Separation of nitrocellulose fines from wastewater with polymers
- Univ. of Wisconsin, Madison, WI (United States)
Nitrocellulose (NC) fines are discharged to wastewater streams during manufacturing. Laboratory-scale tests were conducted to evaluate the turbidity and total suspended solids reduction by coagulation/flocculation/sedimentation, to determine the settling characteristics of flocculated NC fines, and to evaluate thickening and dewatering characteristics of settled flocculated NC fine sludge. Cationic polymers were very effective in treating the negatively charged NC-manufacturing wastewater. Under an optimum flocculation condition, the supernatant turbidity of below 1 mg/L was obtained. High turbidity removal was achieved at a wide dosage range of 0.2 to 1.0 mg/L. Optimum flocculation was found to occur at low doses of the polymers tested and the polymer with a higher charge density performed better. High molecular weight polymers produced large flocs which had a high floc settling rate. Therefore, a high charge density and molecular weight polymers are preferred to separate NC fines from wastewater streams. Turbidity removal was improved with increasing Gt values and tapered flocculation. High velocity gradient facilitated adequate dispersion of a polymer. On the other hand, long rapid mixing would cause some floc breakup. Significant improvement of dewatering characteristics of NC-manufacturing wastewater sludge was found to be facilitated by the residual effects of the polymers having undergone flocculation of the wastewater. It appears that further chemical conditioning of the sludge is not necessary.
- OSTI ID:
- 416905
- Report Number(s):
- CONF-951023--
- Country of Publication:
- United States
- Language:
- English
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