Monitoring Water Quality & Security in Distribution System
Once water leaves the drinking water plant and travels into the distribution system we essentially ‘go blind’ to its water quality. Current grab sampling regimens offer some information to the quality of water, but only for brief moments in time. Clearly on-line monitoring would greatly aid in the visibility of current water quality. Understanding the water quality baseline and deviations from baseline could potentially result in reducing the response time to such an event, minimizing damage to infrastructure and populations. Various water quality and security events have occurred throughout the world.
In Depth Discussion:
The ability to detect and act upon changes in water quality is a critical component in the drive to protect our drinking water supplies from intentional or accidental contamination. The twin motivators of the terrorist threat to water along with consumer demands for safe and potable supplies has lead to a sea change in the drinking water industry. The distribution system represents the last analytical frontier in the water quality industry that has been, to date, overlooked and ignored since the inception of modern drinking water systems. The monitoring of treatment plant processes has progressed to a level at which we can be confident that we are providing good quality water from the plant to the distribution system. Once the water reaches our aging distribution systems, however; our knowledge as to its continued integrity is limited by the quality and amount of available data. From a historical perspective, most monitoring in the distribution system has been relegated to the occasional snapshot provided by grab sampling for a few limited parameters or the infrequent regulatory testing required by mandates such as the Total Coliform Rule.
A number of studies conducted since 9/11 have shown that bulk monitoring of basic water quality parameters has the potential to indicate the presence of many harmful agents in water at the levels of interest. The realization of the potential of bulk parameter monitoring as a practical tool to detect terrorism related events has lead to the development of a number of sensor packages designed for deployment in the distribution system.
The first priority for any event detection system (EDS) is that it detects contaminants so that people and infrastructure can be protected in some effective way. While the ability to detect contamination is critical, if a system is to be capable of offering a likely return on investment (ROI) and achieve widespread deployment, it would also be useful if the EDS can inherently provide information that would be useful on a day-to-day basis. It is presumed that an EDS spends very little of its total time in an actual alarm condition. What is it doing for the rest of the time? Justification of the cost can include:
- Optimization of daily operations within the system monitored,
- Providing alarms for operational events not related to contamination threats,
- Replace grab sampling for compliance with other regulations with continuous monitoring,
- Document system operation anomalies to assist with planning maintenance activities or planning and justifying major system upgrades (line replacement)
- Building consumer confidence by continuously documenting system water quality
Such capabilities can reduce the cost of operations for the system being monitored, and provide information that can be useful to those people who use the monitored system.
In the past, most of our analytical muscle was brought to bear at the treatment plant. Little consideration was given to source waters or the distribution system as areas needing constant monitoring. That paradigm has changed with the recognition that all areas of the water supply network are vulnerable to intentional contamination, most particularly the distribution system via a method known as backflow attack.
Backflow Attacks: A backflow attack occurs when a pump is used to overcome the pressure gradient that is present in the distribution system’s pipes. The pressure gradient can be easily overcome by using pumps available for rent or purchase at most home improvement stores. After the pressure has been overcome and a contaminant introduced, Bernoulli effects pull the contaminant into the flowing system and the normal movement of water in the system acts to disseminate the contaminant throughout the network affecting areas surrounding the introduction point. The introduction point can be anywhere in the system. Studies conducted by the US Air Force and Colorado State University have shown this to be a very effective means of contaminating a system. A few gallons of highly toxic material was enough, if injected at a strategic location via continuous feed, to contaminate an entire system supplying a population of 150,000 people in a matter of a few hours. (Allman) A terrorist could launch such an attack and be on a plane out of the country before the first casualties begin to show up.
Terrorists have definitely shown an interest in this sort of attack. On February 20, 2002 at 3:39 PM the Associated Press released a story with the following headline, “4 arrested with cyanide and Rome water supply maps.” The article detailed a raid on an apartment and the arrest of four Moroccan terrorists. They were part of the Salafist Group for Call and Combat, an Algerian organization with ties to Ossama bin Laden and the al Qaeda network. According to the article, they were in possession of a common cyanide based industrial chemical later identified as Potassium Ferricyanide, false documents, and detailed maps of the area surrounding the US Embassy. The maps found in the apartment included details of the city’s water system. The U.S. Embassy was circled on the maps. Investigators believed the suspects planned to contaminate the water supplies in the capital, including the commercial area around Via Veneto where the U.S. Embassy is located.(BBC News)
- Evaluating monitoring methodologies [pdf]
- ACCESSING DATA AND COMMUNICATING WITH MONITORI [pdf]
- Countering Terrorism with monitoring [pdf]
- Dual use monitoring for security and quality [pdf]
- Enhancing Security in Water Distribution System [pdf]
- WATER TERROR ATTACK [pdf]
- Addressing alarms Is It Real Or Is it not [pdf]
- Methodology for Evaluating Distribution Monitori [pdf]
- Real Water Events [pdf]
- Safeguarding the Distribution System [pdf]
- Science behind GuardianBlue [pdf]
- Switching from chlorine to monochloramine [pdf]
- The role of technology in Security [pdf]
- Utilization of the ToxTrack [pdf]
- Water as a weapon [pdf]
- Opflow Optimizing Water Quality [pdf]