United Water Lambertville Taste and Odor Q and A

United Water
200 OLD HOOK ROAD
HARRINGTON PARK, NJ 07640
TEL: 877 565 1456
FAX: 201 525 2325
United Water Lambertville- Taste and Odor Q&A
Q. What actions has United Water taken regarding unpleasant taste and odor in the Lambertville
water system?
A. Following reports of unpleasant taste and odor incidents in early October, United Water contracted with
Princeton Hydro Inc. to conduct microscopic analysis and produce algae counts of Swan Creek Reservoir,
Lambertville’s water supply. Results of the testing showed that an algae bloom had occurred in the
reservoir and likely caused the taste and odor issues.
Q. How common is it to have algae blooms in reservoirs?
A. They are common in surface water, such as ponds, lakes, and reservoirs. The size of the algae bloom
dictates how effective conventional water treatment is in reducing taste and odors. In 2012, the Swan
Creek Reservoir was treated a total of seven times for algae growth beginning in April.
Q. How does algae bloom affect taste and smell of water?
A. As different types of algae decay, they can release taste and odor related compounds. In the case of
Lambertville, the algae bloom and subsequent decay produced Geosmin, a naturally occurring chemical
that is very commonly associated with algae blooms. The production of Geosmin is a challenge for many
drinking water systems that use surface water as a source. In addition to water, Geosmin can also
contribute to a distinct earthy taste in wine and certain fish species.
Q. Are there additional contributing factors to the unpleasant taste and smell?
A. United Water believes it was a combination of the algae bloom and a turnover of the thermally stratified
reservoir. As with many standing bodies of water, Swan Creek Reservoir has distinct layers, including a
colder, denser level at the bottom. A lack of mixing of those strata contributes to algae growth.
Q. If the odor is caused by an algae bloom, is the water unsafe to drink? Can it be used to bathe
and cook?
A. Your water is safe to drink and to use for bathing and cooking.
Q: What type of additional sampling has been done to monitor the situation and ensure safety of
water quality in the distribution system?
A: In addition to all scheduled regulated water quality sampling, expanded distribution sampling by a licensed
third party laboratory has included several analyses: microscopic (to ensure no algae made its way
through the treatment system), bacteriological (to ensure no harmful coliform bacteria were present as
well as heterotrophic organisms) and general chemistry (which include dissolved metals). Sample results
indicated no abnormal or harmful levels. Aesthetic testing for taste, odor, MIB and Geosmin (taste and
odor causing compounds) are and have been collected to monitor the progression and effects of treatment
activities on the drinking water and help guide decisions to define appropriate treatment implementation
for both now and in the future.
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Q. How long does it take for treatments to work?
A. That depends on many factors, including the size of the bloom. In the case of Lambertville, microscopic
analysis of reservoir samples one week after treatment showed that the algae in question had been
largely eliminated and the musty taste and odor was reduced but still apparent due to the by-products of
the algae bloom.
Q. What is United Water doing now to address the taste and odor of the water?
A. In October, an expanded distribution sampling program was initiated for various locations in our
system. Additional tests were conducted for taste and odor, algae, general water quality and secondary
parameters.
Though we are out of the active algae growing season and the musty taste and odor has been largely
reduced, the extent of the bloom has left a residual impact to the reservoir that has changed the
characteristics of the source water and will require installation of additional equipment to treat both the
reservoir and in the treatment facility. These changes take time to develop the correct approach so that
there are not unintended consequences on other treatment mechanisms. It also takes some time to
procure, install and test the new equipment and treatment processes.
In mid-January powdered activated carbon (PAC) will be applied to water in the treatment plant. PAC is
approved by the NJ Department of Environmental Protection (NJDEP) as a treatment method for taste and
odor control, and is used successfully at other United Water facilities for seasonal taste and odor control
concerns.
Q. What is United Water doing to address problems related to future algae blooms in
Swan Creek Reservoir?
A. While these odor events can be difficult to predict and avoid, United Water is taking additional preparatory
steps. These steps include earlier and more frequent profile testing of the reservoir to look for the specific
taste and odor compounds; and how they relate to algal counts. To control algae blooms, United Water
will continue to apply small amounts of copper sulfate to the reservoir, adhering to strict federal and state
environmental protection guidelines outlined in United Water’s NJDEP-issued treatment permit.
Also, United Water is in the process of installing an enhanced aeration system in the reservoir to both
aerate water and mix the distinct layers of water to create an environment that inhibits large algae
blooms from forming in the future.