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Dennis Maple always knew that when Carson City, NV, officials agreed to automate the municipality’s drinking water and wastewater treatment systems it would bring both financial and operational benefits to the municipality.
Events in 2004 just provided additional evidence.
That year, a huge fire struck the woods surrounding Kings Canyon Falls, a popular waterfall near Carson City. The fire was devastating, destroying more than 12 homes as it swept through the forest.
The fire also moved so close to Carson City’s primary water treatment facility that public works personnel could not safely man the plant to check on water levels. Fortunately, back in 1992, the city had installed a supervisory control and data (SCADA) system, in the form of a Wonderware SCADA Software Solution, to automate the operation of its wastewater recycling and water purification systems. Public works officials needed only to log onto the plant's automated SCADA systems to make sure that the treatment facility was working properly.
The city’s SCADA system even helped water-management staffers determine whether they needed to add to their water reserves from other areas to help fight the big fire and maintain enough water to serve their customers until firefighters beat back the flames.
That’s an extreme example of the value of a SCADA system to a municipality. But for Maple, control systems supervisor with the public works department at Carson City, there are countless everyday reasons to rely on a SCADA system to monitor the efficiency—and to identify potential problems—for both the main and clustered wastewater systems at municipalities both large and small.
“Our automated system has allowed us to really take control of our wastewater treatment without having to add a lot of full-time employees,” Maple says. “Our population has grown by about 20,000 people in the 15 years since we’ve added SCADA. We’ve opened more wells. But thanks to our automated systems, we’ve been able to absorb all these additional points without adding new employees. SCADA has kept us efficient.”
SCADA systems, which are basically a network of automation and data-monitoring software and hardware, provide a whole host of data to utilities. Not only can SCADA systems pinpoint unusual water pressure in a system, they can tell plant officials how long the pressure’s been too high or too low. They can help plant managers forecast periods of peak demand. They can identify possible leaks or malfunctions long before human engineers can find the same problems.
The wastewater treatment industry isn’t the only one that is relying on SCADA systems for gathering and analyzing real-time data. The systems can be found in the energy, oil, gas-refining, and telecommunication industries, to name a few.
At its most fundamental level, a SCADA system is a computer system that monitors and controls an entire plant or select equipment within that plant. Such systems can tell plant managers where leaks are springing in their systems, when unusual amounts of energy or water are being consumed, and whether chemical levels have risen too high.
The system then sends this information to a central site. Plant officials can analyze this information and decide what action, if any, to take to resolve a problem.
SCADA systems come in all shapes and sizes. Some are simple, perhaps monitoring energy use in a single commercial building. Others are highly complex, such as the ones that monitor data for entire water treatment systems.
Companies manufacturing SCADA systems say they aren’t surprised at their steadily growing popularity. Federal regulations are stricter when it comes to water treatment. Utilities commonly face budget pressures, too, being asked by their municipalities to deliver quality service at lower costs. Automated systems can help municipalities lower their labor costs as fewer employees are needed to monitor outlying plants, especially important for municipalities running cluster wastewater systems. SCADA systems that pinpoint problems before they become big ones can help utilities further lower their bills.
Then there is the trending information that SCADA systems provide. By monitoring their systems and analyzing the data they provide, wastewater officials can pinpoint times of peak use and plan their budgets and any system expansions accordingly.
“When we first implemented our system, it was mainly to alert us to alarms and malfunctions,” Maple says. “As time went on, we realized how important the trending ability of the system was. We started adding sensors to do more fine-tuning on pressure zones and our hydraulic monitoring. This gave us a little more control of our system. It allowed us to see into the future what we might need to do as far as additional development goes.”
Automation on the Rise
Roy Kok has seen firsthand just how popular SCADA systems have become. He’s product manager for SCADA software at GE Fanuc, one of the largest manufacturers of automation products, including SCADA systems.
Not only does Kok see demand for the systems increasing at his job, he lives next door to a real-time example of the benefits of automation software.
Kok lives next to a small wastewater treatment plant. Municipal officials now monitor the plant with a SCADA system. The system alerts employees whenever a problem pops up, using an auto-dialing program to call supervisors whenever a specific situation—programmed into the SCADA system in advance by wastewater officials—triggers an alarm. It also spits out usage and treatment data on a monthly and weekly basis.
The plant is so automated that it remains completely unmanned during evening and weekend hours, providing the municipality with valuable savings in labor dollars.
