, the Guidance
Manual should be used should the instructor wish to go into this subject in any detail. 

## Slide 78

## Slide 79

## Giardia Inactivation: CT

- CT (mg-min/L)  = Concentration of Disinfectant 				(mg/L) X Contact Time 					(minutes)

**Notes:**
CT is defined in the rule as the concentration of disinfectant in mg/L multiplied by
the time in minutes.  CT, then must be measured in mg-min/L.

## CT Calculations

**Transmission**

**Transmission**

**Distribution System**

*CT Calculations*

- Storage with 0.1 Baffling Factor

**Storage**

**Notes:**
At this slide the instructor should discuss the procedure for determining theoretical
contact time for each segment in the treatment scheme.  Then determine T10 by 
multiplying the theoretical contact time by the baffling factor.  The total time credited
for T10s in all units is then multiplied times the disinfectant residual in mg/L as
measured before the first customer.

## CT Calculations

*CT Calculations*

- CT in mg-min/L
- V1 = Volume of First Unit
- BF1 = Baffling Factor of First Unit
- Q = Flow in gpm @ Peak Hour

**Notes:**
This generic equation can be used to show how the CT can be calculated for the
previous slide.

## CT Calculations

*CT Calculations*

- CT Is in mg-min/L
- Use Tables in SWTR Guidance Manual to Determine How Many Logs of Inactivation You Have.
- Interpolate or
- Use Conservative Numbers

**Notes:**
At this slide the instructor should use the CT tables from the rule or from the Guidance
Manual and discuss how they are used.  First select the tables for the disinfectant
the system is using, then select the table with the correct water temperature.  Use the
table with the next lowest temperature if there is no table for the exact water temperature
in order to be conservative.  Then go the to part of the table with the correct pH, then
read across from the proper disinfectant residual.  For 3 log Giardia lamblia inactivation
the CT required can then be read from the table.

Point out that it is possible to use straight line interpolation between different temper-
atures and pHs.

## CT Workshop

*Single Point of Application*

## Example Calculation

**Transmission**

**Transmission**

**Distribution System**

**Storage**

**Storage**

*Example Calculation*

**V****1**** = 100,000 gal**
**BF****1**** = 1.0**

**V****2****=100,000 gal**
**BF****2****=0.1**

**V****3****=300,000 gal**
**BF****3****=1.0**

**Residual Monitoring Point**
**Cl****2****=1.0**
**pH = 8.0**
**Temp. = 0.5 C**

**First Customer**

**Cl****2**** Addition**

**Notes:**
Have the class break into groups and calculate the CTcalculated available for this particular
situation assuming the peak hour flow is 1,000 gpm.  Then determine whether
the system is in compliance with the 3 log Giardia lamblia inactivation requirement by
dividing CTcalculated  by CT required for 3 log inactivation (CT required being the 
number derived from the table).

If CT calculated divided by CT required is  1.0, the system is in compliance.
Part 2:
Point out to the class that the system would have the opportunity to measure the
residual disinfectant at points along the line and determine log inactivation for each
segment.  Because the residual disinfectant will be greater upstream (because of
chlorine demand), this will offer them the opportunity to more fully take advantage of
the actual inactivation the system is providing. 

## §141.74—Inactivation Ratios

**0.2 MG**

**First**
**Customer**

**ClO****2**

**Chlorine**

**Chlorine**

**FM**

**FM**

*§141.74—Inactivation Ratios*

- Inactivation Ratios May Have to Be Calculated for Different Segments of the Treatment Process

- FM indicates Flow Monitoring

**Notes:**
The next 3 slides show examples from the SWTR Guidance Manual.  More
information can be obtained by referring to this manual.

When disinfectants are added at multiple points, the log inactivation must be 
calculated in segments unless one segment meets the requirements of the SWTR.  
In the above situation the system could calculate the CT for the segment nearest the 
first customer and it if provided 3 and 4 log Giardia lamblia  and virus inactivation
respectively, report compliance.  If the CT in the first segment was inadequate for
compliance the next step would be to calculate CT for the next segment upstream, 
and the next, etc. until compliance is achieved.  

The SWTR doesn’t require the system to show all the inactivation they have.  The
system simply has to show adequate CT to achieve compliance.

