Akron Water Algae Treatment- In Depth
Background information as of January 27, 2006
The City of Akron Public Utilities Bureau
("Water Department") has determined the taste and odor occurrence in the local
drinking water supply since mid-December appears to be a result of compounds released from
algae and soil bacteria. Due to the tremendous amount of snowmelt, rainfall and runoff
into the upper Cuyahoga River watershed during late November, and possibly aggravated by
the rapid forming ice cover on Lake Rockwell, a compound found in naturally occurring blue
green algae has been identified in elevated levels. In addition, another compound found in
actinomycetes, a common soil bacteria, is present. The two naturally occurring compounds,
2-methylisoborneol (MIB) and Geosmin, are normally present in drinking water at very low
levels and many times cannot be detected at all with currently available technologies.
Unfortunately, these compounds are very powerful taste and odor causing compounds that can
be detected by humans at levels of less than 10 parts per trillion (ppt). As a comparison,
one part per trillion is approximately equal to one drop of water in 15 million gallons of
water or one inch in 16 million miles.
With the events of late November, large quantities of MIB and to a lesser degree,
Geosmin, were washed into the lakes, blue green algae experienced a growth spike due to an
increased nutrient supply washed into the lake, and disturbed lake and river bottom
MIB is commonly found in the bottom layers of lakes, concentrated there from the
decomposition of the blue green algae found in lakes and is often described as imparting a
musty taste or odor to the water. Geosmin is the same substance that gives soil its
characteristic soil odor. Many customers have described the recent taste and odor
occurrence as being a musty, earthy taste or odor. Both MIB and Geosmin have no known
health effects and are not regulated with any health standards. All water quality tests
indicate the drinking water is meeting all EPA standards and is safe to drink and use.
The Water Department has utilized several different strategies to combat this taste and
odor episode. The use of oxidants at the start of the treatment process was discontinued
as it was thought to add to the intensity of the problem due to additional destruction of
the taste and odor causing bacteria and algae, releasing the MIB and Geosmin compounds
before the bacteria and algae could be removed by the water treatment process. To assist
in the removal of the taste and odor causing compounds additional carbon in a powdered
form has been and continues to be added to the water. The powdered activated carbon is
used to remove organic matter and thus the cause of the offensive tastes and odors. The
carbon acts like a sponge in absorbing the organic materials that cause the tastes and
Laboratory analyses of the water have indicated MIB levels were originally at high
levels in the raw water and treated water. Geosmin levels have been low in the raw water,
and below detection levels in treated water. These compounds can be detected by humans at
levels as low as 4-5 parts per trillion. The water in Lake Rockwell had levels of 250 ppt
for MIB on December 28, dropping to 42 ppt as of January 23. Geosmin levels during the
same timeframe dropped from 14 ppt to 6.8 ppt. In the upper watershed in Geauga County,
MIB levels in the East Branch Reservoir on January 10 were 1100 ppt, while less than
detection (<5 ppt) at LaDue Reservoir. In the upper watershed in Portage County, MIB
levels in the Cuyahoga River at SR 303 on January 16 were 58 ppt. At the higher levels of
MIB in the raw water, it is virtually impossible to remove all of the MIB taste and odor
causing compound through the conventional water treatment process.
MIB levels in the treated water were 260 ppt on December 28, dropping to 16 ppt on
January 23. Geosmin levels in the treated water during the same timeframe dropped from 8
ppt to below detection (<5 ppt). Changing the application point of powdered activated
carbon to the water intake and changing the type of powdered activated carbon from
bituminous to lignite appears to be effective in reducing the MIB levels by 65-75%.
MIB levels in the distribution system are being monitored in addition to the raw and
treated water. MIB levels in the water distribution system follow the treated water levels
on a delayed basis. When noticeable improvements are achieved in the treated water, the
improvements take a few days to be reflected across the distribution system due to travel
time. For example, the MIB levels in the distribution system on January 10 averaged 120
ppt MIB compared to the treated water level of 68 ppt MIB, and on January 23 the
distribution system level averaged 26 ppt MIB compared to the treated water level of 16
With less precipitation and runoff, the water quality in the lakes is improving. The
clarity of the water is improved indicating there is less material (silt and algae for
instance) in the water. This also indicates that bottom sediments that may have been
disturbed with the heavy flows through the lakes, have settled down. Additionally, with
the colder temperatures, biological activity is slowing. This will lead to lower levels of
the odor causing bacteria and algae through the winter months. Also, Lake Rockwell
received an algae control treatment on January 18. All of these factors are leading to an
improvement in the taste and odor of the water.
Customers are advised to chill water before consumption as the colder the water is the
less noticeable the taste and odor appears.
The Water Department continues to consult with drinking water taste and odor experts in
an effort to resolve this situation and be better prepared for future situations. The
Water Department also continues to be in contact with the Ohio EPA, Akron Health
Department and Summit County Health Department during this situation.
The Water Department serves approximately 300,000 Summit County residents in all or
part of the cities of Akron, Stow, Tallmadge, Fairlawn, Mogadore, Cuyahoga Falls and
Hudson, along with parts of the townships of Bath, Boston, Copley, Coventry, Springfield
January 13, 2006
What is the Akron Public Utilities Bureau doing to fix the water taste and odor
- We are monitoring the odor level of raw water coming into the Water Plant and water
after treatment. Odor monitoring assists water treatment staff in making adjustments to
the treatment process.
- We are sending samples of raw water, treated water at the treatment plant, and water in
the distribution system for analysis of the odorous compound (MIB) levels. These analyses
assist the Akron Public Utilities Bureau staff in making adjustments to the treatment
process and distribution system.
- We are consulting with other water utilities and industry experts to gain knowledge on
dealing with and resolving this situation.
- We have constructed a temporary facility at the water treatment plant to add powdered
activated carbon (PAC) at the water intake. This installation will give the PAC more time
to absorb the odor causing compound before the treatment process chemicals are added.
- Be assured that we are taking this situation seriously and are doing what we can with
our available treatment options. We apologize for any inconveniences this situation has
caused for our customers. The treated water meets all Ohio EPA regulations, which is the
standard for water being safe to drink and use.