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Supervisory Control and Data Acquisition (SCADA) Utilization For Capacity,
Management, Operations, and Maintenance (CMOM) Program Compliance in Wastewater
Collection Systems
John J. Cronley
Marketing Communications Manager
Mission Communications
678-969-0021, x1008
john.cronley@123mc.com
CMOM, a widely recognized acronym for the EPA’s Capacity, Management,
Operations, and Maintenance program, has become a familiar term to the wastewater treatment
industry. The 1987 Water Quality Act brought wastewater under the authority of an earlier law,
The 1972 Clean Water Act, and required federal oversight of discharges from sewage treatment
plants. The CMOM program was established by the Environmental Protection Agency (EPA) to
help reduce regulatory non-compliance in wastewater collection and treatment systems. The
CMOM program is a valuable tool which treatment plant operators can use to help demonstrate
compliance with federal and state regulations governing the water treatment industry. Used
correctly, the CMOM program will help save labor, equipment, and potential fines for almost any
wastewater treatment facility. This paper briefly describes the origins of the CMOM program and
details the principal ways that the program is applied to wastewater collection and treatment
systems. The paper contains real-world examples which illustrate ways in which a properly
functioning SCADA system can assist facilities to implement and operate their CMOM
programs, helping to avoid potential violations and fines, to optimize efficiency, and to provide
proper stewardship of public resources.
© 2011 Mission Communications, LLC
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Most of us in the water industry have heard the term “capacity, management,
operations, and maintenance programs”. Most often, this term is shortened to the familiar
acronym, “CMOM”. Fewer of us understand the origins of CMOM, or why it is so critical to our
industry and to the operation of lift stations in particular. One of the primary goals of CMOM
programs is to “help communities ensure they have adequate wastewater collection and
treatment capacity”1. The indirect authority of the CMOM program is derived from the Federal
Water Pollution Control Amendments of 1972, more commonly known as the Clean Water Act
(CWA), which is the principal law governing the release of water into all U.S. waterways. Later
legislation, primarily the Clean Water Act of 1977 and the Water Quality Act of 1987 (WQA),
expanded the CWA to include the wastewater operations field. The 1972 CWA created the
National Pollution Discharge Elimination System (NPDES) and clarified standards for effluent
treatment. The 1987 WQA expanded the NPDES program to cover stormwater discharges from
municipal and industrial sources2, and required permits for all U.S. wastewater treatment plants.
Although CMOM itself is not a regulation, and is not designed to be legally binding,3 it is an
excellent tool to assure that your facility is doing everything that it reasonably can to comply with
EPA and CWA directives.
A principal reason cited by the EPA as giving the agency the authority to regulate
wastewater treatment plants is the potential for sanitary sewer systems to experience overflows
(SSOs). The EPA has stated that every sanitary sewer system has the capacity to have an
SSO4, and because SSOs have the potential to impact public health, it is within the scope of the
agency to oversee sewer system operation and design. Under the authority delegated through
the above referenced legislation, the EPA designed and implemented the CMOM program.
CMOM is designed to assist the wastewater facilities operator to5:
1.
2.
3.
4.
Better manage, operate, and maintain collection systems
Investigate capacity constrained areas of the collection system
Proactively prevent SSOs
Effectively respond to SSO events.
An unintended, but significant, by-product of the CMOM process is that the
operator may not only become more aware of issues that negatively affect the environment, but
is also able to communicate with the public constituency the scope and nature of any relevant
issues and to demonstrate the safeguards that have been implemented to prevent SSOs. The
public has a need to understand the high degree of professionalism and integrity with which
1
EPA. 2001. Proposed Rule To Protect Communities From Overflowing Sewers, U.S.
Environmental Protection Agency, Office of Water(4201), Washington D.C. EPA 833-01-f-001.
2
Wikipedia.org, Clean Water Act, page 7. Available at:
http://wn.wikipedia.org/wiki.Clean_Water_Act.