## §141.74—Inactivation Ratios (cont.)

*§141.74—Inactivation Ratios (cont.)*

**A**

**B**

**C**

**a, b, c**

**D**

**d**

**Individually Disinfected and**
**Combined at a Single Point**

**First**
**Customer**

**Cl****2**

**Cl****2**

**Cl****2**

**Notes:**
In this case the system would calculate CT for segment D first.  If compliance is 
achieved, report to the State.  If the CT of D is inadequate, A, B, and C calculations
must be performed and the log inactivation of each individually, must be added to
D’s log inactivation to ensure that water from each source is receiving adequate
treatment.

## §141.74—Inactivation Ratios (cont.)

*§141.74—Inactivation Ratios (cont.)*

**Multiple Combination**
**Points for Individually**
**Disinfected Sources**

**A**

**B**

**C**

**a, b**

**D**

- c

**First**
**Customer**

**Cl****2**

**Cl****2**

**Cl****2**

**d**

**E**

**e**

**Notes:**
In this case the system, to show compliance, would calculate CT for segment E first,
C and D second, then A and B third to show all water provided from both sources would
meet the requirements.

## §141.74—Residual Monitoring -- Entry Point

- Residual Entering the Distribution System Must Be Monitored Continuously
- Record Lowest Value Each Day
- Take Grab Samples Every 4 Hours If Equipment Fails
- No More Than 5 Working Days
- Grab Samples Are Acceptable for Systems Serving 3,300 or Fewer

**Notes:**
The rule has requirements for disinfectant residual monitoring to help ensure
continuous and adequate disinfection.

## §141.74—Residual Monitoring -- Entry Point (cont.)

- Entry Point Monitoring for Small PWSs

**Notes:**
Small systems can get approval for grab sampling entry point residual disinfectant.
The number of grab samples/day is dependent upon the size of the system.  Many
States required continuous residual disinfectant monitoring for all surface water 
systems.

The day’s samples cannot be taken at the same time.  Sampling intervals are 
subject to State review and approval.

## §141.74—Residual Monitoring -- Entry Point (cont.)

- For Systems Using Grab Samples
- If the Residual Falls Below 0.2 mg/l Grab Samples Must Be Collected Every 4 Hours Until the Concentration Is Back to 0.2 mg/l

**Notes:**
This requirement ensures the system using grab samples in lieu of continuous
monitoring will take action to correct problems that are causing the low entry point 
residual.  

## §141.74—Distribution Residuals

*§141.74—Distribution Residuals*

- Must Monitor Residual at the Same Time and Place As Coliforms1
- HPC May Be Monitored in Lieu of Disinfectant Residual
- If HPC Monitoring Is Not Practical the State May Determine the System’s Disinfection Is Adequate

**Notes:**
The disinfectant residual must be monitored in the distribution system at the same
time and place as coliform samples are collected.  Section §141.72 of the SWTR
requires that no more than 5% of these measurements may be undetectable for
any two consecutive months.  

Should a sample not show detectable residual disinfectant the system may have
a heterotrophic  plate count performed on a sample of water from the location (same
time and place) and if the HPC is less than or equal to 500 colony forming unit (cfu) 
per ml, it can be treated as if residual was detected.

Note: The Stage 1 DBPR sets MRDLs in the distribution systems for disinfectants.  
For chlorine and/or chloramines the MRDL is 4 mg/L and the MRDL for chlorine
dioxide is 0.8 mg/L.

## Surface Water Treatment Rule

*Filtered Systems*

- Filtered

## §141.72—Disinfection of Filtered Systems

- Filtered

*§141.72—Disinfection of Filtered Systems*

- Subpart H Systems Not Meeting Avoidance Criteria Must Provide
- Disinfection
- Sufficient to ensure a total of
- 3 log *Giardia lamblia* Inactivation
- 4 log Virus Inactivation    AND
- A Suitable Filtration Technology
- Conventional or Direct
- Slow Sand or DE
- Other Technologies

**Notes:**
Systems that do not meet the avoidance criteria must provide an acceptable method of filtration as well as full-time disinfection.  The two, in combination, must then meet the 3 and 4 log removal and/or inactivation requirements.

Conventional and direct granular media filtration as well as slow sand and diatomaceous earth filtration are specifically mentioned in the rule as being acceptable technologies.

Other technologies can be approved by the primacy agency when shown to be acceptable.  The burden to show the acceptability of alternative technologies lies upon the systems that use them.

Note:  The IESWTR and LT1ESWTR (beginning Jan. 14, 2005) require 2 log removal of Cryptosporidium.

