Research on the mechanism of synergistic-dehydration/detoxification for sludge under treatment with double-modified potato residue

Abstract

A green organic waste potato residue (PR) was double-modified for synergistic sludge dehydration-detoxification. In this work, the properties of modified product (signed as D-MPR), and its crucial effects on sludge properties were investigated. Besides, role of D-MPR in sludge co-dehydration/decontamination was also explored. Results showed that etherification and grafting modification produced D-MPR of high-performance. It largely and synergistically reduced sludge volume and toxicity by adjusting distribution of bound water, microbes, organics, and heavy metals in sludge. Adding 12–15‰DS (mass of dry solids in sludge) of D-MPR, about 94% of bound water was removed from sludge, and few intracellular bound water was left in sludge. Besides, approximately 90.53% of bacteria, 73% of dissolved organics and 54.46% of total risky heavy metals were removed. As the main toxic substance in sludge, 92.41% of CdF1/F2/F3, 90.67% of CrF1/F2/F3, 55.92% of CuF1/F2/F3, and 64.56% of ZnF1/F2/F3 were removed in the chelation process caused by D-MPR and organics. However, 54.17% of PbF1/F2/F3, 70.08% of NiF1/F2/F3, and 65.44% of AsF1/F2/F3 were removed by flocs sweeping. Moreover, the Partial Least Square Regression (PLSR) model showed that, by enhancing Binding Energy (Eb) of bound water, reducing Fractal Dimension (DF) of sludge flocs and humic acid content could highly reduce sludge quality and poisonousness. Particularly, compared with the commonly used method such as Fenton processing, freezing and thermal treatment, the method is cheaper, more energy-conserving, more effective, and more environmentally friendly.