Beyond Process Control
Today's integrated monitoring and control technologies provide operational and economic benefits for municipalities of all sizes
- By Douglas Johnson
- Dec 01, 2004
The environment in which the water and wastewater industries operate has never been more challenging. Increasingly complex financial and environmental regulations, security concerns, and shrinking budgets are just a few of the realities keeping managers up at night. Simultaneously addressing these sometimes conflicting demands may seem overwhelming on the surface, but it doesn't have to be. Experience shows that integrating information -- both horizontally and vertically throughout an organization -- can make it easier to satisfy these competing concerns, while at the same time producing additional measurable benefits.
Over the last few years, the municipal water and wastewater industries have begun to move in this direction as they have become more aware of the control options available to them. They are increasingly moving beyond programmable logic controller- (PLC) based control to technology that can not only be used for basic control and monitoring, but for fleet-wide or district-wide integration as well.
To fully understand and appreciate the benefits and impact integrated control technologies can have at the plant and throughout the entire organization, it is helpful to first explore in more depth some of the pressures driving their adoption.
First, there is supply and demand. The total Clean Water State Revolving Fund (CWSRF) eligible needs for the nation as of January 2000 are $181.2 billion. Shortages of new fresh water supplies, population growth and movement, and the growth of new water treatment technologies combined with major infrastructure funding gaps -- estimated by the U.S. Environmental Protection Agency (EPA) and U.S. Congress to be $1 trillion over the next 20 years -- are driving the U.S. water industry to change. In order to meet the needs of the nation, it has been estimated that more than 1,000 new treatment facilities will need to be built, extending treatment capacity by more than 5,000 million gallons per day (mgd).
On the human side, plant managers must do more with less since downsizing has cut staff and other resources below practical levels to the point that there is more outsourcing, even for previously routine internal activities.
Security, which has always been a concern, has taken on increased significance in the wake of 9/11. Title IV of the Bioterrorism Act (Public Health Security and Bioterrorism Preparedness and Response Act) of 2002 stipulates that each community water system conduct a vulnerability assessment to a terrorist attack or other intentional act that disrupts the supply of drinking water, and prepare/revise and maintain an emergency response plan.
Much security work has focused on physical security -- fences and perimeter security, guards, security procedures, and intrusion detection, etc. However, efforts pertaining to contaminant detection and abatement, system hacking, and data integrity and verification have an increased urgency.
But that's not all. Reporting requirements for new and increasingly complex environmental and financial regulations are also a top priority.
Since the U.S. Congress passed the Clean Water Act (CWA) in 1972, the EPA's Office of Wastewater Management (OWM) has added numerous programs and policies to promote compliance with the requirements of the act, including the National Pollutant Discharge Elimination System (NPDES) permitting program that also pertains to stormwater management, the Combined Sewer Overflow (CSO) Policy, and the proposed Sanitary Sewer Overflow (SSO) Policy.
Any facility that discharges pollutants from a point source into the waters of the United States must have an NPDES permit. Combined Sewer Systems (CSS), which can frequently overflow untreated sewage into waterways during wet weather, are regulated under the NPDES program. The permit basically serves as a license to discharge only a finite amount of a pollutant into receiving waters under specific conditions. The permit holder must meet nine measures outlined in the Combined Sewer Overflow (CSO) Policy in order for the NPDES permit to be renewed. These measures are:
- Proper operation and regular maintenance programs for the sewer system and the CSOs;
- Maximum use of the collection system for storage;
- Review and modification of pretreatment requirements to assure CSO impacts are minimized;
- Maximization of flow to the publicly owned treatment works for treatment;
- Prohibition of CSOs during dry weather;
- Control of solid and floatable materials in CSOs;
- Pollution prevention;
- Public notification to ensure that the public receives adequate notification of CSO occurrences and CSO impacts; and
- Monitoring to effectively characterize CSO impacts and the efficacy of CSO controls.
In addition, CSO communities are also expected to develop long-term control plans.
Communities with separate sanitary sewer systems, which carry wastewater only, theoretically do not have any point sources for pollutant discharge, so they have not been required to obtain an NPDES permit. However, EPA has found that at least 40,000 SSOs occur annually nationwide from unintended point sources such as manholes or deteriorated pipes. Therefore, EPA has developed the SSO Rule, which will require separate sanitary sewer communities to obtain an NPDES permit for their collection systems. The goal of the regulation is to improve the operation of municipal sanitary sewer collection systems, reduce the occurrences of sanitary sewer overflows, and provide more effective public notification if overflows do occur. While the SSO Rule is not yet finalized, it has been submitted to the Office of Management and Budget (OMB) and is expected to be enacted in the near future.
