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Policy Statement 462 - Disinfection of Drinking-Water

Approved by the Energy, Environment, and Water Policy Committee on March 21, 2013
Approved by the Public Policy Committee on May 4, 2013
Adopted by the Board of Direction on July 12, 2013

Policy

The American Society of Civil Engineers (ASCE) supports continued research into improved methods governing the disinfection of drinking water to protect public health from any harmful byproducts.

Issue

Waterborne diseases were a major threat to public health prior to the introduction of disinfection treatment of drinking water in the early 20th century.  A major challenge for water suppliers is how to control and limit the risks from pathogens and disinfection byproducts. It is important to provide protection from pathogens while also minimizing health risks to the population from disinfection byproducts.  Chlorine and chlorinated compounds are very effective means to disinfect drinking water, and are widely used in the United States.  However, chlorine can react with naturally occurring compounds in water to form byproducts such as trihalomethanes, which have been linked to adverse health effects including cancer, kidney damage, and reproductive problems.  The Environmental Protection Agency enacted rules in 1998 and 2005 establishing health-based levels for chlorine, chloramine, and chlorine dioxide. These are the three most commonly used disinfectants because they are effective in purifying water during the treatment process and within the distribution pipes that deliver water to homes and businesses.  Ozone and ultraviolet decontamination are processes that currently are not widely used because neither method is effective in controlling biological contaminants in the distribution pipes.

Rationale

Disinfection of drinking water continues to be important to the protection of public health.  Civil engineers design and construct water treatment plants and distribution systems and conduct research into treatment technologies.  Selection of the appropriate method of disinfection for a particular system should be based on site specific considerations, such as quality of the source water and economics of the project.  Continued research into all viable disinfection technologies is needed to improve disinfection performance, minimize creation of harmful disinfection byproducts and more completely understand the impacts of each method of disinfection.

ASCE Policy Statement 462
First Approved in 1997