| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4481569 | Water Research | 2014 | 9 Pages |
•Flocculation performance varied significantly for the twenty-four polymers tested.•Higher FBRM percent removal values corresponded to lower CST values.•Variation in dewatering performance is not due to flocculation kinetics.•FBRM results were similar in magnitude for different digestate sources.•Significant opportunities exist for optimization of both polymer type and dosage.
The current challenges associated with the design and operation of net-energy positive wastewater treatment plants demand sophisticated approaches for the monitoring of polymer-induced flocculation. In anaerobic digestion (AD) processes, the dewaterability of the sludge is typically assessed from off-line lab-bench tests – the capillary suction time (CST) test is one of the most common. Focused beam reflectance measurement (FBRM) is a promising technique for real-time monitoring of critical performance attributes in large scale processes and is ideally suited for dewatering applications. The flocculation performance of twenty-four cationic polymers, that spanned a range of polymer size and charge properties, was measured using both the FBRM and CST tests. Analysis of the data revealed a decreasing monotonic trend; the samples that had the highest percent removal of particles less than 50 microns in size as determined by FBRM had the lowest CST values. A subset of the best performing polymers was used to evaluate the effects of dosage amount and digestate sources on dewatering performance. The results from this work show that FBRM is a powerful tool that can be used for optimization and on-line monitoring of dewatering processes.
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