As part of the homeland security activity in the United States, the Environmental Protection Agency (EPA) continues to test commercially available water quality sensors for their ability to provide a warning alarm due to deliberate or unintentional contamination events within a drinking water system. The Intellisonde™ in-pipe water quality monitor from UK based Intellitect Water is one of several instruments being assessed by the US EPA in a simulated network at its Ohio Test and Evaluation Facility.
The project’s work on water quality sensors is in support of the Water Security Initiative, which is developing contaminant warning systems and addressing the risk of intentional contamination in drinking water distribution systems.
The trial with the Intellisonde has been underway for over a year. Summarising the Intellisonde’s™ preliminary results, the EPA’s John Hall says; "We have monitored a number of parameters such as pH, Conductivity, ORP and Temperature, however, the Chlorine and Flow data have proved to be particularly useful. Free Chlorine levels, for example, are significantly affected by a broad range of contaminants and the flow data can be used to reduce alarms due to operational events.
"Overall, the Intellisonde™ has provided reliable chlorine data for over 6 months without changing the probe, which represents an improvement in this principle of detection. Wide-spread deployment of solid state chlorine probes within the US water distribution network will be dependent largely on the reliability of the data and the cost of operation and maintenance for the sensor.
"Additionally, the Intellisonde™ has been easy to use once aligned in the pipe properly and we look forward to reporting further findings as the project progresses."
Developed to continuously monitor up to 12 parameters within drinking water distribution networks, the Intellisonde™ is a small water quality monitor that can be inserted into pressurised pipes through a 1½ inch valve. Measurement options include Free Chlorine, Total Chlorine, Mono-chloramine, Dissolved Oxygen, Conductivity, pH, ORP/Redox, Flow, Pressure, Temperature, Turbidity and Colour. Importantly, none of these requires membranes or reagents and the sondes can be deployed for long periods without the need for frequent recalibration or maintenance.