Chemical Agents of Opportunity for Terrorism: TICs & TIMs

Chemical Agents of Opportunity for Terrorism
Training Support Package
Participant Guide
Slide 3
Chemical Agents of Opportunity for Terrorism:
TICs & TIMs
Water Treatment
• State / federal EPAs regulate public drinking water
safety (Safe Drinking Water Act) in US
• Common treatment steps:
– Coagulation / Flocculation
– Sedimentation
– Filtration
– Disinfection
Module One - Chemical Contamination of Food, Water, and Medication
3
This module will present the steps involved for most of the U.S. population in bringing
water from a reservoir or aquifer to the home or business.
Federal and state Environmental Protection Agency (EPA) regulate pubic drinking water
safety via the Safe Drinking Water Act. There are a number of water characteristics (e.g.
turbidity – a measure of clarity) and contaminants (e.g. lead) that are regulated by
maximum contaminant levels (MCLs). Although assays for nearly 100 contaminants are
performed, there are many elements and compounds that are not regulated or
measured.
Some common steps used in the treatment of water to make it safe for drinking are
coagulation/flocculation, sedimentation, filtration, and disinfection.
The Safe Drinking Water Act was first passed in 1974, with the latest revision in 1996.
This statute defines water qualities that are mandated for public drinking water. All
“states” except Wyoming, the District of Columbia, and most tribal nations have
“primacy”, meaning that the states take responsibility for complying with water safety
standards. Federal EPA provides oversight and monitoring for the others.
There are more than 170,000 community drinking water systems in the U.S.,
approximately 1/3 of those use ground water (wells/aquifers), while 2/3 originate from
surface water (rivers, lakes, reservoirs).
Each of the water treatment steps will be expanded in the next slides, but a basic
definition includes:
1. Coagulation/Floculation: adding alum or other agglomerating agents that cause large
particulates to clump together
2. Sedimentation: removal of larger particles by gravity
3. Filtration: removal of small particles (potentially down to the micrometer size or smaller
4. Disinfection: (usually with a chlorine containing compound in this country). The chlorine
kills viruses/bacteria well, but spores & protozoa such as Giardia & Cryptosporidium are
December 2008 Version 2.0 Page 258