1070-4272/03/7612-1951 $25.00 C 2003 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 76, No. 12, 2003, pp. 1951!1954. Translated from Zhurnal Prikladnoi Khimii, Vol. 76, No. 12, 2003,
Original Russian Text Copyright + 2003 by Kurenkov, Gogolashvili, Molgacheva, Gaisina.
OF CHEMISTRY AND TECHNOLOGY
Cationic Polymers as Organic Coagulants in Water Treatment
at Heat and Electric Power Plants
V. F. Kurenkov, E. L. Gogolashvili, I. V. Molgacheva, and A. I. Gaisina
Kazan State Technological University, Kazan, Tatarstan, Russia
Tatarenergo Joint-Stock Company, Kazan, Tatarstan, Russia
Energoprogress Engineering Center, Kazan, Tatarstan, Russia
Received June 2, 2003
Abstract-The efficiency of water treatment with organic coagulants (cationic polymers) and calcium
hydroxide (alkalizing agent) in combination with iron(II) sulfate (mineral coagulant) was studied as influenced
by the nature and concentration of an organic coagulant and concentration of a mineral coagulant.
Coagulation treatment of natural water to remove
coarse and colloidal admixtures is an important stage
of water pretreatment at heat and electric power plants
(HEPPs). Pretreatment is usually performed with var-
ious salts of Al(III), Fe(II), and Fe(III) (mineral co-
agulants); for simultaneous water softening, this pro-
cess is often combined with liming [Ca(OH)
to the treated water].
To intensify the treatment after liming and coagula-
tion, natural water was treated with Praestol high-
molecular-weight polyacrylamide flocculants .
The use of flocculants at the water-treatment installa-
tion the Kazan HEPP-2 improved the quality of water
passed through ion-exchanging filters in further stages
of water treatment and was economically efficient.
In the recent decades, organic polymeric coagulants
have found increasing application; these water-soluble
cationic polymers are mainly used for treatment of
wastewater and more complete dehydration of pre-
cipitates. Positively charged macromolecules of or-
ganic coagulants interact with negatively charged pol-
lutant particles in water, causing their destabilization
and rapid flocculation to form coarser aggregates.
Mineral coagulants are less expensive, but organic
coagulants provide more efficient removal of colloi-
dal and dispersed particles. It should be noted that, in
the absence of mineral coagulants, the salt content in
purified water would be lower, which, in turn, should
decrease the load on the ion-exchange filters and the
mineralization of wastewater. Moreover, the concen-
trations of organic coagulants required for water treat-
ment are significantly smaller than those of mineral
compounds; they can be used in a wide pH range and
do not affect the acidity of the medium.
Organic coagulants for water treatment are widely
used in the Republic of South Africa . The long-
time use of organic coagulants (Zetafloc LP526 poly-
amines) significantly improved the quality of drinking
water and decreased its cost. Its has been found 
that the best results are obtained in a narrow concen-
tration range of organic coagulants, whereas the over-
charge of a mineral coagulant does not affect the qual-
ity of purified water.
Good results have been obtained with Kemazur
4535 organic coagulant in the stage of water pretreat-
ment at a water-desalinating electrodialysis installa-
tion of a cement plant in Tunisia . The water fed
into this installation was characterized by wide fluc-
tuations of the content of colloidal and dispersed
particles, and the optimal charge of the organic coagu-
lant and flocculant substantially improved the quality
of desalinated water and prolonged the service life of
the filters. It should be noted that the organic coagu-
lants are most widely used in North America, in con-
trast to Europe, where various inorganic coagulants
are preferred .
Previously , we studied the water treatment with
organic coagulants formed by degradation of high-
molecular-weight cationic Praestols [copolymer of