Trihalomethane formation potential of organic fractions in secondary effluent

Organic matter is known to be the precursor of numerous chlorination by-products. Organic matter in the secondary e uent from the Wenchang Wastewater Treatment Plant (Harbin, China) was physically separated into the following fractions: particulate organic carbon (1.2–0.45 m), colloidal organic carbon (0.45–0.1 m), fine colloidal organic carbon (0.1–0.025 m), and dissolved organic carbon (DOC) (< 0.025 m). Moreover, < 0.45 m fraction was chemically separated into hydrophobic acid (HPO-A), hydrophobic neutral (HPO-N), transphilic acid (TPI-A), transphilic neutral (TPI-N), and hydrophilic fraction (HPI). The chlorine reactivity of these organic fractions obtained from both size and XAD fractionations were evaluated. The structural and chemical compositions of the HPO-A, HPO-N, TPI-A, and TPI-N isolates were characterized using elemental analysis (C, H, O, and N), Fourier transform infrared spectroscopy (FT-IR), and proton nuclear magnetic resonance spectroscopy (1H-NMR). Results showed that DOC was dominant in terms of total concentration and trihalomethane formation potential (THMFP), and there was no statistical di erence in both specific THMFP (STHMFP) and specific ultraviolet light absorbance among the 0.45, 0.1, and 0.025 m filtrates. HPO-A had the highest STHMFP compared to other chemical fractions. HPO-A, HPO-N, TPI-A, and TPI-N contained 3.02%–3.52% of nitrogen. The molar ratio of H/C increased in the order of HPO-A < HPO-N < TPI-A < TPI-N. The O/C ratio was relatively high for TPI-N as compared to those for the other fractions. 1H-NMR analysis of the four fractions indicated that the relative content of aromatic protons in HPO-A was significantly higher than those in the others. The ratio of aliphatic to aromatic protons increased in the order of HPO-A < HPO-N < TPI-A < TPI-N. FT-IR analysis of the four fractions showed that HPO-A had greater aromatic C==C content whereas HPO-N, TPI-A, and TPI-N had greater aliphatic C–H content. TPI-N contained more oxygen-containing functional groups than the other fractions.     

正渗透去除地表水中DOM的效能研究

采用经砂滤处理后的滆湖水作为原料液,氯化钠溶液作为汲取液,在不同影响因素条件下进行正渗透试验,并对试验后的膜片进行清洗,探究膜污染的可逆性.结果表明:提高汲取液浓度、运行温度及膜面流速均可有效增加膜通量;正渗透对滆湖水体中的溶解性微生物代谢产物、类色氨酸、类富里酸和腐殖酸四种主要DOM成分均有较好的去除效果,DOC、UV₂₅₄截留率均在96%以上;短期运行通过水力清洗几乎可以完全恢复膜通量,而长期运行通过超声清洗可以基本恢复全部膜通量,通过分析膜清洗液可知造成膜污染的主要物质为类色氨酸类和类富里酸类物质.     

臭氧耦合陶瓷膜过滤对膜性能及出水消毒副产物的影响

利用臭氧（O₃）-陶瓷膜过滤（CMF）处理常规工艺出水,研究了不同O₃-CMF耦合方式对膜性能和消毒副产物（DBPs）的影响.结果表明,与单独CMF相比,异位O₃-CMF和原位O₃-CMF均可以有效缓解膜污染,原位O₃-CMF控制效果最佳.异位O₃-CMF对进水（常规工艺出水） DOC去除率（26.25%）略高于原位O₃-CMF（22.31%）,但是其SUVA去除率（83.91%）明显低于原位O₃-CMF（93.10%）.羟基自由基（·OH）生成特征表明原位O₃-CMF可促进O₃产生更多的·OH.在O₃、·OH氧化和陶瓷膜截留协同作用下,异位O₃-CMF和原位O₃-CMF出水中总荧光响应强度和相对分子质量大于0.3×10³,有机物含量降低,进而使得出水中含碳消毒副产物（C-DBPs）生成量分别降低了21.86%和32.35%,含氮消毒副产物（N-DBPs）生成量分别降低了16.16%和19.13%.但O₃和·OH氧化后生成的小分子有机物因难以被CM截留导致其在出水中含量增加,进而增加了卤代酮（HKs）、水合氯醛（CH）和三卤硝基甲烷（THNMs）的产生.本研究对于不同O₃-CMF方式下O₃与CM的协同机制的探讨,改善膜性能和提升DBPs前体物的去除具有一定指导意义.     