Also having an impact is the Government Accounting Standards Board Statement (GASB) No. 34 (Basic Financial Statements -- and Management's Discussion and Analysis -- for State and Local Governments), which brings a major change in financial reporting requirements for state and local governments. The rationale for the reporting change is to not only improve accountability, but also to create a more informed decision-making process.
To comply, governments must define the value of all assets -- process (plant) assets, such as subsystems of pipes, controls, and instruments; infrastructure assets, including pipelines, wells, and pumping stations; building assets; site assets (parking lots, fences, etc.); and equipment and furnishings. The statement is being implemented in phases based on government revenue. The final phase required governments with less than $10 million in revenue to implement Statement No. 34 for fiscal years beginning after June 15, 2003. As many municipalities invest public funds in the automation of their treatment facilities, water distribution systems, and wastewater collection systems, the management of those automation assets becomes an important element of overall compliance with GASB No. 34 requirements.
The Sarbanes-Oxley Act, another financial requirement, is also having an effect, primarily on investor-owned utilities. Enacted by Congress in 2002 in response to corporate accounting scandals, the legislation tasks corporations and their management with greater transparency and accountability to protect investors. While this is primarily an information technology (IT) issue now, it will eventually link to automation systems to validate operational data, which is key for investor-owned utilities.
Integrated Control Technologies: Meeting the Challenges of Today and Tomorrow
Until recently, many municipalities utilized PLCs mainly to control processes and collect basic information. And while they serve this purpose well, water/wastewater industries are discovering what other process industries have known for some time -- integrated monitoring and control technologies offer further economical and operational advantages. Going far beyond the basic definition of process control, these systems are ensuring cleaner, safer water supplies; reducing environmental hazards; and delivering significant operational cost savings. And, just as important for managers with limited resources, these innovative technologies can easily and cost-effectively be incorporated with the plant's existing monitoring and control methods.
Early water/wastewater adopters of integrated control technologies tended to serve larger markets -- Detroit, San Diego and Sacramento to name a few. But, just as cell phones have gone from novelty item to must-have in a handful of years, there has been a trickle-down effect. Mid-sized and even small municipalities like Ridgway, Pa., which supplies water for approximately 8,000 people, are catching the technology wave.
One of the factors that makes integrated control systems appealing to municipalities of all sizes is their use of widely recognized, commercially available hardware, software, networking, and communication interfaces. A major benefit of this open systems approach versus proprietary systems is that it allows organizations to easily and cost-effectively modify and expand the system to meet future needs.
The integrated control system architecture for water/wastewater industries often incorporates a supervisory control and data acquisition (SCADA) system for wide-area monitoring and control of operations from a single location. These operations may include remote pumping stations, wastewater collection systems, water distribution, PLCs, sewer diversion, water irrigation, wet weather overflow protection, and weather monitoring. This integrated architecture ensures that operating parameters are adjusted according to changing situations, thereby helping the plant to run smoothly. For example, during heavy rains, data from remote locations alerts the plant control system, which can then take appropriate measures to prepare for the surge.
In the SCADA configuration, remote terminal units (RTUs) at remote locations communicate to either one or more central monitoring facilities or other remote locations. SCADA design can utilize either an existing communication infrastructure or a new communication network. It can be configured with leased lines, licensed radio, unlicensed radio, or a combination of the three.
Obviously, water and wastewater treatment plants depend upon reliable operation of remote equipment to continuously and safely manage operations throughout the service area to the main station. There are several areas of management that could be improved through the integration of SCADA and plant controls:
- System monitoring. Provides continuous up-to-date information from remote facilities.
- Detection of failures. Early detection of equipment failures can eliminate potential environmental problems and avoid payment of fines.
- Flow adjustments. Automatically compensates for seasonal flow and wet weather.
- Control decisions. Decisions can be made for the entire plant -- and even the entire district -- instead of individual processes.
- Maintenance costs. Reduced amount of regularly scheduled maintenance visits.
- Workforce resources. Centralized monitoring and control can ensure the workforce is most effectively deployed. For example, personnel assigned to auxiliary equipment operation and maintenance can be redeployed to other areas as needed.