3
EPA, 2005. Guide For Evaluating Capacity, Management, Operation, And Maintenance
(CMOM) Programs At Sanitary Sewer Collection Systems, U.S. Environmental Protection Agency, Office
of Enforcement and Compliance Assurance (2224A), Washington D.C. EPA 305-B-05-002. pg 1-5
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EPA 305-B-05-002, pg 1-3
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EPA 305-B-05-002, pg 1-4
© 2011 Mission Communications, LLC
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most operators conduct their duties. Better information and communications about potential
issues can only help that process.
The ultimate goal of the CMOM process, as it applies to the wastewater treatment
industry, is to assure that discharges from treatment facilities are free from pollutants. The term
“pollutants” is somewhat vaguely defined by the existing laws as, “any type of industrial,
municipal, and agricultural waste discharged into water”. This includes, but is not limited to6:
•
•
•
•
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Solid waste
Sewerage
Sludge
Chemicals
Biological materials.
SCADA (Supervisory Control and Data Acquisition) was first used in the 1960s to
provide a means of efficiently controlling remote equipment. It gained popularity in private
industry before being adapted for use in the municipal water industry. Properly used, the term
SCADA implies both the ability to monitor remote equipment and some level of control of that
equipment. The term telemetry would be more correctly used for an alarm or notification only
situation, without the ability to effect some level of control at the remote site. For the purposes of
this paper, we will only use the term SCADA.
SCADA has long been used by large wastewater treatment systems to collect the type
of data required to show compliance with CMOM program elements. The modern SCADA
system is geared towards providing moment-by-moment data that includes trending, monitoring,
reporting, maintenance records, and maintenance schedules which can be used as the basis of
the CMOM plan. Over the last several decades improvements in the field of data transmission,
specifically nation-wide cellular networks, has made modern SCADA much less expensive,
easier to install, and simpler to maintain. SCADA is more readily available to medium and small
system operators, making it more efficient for those operators to capture and record the
information that is required to establish a baseline and on-going data input for a CMOM
program.
The framework of the CMOM program allows for periodic reviews, by EPA and state
inspectors, of a collection system to assure compliance with the program elements. It is not the
intent of this article to thoroughly outline the requirements, as we understand them, of the
CMOM program. That article would, unfortunately for those tasked with compliance, require
volumes. It is, however, our intent to detail some of the ways in which implementing a SCADA
system may help to satisfy certain key elements of the CMOM structure and assist in the
gathering of data for CMOM compliance reviews.
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http://cfpub.epa.gov/npdes/aafaqs.cfm?program_id=0. National Pollutant Discharge Elimination
System (NPDES), NPDES Frequently Asked Questions, pg 7.
© 2011 Mission Communications, LLC
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Typically, any system review would follow an established framework consisting of
examining records, interviewing staff, and conducting field investigations.7 Field investigations
will normally be conducted after establishing a solid understanding of the underlying operation
and should include, among other items, the following8:
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Pump stations
Dispatch and Supervisory Control And Data Acquisition (SCADA) systems
Sites of any Sanitary Sewer Overflows (SSOs)
A broad overview of the CMOM program elements includes the following:
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collection system Capacity evaluation
collection system Management
collection system Operation
collection system Maintenance
The first element of a CMOM program, Sewer system capacity evaluation, generally
involves the following elements9:
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Flow monitoring
Sewer system testing
Sewer system inspection
Sewer system rehabilitation
Kris Riemann is Director of Engineering for the city of Gulfport, Mississippi. As part of his
duties he is directly responsible for the planning, budgeting, and execution of all capital projects,
including water and sewer projects. The Gulfport system is heavily reliant on Mission SCADA to
keep them abreast of all system functions outside their plants, both in collection and distribution.
Mr. Riemann worked closely with Mission’s engineers to develop the “Capacity Estimator” tool,
which is a standard part of the Mission web-based software that is included as a part of every
Mission unit. “We use the ‘capacity estimator’ to help us determine if capacity is keeping up with
development and I and I (Inflow and Infiltration) within each branch of our collection system,
which helps us prevent overflows and overtaxing system capacity. We follow CMOM
recommendations to show compliance with CMOM standards. The EPA recommends that all
systems install SCADA and our installation of Mission equipment demonstrates that we follow
those guidelines. Using our Mission equipment to collect data, and the Mission website tools to
evaluate the data helps us to accurately evaluate our capacity and stay in compliance with the
rules.”
