| The impurities from the waste paper bring about more and more serious problems, and the accumulation problems of stickies are especially paid attention. The accumulation of stickies in waste paper stock and follow-up white water system will make drainage in the wet-end of the paper machine become uneven, resulting in paper flaws such as paper hole and stain. In addition, with other pollutants a series of corrosion problems will cause the resin obstacles, which will affect production. Therefore the research on the accumulation problems of stickies is significant for the recycle of regenerated fibre.The treatment of recycled fiber pulp wastewater with particle flocculation system constituted by bentonite+CPAM was researched in this paper. The most important part is how to remove pollutants, especially stickies substances from wastewater by adsorption and particle flocculation. On the basis of the research on the conventional wastewater characteristics, the optimum conditions for particle flocculation treatment was explored and optimized. Under optimal conditions, wastewater characteristics were analyzed and compared before and after the flocculation treatment was carried. Besides, the stickies in recycled fiber pulp wastewater were studied. The stickies changes in wastewater were detected by infrared spectroscopy analysis, GC-MS analysis and image analysis methods. The results showed that the particle flocculation system was effective for the treatment of recycled fiber pulp wastewater, especially for controlling the stickies.The pollution indicator results of recycled fiber pulp wastewater are as follows:the average particle size was 108.00NTU,40.95μm respectively and the CODcr was 3020 mg/L, pH was 6.4. The CD of the wastewater was as high as 1065.4μmol/L.Infrared spectra showed that a very strong broad band near 1300-1000 cm-1 which was due to the interactions of water with CO-O-C and C-O-C stretching of the ester and ether bonds, and the weak absorption band observed around 3600cm-1 due to the groups of O-H stretching of alcohols and phenols shown there were few hydroxyl groups of alcohols and phenols in the wastewater. Over 30 substances were detected by the GC-MS and the most of them were p-hydroxybenzoic acid dodecanoic acid tetradecanoic acid hexadecanoic acid dehydroabitetic acid and icosanoic acid.The optimal conditions for recycled fiber pulp and wastewater treatment was found as bentonite dosage of 100 mg/L, CPAM dosage of 5 mg/L, the reaction temperature of 40° C, pH value of 7.0, mixed reaction stirredtime of 2min, stirring speed of 100rpm.Under these optimal conditions, the removal rate of CODcr, turbidity, SS and color reached 89.67%,99.56%,95.58% and 93.08%, respectively. The average particle size in the treated wastewater pollutants is reduced from 40.95μm to 0.5μm. It showed that the adsorption coagulation aid treatment which is mainly used to remove larger particles and colloids suspended material and flocculation treatment was similar.The removal of MTBE extract and cationic demand reached 91.26% and 86.93%, reflecting a very good treatment effect and the removal effect of stickies in waste liquid. Although there were no evident changes about organic types and quantity before and after the treatment according to the infrared spectroscopy scan and GS-MS analysis, there were great changes about the relative content of various types of organic. The content of some lipids was evidently reduced, and some carboxylic acids were slightly increased, which indicated that the particle flocculation system had a good capacity of stickies removal.The copy piece of wastewater was analyzed by using image method before and after treatment. The result showed that the dust removal rate was 93.24%, the dust removal rate of the total area was 89.57%, the removal rate of relative content was 89.65% and the dust removal rate of unit area was 93.40%. Besides, there was a very small amount of dust in the treated water. Most of the dust was about 0.005mm2 ultra-small particles and no dust was greater than 0.1mm2. |
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