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 and estimate consequences
- create modeling tools for vulnerability and consequence assessment and improved 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 component of the Threat Ensemble Vulnerability Assessment (TEVA) Sensor Placement Optimization (TEVA-SPOT) tool, allows 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 incidents 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.
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.
The downloadable software package, EPANET, simulates flow and water quality in pressurized pipe networks for water utility distribution systems and is the foundation of EPA’s water security modeling and simulations tools. Further development of and maintenance of EPANET is being handled through open source projects (See related links, below). Open source means that the original source code for the software is made freely available for distribution and for others to modify.
EPA researchers developed extensions to EPANET that work with the existing software to extend its capabilities. EPANET–MSX (Multi–Species eXtension) simulates the interactions between multiple chemical and biological agents and their interactions with the piping in water distribution systems.
The EPANET-RTX (Real–Time eXtension) software libraries were released as an open source software project (a public collaboration) to advance real-time modeling capabilities using the hydraulic and water quality solvers (pieces of software that 'solve' mathematical problems) of EPANET.
EPANET-RTX provides the methods and software tools by which operational data can be connected with a network infrastructure model, and the resulting network simulation model can be calibrated, verified, and continually tested for accuracy using operational data. EPANET-RTX is software for building real-time hydraulic and water quality models.
EPANET-RTX brings real-time analytics to water distribution system modeling, planning, and operations. Analytics refer to the discovery and interpretation of patterns in data. EPANET-RTX software works by providing access accessing available utility data and effectively using it to run a hydraulic and water quality model.
Water utility operational data are collected and managed through what is commonly referred to as a Supervisory Control and Data Acquisition (SCADA) system. SCADA data systems in water utilities have been commonly used for decades. EPANET-RTX software technologies provide the ability to access a SCADA database to run hydraulic and water quality simulations. While SCADA data is inherently messy, EPANET-RTX analytics software uses filtering, smoothing, and other data transformation methods to make using SCADA data easier to use.
Building an EPANET-RTX model consists of four important steps. The first, level 0, is getting access to a utility's operational data. Level 1 is configuring the real-time model, which is an exercise in integrating the model and SCADA data, as well as suitably transforming the SCADA data streams. And finally, level 2 is prediction, which involves using the EPANET-RTX framework to efficiently assess model accuracy. Level 3 is predicting the water utiliy system's behavior.
RTX:LINK is an EPANET-RTX-based software tool (an EPANET-RTX application) for small and large water utilities to download and use to increase their understanding and the value of their SCADA data and the power of real-time analytics. RTX:LINK can provide a web browser (i.e., smart phone, tablet or computer) view of all available utility SCADA data to an open-standards cloud analytics service to allow the water utility to remotely access and analyze their SCADA data in real-time. RTX:LINK can provide a real-time, web browser-based view of hydraulic and operational assets (e.g., tank levels, flows, and pressures) and provides some water quality metrics (e.g., percent tank turnover per day or per week) to help inform and alert operators, engineers or managers to potential problems.
Real-time analytics offers water utilities the ability to evaluate distribution systems in real-time and more easily resolve routine operational problems. Additionally, real-time analytics offers water utilities the ability to more accurately identify when contamination has entered the water system, where it entered the system, and, most importantly, the valuable information to enable timely and effective response. 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 Asessment–Sensor Placement Optimization Tool (TEVA–SPOT) utilizes EPANET to simulate flow and water quality in water distribution systems. The software helps water utilities perform system-specific vulnerability and consequence assessment and 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.
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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Water Treatment and Infrastructure Decontamination
Many kinds of contaminants, including chemical, biological, or radiological, 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 protect public health. 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
Furthermore, EPA has the ability to test contaminant persistence and decontaminate on the bench, pilot and field scales. Bench and pilot scale pipe loop studies take place at EPA’s Test and Evaluation (T&E) facilty in Cincinnati, OH.
Field scale decontamination studies using real water pipe can occur at EPA’s Water Security Test Bed (WSTB) located on the grounds of Idaho National Laboratory. The WSTB is made of 450 ft of 8-inch used drinking water pipe that was excavated from the INL grounds. Water flows through the pipe just as it would in a real city, and the pipe has removable coupons so the inside pipe surface can be sampled for contaminant persistence and decontamination effectiveness.
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.
Water infrastructure cyber security research is also being developed at the pilot and field scale identifying best practices involving the links between Information Technology and Operational Technology at the treatment works and distribution/collection systems.
The treatment of large volumes of contaminated water presents a challenge. This wastewater can be generated in a number of ways: 1) Intentional or unintentional direct contamination of drinking water and wastewater by chemical, biological and radiological (CBR) agents; 2) Washdown activities involving CBR agents from indoor-outdoor areas, which could include fire fighting; and even 3) Runoff during precipitation events prior to or during decontamination activities. This water may need to be treated before release into public treatment systems (sewers) or the environment. The issue is complex and EPA is working with the wastewater industry to address it. For instance, EPA investigates enhancements on existing methods for handling and disposing of large volumes of contaminated water by evaluating commercially available and portable treatment units.
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