John J. Cronley Marketing Communications Manager Mission Communications , x1008

Transcription

1 1 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 , x1008 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.

2 2 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 sources 2, 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 SSO 4, 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 to 5 : 1. Better manage, operate, and maintain collection systems 2. Investigate capacity constrained areas of the collection system 3. Proactively prevent SSOs 4. 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 Proposed Rule To Protect Communities From Overflowing Sewers, U.S. Environmental Protection Agency, Office of Water(4201), Washington D.C. EPA f Wikipedia.org, Clean Water Act, page 7. Available at: 3 EPA, 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 pg EPA 305-B , pg EPA 305-B , pg 1-4

3 3 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 to 6 : 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. 6 National Pollutant Discharge Elimination System (NPDES), NPDES Frequently Asked Questions, pg 7.

4 4 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 following 8 : 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: 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 elements 9 : 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. 7 EPA 305-B , pg EPA 305-B , pg EPA 305-B , pg 2-36

5 5 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 30 th. 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 following 10 : Protection of public health and prevention of unnecessary property damage 10 EPA 305-B , pg 2-4

6 6 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 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

7 7 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 following 11 : 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 Mr. Kellogg has found that the SCADA system they 11 EPA 305-B , pg 2-17

8 8 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 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.

9 9 The fourth element of the CMOM program, collection system maintenance, should focus on the following goals 12 : 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 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 12 EPA 305-B , pg 2-27

10 10 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.