Sha Li, Yu Xiaoyan, Wu Zhangxiang, Liu Xingxin, Wang Haozhe, Jiang Qingqing, Zhang Shuting
School of Environmental Science and Engineering, Tianjin University, Tianjin, 300354, China.
School of Environmental and Safety Engineering, Taiyuan Institute of Technology, Taiyuan, 030008, China.
Environ Res. 2021 Jul;198:110453. doi: 10.1016/j.envres.2020.110453. Epub 2020 Nov 12.
The high energy consumption of high apparent electrical resistivity (AER) in sludge during the later stages of the electro-dewatering (EDW) process is a difficult problem; however, analysis of sludge AER may contribute to a reduction in energy consumption. In this study, the variations in the AER of activated sludge and potential mechanisms related to sludge properties were systematically examined. First, a sludge cake was divided into four horizontal layers, in order to investigate the sludge AER in each layer. Then, the effects of variations in water distribution, oxidation-reduction potential (ORP), pH, metal ions, sludge conductivity, zeta potential, temperature, and sludge microstructure on the AER in each layer were explored. The results showed that the sludge AER began to increase from the bottom layers to the top layers when the moisture content (MC) was decreased to 60%. The formation of nonionic chemical systems and the gas barrier layer could increase the AER in the top layers, and the increase in sludge AER in the bottom layers was due to the decrease in MC and sludge conductivity. In addition, electrolyte release and electromigration had a significant effect on the sludge AER. This work identifies potential causes for the increase in AER, and provides a reference for solving problems related to high AER in sludge during the later stages of the EDW process.
在电脱水（EDW）过程后期，污泥中高表观电阻率（AER）导致的高能耗是一个难题；然而，对污泥AER的分析可能有助于降低能耗。在本研究中，系统地研究了活性污泥AER的变化以及与污泥性质相关的潜在机制。首先，将污泥饼分成四个水平层，以研究每层的污泥AER。然后，探讨了水分分布、氧化还原电位（ORP）、pH值、金属离子、污泥电导率、ζ电位、温度和污泥微观结构的变化对每层AER的影响。结果表明，当含水率（MC）降至60%时，污泥AER从底层到顶层开始增加。非离子化学体系和气障层的形成会增加顶层的AER，底层污泥AER的增加是由于MC和污泥电导率的降低。此外，电解质释放和电迁移对污泥AER有显著影响。这项工作确定了AER增加的潜在原因，并为解决EDW过程后期污泥中高AER相关问题提供了参考。
