First International Conference on MOLDAVIAN RISKS – FROM ...

<strong>First</strong> <strong>International</strong> <strong>Conference</strong> on MOLDAVIAN RISKS - FROM GLOBAL TO LOCAL SCALE
16-19 May 2012, Bacau, Romania
RESEARCH ON THE USE OF ORGANIC FLOCCULANTS IN
TREATING THE SLUDGE FROM THE MUNICIPAL
WASTEWATER TREATMENT PLANTS
Mariana Turcu 1, 2 , Valentin Nedeff 2 , Narcis Barsan 2
1 SC ECO SISTEM PROIECT SRL
2 “Vasile Alecsandri" University of Bacau, Department of Environmental Engineering and
Mechanical Engineering
Corresponding author: Turcu Mariana, ecosistemproiect@yahoo.com
Abstract: The quality of the water represents the conventional assembly of values of
certain physical, chemical and biological properties which differ according to the
consumption type. The water pollution involves changes of the functional specifications
due to the presence of the physical chemical and biological compounds, which have values
over a limit imposed under the standard regulations. After any type of use, the water is
transformed in what we can call it, under a general tern “wastewater”. The classification of
the wastewater is made upon two main directions, depending on the source of their origin
it is classified in domestic wastewater and industrial wastewater. Sequence to any
treatment process of the domestic wastewater results residual sludge, which is classified
according to the type of water use and to the treatment procedure type applied. Mainly, the
sludge come from the primary and secondary decantation of the wastewater, and their
physical, chemical, biological and bacteriological specification highly depend on their
origin. In the sludge treatment process, three important phases are to be noted: the
preliminary phase, for the sludge thickening, the stabilization phase and the dehydration
phase. In the present work the identification of the most efficient organic cationic
flocculants was studied, which may be used in the process of the thickening and
dehydratation of the sludge result from the municipal wastewater treatment plants. The
organic synthesis flocculants are macromolecules with long chains, obtained by associating
synthetic monomers having electrical loads or ionisable groups. Also the organic synthesis
flocculants are like solid products, emulsions or solutions (20 g/L in water). Before using
the organic flocculants for specific industrial applications, it is necessary the achievement
of a testing stage at the laboratory level. Any testing procedure in a laboratory aims the
simulation of the industrial conditions. In this sense, the present research has aimed the
testing of the organic cationic flocculants, Zetag type, to identify the most efficient
flocculant from this category. The main parameters followed during the laboratory tests
were: the reaction time; flocculants dimension; sedimentation time; clearing; mixing and
strength of the flocculants. After the result of the laboratory tests can be specifying that the
laboratory tests are sufficiently precise to extrapolate the results to industrial applications.
Key words: sludge treatment process, organic cationic flocculants, laboratory tests.
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