Li Yingte, Liu Yong, Yu Xiaoyan, Li Qian, Zhang Rui, Zhang Shuting
School of Environmental Science and Engineering, Tianjin University Tianjin 300354 China
School of Energy and Chemical Engineering, Liaoning Technical University Huludao 125105 China.
RSC Adv. 2020 Jan 17;10(6):3153-3165. doi: 10.1039/c9ra09126b. eCollection 2020 Jan 16.
Electro-dewatering (EDW) is considered as one of the most promising dewatering technologies due to saving power consumption. In this study, the potential effects of anaerobic biological conditioning (BC) on sludge EDW treatments was investigated. The results showed that without any additives BC pretreatment of sludge enhanced EDW dewaterability and energy efficiency. At 35 °C BC for 3 days, the dry solids (DS) of sludge dewaterability limit could increase up to 49%, which corresponded to an increase of 13% of DS in dewatered sludge cake without BC pretreatment, and the dewatering time was shortened by 22%. There was an economic advantage saving in energy consumption of around 49.5% in the case of BC-EDW when the DS of sludge was up to 38%. Then, the mechanism of BC to improve EDW performance was studied. The principal component regression (PCR) analysis showed that the DS content of dewaterability limit mainly depended on the degradation of organic matter and the change of conductivity in sludge. Fourier transform infrared spectroscopy (FTIR), zeta potential and bound water in sludge were also determined in an attempt to explain the observed changes in sludge BC-EDW. It was indicated that the increase of negatively charged hydroxyl groups on the surface of sludge particles resulted in an increase of the absolute value of the zeta potential and significantly promoted EDW. The tightly bound EPS (TB-EPS) decreased and it loosened the bond between water or metal cations and sludge particles, and the bound water was also found to be released into free water in sludge during BC.
由于能节省电力消耗，电脱水（EDW）被认为是最具前景的脱水技术之一。在本研究中，考察了厌氧生物调理（BC）对污泥电脱水处理的潜在影响。结果表明，污泥的BC预处理无需任何添加剂即可提高电脱水的脱水性能和能源效率。在35℃下进行3天的BC处理，污泥脱水性能极限的干固体（DS）可提高至49%，这相当于未经BC预处理的脱水污泥饼中DS增加了13%，且脱水时间缩短了22%。当污泥的DS达到38%时，BC-EDW在能源消耗方面具有约49.5%的经济优势。然后，研究了BC改善电脱水性能的机制。主成分回归（PCR）分析表明，脱水性能极限的DS含量主要取决于污泥中有机物的降解和电导率的变化。还测定了污泥的傅里叶变换红外光谱（FTIR）、zeta电位和结合水，以试图解释在污泥BC-EDW中观察到的变化。结果表明，污泥颗粒表面带负电荷的羟基增加导致zeta电位绝对值增大，并显著促进了电脱水。紧密结合的胞外聚合物（TB-EPS）减少，它使水或金属阳离子与污泥颗粒之间的结合变松散，并且在BC过程中还发现结合水释放为污泥中的自由水。
