2/24/2009 US EPA

WATER SYSTEMS, DISINFECTION BYPRODUCTS, AND THE USE OF

MONOCHLORAMINE

11) Other than chlorine and monochloramine, what options could water utilities
consider to control the levels of disinfection byproducts?

Water utilities have several options for reducing disinfection byproducts other than
chlorine and monochloramine.1

•	One option for reducing disinfection byproducts is to reduce the amount of time water
spends in pipes.2

•	Another option for reducing disinfection byproducts is to use ozone or ultraviolet (UV)
light.3

•	A third option for reducing disinfection byproducts is improving filtration to reduce
natural organic matter in water that react with disinfectants to form byproducts.4

The options for reducing disinfection byproducts have disadvantages.

•	Better system management to reduce the amount of time water spends in pipes or
improved filtration methods may still not be enough to reduce regulated byproduct
levels.

•	Ozone, UV and some improved filtration processes require a high level of
sophistication, expertise, and management skills to operate successfully.

•	One disadvantage of ozone and ultraviolet (UV) light is they often require the installation
of new and expensive technology, making it impractical for many utilities.

Utilities use chlorine or monochloramine to protect drinking water from harmful
organisms in pipes.

•	The major disinfection alternatives to chlorine and monochloramine can reduce the
formation of some disinfection byproducts but can increase the production of others.

•	The major treatment alternatives for reducing disinfection byproducts do not by
themselves provide adequate protection for drinking water as it moves through water
pipes.

•	EPA encourages water utilities to consider a full-range of alternative technologies and
operational practices2 for reducing disinfection byproducts.

Additional Supporting Information:

1.	Guidance manuals are available at:

http://www.epa.gov/safewater/disinfection/stage2/compliance.html. Hard copies are available by
ordering publications through EPA's Water Resource Center (phone: 202-566-1729).

2.	Certain regulated disinfection byproducts may increase over time as water continues to react with
natural organic matter. Natural Organic Matter. Complex organic compounds that are formed from
decomposing plant, animal and microbial material in soil and water. They can react with disinfectants
to form disinfection by products. Total organic carbon (TOC) is often measured as an indicator of
natural organic matter. Operational practices for reducing water age include flushing programs and
eliminating dead-end locations in pipes.

3.	UV is effective at inactivating disease-causing protozoa such as Cryptosporidium.

4.	In some cases, natural organic matter (precursors to DBP formation) can be removed. Removal
technologies include nanofiltration, enhanced coagulation, granular activated carbon, enhanced coagulation,
or ozone followed by biologically active filtration.

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