State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China; Research Center for Environmental Nanotechnology (ReCENT), Nanjing University, Nanjing 210023, China.
Water Res. 2019 Jun 15;157:472-482. doi: 10.1016/j.watres.2019.04.002. Epub 2019 Apr 5.
As one of the key economic modes in China, chemical industry park (CIP) has made great contribution to the Chinese rapid economic growth. Concomitantly, how to effectively and safely dispose of the CIP wastewater (CIPWW) has been an unavoidable issue. Molecular transformation of dissolved organic matter (DOM) in CIPWW treatment is essential to optimize the employed process and to provide solid basis for risk evaluation of the discharged effluent as well. In this study, electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS) was used to characterize the molecular transformation of DOM during full-scale treatment of integrated chemical wastewater in a centralized wastewater treatment plant (CWWTP), where the combined process follows hydrolysis/acidification (HA)-flocculation/precipitation (FP)-A/O-membrane bioreactor (MBR)-ultrafiltration (UF)-reverse osmosis (RO). Compared to municipal wastewater, DOM in CIPWW exhibited higher unsaturation degree, lower molecular weight, and higher toxicity. In FP unit, DOM of C and higher nominal oxidation state of carbon (NOSC) values was preferentially removed. The HA and anaerobic units are capable of significantly degrading DOM, resulting in great changes in molecular composition of DOM. However, the anoxic, oxic, and MBR units only lead to a slight change of the molecular formulae. The terminal units of UF and RO can remove most DOM, with the concentration of dissolved organic carbon (DOC) declining by 19.2% and 94.6% respectively. The correlation between spectral indexes and acute toxicity with the molecular formulae of DOM suggested that polyphenols and highly unsaturated phenols were positively correlated with the specific UV absorbance at 254 nm (SUVA). In addition, both compounds (0.32 < O/C < 0.63) as well as the aliphatic ones (0.22 < O/C < 0.56) presented positive correlation with acute toxicity. Further, the pairwise correlation analysis illustrated that SUVA, O/C, double bond equivalence (DBE), and NOSC were positively correlated with each other, whereas the acute toxicity was positively correlated with humification index (HIX), O/C, and DBE.
作为中国的主要经济模式之一，化工园区（CIP）为中国的快速经济增长做出了巨大贡献。同时，如何有效地、安全地处理 CIP 废水（CIPWW）已成为一个不可避免的问题。CIPWW 处理过程中溶解有机物（DOM）的分子转化对于优化所采用的工艺以及为排放出水的风险评估提供坚实的基础是至关重要的。在本研究中，采用电喷雾电离与傅里叶变换离子回旋共振质谱（ESI-FT-ICR-MS）联用技术，对集中式污水处理厂（CWWTP）综合化工废水全流程处理过程中 DOM 的分子转化进行了表征，该联合工艺依次为水解/酸化（HA）-絮凝/沉淀（FP）-A/O-膜生物反应器（MBR）-超滤（UF）-反渗透（RO）。与城市污水相比，CIPWW 中的 DOM 具有更高的不饱和程度、更低的分子量和更高的毒性。在 FP 单元中，优先去除 C 级和更高的名义氧化态碳（NOSC）值的 DOM。HA 和厌氧单元能够显著降解 DOM，导致 DOM 分子组成发生很大变化。然而，缺氧、好氧和 MBR 单元仅导致分子公式略有变化。UF 和 RO 的末端单元可以去除大部分 DOM，其中溶解有机碳（DOC）的浓度分别下降了 19.2%和 94.6%。光谱指数与急性毒性与 DOM 分子公式之间的相关性表明，多酚和高度不饱和酚与 254nm 处的特定紫外吸光度（SUVA）呈正相关。此外，这两种化合物（0.32<O/C<0.63）以及脂肪族化合物（0.22<O/C<0.56）与急性毒性呈正相关。此外，两两相关分析表明，SUVA、O/C、双键等价物（DBE）和 NOSC 彼此呈正相关，而急性毒性与腐殖化指数（HIX）、O/C 和 DBE 呈正相关。