## §141.73—Filtration:  Conventional or Direct

- Considers This to Be CFE, Some States Apply the Limit to Individual Filters.

*§141.73—Filtration:  Conventional or Direct*

- At Least 95 Percent of the CFE1 Turbidity Samples Must Be  0.5 NTU Each Month Except That
- The State Can Determine That Some Level Higher Than 0.5 NTU but 1 NTU Will Inactivate And/Or Remove 99.9 Percent of *Giardia lamblia* Cysts
- The CFE Turbidity Must at No Time Exceed 5 NTU

- Filtered

**Notes:**
These are the performance standards that are applied to conventional and direct 
filtration plants.  They are based upon the measurements taken at least once
every 4 hours, unless reduced by the State for systems serving 500 or fewer people.

Note: The IESWTR and LT1 (beginning January 14, 2005) supersede the combined
filter effluent requirements (CFE) for conventional and direct filtration plants by requiring 
95% of CFE turbidity measurements to be less than or equal to 0.3 NTU each month 
with a maximum level not to exceed 1 NTU.

## §141.73—Filtration:  CFE Turbidity

*§141.73—Filtration:  CFE Turbidity*

- Filter No. 1

- Filter No. 2

- Filter No. 3

- Clearwell

- 0.1 NTU

- 0.1 NTU

- 0.6 NTU

- CFE
- 0.28 NTU

- Filtered

**Notes:**
The SWTR requires that turbidity “of representative samples of the system’s filtered
water” be monitored.  EPA considers the proper site for monitoring to be the 
combined filter effluent.  Some States may allow monitoring to be conducted out of
the clearwell.  In any event it is important to note that, as shown above, the blended
water that is monitored in plants with multiple treatment trains can mask problems
of individual trains (filters).  This risk is addressed in the IESWTR and LT1ESWTR by 
requiring monitoring of individual filter effluent of conventional and direct filtration 
plants.

## §141.73—Filtration:  Conventional

**Flocculators**

**Clearwell**

**RM**

_**Guidance Manual Suggests:**_
**Removals:**
- 2.5 Log Removal *Giardia*
- 2.0 Log Removal Viruses
**Inactivation:**
- 0.5 Log Inactivation *Giardia*
- 2.0 Log Inactivation Viruses

*§141.73—Filtration:  Conventional*

**Sedimentation**
**Basin**

**Filters**

**Notes:**
The SWTR does not have specific requirements for how much cyst and/or virus removal credit the State should allow for various types of filtration technologies.  However, guidance is provided in the SWTR Guidance Manual.

For conventional filtration plants the Guidance Manual suggests that no more than 2.5 log Giardia lamblia cyst removal and 2.0 log virus removal be provided to systems that are meeting the performance requirements of the rule.  The balance of the required removal/inactivation would then have to be provided by disinfection with adequate contact time.
The Guidance Manual suggests that the State always requires at least 0.5 log Giardia lamblia inactivation as a minimum.

Note:  Conventional and direct filtration plants are assumed to remove 2 logs of Cryptosporidium.

## §141.73—Filtration:  Direct

**Removals:**
- 2.0 Log Removal *Giardia*
- 1.0 Log Removal Viruses
**Inactivation:**
- 1.0 Log Inactivation *Giardia*
- 3.0 Log Inactivation Viruses

**(Optional)**

*§141.73—Filtration:  Direct*

**Flocculators**

**Clearwell**

**RM**

**Filters**

**Notes:**
These are the suggested numbers for direct filtration plants meeting performance standards of the rule.

Note: Conventional and direct filtration plants are assumed to remove 2 logs of 
Cryptosporidium.

## Contact Adsorption Clarifier (CAC)

**Notes:**
Many systems installed subsequent to the promulgation of the SWTR are referred to 
contact adsorption clarifiers or CAC systems.  Guidance for removals credits is not
provided in the SWTR Guidance Manual.  States have flexibility to make their own 
determinations for these (and all other) systems.

## Slide 100

**Notes:**
This is a photograph of a CAC being backwashed.  One advantage to these systems 
is that backwash of the clarifier is provided with untreated water.  This minimizes
the use of treated water and saves treatment costs.

