When it comes to dewatering of sludge, the most important initial process is to flocculate the solids for the right size and right strength to be resistant to the applicable pressure and shear force of a used dewatering technology. Polymer flocculant can be generally categorized as linear polymer, branched polymer, and cross-linked polymer and a right type of polymer should be chosen for each different application or a dewatering technology used.
2 main benefits of cross-linked polymer that a chemical company will tell you.
- Sludge that is difficult to be dewatered with linear or branched polymer can be dewatered well with a high degree of cross-linked polymer. In order to squeeze the water out, the dewatering technology tries to apply as strong shear force as possible, but if the flocs are weak due to the nature of the sludge (eg. lack of fibers), the fine solids will easily pass through the filters of the dewatering press and not be dewatered well. YESfloc® COEX88, although this is not a water-based biodegradable polymer, we have seen it being the most versatile for different sludge types and different dewatering technologies due to its very high degree of cross-links.
- Cross-links can help reduce the polymer consumption. Because cross-linked polymer works like a spider web catching a lot of fine solids that a linear or branched polymer could not catch, it works more efficiently with a lower dosage. While polymer flocculant can be the largest operational cost of a wastewater treatment plant, CHEM.ENGI has seen dozens of customers switching to a cross-linked polymer to save total chemical OPEX even though a unit price of cross-linked polymer may be more expensive.