Water remediation is a critical process undertaken by drinking water or wastewater utilities to restore normal service following a confirmed contamination incident. A contamination incident refers to the confirmed presence of any chemical, biological, or radiological substance in a concentration significant enough to adversely affect public health and/or the environment.
The timeframe for a remediation process is determined on an incident-specific and site-specific basis and can vary from hours to months or even years if infrastructure replacement is required. The remediation process is divided into three phases: Characterization, Decontamination, and Clearance. However, these phases may overlap or occur simultaneously depending on other response efforts.
Characterization Phase
The Characterization Phase aims to discover as much as possible about the extent of contamination. This includes defining the contaminants and their interaction and movement in water, measuring contaminant concentrations to determine the magnitude of contamination, and locating the contaminants throughout the system to identify the extent of required remediation. This is achieved through coordination and communication with various emergency response partners and strategic sampling throughout the system.
During this phase, information on public health and environmental risks are used to identify any protective measures, such as a boil water notice, that may be needed throughout the remediation process. Once the extent of contamination and the risks are defined, a clearance goal is set, which is the contaminant concentration at which the system may be returned to normal service and is not expected to present a risk to public health and the environment.
Decontamination Phase
The Decontamination Phase involves the selection and implementation of water treatment and infrastructure decontamination. Water treatment methods are selected based on a variety of factors including effectiveness, availability of resources, time, and cost.
Depending on the contaminant properties and the locations identified throughout the system, infrastructure decontamination may be necessary. This could include removing contaminants from surfaces like pipes, valves, and tanks, or replacement of certain infrastructure altogether.
The Decontamination Phase also includes the management and disposal of any contaminated wastes. This could include contaminated water or infrastructure unable to be decontaminated, or byproducts generated during decontamination activities.
Clearance Phase
The Clearance Phase involves sampling and data review to determine if the clearance goals have been met. Clearance sampling is done through EPA-approved analytical methods to ensure compliance with regulations.
If clearance has been met, the water system can be returned to normal service. In some cases, specific areas of the system might be cleared while other areas are still undergoing decontamination. The system may also need to perform long-term monitoring after the system has been cleared and normal service has been restored. Long-term monitoring provides information to confirm the effectiveness of the remediation process.
In conclusion, water remediation is a complex process that requires a systematic approach and a thorough understanding of the contaminants involved. It is a critical step in ensuring the safety and health of the public and the environment following a contamination incident