## §141.73—Filtration:  Slow Sand

- At Least 95 Percent of the CFE Turbidity Samples Must Be  1 NTU Each Month Except That
- The State Can Determine There Is No Interference With Disinfection at Some Higher Level Than 1 NTU
- The State May Substitute This Level for the System
- Turbidity Can at no Time Exceed 5 NTU

- Filtered

**Notes:**
These are the performance standards for slow sand filters.  The performance 
standards have been established based upon research showing actual removal
efficiencies.  Slow sand will sometimes pass inorganic colloidal particles while
removing cysts and viruses.  Therefore, States may allow higher turbidities when
they are convinced disinfection will not be impacted negatively.  

Once again , CFE monitoring is based on measurements taken at least every 4 hrs 
unless reduced by the State.  

Note:  Under the IESWTR and LT1ESWTR, these requirements are maintained.

## §141.73—Filtration:  Slow Sand

**Clearwell**

_**Guidance Manual Suggests**_**1**_**:**_
**Removals:**
- 2.0 Log Removal *Giardia*
- 2.0 Log Removal Viruses
**Inactivation:**
- 2.0 Log Inactivation *Giardia*
- 2.0 Log Inactivation Viruses

*§141.73—Filtration:  Slow Sand*

**Filters**

**1.  Pages 106 - 107**

**Notes:**
These are the suggested removal credits for slow sand.  
Note:  Slow sand filtration, when properly operated, is assumed to remove 2 log
Cryptosporidium.

## Slide 103

**Notes:**
This is a slow sand filter that treats a high quality, low turbidity, surface water source
in northern Idaho.

## Slide 104

**Notes:**
Much of the removal of viruses, bacteria and cysts is accomplished in biological
layer that forms on and in the first few millimeters of sand.  Eventually the 
biological growths will accumulate to the point that flow will be greatly diminished
through the filter and it must be cleaned.  Cleaning is accomplished by removing
a thin layer of sand with much of the biological material.

After cleaning the filter must be allowed to filter to waste for a period of time until
enough biological growth accumulates to accomplish proper filtration.

## §141.73—Filtration:  Diatomaceous Earth

- At Least 95 Percent of the CFE Turbidity Samples Must Be  1 NTU Each Month
- The Turbidity Must at No Time Exceed 5 NTU

- Filtered

**Notes:**
These are the performance standards for DE filters based on measurements every 
4 hrs, unless reduced.by the State for systems serving 500 or fewer.

Note:  Under the IESWTR and LT1ESWTR, these requirements are maintained.

## §141.73—Filtration:  DE

**Removals:**
- 2.0 Log Removal *Giardia*
- 1.0 Log Removal Viruses
**Inactivation:**
- 1.0 Log Inactivation *Giardia*
- 3.0 Log Inactivation Viruses

**Precoat**

*§141.73—Filtration:  DE*

**Clearwell**

**Filters**

**Notes:**
These are the recommended removal credits that States might allow for DE filters.

Note:  Direct filtration is assumed to remove 2 logs of Cryptosporidium.

## Slide 107

**Notes:**
DE filters are typically used for low turbidity waters.  They are common for treating 
water at swimming pools, but less common for drinking water.  Some filter under 
pressure and some under vacuum.

## Slide 108

**Notes:**
A layer of diatomaceous earth builds up on a septum and turbidity particles and
pathogens are removed from the water by “sieving” as they pass through the DE
layer.  DE is fed continuously during the process and the DE layer keeps building
up.  This helps reduce the accumulating head loss and increase the filter run time.

## Slide 109

**Notes:**
This is a large DE unit that treats drinking water for Carson City, NV.  Note one of the
circular filtration units (septa) leaning against the DE filter on the right side of the photo.

## Slide 110

**Notes:**
This is a photo of the internal septum.  There are many of these within the DE filter
and the water is filtered, through a layer of DE, through both sides and into the center, then to a collector pipe, and to the clearwell.

## Slide 111

**Notes:**
This photo is taken through a lighted porthole in the side of the DE filter.  It is looking 
at the outer circumference of two of the circular septa.  Note the layer of DE built up
on both sides of each septa and the “body feed” DE that is constantly fed with the 
raw water.

## Log Removal and/or Inactivation1

**1. Pages 81 & 106-107**

**Notes:**
This is a table summarizing the suggested removal credits for the common types
of filtration based on the SWTR Guidance Manual.

