Dewatering of drinking water treatment sludge using the Fenton-like process induced by electro-osmosis

In the present study, the benefits of a Fenton-like treatment process in enhancing the dewaterability of drinking water treatment sludge have been investigated. It is found that using a vacuum electro-osmosis dewatering reactor often results in a low dewatering efficiency, while it can be improved significantly (by about 63% under the optimal condition) by adding the Fenton-like process in combination with acidification. The results based on the three-dimensional (3D) excitation-emission matrix fluorescence spectroscopy and Fourier-transformed infrared spectroscopy indicated that the sludge treated by the Fenton-like process could make fulvic acid-like substances disappear such that the extracellular polymeric substances (EPS) is broken and the dewaterability efficiency is improved. Furthermore, the scanning electronic microscopy analysis and particle size distribution analysis showed that the Fenton-like process and acidification destroyed the stable sludge flocs such that the water trapped in the flocs could be released easily and the dewaterability efficiency was enhanced. The 3D response surface of the water removal efficiency evidenced that the optimal operating parameters were Fe3+ dosage of 54 mg g−1 sludge, H2O2 dosage of 87 mg g−1 sludge and pH of 6.3. The results obtained in this study are expected to provide guidance and support for using the Fenton-like treatment process together with acidification to dewater drinking water treatment sludge.