Prechlorination routinely applied for the treatment of algae-laden raw water has received extensive attention due to its influence on water quality and aquatic microbes. In this study, prechlorination experiments with different doses were conducted in sets of model raw water distribution systems. With the elevated dose of chlorine and prolonged hydraulic retention time (HRT), the ratio of intact algal cells decreased, and the stability of water enhanced. Dissolved organic carbon (DOC) and nitrogen (DON) increased when chlorine dose elevated from 0 to 0.5 mg/L but decreased with elevations from 0.5 to 2.0 mg/L, while UV254 showed a monotonically increasing tendency. DOC, DON and extracellular microcystin-LR increase initially and decrease thereafter with the pro-longed HRT. Notably, the effects of prechlorination on extracellular polymeric substances aggregation behavior on pipe walls and microbial community composition was revealed, providing more profound understanding of the community dynamics in this engineered system. This study helped optimize strategies to improve the stability and efficiency of pretreatment of algae-laden water.

In this study, a new methodology for evaluating full-scale landfill leachate treatment processes by non-targeted analysis using comprehensive two-dimensional gas chromatography quadrupole time-of-flight mass spectrometry (GC × GC-QTOF-MS) was proposed. The method revealed the chemical complexity of organic compounds in landfill leachate samples at the molecular level and evaluated the removal efficiency of the anaerobic-anoxic-oxic (A2O) - membrane bioreactor (MBR) - nanofiltration (NF) treatment process in conjunction with multi-level classification of organic compounds. Results showed that the results of non-targeted analysis combined with multi-level classification of organic compounds had a significant correlation with the conventional water quality parameters and can be used to evaluate the treatment process. A total of 2508 organic compounds were detected in 6 samples. 17 emerging contaminants (ECs) with known potentially hazards were detected, including Diisobutyl Phthalate (DIBP), which is toxic to male reproduction and development, and 4-Tert-Butylphenol, which causes endocrine disruption in animals. The removal rate of organic compounds by this full-scale landfill leachate treatment processes reached 79.14%. The anaerobic tank played a crucial role with 64.98% contribution. For compounds, the removal rate of heterocyclics was as high as 94.67%, and the removal rate of aliphatics was poor, only 63.49%. This treatment process had almost perfect removal effect on the steroids in alicyclics and phenols in aromatics, but poor treatment effect on saturated alkanes in aliphatics and naphthenes in alicyclics. This study provides a methodology for accurate assessment of the molecular level of treatment processes, new insights for process optimization in waste treatment plants, and data support for the detection of emerging contaminants. The environmental hazards of landfill leachate can be further evaluated in the future in conjunction with ecotoxicity assessment studies.

备用水源原水管道较为封闭,原水停留时间过长会导致溶解氧(DO)浓度降低,管道环境由好氧变为缺氧甚至厌氧,从而引起水质恶化.实验室模拟M、N两种不同水源条件在原水管道的备用状态,以DO降至2 mg/L确定停留时间,探究相应的水质变化以及原水的化学稳定性和管壁微生物群落多样性.结果表明,DO在水质较差水源条件下的衰减时间明显短于水质较好的水源.两种水源水都具有严重腐蚀性,出水pH、总碱度和钙硬度均显著升高.M装置进水水质相对较差,微生物存在水平高,对有机物的去除率更高,CODMn和UV254的去除率分别为27.8％和22.9％,而N装置分别为24.6％和21.4％;M装置中的硝化作用更强,NO3--N生成率为23.4％,而N装置为16.2％.两组装置管壁生物膜中的优势菌门基本相同,但丰度较高的菌门差异较大,而丰度较低的菌门差异不明显.较高的NH4+-N浓度有利于增加硝化螺旋菌门的丰度,从而促进硝化作用.良好的水质可以增加管道内的微生物多样性,更有利于管道内生态系统的稳定.