And this is far from the only way that SCADA systems can save municipalities money. By studying the data provided by these systems, municipal officials can determine the optimal treatment for their wastewater, thus sparing the expenses generated whenever cities or towns add chemicals unnecessarily.
“A lot of municipalities are looking at, say, their filter levels, trying to determine when they need to make a change, when they have to backwash filters,” Kok says. “They are looking at how they use their chemicals. With SCADA systems you get trending information showing when your pH levels are high or low. By having accurate trending information, plant operators can best determine when they really have to add chemicals or backwash their filters. That is a major cost to municipalities. These systems can help them reduce their chemical usage significantly.”
Kok points to a number of different reasons for the growth of SCADA systems, everything from cost savings to reducing manhours at traditional and cluster treatment plants to identifying potential problems, such as leaks or malfunctioning valves, before they develop into more serious issues.
For wastewater treatment plants, though, the main benefit is probably the wealth of operational data—on usage history, demand, and past water treatments—that SCADA systems provide.
“It really improves the visibility that plant monitors have,” Kok says. “It knows what is going on at its plants at all times. They just call up a screen and get all the key indicators that they need. The screens immediately show you if anything is going awry. The alarm capability automatically changes the screen’s color and launches views appropriate to whatever the situation is. You can call up documentation specific to the type of problem you are having.”
Then there is the cost-savings aspect. It’s clear that SCADA systems can reduce the amount of labor costs that municipalities have to pay to maintain and operate their wastewater facilities. This is important, as residential and commercial customers ask their utilities to do more with less revenue.
But SCADA systems can provide cost savings in less obvious ways, too. For instance, Kok says, a municipality’s wastewater system may be designed to handle 1 million to 2 million gallons per day of wastewater flow that needs to be treated. If a severe rainstorm hits the area, the flow could rise to 10 times that amount.
In the most severe of storms, a plant may not be able to handle that increased amount of flow. Plant officials might then have to resort to a controlled dump of sewage, something no plant manager wants to authorize but an emergency measure that could be necessary depending on the amount of increased water flow. Regulatory bodies, of course, do not like sewage dumps, and impose heavy fines if they determine that plant operators took such drastic actions unnecessarily.
But by having a SCADA system in place, treatment plant officials can bring flow data to regulatory agencies showing that indeed the plant was running at full capacity and that the dump happened because of need, not because of a motor outage.
By being able to prove this to regulatory bodies, a municipality can save significant dollars in fines.
“You can show that there was nothing you could have done about this,” Kok says. “It had to happen.”
Left Behind?
The officials who help build and install SCADA systems say the day is rapidly approaching when it will be unusual for wastewater treatment plants, whether centralized or cluster, not to boast automation software.
SCADA systems provide so many benefits that it will soon become more fiscally irresponsible not to have them than it is costly to install them, these officials say.
Steve Garbrecht, marketing program manager for platforms and SCADA systems at Wonderware, says his company is seeing a boom in the demand for SCADA systems.
Part of the reason is that there is so much residential and commercial building taking place across the country, Garbrecht says. New wastewater treatment systems are being built constantly, especially cluster systems to serve growing municipalities in the western portion of the United States.
Established communities, too, are turning more frequently to both new and updated SCADA systems, Garbrecht says. The infrastructures of many established cities and towns are aging rapidly. Officials need to replace worn-out pieces, including the SCADA systems that were first installed in the 1970s and 1980s.
The increased reliance on SCADA systems is little surprising, Garbrecht says.
“Automation in general is increasing,” he says. “Automation provides opportunities to optimize the way a plant is run. It makes the staff more effective in how they do their jobs. It takes them away from some of the more mundane jobs, like creating reports for water-quality and regulatory agencies. It lets them better monitor the way plants are running. They can go out and walk around more; they’re not tied to their computers as much.”
At the same time, the cost of the components in SCADA systems—the remote terminal units, the programmable logic computers, and the human-machine interfaces—is dropping.
Faced with lower costs and a host of benefits, it becomes more difficult for municipalities to justify not boosting the automation of their wastewater treatment plants.
There are still some barriers, of course. Training is one. The staffers at treatment plants new to SCADA or at those looking to add an updated, more efficient automation solution may resent or fear having to learn a new way of operating their plants. The good news, though, is that SCADA systems have become easier to learn and run, says Garbrecht.
