Aluminum applications pose significant risk to biota and possibly to
human consumers of the water if the
of treated water falls below
The dose determination technique is
designed to prevent this occurrence.
Fly ash has also been suggested as a phosphorus inactivant.
rial will produce significant adverse environmental impacts and should not be
added to reservoirs.
Table 3 is a summary of this method.
Summary of Phosphorus Inactivation
Nuisance algal blooms,
transparency, release of
phosphorus from sediments.
Mode of action
Phosphorus release from reservoir sediments is sharply
reduced, producing lowered phosphorus concentrations
in water column.
Highly effective, problem eliminated when accompanied
by significant diversion of external nutrient
Up to 12 years; few long-term evaluations available.
Use of aluminum sulfate will lower
Overdose could produce appearance of toxic dissolved
may contain a high density of bacteria,
Application is labor intensive.
Labor and chemical costs will be high but can be
determined if dose is known (see text for equations).
No published record of use in reservoirs with large
New methods of application may have to be developed to
Treatment of high phosphorus-release areas should be