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Authors: Jincheng Wei, Baoyu Gao, Qinyan Yue, Yan Wang, Weiwei Li, Xiaobiao Zhu
Experiments were The article describes experiments performed using three different coagulants. The percentage humic acid removal was recorded for various pH and dosing conditions.
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Authors: Shung-Shuan Sung, Sheau-Pyng Ju, Chien Hsu, Arun S. Mujumdar, and Duu-Jong Lee
Summary of Experiment: The effects of natural organic matters (NOM) on AlAluminum-floc stability were investigated by on-line probing of changes in floc diameters and interior fractal dimensions at alternative shearing using the small angle light-scattering technique. In this experiment, Humic acid is often was used to simulate NOM in water. Conditions used for experiment: Water with turbidity of 100 NTU, The influent Water for this experiment has a final pH =7 . after the Humic acid (pH=7) was added to the water and well mixed.
General Conclusions:Generally, Humic acid in the water will cause the flock size to decrease dramatically. In this particular experiment, the diameters of the flocs decrease from 32 nm to 25 nm. The more humic acid, the smaller the flocs. At low levels of humic acid, increased shear rate can allow the particles to regain their size. However, at higher levels of humic acid, decrease in floc size is completely irreversible. Note that when no humic acid is present and shear rate increases, floc size also increases. In addition to causing floc size to decrease, the humic acid also results in "loose" floc formulation.
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Authors: Sangyuna Lee, Anthony G. Fane, and T. David White
Summary of Experiment: Examine This experiment examined the effect of a well-defined humic acid on the aggregation behavior of hematite colloids and, subsequently, assess the impact on the specific resistance and compressibility of microfiltration cakes formed from these aggregates.
General Conclusions:Floc In this experiment, the floc size increases as a function of time when no humic acid is present. However, when humic acid is added, floc size decreases as a function of time. In general, more humic acid makes the decrease in floc size more pronounced.
What to Expect
Based on the articles above, experiments should yield smaller floc size than experiments without NOM. Based on the capture velocity theory, the effluent turbidity should increase. In addition, not all of the humic acid will be removed from the water, so the effluent water will contain NOM.