| 摘要 |
A process for treating a liquid fraction of effluent wastewater from post anaerobic digestion containing fine solids having a size less than about 25 microns is disclosed. A metal salt flocculant is added to the liquid fraction in an amount ranging from about 50 to 500 ppm in the liquid fraction. The metal salt flocculant is selected from inorganic iron and aluminum flocculent compounds having a +2 or +3 valence. A cationic organic polymer is added to the liquid fraction in an amount ranging from about 10 to about 150 ppm in the liquid fraction. The cationic organic polymer has a molecular weight greater than about 3,000,000 and cationicity in the range form 1.25 mole % to 30 mole %. The metal salt flocculent and the cationic organic polymer produce a separable solid fraction which is recovered. Pre-treatment with a small amount of the cationic organic polymer provides improved results.
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