Nova-Tech Floc-Tester ET 750 - Manuel (Page 14)

14 Floc-Tester_ET740_ET750_1 12/2008
GB Analytical metods
Other measurements relate to the pH of water after chemical treatment (lime raises the
value while iron and aluminium salts lower it) and the temperature of water at which the
experiments are performed .
References
American Society for Testing Materials Norm ASTM D-2035-G4 T
Passino R . and M .Beccari (1970) .
Standardization of jar test in coagulation-flocculation processes for the removal of inorga-
nic turbidities (in Italian) . Acqua e Aria, Milano, 1-10, October 1970 .
Degremont (1978) . Etude de la coagulation et de la floculation des eaux . Methode n .703,
948-950 . Memento technique de l‘eau . 1200 pages, Paris .
U .S . Association of Environmental Engineering Professors (1972) . Environmental Enginee-
ring Unit Operations and Unit Processes Laboratory Manual. J.T. O‘Connor Ed. 350 ppg.
Leaching test
Leaching tests are used to simulate the behaviour of a waste in a dump that is submitted
to the leaching activity of rain water . There are two different methods that use leaching
solutions of different type:
a) acetic acid, proposed for dumps receiving both organic and inorganic wastes;
b) carbon dioxide saturated water, for dumps receiving only inorganic wastes .
Waste sample to be examined:
If a liquid phase is present it must be removed by filtration or centrifugation and preserved
in a refrigerator at 2-4°C . The granulometry of the solid phase, must be lower than 9 .5
mm (standard sieve) .
Waste extraction:
20-25 g of the solid phase are weighed with a precision of ± 0 .1 g .
Method A. A volume of distilled water corresponding to 16 times the weight of the sam-
ple is added .
The pH of the mixture is kept to 5±0 .2 using 0 .5 N acetic acid . The stirring is performed for
24 hours, controlling the pH every 15 minutes during the first hour and then every hour .
The pH is corrected to 5±2 using again 0 .5 N acetic acid . If after 24 hours of stirring the pH
is higher than 5 .2, a new correction is made and the stirring prolonged for other 4 hours .
Method B. The leaching solution is given by a volume corresponding to 20 times the sam-
ple weight of distilled water saturated by carbon dioxide for not less than 15 minutes . The
stirring is performed during 6 hours without any pH correction .
Stirring speed
Must be able to maintain continuously mixed the solid phase with the leaching solution .
Analysis of extract
The leaching solution and the liquid phase if present in the original sample are filtered by a
membrane filter of 0 .45 µm porosity and submitted to analysis for the single metals by the
methods commonly used for waters .