臭氧-活性炭对某市饮用水中消毒副产物和生物稳定性控制的研究

为了研究臭氧-活性炭工艺对某市饮用水中消毒副产物和生物稳定性的影响,在原有工艺的基础上,于反应池前增加了预臭氧氧化工艺,分两级投加臭氧,同时将臭氧尾气回收,以增加水体中臭氧的吸收率以及混凝、反应、沉淀的效果。系统稳定运行6个月,出水浊度为0．2NTU左右,出水色度为2～3度,CODM。出水浓度为0．6mg／L,平均去除率为88％,氨氮经折点加氯后可降至0．2mg／L以下,均达到饮用水标准。对于试验水质条件下,臭氧化与活性炭吸附联合作用能够有效地去除水中AOC和氯化消毒副产物前质。     

O3/TiO2催化氧化工艺对饮用水中AOC的影响

以陶粒、硅胶和沸石为载体,分别负载二氧化钛（TiO₂）进行臭氧催化氧化去除硝基苯的实验,并对饮用水中生物可同化有机碳（AOC）所代表的小分子有机物(酮、醛、醇和羧酸类物质)的生成情况进行了研究.发现臭氧催化氧化比单纯的臭氧氧化能更彻底地将部分大分子有机物氧化成小分子中间产物,陶粒、硅胶和沸石负载TiO₂ 3种催化剂分别将AOC从大约300　μg·L^-1增加到 674.1　μg·L^-1、847.2　μg·L^-1和882.1　μg·L^-1,并且分别使AOC/TOC从原水的4.68%升高到30.5%、33.21%和46.04%,大大地提高了水中有机物的可生物降解性.如果增加臭氧投量,催化氧化可使小分子有机物部分被氧化,致使水样AOC又略有回降.在这一过程中,AOC-NOX所代表的羧酸类物质急剧增加,达到总AOC的90％以上,取代AOC-P17成为了AOC的主体组成部分.     

某市饮用水水质生物稳定性研究

研究某市的几个典型水厂的ＡＯＣ和ＢＤＯＣ含量和其在处理工艺和管 的变化规律,以及对爆管管道取样作扫描电镜分析,得到初步结论：（１）水源水质较好的水厂其出厂水和管网水中ＡＯＣ含量相对较低,反之则高,（２）在饮用水中ＡＯＣ与ＢＤＯＣ之比变化较大,但大量数据统计结果表明平均约为３０－４０％,因此如果以ＢＤＯＣ作为饮用水生物稳定性的评价指标也是可以的,（３）常规给水处理工艺对ＡＯＣ的支 动较大,大多数情况     

饮用水生物稳定性控制指标体系研究

主要阐述了饮用水生物稳定性的主要控制指标AOC(可生物同化有机碳)、BDOC(可生物降解溶解性有机碳)、TP(总磷)、MAP(可生物利用磷)、BGP(细菌生长潜力)及其测定方法和AOC-T DWMS评价体系.利用层次分析法确定了在城市输水管网中各控制指标的重要性权,使城市饮用水的处理更具有针对性,保证城市饮用水的生物稳定性.     

Is atmospheric oxidation capacity better in indicating tropospheric O3 formation?

● This study summarizes and evaluates different approaches that indicate O₃ formation. ● Isopleth and sensitivity methods are useful but have many prerequisites. ● AOC is a better indicator of photochemical reactions leading to O₃ formation. Tropospheric ozone (O₃) concentration is increasing in China along with dramatic changes in precursor emissions and meteorological conditions, adversely affecting human health and ecosystems. O₃ is formed from the complex nonlinear photochemical reactions from nitrogen oxides (NO_x = NO + NO₂) and volatile organic compounds (VOCs). Although the mechanism of O₃ formation is rather clear, describing and analyzing its changes and formation potential at fine spatial and temporal resolution is still a challenge today. In this study, we briefly summarized and evaluated different approaches that indicate O₃ formation regimes. We identify that atmospheric oxidation capacity (AOC) is a better indicator of photochemical reactions leading to the formation of O₃ and other secondary pollutants. Results show that AOC has a prominent positive relationship to O₃ in the major city clusters in China, with a goodness of fit (R²) up to 0.6. This outcome provides a novel perspective in characterizing O₃ formation and has significant implications for formulating control strategies of secondary pollutants.     