## §141.73—Filtration:  Other Technologies

- Must Demonstrate to the State Using Pilot Plants or Other Means the Alternative Technology Provides
- 3-Log *Giardia lamblia* and
- 4-Log Virus
- Removal and/or Inactivation
- Slow Sand Turbidity Limits Apply

- Filtered

**Notes:**
The SWTR applies the performance standards for slow sand filters to alternative 
technologies approved by the State based on measurements every 4 hrs unless 
reduced by the State.

Note: The IESWTR and LT1ESWTR (beginning Jan. 14, 2005) require systems to 
demonstrate that their alternative technology consistently removes 2 logs of 
Cryptosporidium.  Based on this information, the State is required to set turbidity 
limits not to exceed 1 NTU for 95% of the turbidity measurements taken each month 
and not  to exceed a maximum value of 5 NTU.

## Slide 114

**Notes:**
This is an example of a typical alternative technology for a small surface water system
using a high quality (low turbidity) surface water.  These kinds of systems are 
often used by noncommunity PWSs.  There are usually two or more filters in series
with the first filter(s) serving as roughing filters and the final filer ensuring adequate
removal of cysts.  

## Slide 115

**Notes:**
This is a system serving a small noncommunity PWS.  It has a roughing filter 
(10 micron) followed by a 1 micron filter.  Then the water is disinfected with UV
light followed by chlorine with contact time sufficient for 1.0 log Giardia lamblia
inactivation.  Note the 2 parallel trains that allow the system to continuously operate
while filter cartridges are changed.

## Pressure Dual Media Filter

**Notes:**
This is a photo of a dual media pressure filter that is used as a roughing filter.  No 
chemical is added for coagulation and the filtered water is then passed through both 
cartridge and bag filters.

## Cartridge & Bag Filters

**Notes:**
These are the cartridge and bag filter units that are arranged in series with the
dual media pressure filter shown in the previous slide.  The water is then chlorinated
and contact time is provided in a storage tank.

## Slide 118

**Notes:**
This is a photograph of a micro membrane filtration plant.  These kinds of facilities
are becoming more common on surface waters.

## §141.74(c)—Filtration:  Monitoring

*§141.74(c)—Filtration:  Monitoring*

- Beginning June 29, 1993 or When Filtration Is Installed
- Turbidity Measurements Must Be Taken Every 4 Hours, or More Frequently, the System Serves Water to the Public1
- Continuous Monitoring May Be Substituted If Validated

- Filtered

**Notes:**
Turbidity measurements must be taken and recorded every four hours of operation.
In most cases the samples are taken at the combined filter effluent.  If a plant operates
intermittently (start/stop) during the day, many States require one reading at the end
of each operating period that is less than 4 hours.

Note:  The IESWTR and LT1ESWTR (beginning Jan. 14, 2005) requires continuous
 individual filter monitoring with measurements recorded at least every 15 minutes for 
systems using conventional or direct filtration.

## §141.74(c)—Filtration:  Turbidity Monitoring

- Filtered Systems
- The State May Reduce Sampling Frequency to Once Per Day for Slow Sand and “Other Technologies” but Not for
- Conventional
- Direct
- Diatomaceous Earth
- Also, Monitoring Frequency May Be Reduced to _**Once Per Day**_ for Systems Serving  500 Persons
- All Technologies

- Filtered

**Notes:**
The rule allows for some reductions in turbidity sampling frequency.

## §141.74(c)—Filtration:  Disinfection Residual Monitoring

- Residual Entering the Distribution System
- Monitoring Frequency, Locations, Residual Requirements, etc. are Identical to Those For Unfiltered Systems

- Filtered

## Workshop

*Filtered System Removal/Inactivation*

**Notes:**
Each of the following schematics should be discussed in terms of the removal credit
the State should allow and how much CT would then be necessary to provide the
full regulatory requirements.

## §141.73—Regulatory Calculations -- Conventional Plant

**Cl****2**

- Raw Turbidity
- CFE Turbidity
- Peak Hour
- Chlorine Residual
- pH
- Temperature

**Residual**

*§141.73—Regulatory Calculations -- Conventional Plant*

**Flocculators**

**Clearwell**

**RM**

**Sedimentation**
**Basin**

**Filters**

- 1,200, 85 NTU Ave.
- = 0.3 NTU
- = 1,000 gpm
- = 1.0 mg/l
- = 7.0
- = 50 C

- Filtered

**Theoretical Hydraulic Detention Time = 3 Hours**

**Notes:**
In this situation the system is a conventional plant that meets and exceeds the SWTR’s
performance standards.  Most States would give 2.5 log Giardia lamblia removal
credit and require at least 0.5 log inactivation by disinfection and contact time.  It 
should be noted that, when chlorine in used, Giardia lamblia inactivation will be the
limiting factor.  In other words, if adequate cyst inactivation is occurring, more than
adequate virus inactivation will be occurring simultaneously.

