Full Scale Drinking Water System Decontamination at the Water Security Test Bed

Area of Science:

• Environmental Science
• Water Quality
• Microbiology

Background:

• The U.S. Environmental Protection Agency (EPA) established the Water Security Test Bed (WSTB) facility, a full-scale drinking water distribution system.
• The WSTB was developed in collaboration with Idaho National Laboratory (INL) to evaluate water infrastructure decontamination technologies.
• It supports research on real-time sensors, mobile water treatment, and premise plumbing decontamination.

Purpose of the Study:

• To assess the effectiveness of decontamination methods for Bacillus globigii (BG) spores and Bakken crude oil in a simulated drinking water distribution system.
• To evaluate the removal of contaminants from bulk water and pipe surfaces.
• To inform water systems on effective response methodologies for contamination incidents.

Main Methods:

• Full-scale testing within the Water Security Test Bed (WSTB) facility.
• Decontamination experiments using Bacillus globigii (BG) spores, a surrogate for Bacillus anthracis.
• Decontamination experiments using Bakken crude oil, focusing on soluble components and persistent residues.
• Evaluation of flushing and chlorination as decontamination techniques.

Main Results:

• Flushing and chlorination effectively removed the majority of BG spores from the bulk water.
• BG spores persisted on pipe wall coupons even after decontamination attempts.
• Soluble components of Bakken crude oil were removed by flushing.
• Oil residues remained in appliances such as dishwashers and refrigerator water dispensers.

Conclusions:

• Standard decontamination methods show limitations in fully removing microbial surrogates and crude oil from all parts of a water distribution system.
• Further research is needed to address persistent contaminants on pipe surfaces and within appliances.
• The WSTB facility provides a critical platform for risk-free testing of water contamination response strategies.