But the ability to monitor and control a single plant -- or plant and remote sites -- is really just the tip of the iceberg. Integrated control architecture goes several steps beyond, providing asset management, process optimization, and enterprise resource planning (ERP) integration.
It all starts at the plant, where this comprehensive architecture provides seamless integration with intelligent field devices and widely adopted bus technologies. The intelligent field devices give plant personnel immediate access to vital data from plant analysis and measurement instrumentation. This timely access to and control of real-time information helps assure both process quality and compliance with environmental regulations.
A next step toward an integrated enterprise-wide information system is to tie in predictive maintenance and optimization applications. Asset management software applications incorporated into the control system ensure critical equipment assets -- including mechanical equipment, electrical systems, process equipment, and instruments and valves -- are properly operating, thereby helping water and wastewater facilities meet environmental mandates and lower overall operation and maintenance costs.
After that, other information systems from the organization are integrated. These information systems may include:
- Maintenance management systems, such as those for work management, purchasing, and project management;
- Laboratory information management systems;
- Plant design systems, such as those for electronic document management;
- Geographic information systems; and
- Financial information systems, such as those for inventory, payroll, and human resources.
The end result: a single seamless system that integrates real-time process and equipment information with transaction-based enterprise business systems. This information integration gives management a window into the organization, providing them with the information they need to make informed decisions.
The advantages of adopting an integrated control architecture are widespread. From a top line view, these interrelated benefits can be broadly categorized as environmental, financial, and operational.
From an environmental standpoint, the wealth of integrated information available makes it easier to comply with NPDES reporting requirements. Also, the tighter overall control and process visibility made possible by the integrated control architecture can translate into improved management of treatment processes. For example, the control system can constantly adjust chemical deployment based on flow levels and critical process measurement, resulting in better control over the amounts of chemicals used in a treatment process.
Having an integrated view of the operation enables operators to see and immediately respond to abnormalities. This capability, coupled with better analytical information, has strong implications for maintaining plant security.
By reducing equipment downtime and improving plant reliability, an integrated control system translates into numerous financial and operational benefits. One example of this is improved workforce deployment. Due to increased fiscal pressures, municipalities are constantly challenged to do more with fewer resources. Keeping plant assets well managed enables field crews to be more readily available for preventive maintenance and emergency situations.
Furthermore, spare parts expenses are minimized through the inventory of a single set of spares versus parts associated with multiple pieces of monitoring and control equipment. Training costs also will be decreased due to control instruction on one system as opposed to several. What's more, system replacement costs are reduced, as the open systems design and well-thought-out migration planning protect against control system obsolescence.
And it's important to note that the system can be expanded easily and cost effectively to meet growing demands on water/wastewater treatment processes. The open system design of today's cutting-edge technologies allows for integration with existing third-party systems, ensuring that a municipality's current investment in control equipment will not be lost. Implementing an integrated control architecture as part of a multi-year automation master plan enables municipalities to build on resources they already have so they can move along a charted path to the future with fewer problems.
The ability to streamline information flow, thereby improving decision making throughout the enterprise, is another area that cannot be ignored: improved inventory planning and utilization of historical data for analysis and reporting are just two examples of increased efficiencies and capabilities in this area. It's clear that financial, security, and environmental reporting requirements are on the rise, with no sign of abating. Having a global database that puts all of the information needed for any reports into one place makes generating reports required now -- or the ones that will be required in the future -- simple.
The Tide Has Turned
Of course, none of this happens overnight. In the real world, information systems are upgraded or replaced as necessity or opportunity dictates. In other words, enterprise integration takes place over time and the key is to plan ahead. However, it's important to note that benefits and savings can be achieved at each incremental stage of implementation -- it's not an "all or nothing" proposition.
The pressures in which the water and wastewater industries operate may be complex, but the bottom line is simple. Adopting an integrated monitoring and control approach has been proven to improve the economics of water/wastewater organizations by delivering operational flexibility, improved reliability, increased operating efficiencies, the ability to meet operations and maintenance budgets, and maintain environmental and regulatory compliance. Not just for the large municipalities, these systems and the operational and economic advantages they provide are within reach of municipalities of all sizes. Simply put, the tide has turned.
This article originally appeared in the 12/01/2004 issue of Environmental Protection.