Here the instructor can walk the class though the use of the CT tables to show the 
system is in compliance.

## §141.73—Regulatory Calculations

**Cl****2**

- Raw Turbidity
- CFE Turbidity
- Peak Hour
- Chlorine Residual
- pH
- Temperature

**Residual**

*§141.73—Regulatory Calculations*

**Flocculators**

**Clearwell**

**RM**

**Sedimentation**
**Basin**

**Filters**

- = 800, 50 NTU Ave.
- = 0.4 NTU
- = 1,000 gpm
- = 1.0 mg/l
- = 7.0
- = 50 C

- Filtered

**Theoretical Hydraulic Detention Time = 32 Minutes**

**Notes:**
Use the same process as in the previous slide.

## §141.73—Regulatory Calculations -- In-Line Filtration

- Raw Turbidity
- CFE Turbidity
- Peak Hour
- Chlorine Residual
- pH
- Temperature

**Residual**

*§141.73—Regulatory Calculations -- **In-Line Filtration*

**Flocculators**

**Clearwell**

**RM**

**Filters**

- = < 5 NTU; < 1 NTU Ave.
- =  0.3 NTU
- = 1,000 gpm
- = 1.0 mg/l
- = 7.0
- = 50 C

- Filtered

**Notes:**
Discuss the removal credits that should be allowed here.  Then use the CT tables
to determine how much contact time the system must have to provide adequate CT
given the above conditions.

## §141.73—Regulatory Calculations -- Bag Filter Arrangement

- Pressure
- Sand Pre-
- Filter

- 10
- Micron
- Bag

- Clearwell

- 1
- Micron
- Bag

- Raw Turbidity < 3 NTU
- Finished             < 1.0 NTU

**Notes:**
Discuss the removal credits that should be allowed here.  Then use the CT tables
to determine how much contact time the system must have to provide adequate CT
given the above conditions.

## Giardia Inactivation: CT

- CT Is a Regulatory Threshold That Must Be Met.
- Calculated Using:
- pH
- Peak Hourly Flows
- Disinfectant Residual
- Contact Time
- Baffling Factors
- Tracer Studies

- Filtered

**Notes:**
This slide should be used to summarize the CT requirements for both filtered and 
unfiltered surface water systems.

Remember the system only has to show they have adequate CT to meet the 3 log
Giardia lamblia and 4 log virus removal/inactivation requirements.  They, in many cases
have more but don’t necessarily have to show it to the primacy agency.

## Treatment Technique Requirements

- 3-Logs Removal/Inactivation of *Giardia*
- 4-Logs Removal/Inactivation of Viruses
- Compliance Achieved By:
- Properly Designed and Operated Filtration
- Meeting Filtration Avoidance Criteria

- Filtered _and_ Unfiltered

**Notes:**
This slide summarized the essence of the SWTR.  There are two ways to achieve
compliance with the treatment technique requirements as shown in the final bullets.

Note:  The IESWTR and LT1ESWTR (beginning Jan. 14, 2005) requires 2 log 
removal of Cryptosporidium.

## Surface Water Treatment Rule

*Ground Water Under the Direct Influence of Surface Water (GWUDI)*

## Purpose

- To Ensure Adequate Treatment of Sources That Are Under the Direct Influence of Surface Water
- Subject to Contamination by Macroorganisms Including Cysts
- GWUDI1 Means Any Ground Water With (1) Significant Occurrence of Insects or Other Macro-organisms, Algae, or Large Pathogens Such As *Giardia l*., Or (2) Significant Shifts in Temperature, pH, Turbidity, or Conductivity That Correlate to Surface Water or Climatological Changes

- 1Not the Exact Definition Found in 141.2

**Notes:**
The SWTR defines GWUDI and addresses its treatment.  To determine whether a 
source is “under the direct influence” a determination must be made as to whether 
adequate natural filtration is available to remove macro-organisms such as Giardia
lamblia cysts.  The issue is not just that the ultimate source of water might be a 
surface water source.  It depends upon whether there is a risk of passage of large
pathogens.  Other ground waters that might be vulnerable only to viruses and/or
bacteria are planned to be covered by the Ground Water Rule.