Plant officials can tailor their SCADA systems to work specifically with their plants. This means they can eliminate the features that they don’t need, focusing instead on the ones that they do.
“The beauty of a well-made SCADA system is that it doesn’t force users into using it in a specific, set-in-stone way,” Garbrecht says. “There is no real set way to build a SCADA system. There is no SCADA standard. The systems are meant to be molded, to be a tool set that can be customized for every plant.”
For instance, plant officials can develop a list of key performance indicators for their wastewater systems. If a plant’s operating level dips below these indicators, the SCADA system will issue an alarm.
“The operators don’t have to get into the details of using the SCADA system,” Garbrecht says.
“They just have to watch the dials. If they change to the worse, staffers know where to concentrate that day on fixing things. That makes it all easier. It’s a different way of looking at training. You don’t need to train everyone on every level of detail. The system can flex to meet the demands of every user. What it boils down to is delivering the right data to the right person at the right time.”
Garbrecht says that more wastewater officials are realizing the benefits of SCADA and the ease of automation. At the most recent convention of the American Water Works Association, Garbrecht saw that at least a base level of SCADA is common at facilities. Plant managers now, though, are moving to more intense SCADA functions, installing systems and upgrades that allow them to better monitor how their plants are operating.
“These really have become a necessity,” Garbrecht says. “They’ve gone beyond the base level and are now heading into optimization.”
Efficiency in San Diego
Officials with the City of San Diego’s wastewater treatment system have a lot to keep track of. San Diego operates a major wastewater treatment plant that treats about 175 million gallons of wastewater a day while serving a population of 2.2 million residents. It also operates two major water-reclamation plants that combined reclaim 45 million gallons a day of wastewater, nine large pump stations and 84 smaller pump stations, located throughout the municipal sewer system. Finally, it operates a biosolids treatment facility.
Trying to operate a system this large without a SCADA solution would be a major challenge. Fortunately, the city has long relied on SCADA systems manufactured by Emerson Process Management.
The SCADA systems have allowed the city to save significant dollars. Both of the city’s water-reclamation facilities are unattended at night. One of the reclamation plants is also unattended on weekends.
All of the city’s outlying small pump stations are also unattended.
“Even though we’ve expanded our treatment system, we’ve basically kept the same amount of operations staff,” says Ian Harris, senior control systems engineer with the City of San Diego’s Metropolitan Wastewater Department. “Our staffing has remained relatively constant even though we’ve added three more treatment plants. We’ve seen a lot of savings through automation.”
The SCADA systems manufactured by Emerson also help the wastewater department save money on emergency repairs. The automated systems deliver a constant stream of information to the wastewater department. By analyzing it, department staffers are able to spot problems before they grow into more significant issues.
At the same time, the real-time data generated by the SCADA systems have helped employees cut down on the number of spills generated at the treatment system’s smaller pumping stations. Harris estimates that the department has lessened the number of spills by about four times.
“Before we were doing constant emergency repairs,” Harris says. “The goal was to increase preventative maintenance and decrease emergency maintenance. That way the system uptime is much greater. Chemical usage comes down. That saves a lot of money.”
Doug Johnson, director of business development in the water solutions department of Emerson Process Management, says that SCADA systems make sense for all manner of wastewater treatment plants, including the cluster systems that are generally seen in the industry as a step between traditional municipal systems and onsite versions.
Emerson officials are holding more discussions with municipalities on their long-term wastewater treatment planning, Johnson says. These discussions center, in part, on the many options municipalities have when it comes to tying their water treatment facilities into an automated SCADA system.
“Do you divert wastewater to one plant, or do you handle it with multiple plants?” Johnson asks. “Municipalities are worrying about economics now more than they had in the past. They are doing it now on a long-term planning basis.”
The benefits of operating smaller, onsite treatment centers are many. But one of the disadvantages for municipalities has always been the amount of personnel they would need to employ to staff all these smaller facilities. With the rise of SCADA systems, though, this disadvantage disappears, according to Johnson.
“Automation systems make the idea of running smaller sites across a municipality feasible,” Johnson says. “It’s more of a practical solution now. And then you don’t have the huge collection system and the risks associated with the amount of wastewater transported as you get closer to the large centralized treatment plants. There’s a lot of agreement now that the technology is there to support this kind of an approach.”
Dan Rafter is a technical writer based in Illinois.
OW - March/April 2007 |