Phosphorus limitation on bacterial regrowth in drinking water

Assimilable organic carbon(AOC) test and bacterial regrowth potential(BRP) analysis were used to investigate the effect of phosphorus on bacterial regrowth in the drinking water that was made from some raw water taken from a reservoir located in northern China. It was shown that AOC of the drinking water samples increased by 43.9%—59.6% and BRP increased by 100%—235% when 50 μg/L PO4^3--P(as NaH2PO4 ) was added alone to the drinking water samples. This result was clear evidence of phosphorus limitation on bacteria regrowth in the drinking water. This investigation indicated the importance of phosphorus in ensuring biological stability of drinking water and offered a novel possible option to restrict microbial regrowth in drinking water distribution system by applying appropriate technologies to remove phosphorus efficiently from drinking water in China.     

可同化有机碳(AOC)产率系数测定优化及接种方法对比研究

在对测定可同化有机碳(AOC)所需接种液中荧光假单胞杆菌P17及螺旋菌NOX的浓度随培养时间变化规律进行研究的基础上,进一步研究了两种细菌培养后其浓度与标准乙酸碳(Ac-C)浓度之间的相关性.结果表明,当Ac-C浓度75μg·L~(-1)时,标准乙酸碳溶液的浓度与细菌浓度具有较好的线性关系;当Ac-C浓度75μg·L~(-1)时,两者的线性关系减弱;传统AOC检测方法选取[Ac-C]=100μg·L~(-1)作为产率对照在低浓度条件下是不准确的.本文在此基础上提出了产率系数的优化计算方法并确定其适用范围(AOC-P17:0～75μg·L~(-1);AOC-NOX:0～75μg·L~(-1)),该方法进一步提高了该范围内AOC测定结果的准确性.通过对AOC测定过程中3种接种方式的对比研究,发现分别接种法误差较大;同时接种法在平板计数阶段两种细菌菌落之间存在掩盖现象,结果不稳定;先后接种法测定结果较为准确,可较好地反映水中AOC的浓度.将优化后的产率系数测定方法应用于先后接种法并与传统测定方法进行对比,结果证明,优化后的测定方法准确度更高.     

Variation in assimilable organic carbon formation during chlorination of Microcystis aeruginosa extracellular organic matter solutions

This study investigated the chlorination of Microcystis aeruginosa extracellular organic matter(EOM) solutions under different conditions, to determine how the metabolites produced by these organisms affect water safety and the formation of assimilable organic carbon(AOC). The effects of chlorine dosages, coagulant dosage, reaction time and temperature on the formation of AOC were investigated during the disinfection of M.aeruginosa metabolite solutions. The concentration of AOC followed a decreasing and then increasing pattern with increasing temperature and reaction time. The concentration of AOC decreased and then increased with increasing chlorination dosage, followed by a slight decrease at the highest level of chlorination. However, the concentration of AOC decreased continuously with increasing coagulant dosage. The formation of AOC can be suppressed under appropriate conditions. In this study, chlorination at 4 mg/L, combined with a coagulant dose of 40 mg/L at 20°C over a reaction time of 12 hr, produced the minimum AOC.     

供水管网中可同化有机碳的反应动力学

为了深入研究实际管网中可同化有机碳(AOC)的反应动力学,引入效率因子的概念,在简单反应器的基础上对AOC 的动力学进行了理论探讨,在几个假设条件的基础上,分别提出了实际管网中主体水和管壁反应的AOC 动力学方程.现场取样测试结果表明,AOC 浓度随时间的变化符合提出的动力学方程(R2>0.7).     

不同的消毒方式对砂滤池出水消毒效果的影响

采用中置O3-BAC工艺进行中试实验,通过对微生物、微型生物、消毒副产物和AOC进行检测分析,研究了不同的消毒方式对砂滤池出水消毒效果的影响。结果表明,氯消毒对微型生物、微生物的去除效果稍弱于臭氧联合氯消毒;对于消毒副产物而言,氯消毒产生的卤代烃、氯酸盐的含量高于臭氧联合氯消毒,产生的溴酸盐两者处于同一水平,而产生的甲醛则是氯消毒低于臭氧联合氯消毒;氯消毒最终砂滤池出水AOC平均含量75.93μg乙酸碳/L,臭氧联合氯消毒为101.23μg乙酸碳/L,大于100μg乙酸碳/L,不利于供水管网的生物稳定性。