考察了臭氧强化混凝沉淀对溶解性有机物(DOM)去除的影响,针对长荡湖原水、直接沉后水、预臭氧出水和臭氧沉后水四种水样,利用液相色谱-有机碳检测仪(LC-OCD)和傅里叶变换离子回旋共振质谱仪(FT-ICR MS)等从不同层面探究DOM的演变.经试验确定,预臭氧和聚合氯化铝(PAC)的最佳投加量分别为1.0、30mg/L,并在此工况下进行研究.原水中主要存在类色氨酸和类富里酸两种有机物,臭氧强化混凝沉淀对有机物的去除效果最好,对类色氨酸、类富里酸和类腐殖酸类物质的去除率分别为80.75％、77.39％、80.28％.经LC-OCD分析,原水中亲水性有机物总浓度最高为3 776.74 μg/L.臭氧沉后水中腐殖质降解产物增多,其他几类有机物均减少.在小分子DOM中,CHOSP-DOM占比最大,CHOP-DOM占比最小.臭氧强化混凝沉淀对各类分子相对丰度的分布影响最大,峰值出现在C10H10O3(177.06u)、C13H18O6(269.10u)和C15H20O7(311.11u),且质荷比＞680的分子分布明显减少.原水经不同工艺处理后,小分子DOM分布范围均变广,并逐渐向高H/C、低O/C转移,各水样中碳水化合物类、不饱和碳氢化合物、单宁酸类和稠环化合物类占比很少,总占比为10.90％～18.25％.四种水样中小分子DOM的DBE平均值分别为6.6、6.5、6.3和6.1,可以看出臭氧对芳香性或不饱和度的降低起关键作用.总体来看,臭氧强化混凝沉淀工艺的处理效果最好,可以降低水厂后续工艺对有机物的处理难度.

文章利用傅里叶变换离子回旋共振质谱法深入探究某浅水型湖泊为水源的水厂中原水、混凝沉淀出水、臭氧活性炭出水、砂滤池出水和出厂水中小分子溶解性有机物(DOM)的分子组成、质荷比、芳香性等变化.研究表明小分子DOM中CHOSP(含有C、H、O、S、P元素的小分子DOM,15.99％～25.99％)占主导地位,CHOP(2.26％～5.30％)占比最小.加氯消毒工艺对小分子DOM影响最大,CHONSP和CHOP分子式种类分别增加183.59％和141.91％,各类小分子DOM相对丰度均明显增加,芳香性及不饱和度趋于降低.总体上小分子DOM逐渐向低H/C、高O/C转移,出水中碳水化合物类、稠环化合物类和单宁酸类增加较为显著,类蛋白类也有所增加,脂质类、不饱和碳氢化合物类和木质素/CRAM类减少,小分子DOM的芳香性或不饱和度在动态变化中没有明显规律.

蓝藻水华暴发时原水管道可能混入大量藻细胞,威胁饮用水安全.研究采用BAR模拟管道装置,对比探究105 cell/mL、106 cell/mL两种不同浓度含藻原水在长距离输送过程中的水质变化.以无藻原水作为对照,采用高通量测序研究管壁生物膜群落结构多样性,以探究原水管道中藻类浓度对水质及管壁生物膜的影响.结果表明,两种藻类浓度下原水pH略微上升,溶解氧和浊度逐渐降低,UV254和总磷呈下降趋势,而溶解性有机碳在高藻水中先上升后下降.胞外有机物在低藻水中变化不大,在高藻水中波动上升,而胞内有机物均不断增加.高藻水可能存在藻毒素超标风险.原水中藻类浓度增加有利于管壁生物膜群落多样性的提高,其对管壁生物膜影响不大,优势菌门均为变形菌门和拟杆菌门.

Landfill leachate is a type of complex organic wastewater, which is prone to cause serious negative impacts on the ecological environment and human health. Using fuel cells to remove the organic matter in landfill leachate is an efficient and feasible approach. The fuel cells are primarily limited by the cathodic oxygen reduction reaction (ORR) with sluggish kinetics, which requires catalysts with high electrochemical properties to improve ORR activity. Herein, Pt-Te nanowires (NWs) with high activity and durability were synthesized. The transmission electron microscope (TEM) images indicated that Pt nanoparticles were uniformly decorated in the Te nanowires to form active sites. The electrochemical activities of the catalysts were investigated using the rotating disk electrode (RDE) system. Compared with Pt/C and pure Te NWs catalysts, the Pt-Te NWs exhibited a stronger reduction peak and higher current density for ORR. Additionally, the fuel cell coupled with Pt-Te NWs possessed a high performance on the removal of the organic matter.