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EPA 305-B-05-002, pg 2-1
EPA 305-B-05-002, pg 2-3
EPA 305-B-05-002, pg 2-36
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Figure 3- The Mission Peak Flow Capacity Estimator tool. Based on pump data and actual
runtimes, the tool gives an accurate prediction on expected capacity of a collection system. This
screen demonstrates the peak flow for this three month period reached 91K gallons, or 76%, on
January 30th.
The second element of the CMOM program, collection system management, consists of
several parts. The primary goals of this element, as it relates to lift station maintenance, are the
following10:
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Protection of public health and prevention of unnecessary property damage
EPA 305-B-05-002, pg 2-4
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Minimization of infiltration, inflow, and exfiltration, and the maximum conveyance
of wastewater to the wastewater treatment plant
Provision of and prompt response to service interruptions
Efficient use of allocated funds
Identification of and remedy solutions to design, construction, and operational
deficiencies
Performance of all activities in a safe manner to avoid injuries
A modern SCADA system is extremely reliable and robust. Many of the above stated
EPA goals for collection system management can be easily and inexpensively satisfied by the
procurement and installation of a variety of remote terminal units (RTUs) which can be quickly
installed and activated in any collection system. The timely receipt of alarms and notifications
from a typical SCADA system will dramatically reduce the potential for lift station failure, thereby
reducing the potential for SSOs, the potential threat to public health, and potential property
damage. The ability to receive real-time notifications of potential back-ups and to quickly
respond in an organized, logical manner is dramatically enhanced by the operation of a SCADA
system. Any well-designed SCADA system should minimize the risk for service interruptions by
monitoring the operation of critical pumps and equipment. Most repairs can be anticipated with
timely information and those that cannot be anticipated can be handled quickly through prompt
and efficient notification of responsible personnel.
Additionally, a well designed SCADA system can track the efficiency of pumps and other
equipment. Inefficient pumps can cause a reduction in the flow-rate out of a lift station. That
reduction, in turn, can cause a backup and cause a potential overflow situation to develop.
Monitoring the efficiency of pumps enables the operator to repair or replace worn or inefficient
equipment before the SSO scenario develops. The implementation of the SCADA system also
demonstrates to regulators that the “best practices” are being adhered to.
Of major to concern to many collection systems is the impact of inflow and infiltration (I
and I) on their systems. Understanding I and I starts with analyzing data to determine if the I and
I exists and, if possible, narrowing down the target areas to investigate. The ability to measure
and analyze potential I and I allows the operator to design and implement a plan to minimize the
impact on the collection system and to isolate, identify, and to correct or repair problem areas
within the system. A well designed SCADA system will streamline and simplify record keeping
and will aid in the eventual isolation of problem areas. The data reporting features of a SCADA
system can allow the operator to easily track and record data, compare month-to-month or yearto-year, track the impact of growth in the system, and to make plans for worst-case scenarios.
An important feature of a properly designed system is that it enables an operator to provide his
regulators and governing board or council hard evidence of shortcomings and successes.
Joanne Massony, Kenner (LA) Project Manager for Veolia Water, first installed SCADA
in 2007. “When we installed the Mission Communications SCADA units”, reports Ms. Massony,
“We found that several pumps ran too long because we had some I and I or capacity issues,
this led to serious maintenance issues. When we had a heavy rain we discovered that some
pumps might run all day. The Mission system helped us to identify the pumps that were running
© 2011 Mission Communications, LLC
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too long and the pumps that were not running efficiently and that led to quicker and better
targeted maintenance.”
The third element of a CMOM program, Collection System operation, involves numerous
parts. These may include, but are not limited to, the following11:
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Budgeting
Monitoring
Equipment and collection system maintenance
Figure 1- Pump runtime graph, reporting the total runtime per day, overlaid with a graph of the
rainfall in the same period. Notice the correlation between rainfall and increased pump runtime,
indicating potential Inflow and/or Infiltration. Pump one is also running consistently longer than
pump two, which may indicate (if equally rated to pump two) that it is operating less efficiently and
should be checked.