States are required by the rule to make determinations on each ground water source
as to whether it is GWUDI or not.  It is critical for States to get these determinations 
completed because of the risks that might be associated with GWUDI sources.

## Potential Ground Water Sources Under the Influence

- Shallow Wells 	(EPA Says Less Than 50 Feet)
- Springs
- Infiltration Galleries
- Ranney Collectors
- Poorly Constructed Wells

**Notes:**
These are examples of ground water sources that might be most likely to be GWUDI.

## Slide 132

**Notes:**
This is a drawing of a Ranney Collector.  Such systems are often installed under
or near surface water sources and are generally designed to obtain surface water but
after adequate treatment.  The effectiveness of the natural filtration provided by the
overlying soils are generally a function of the types of geological materials in the area
as well as the depth and design of the lateral collectors.  Some of these systems
have been determined to be GWUDI, and some have been determined to be ground
water.

## Considerations for GWUDI

- Depth
- Construction
- Location (Greater Than 200 Feet)
- Water Quality Records
- Coliforms
- Turbidity
- MPA
- Seasonal Fluctuations

**Notes:**
Most States do a preliminary assessment of each of their ground water sources to
determine what sources might be at risk for surface water influence.  The above are
some of the indicators States might use to determine if a source needs to be more
closely examined to determine influence.  High turbidity, occurrence of bacteria, 
microscopic particulate examinations showing macro-organisms, and seasonal 
fluctuations of temperature, pH, etc. all might be signs of surface water influence.

## Compliance with GWUDI

- Modification
- Alternate Sources
- Treatment
- Filtration
- Avoidance Criteria

**Notes:**
After a source has been determined to be under the direct influence of surface water
it is treated as a surface water source and must come into compliance with the 
SWTR.  Some of the potential alternatives for doing so are listed above.

## Balanced Protection Under the SWTR

- 1. Watershed Protection
- 2.  Source water quality
- 3.  3 & 4 logs inactivation
- 4.  Redundant facilities
- 5.  Source monitoring
- 6.  Treated water Monitoring
- 7.  Distribution monitoring

- 1.  Filtration (removal)
- 2.  Inactivation
- 3.  Treated water monitoring
- 4.  Distribution monitoring

**Notes:**
The SWTR is designed to ensure that both filtered and unfiltered surface water sources
provide the public with reasonably safe and equivalent finished water.  The mechanisms
for doing so are, however, different.

It should be pointed out that our current understanding of Cryptosporidium, since it is 
highly resistant to disinfection, has shown us the importance of employing a multiple 
barrier approach.

## SWTR Special Primacy Requirements

*Section 142.16*

## Special Primacy—142.16(b)

- Adopt Rules No Less Stringent Than Subpart H Filtration and Disinfection
- Do Not Have to Address Avoidance Criteria If All Surface and GWUDI Systems Are Required to Filter

**Notes:**
As for all EPA rules, States have to adopt rules equally or more stringent than the 
SWTR.  Some States require filtration of all surface water sources and, thus, do not
need to address unfiltered systems in their rules.

## Special Primacy—142.16(b)(1)

- Enforceable Requirements
- Must Include Enforceable Design and Operating Criteria for Each Filtration Treatment Technology Allowed or
- A Procedure for Establishing Such on a System-by-System Basis

**Notes:**
States have to show EPA how they will enforce the treatment technique requirements
of the SWTR for each type of technology.

## Special Primacy—142.16(b)(2)

- State Practices or Procedures - “Must Include a Description of How the State Will”
- Qualify Operators
- Determine GWUDI
- Determine How Combined Disinfection and Filtration Will Provide 3- and 4-Log Inactivation and/or Removal
- Approve Parties to Conduct pH, Temperature, etc.
- Determine Appropriate Technologies for Waters of Various Qualities

**Notes:**
In the primacy applications the States had to address each of the following areas.

## Special Primacy—142.16(b)(2)

- State Practices or Procedures - “Must Include a Description of How the State Will”
- Accomplish the Following:
- Judge Watershed Control Programs
- Approve Inspectors and Evaluate Results of On-Site Inspections
- For Those Adopting Discretionary Elements, Determine:
- Interim Disinfection Requirements
- A System Is Unable to Measure HPC but Is Providing Adequate Disinfection
- Alternative Turbidity Limits
- Etc. ..........................................