Algae in drinking water supplies can cause a number of problems, including
tastes and odors, filter clogging, interference with coagulation processes, and the
production of toxins.
Phytoplankton monitoring for the city of Columbus, Ohio began in 1938, in response to taste and
odor problems. Since that time, monitoring has expanded as additional water
supply reservoirs were constructed. Phytoplankton at each of the three
reservoirs respond independently and reflect differences in watershed conditions
and source water chemistry.
Historically, the monitoring focus has been on taste and odor causing organisms
and other organisms in the reservoirs that may cause treatment problems.
However, phytoplankton monitoring within the treatment plant can also be very
beneficial. Phytoplankton analysis has been used to evaluate treatment process
efficiency in two full-scale surface water treatment plants. The effects of
chemical dosage and other treatment changes on individual treatment processes
or the entire water treatment plant can be evaluated using phytoplankton.
Phytoplankton analysis has also been used to evaluate filter performance, jar
tests, and to determine the source of high particle counts and turbidity increases.
Phytoplankton monitoring is also used in conjunction with limnological monitoring
of the water supply reservoirs. During summer stratification this monitoring is
used to determine the optimum outlet elevation. The objective is to minimize algae related treatment problems as well as taste and odors associated with low
dissolved oxygen water from below the thermocline.
In the past, copper sulfate was occasionally used in the water supply reservoirs
and river to eliminate plankton blooms. However, phytoplankton control
strategies have changed to prevent the release of cyanobacteria (blue-green
algae) toxins. Now more than ever, phytoplankton monitoring is important to
identify and enumerate toxic algae. Elevated numbers of potentially toxic
cyanobacteria (blue-green algae) are used as a trigger for increasing the
frequency of sampling in the watershed and initiating microcystin ELISA toxin
screening.
Phytoplankton monitoring in the watershed has been a useful tool that gives
advanced warning of potential treatment problems and increases the number of available options when dealing with a phytoplankton bloom. Monitoring
phytoplankton through the treatment process is an additional tool to aid the treatment plant staff and assist in optimizing treatment.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 170 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 2 |
| Published : | 11/01/2002 |