David Kellogg is the Assistant Superintendent of Public Utilities for the city of Gallatin
(TN) Department of Public Utilities. His responsibilities are numerous and include the oversight
of pump station maintenance on the collection side of the Gallatin utility system. His utility
installed Mission cellular SCADA in 2006. Mr. Kellogg has found that the SCADA system they
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EPA 305-B-05-002, pg 2-17
© 2011 Mission Communications, LLC
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installed has been extremely helpful in operating their system safely while reducing the potential
for reportable spills. “If we have a really heavy rainfall or a pump outage, we receive an alarm
through the SCADA system. We can bring in portable pumps to get the effluent into the outflow
pipe, and avoid a potential spill situation.”
The Mission system includes an automatic report function that measures pump
runtime variance. The software keeps track of all runtimes for each individual pump over the
current 30 day time frame. Any runtime that exceeds the predetermined statistical variance for
the past 30 days is flagged and Mr. Kellogg receives an email notification from his HMI
software. “The pump runtime variance report alone has helped us prevent numerous potential
spills. If any pump runs a lot longer, or shorter, than it normally does, that’s something I want to
know about”, added Mr. Kellogg. Statistical tools, such as measuring runtime variance, can help
an operator quickly identify stations in which pumps are working more, or less, than their usual
level. These stations are obvious targets for immediate routine maintenance, even if the system
is not receiving alarm calls for bad pumps or high wet-wells. Properly interpreted, accurate
runtime information can prevent many problems before they happen.
Figure 2- Runtime Variance Analysis report, showing the average runtime the past 30 day period for
each station along with the standard deviation. Deviations outside the normal statistical range trigger an
alert message to the operator.
© 2011 Mission Communications, LLC
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The fourth element of the CMOM program, collection system maintenance, should focus
on the following goals12:
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Prevention of overflows
Maximization of service and system reliability at minimum cost
Assurance of infrastructure sustainability
When most operators are asked to name the single most important function of their
SCADA system, they will name the first item above. Some operators install a rudimentary alarm
and notification system in order to satisfy their need to prevent system back-ups and overflows
but never reap the full benefit of the knowledge that a properly utilized SCADA system can
bring.
Several years ago the basic auto-dialer, an electronic device that can automatically dial
pre-programmed telephone numbers to communicate between two points in the established
telephone networks, was considered sufficient, and in many places these basic units are still in
use. The cost of an auto-dialer can vary a great deal. The more complex, multi-number, multiline, programmable units can be as high as $4000 each. Auto-dialers require the owner to
establish and maintain the connections through the local telephone exchange, at a cost of $30
to $60 per month. Generally “dialers”, as they are often called, do not have a mechanism to
monitor the integrity of the line, which has been a major detriment of the technology. If a unit or
telephone line is damaged, the alarm call cannot be completed and the end recipient will not
receive notification that the phone line is damaged.
Ryan Eastwood came to the Ashland, Kentucky system in mid-2009. His first task was to
fix the water distribution system, which had become less efficient over time due to the expense
of maintaining it. One of his predecessors had installed traditional radio-based SCADA a few
years before, but that system had become unusable due to the high cost of service and the
frequent outages. One of Eastwood’s first decisions was to install Mission RTUs at all his lift
stations. Not only has Ashland reduced overflows and repaired problem areas, they have
actually been able to reduce their operational man-hours. “We’ve definitely reduced overtime”,
reports Mr. Eastwood, “We spend much less time driving so we are able to spend more time
working. Our new Mission SCADA system is very reliable. I keep myself on the first responder
call-out list and when there is a problem the system always calls me. It is really easy to get
information right from the phone or from my computer at home. I can even turn on or off pumps
from my smartphone if I have to handle a back-up or maintenance issue. Having that level of
control is great.”
The design and implementation of the CMOM program is a valuable exercise for
every wastewater utility. Finding effective ways to implement the recommendations of the
CMOM program can only help your utility to meet its ultimate goal of effectively serving the
public. Properly applied, the CMOM guidelines should save most utilities a significant amount of
ratepayer money that had previously been lost to system inefficiencies. Mission
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EPA 305-B-05-002, pg 2-27
© 2011 Mission Communications, LLC
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Communications low-cost cellular based SCADA may be a valuable tool to help start get your
CMOM program started, and to help it remain on-track.
© 2011 Mission Communications, LLC