School of Resources& Civil Engineering, Northeastern University, Shenyang 110819, China; School of Chemical Engineering, Northeast Electric Power University, Jilin 132012, China.
School of Chemical Engineering, Northeast Electric Power University, Jilin 132012, China.
J Environ Sci (China). 2022 May;115:37-46. doi: 10.1016/j.jes.2021.07.012. Epub 2021 Aug 1.
Manganese ion (Mn) generated from metallurgical, steel making and chemical industries enters sewage treatment plants and affects the sludge activity and flocculation. The effect of Mn on the removal of chemical oxygen demand (COD) and total phosphorus (TP) and sludge activity were investigated in anoxic zone of an anaerobic/anoxic/oxic (AO) process. The compositions and structures of extracellular polymeric substances (EPS) were characterized using three-dimensional excitation emission matrix fluorescence spectroscopy (3D-EEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) to reveal the relationship among Mn, EPS and sludge flocculation. The results showed that low concentration of Mn (<5 mg/L) improved removal efficiencies of COD and TP and increased the activity of alkaline phosphatase, acid phosphatase and dehydrogenase. Meanwhile, the addition of Mn increased total EPS, sludge contact angle, Zeta potential and sludge particle size, and thus enhanced sludge flocculation. However, high concentration of Mn (>10 mg/L) hindered microbial flocculation and reduced removal efficiencies of the pollutants. When Mnwas 5 mg/L, removal efficiencies of COD and TP reached 65% and 90%, respectively. Sludge flocculation was the best and SVI was 70.56 mL/g. The changes of Mn concentration caused deviation of groups' compositions in LB-EPS and TB-EPS, where the main components were always protein (PN) and polysaccharide (PS). The addition of Mn resulted in the degradation of humic acids. However, it did not give rise to significant morphology changes of EPS.
锰离子（Mn）来自冶金、炼钢和化工行业，进入污水处理厂，影响污泥活性和絮凝。本研究考察了缺氧区厌氧/缺氧/好氧（AO）工艺中 Mn 对化学需氧量（COD）和总磷（TP）去除率及污泥活性的影响。采用三维荧光激发发射矩阵光谱（3D-EEM）、X 射线光电子能谱（XPS）和傅里叶变换红外光谱（FTIR）对胞外聚合物（EPS）的组成和结构进行了表征，以揭示 Mn、EPS 和污泥絮凝之间的关系。结果表明，低浓度 Mn（<5mg/L）提高了 COD 和 TP 的去除率，增加了碱性磷酸酶、酸性磷酸酶和脱氢酶的活性。同时，Mn 的添加增加了总 EPS、污泥接触角、Zeta 电位和污泥粒径，从而增强了污泥絮凝。然而，高浓度 Mn（>10mg/L）会阻碍微生物絮凝，降低污染物的去除率。当 Mn 为 5mg/L 时，COD 和 TP 的去除率分别达到 65%和 90%。污泥絮凝效果最佳，SVI 为 70.56mL/g。Mn 浓度的变化导致 LB-EPS 和 TB-EPS 中各分组组成出现偏差，其中主要成分始终为蛋白质（PN）和多糖（PS）。Mn 的添加导致腐殖酸降解，但未引起 EPS 形态发生显著变化。
