Conclusion
In this work, we found that the addition of skeleton builders can significantly improve the dewatering effect of sludge, The sludge dewatering effect of sawdust or RHC was much better than that of PCA. These differences were related to their own properties, such as pore volume, average pore size, surface morphology, at low dose (< 2.5%) of skeleton builder addition, negligible dewatering can be attached, while higher doses can construct the microstructure with sludge and form a fast water discharging. Especially, the fast dewatering process can also form a layered structure of sludge cake, which further favors the interior water discharging. Pipe network and interlayer channel effects can well explain the improved dewatering of sludge.
