Cationic polymer and clay or metal oxide combinations for natural organic matter removal.
The effect of adding suspended matter in the form of clay or metal oxide when a cationic polymer was employed as the primary coagulant was found to be beneficial. The solids provide both an adsorbent for natural organic matter (NOM) and a nucleating species for precipitating the NOM-polymer complex. Metal oxides in conjunction with a cationic polymer were more promising than clay, with effectiveness in the order Fe2O3 > Fe3O4 > Al2O3 > MnO2. Magnesium oxide at a much lower dose was nearly as effective as ferric oxide, but of course raised the pH level significantly. A simpler and more convenient way of having reactive solids present was to add alum to form flocs; for one of the waters studied the alum dose could be reduced by 67% by adding 1 mg/L of polymer, to give equal or better performance than alum alone at the optimum dose.
Bolto
B
B
CSIRO Molecular Science, Clayton South, Vic., Australia. brian.bolto@molsci.csiro.au
Dixon
D
D
Eldridge
R
R
King
S
S
D000327:Adsorption; D000534:Alum Compounds / Q000494:pharmacology; D000538:Aluminum Silicates / Q000378:metabolism*; D001546:Bentonite / Q000378:metabolism; D002244:Carbon / Q000378:metabolism*; D002412:Cations / Q000494:pharmacology; D011232:Chemical Precipitation; D000077215:Clay; D004573:Electrolytes; D005290:Ferric Compounds / Q000494:pharmacology*; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D007616:Kaolin / Q000378:metabolism; D046911:Macromolecular Substances; D010087:Oxides / Q000494:pharmacology*; D011108:Polymers / Q000494:pharmacology*; D018508:Water Purification / Q000379:methods*
D000534:Alum Compounds; D000538:Aluminum Silicates; D002412:Cations; D004573:Electrolytes; D005290:Ferric Compounds; D046911:Macromolecular Substances; D010087:Oxides; D011108:Polymers; D001546:Bentonite; D007616:Kaolin; D002244:Carbon; D000077215:Clay