Water System Security and Resilience in Homeland Security Research
Healthy, secure communities require clean drinking water and sanitary waste treatment. EPA provides water utilities with tools and strategies needed to improve drinking water and wastewater system resiliency to disasters, and to quickly recover from contamination involving chemical, biological, radiological, (CBR) agents. EPA also helps water utilities to enhance the cyber-security of their water systems.
Drinking and Wastewater Infrastructure Protection
EPA partners closely with other state and federal agencies and organizations and provides water utilities with tools and methods to identify, prioritize and respond to threats to the nation’s drinking water and wastewater systems.
The Bioterrorism Act of 2002 requires that drinking water utilities serving more than 3,300 people conduct vulnerability assessments and develop emergency response plans. EPA and its partners help utilities meet these requirements by developing tools and methodologies that:
- identify and prioritize threats to drinking water and wastewater infrastructure
- evaluate vulnerabilities
- create standard frameworks for risk management
- plan for countermeasures to reduce the risk of intentional contamination
In addition to contamination incidents, attacks on water systems involving explosives are possible. The Blast Vulnerability Assessment (BVA) tool, desktop computer tool developed by EPA, can be used with minimal training. A variety of options allow for different scenarios, providing estimates of damage that could occur from an attack using explosives. This tool is available from the Water Information Sharing and Analysis Center (WaterISAC): a secure website with a controlled subscription list.
The Consequence Estimation Tool, a component of the Threat Ensemble Vulnerability Assessment (TEVA) Sensor Placement Optimization (TEVA-SPOT), allow water utilities to estimate health consequences, risks, and vulnerabilities from contamination. Utilities can harden their system against contaminant attacks, better handle security incidents, while improving day-to-day operations through the use of this tool.
EPA has collaborated with the American Water Works Association (AWWA) to develop contingency plans in the event of a large-scale disaster. Planning for an Emergency Drinking Water Supply has recommendations on planning for alternative drinking water sources and water and wastewater treatment.
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Research to Support Utilities in Contaminant Detection
An effective contamination warning system will identify contamination events in real time, while minimizing false alarms. EPA evaluated approaches to warning systems that integrate information from a variety of sources, including:
- data from online monitoring instruments and sensors
- water quality data required by the Safe Drinking Water Act
- solicited and unsolicited customer complaints about water
- public health reports on symptoms possibly related to water contamination
Sensor Studies
Most drinking water utilities use commercially available water quality sensors to monitor for changes in acidity, levels of free or total chlorine, total organic carbon, and other water quality indicators. EPA tested some of these commonly used sensors to determine if they can detect water contamination involving chemical, biological, or radiological agents, in addition to detecting routine water quality variations.
Water Security Modeling and Simulation Research
One major challenge in the use of sensors to monitor water quality is how to distinguish between normal fluctuations in water quality and changes due to contamination or operational problems. EPA researchers and collaborators developed computer modeling programs that use mathematical and statistical techniques to distinguish unusual water quality changes from normal water quality fluctuations.
The downloadable software package, EPANET, simulates flow and water quality in pressurized pipe networks for water utility distribution systems.
EPA researchers developed extensions to EPANET that work in conjunction with the existing software to extend its capabilities. EPANET–MSX (Multi–Species eXtension) simulates the interactions between multiple chemical and biological agents and their intereactions with the piping in water distribution systems.
EPANET–RTX (Real–Time eXtension) enables simulation of conditions in a distribution system using real–time hydraulic measurements of water quality, pressure and flow rates. The ability to evaluate distribution systems in real-time will improve contamination event detection, source identification, and the potential effectiveness of responses to contamination or operational problems.
The Threat Ensemble Vulnerability Analysis–Sensor Placement Optimization Tool (TEVA–SPOT) utilizes EPANET to simulate flow and water quality in water distribution systems. The software helps water utilities optimize the number and location of sensors needed to support a contamination warning system that can detect contamination incidents in time to mitigate both economic and public health consequences.
CANARY Event Detection System software assists water utilities in interpreting large amounts of water quality data. It can automatically review incoming data, detect unusual conditions, and send alerts for the water utility to take further action. CANARY can detect unusual conditions resulting from contamination incidents, as well as detecting unexpected, but normal operating upsets, such as a sensor malfunction or a pipe break.
Integrating water quality data with public health information can create more robust contamination warning systems. Public health surveillance includes monitoring poison centers and 911 emergency calls, over–the–counter medication sales, and the number of patients reporting certain symptoms to doctors. Increases in any of these indicators could signal a disease outbreak.
Integration of this information with water quality data could indicate whether water contamination was the source of the outbreak. EPA researchers have been working to integrate an established public health surveillance system, the Electronic Surveillance System for the Early Notification of Community–based Epidemics (ESSENCE), with water quality data to improve the effectiveness of contamination warnings systems.
Pathogen Concentration
The need to rapidly and effectively detect low concentrations of potentially dangerous microorganisms in water led to the development of an ultrafiltration device that greatly reduces the size of samples, making transport to the laboratory safer. The ultrafiltration device can concentrate the microorganisms contained in a 26-gallon water sample into less than two cups of water in about an hour. Concentrated samples allow for more accurate detection of low levels of microbes in water samples.
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Containing Contamination and Mitigating Impacts
EPA researchers continue to develop software tools that can help water utilities respond to contamination events, as well as to mitigate the effects of these events. The response tools include previously developed tools (TEVA-SPOT, CANARY and the EPANet extensions) and additional modules to allow for optimizing and implementing response actions in real–time. The tools includes the ability to identify:
- a contaminant source
- optimal sampling locations
- optimal flushing locations
- valves that could be opened or closed to isolate the contaminant
- locations where disinfectants or decontaminating agents could be added
EPA has collaborated with the American Water Works Association (AWWA) to develop contingency plans in the event of a large–scale disaster. Planning for an Emergency Drinking Water Supply has recommendations on planning for alternative drinking water sources and water and wastewater treatment.
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Water Treatment and Infrastructure Decontamination
Many kinds of contaminants, including chemical, biological, or radiological weapons, could contaminate a drinking water distribution system and affect human health, resulting in extremely high recovery costs.
Water utilities need the ability to detect contamination incidents as they happen, and to isolate a contaminant before public health is affected. Following contaminant isolation, decontamination and disposal plans could be put into action.
EPA has developed optimization models that simulate the flow and water quality in pressurized pipe networks in real-time. The ability to perform real-time simulations can guide decontamination activities by predicting the impact of flushing or isolating sections of the distribution system, identifying optimal locations where disinfectants or decontaminating agents could be added, and displaying the impacts of these actions.
Many contaminants can adhere to or become embedded in rusty or corroded pipes or biologically active layers (biofilm) on the pipe walls. Chemicals and biological organisms also react with substances in the water and on the pipe walls. EPA found that, due to these complexities within the distribution system, contaminants can persist even after decontamination treatments. EPA investigates the impacts of various factors on infrastructure decontamination, including:
- various chemical, biological, and radiological contaminants
- different water flow rates
- different pipe materials used in distribution systems
- water acidity
- different decontamination methods
Water system contamination involving biological agents may not require decontamination of the infrastructure if the biological agent(s) can be inactivated or killed. Although common water treatments, such as chlorination, inactivate many microorganisms, some biological agents are resistant. EPA conducts inactivation studies to identify treatment methods that will be effective against resistant organisms.
The treatment of large volumes of contaminated water generated during decontamination activities presents a challenge. This water must be treated before release into public treatment systems (sewers) or the environment. EPA investigates enhancements on existing methods for handling and disposing of large volumes of contaminated water by evaluating commercially available and portable treatment units.