污泥中典型人工甜味剂在厌氧消化过程中的转化规律及影响行为研究

Artificial sweeteners (AS) are emerging pollutants and widespread in the environment. The efficient biodegradation of AS was of vital regarding to their potential ecological threats. Wastewater treatment plants (WWTPs) are one of the main transfer stations for AS in the environment. However, the removal efficiencies of AS were relatively low via the conventional treatment processes in WWTPs, especially for the acesulfame and sucralose, which led to the massive entry of AS into waste activated sludge. Anaerobic digestion is considered as an efficient strategy for the sludge treatment, by which sludge reutilization and stabilization can be simultaneously accomplished. Nevertheless, to date, few studies have explored the AS biodegradation as well as its mechanisms during anaerobic digestion. Also, as organic pollutants, the AS effects on the sludge anaerobic digestion are unknown. Therefore, this study mainly focuses on the biodegradation of typical AS (acesulfame and sucralose) in sludge and the key influencing factors during anaerobic digestion, and the detailed mechanisms are investigated by the analyses of functional microorganisms, key enzymes and encoding genes related with AS biodegradation as well as the metabolic pathway via molecular biological techniques. Meanwhile, the effects of AS on the anaerobic digestion were also explored and the toxical effects of AS and related mechanisms were demonstrated by the changes of microbial activities and viabilities. It can be seen that the results of this study will not only disclose the biodegradation efficiency and environmental impacts of AS during sludge anaerobic digestion, but also enrich the understanding of anaerobic biodegradation of organic pollutants and the knowledge of AS toxicity, which merited a high academic value and practical significance.

人工甜味剂（AS）作为一种新兴有机污染物，广泛存在于环境介质中，造成潜在危害，因而实现AS的高效降解至关重要。污水处理厂是环境中AS的重要集散地，其常规工艺对AS的去除效果有限，特别是对安赛蜜和三氯蔗糖，导致大量的AS进入到污泥中。厌氧消化是实现污泥资源化和无害化处理的有效途径。然而目前，有关厌氧消化对AS的降解效果及作用机理尚不清楚；AS对厌氧消化的影响也未知。因此，本项目研究了污泥中典型AS安赛蜜和三氯蔗糖在厌氧消化过程中的降解效能及影响因素，并利用分子生物学等手段，获得与AS降解相关的关键微生物、功能基因和酶等信息，结合其代谢途径，阐明AS的厌氧降解机制；同时，考察了AS暴露对厌氧消化过程的影响，从微生物的活性与活力等方面探讨其毒性效应及影响机制。该研究不但能揭示AS在厌氧消化过程中的转化规律和影响行为，还将极大丰富AS的厌氧生物降解理论和生物毒性认知，具有较高的学术价值和现实意义。

本项目主要探究了基于铁催化过硫酸盐（PS/Fe）技术强化污泥厌氧发酵系统中典型人工甜味剂安赛蜜的降解以及资源化产物短链脂肪酸（SCFAs）的生产效能。一方面，考察了PS/Fe调控对安赛蜜的降解效能和动力学特征，安赛蜜的降解效率由空白的6.0%提升至96.2%，并对其关键影响因子进行识别（如自由基的种类与贡献等），重点探究了污泥发酵系统不同底物（如蛋白质、糖、腐殖酸和SCFAs等）对安赛蜜降解的影响及作用机制，最后通过理论计算和LC-MS等方法分析了安赛蜜的潜在降解途径。另一方面，探究了不同PS/Fe作用条件下（比例和剂量）对污泥发酵产酸的影响（包括SCFA的总量与组成），并从污泥厌氧发酵的溶解/水解、酸化和甲烷化等主要阶段针对其有机底物释放、微生物种群结构及活性和活力的变化（关键酶活性，ATP浓度等），结合环境因子的影响（如pH和ORP等）多角度阐释了PS/Fe强化污泥发酵产酸效能的作用原理；同时初步探究了PS/Fe对发酵液中难降解有机污染物以及发酵残渣的脱水性能。该研究成果为污泥的无害化、资源化和减量化的处理处置奠定了一定的理论基础。