Monitoring Aromatic Organics for Optimizing Coagulation
Organics Monitoring (TOC)
Monitoring Nitrates in Drinking Water & Wastewater
Importance of Measuring UVT for UV Disinfection
Disinfection By-Products (DBP) Precursor Monitoring
Water Distribution System Security Monitoring

Water Distribution System Security Monitoring

A water security instrument essentially needs to be able to detect potential contaminants in drinking water. Since a significant number of potential chemical contaminants are organic in nature, a water security monitoring instrument that can detect organic matter in water is perfect for this application.

Real Tech has developed an instrument specifically designed for water security applications called the Real UV254 Security monitor (or model M4100). The Real UV254 Security monitor was recently evaluated by the U.S. EPA's National Homeland Security Research Center (NHSRC) Technology Testing and Evaluation Program (TTEP) with excellent results.

The Real UV254 Security monitor allows detection of sudden changes in organics levels using UV absorbance at the 254nm wavelength. These small, sudden changes in UV254 indicate that the chemical composition of the water is different than the normal composition, signifying a potentially harmful contamination event has occurred.

Detection Versus Identification

It is possible through UV spectral analysis to not only detect the contaminant but to also actually identify the specific contaminant by recognizing it's spectral finger print. Although Real Tech is able to do this type of identification with its Real Spectrum series instruments, identification of the contaminant by the water security monitor is not generally considered particularly useful, which is also a view that is shared by the U.S. EPA.

Contaminant identification is best done after the fact via a portable lab and by follow up lab testing, especially as this will be done anyway. The reason for this is that the same procedure of shutdown and investigation should be taken whatever the particular nature of the contaminant, whether the contamination is from an accidental spill of diesel fuel or an intentional contamination with Ricin.

In the end, the added instrument cost for the unnecessary bonus feature of contaminant identification, is better spent by buying a few more UV254 based water security instruments capable of just straight detection. It is better to have more strategic monitoring points in the distribution system than it is to have fewer points that include the contaminant identification feature.

Detection Sensitivity

Since only a very small concentration of some organic chemical contaminants could potentially cause a significant public health crisis, it is imperative that the chosen monitoring solution be sensitive enough to detect the smallest levels of contamination via the corresponding deviation from the expected baseline.

The technology used in Real Tech's Real UV254 Security monitor allows for extremely sensitive measurement capabilities. The sensitivity of an absorbance instrument is fundamentally linked to the measurement path length through the water. Real Tech's sensitivity is significantly greater than competing absorbance monitoring instruments due to the Real UV254 Security monitors unique ability to use a 25cm path length of light through the water. The longest path length option for competing products is only 10cm. This expected sensitivity advantage was proven during the recent evaluation by the U.S. EPA's National Homeland Security Research Center (NHSRC) Technology Testing and Evaluation Program (TTEP).

The Importance of Instrument Response Time for Contamination Detection

Real Tech's Real UV254 Security monitor provides the most rapid detection of organic chemicals in water and can detect sudden changes from a normal or baseline in only 10-15 seconds. The faster this chemical change is detected the more likely disaster can be averted. It is very important that a contaminant flowing through the distribution system can be stopped before it branches into a wider area of the distribution system, potentially affecting a very large population. Alternative organics monitoring instruments can take more than 10 minutes just to test a single water sample. In that time, the contaminant can potentially spread past strategic blocking points where a valve could be shut to stop the flow of the contaminant any further. Depending on the contaminant and the topography of the distribution system, even a reduction of response time by seconds could actually save lives.

Choosing Sites for Detection Nodes

The topography of a municipal water distribution system is basically a tree structure, with main branches flowing into sub branches and then into sub-sub branches and so on. Some branches have higher flow than others. Some branches travel much further but to lesser populated areas. Some branches go to industrial areas whereas some branches go to residential or commercial areas, and yet others go to potential strategic target sites such as government buildings, hospitals, or administrative centers. Because of the complexity of the distribution system, choosing which sites are good candidates for water security monitoring can be challenging. In the end, the recommended number of detection nodes even for similarly sized cities can vary greatly due to the particular topography of a distribution system.

Even monitoring just a few sites can be quite costly for a water utility both looking at capital cost and also maintenance costs. With this in mind, Real Tech's Real UV254 Security monitor has a low capital cost and the low maintanence and reagentless design of the monitor ensures minimal upkeep costs after installation.

Real Tech's Solutions for Distribution System Monitoring

When it comes to ensuring the security of our drinking water, the Real UV254 Security (M4100) monitor provides an accurate, easy to use, low maintenance and cost effective solution for rapidly detecting accidental or intentional organic contamination within the municipal distribution system.