Ultrafiltration with in-line coagulation for the removal of natural humic acid and membrane fouling mechanism

Experimental and theoretical analysis were made on the natural humic acid removal and the membrane fouling of ultrafiltration （UF） with in-line coagulation. The results showed dissolved organic carbon （DOC） and UV254 removals by the UF with in-line coagulation at pH 7 were increased from 28% to 53% and 40% to 78% in comparison with direct UF treatment respectively. At the same time, the analysis of high performance liquid chromatography showed that UF with coagulation had significant improvement of removal of humic acid with molecular weights less than 6000 Da in particular. Compared to direct UF, the in-line coagulation UF also kept more constant permeate flux and very slight increase oftransmembrane pressure during a filtration circle. Two typical membrane fouling models were used by inducing two coefficients Kc and Kp corresponding to cake filtration model and pore narrowing model respectively. It was found that membrane fouling by pore-narrowing effect was effectively alleviated and that by cake-filtration was much decreased by in-line coagulation. Under the condition of coagulation prior to ultrafiltration at pH 7, the cake layer formed on the membrane surface became thicker, but the membrane filtration resistance was lower than that at pH 5 with the extension of operation time.     

Disinfection byproduct precursor removal by enhanced coagulation and their distribution in chemical fractions

Raw water from the Songhua River was treated by four types of coagulants, ferric chloride(FeCl3), aluminum sulfate(Al2(SO4)3),polyaluminum chloride(PACl) and composite polyaluminum(HPAC), in order to remove dissolved organic matter(DOM). Considering the disinfection byproduct(DBP) precursor treatability, DOM was divided into five chemical fractions based on resin adsorption.Trihalomethane formation potential(THMFP) and haloacetic acid formation potential(HAAFP) were measured for each fraction. The results showed that hydrophobic acids(HoA), hydrophilic matter(HiM) and hydrophobic neutral(HoN) were the dominant fractions.Although both HoN and HoA were the main THM precursors, the contribution for THMFP changed after coagulation. Additionally,HoA and HiM were the main HAA precursors, while the contribution of HoN to HAAFP significantly increased after coagulation.HoM was more easily removed than HiM, no matter which coagulant was used, especially under enhanced coagulation conditions.DOC removal was highest for enhanced coagulation using FeCl3 while DBPFP was lowest using PACl. This could indicate that not all DOC fractions contained the precursors of DBPs. Reduction of THMFP and HAAFP by PACl under enhanced coagulation could reach51% and 59% respectively.     

Advanced oxidation of bromide-containing drinking water：A balance between bromate and trihalomethane formation control

Addition of H2O2 has been employed to repress bromate formation during ozonation of bromide-containing source water. However, the addition of H2O2 will change the oxidation pathways of organic compounds due to the generation of abundant hydroxyl radicals, which could affect the removal efficacy of trihalomethane precursors via the combination of ozone and biological activated carbon （O3-BAC）. In this study, we evaluated the effects of H2O2 addition on bromate formation and trihalomethane formation potential （THMFP） reduction during treatment of bromide-containing （97.6-129.1 μg/L） source water by the O3-BAC process. At an ozone dose of 4.2 mg/L, an H2O2/O3 （g/g） ratio of over 1.0 was required to maintain the bromate concentration below 10.0 μg/L, while a much lower H2O2/O3 ratio was sufficient for a lower ozone dose. An H2O2/O3 （g/g） ratio below 0.3 should be avoided since the bromate concentration will increase with increasing H2O2 dose below this ratio. However, the addition of H2O2 at an ozone dose of 3.2 mg/L and an H2O2/O3 ratio of 1.0 resulted in a 43% decrease in THMFP removal when compared with the O3-BAC process. The optimum H2O2/O3 （g/g） ratio for balancing bromate and trihalomethane control was about 0.7-1.0. Fractionation of organic materials showed that the addition of H2O2 decreased the removal efficacy of the hydrophilic matter fraction of DOC by ozonation and increased the reactivity of the hydrophobic fractions during formation of trihalomethane, which may be the two main reasons responsible for the decrease in THMFP reduction efficacy. Overall, this study clearly demonstrated that it is necessary to balance bromate reduction and THMFP control when adopting an H2O2 addition strategy.     

冬季Z市水源DOM组成、三卤甲烷生成势特性及去除研究

以冬季Z市水源地2条入库河流为研究对象,通过联合运用三维荧光光谱、树脂分离分级和紫外可见分光光度法,探究水源地原水中溶解性有机物（DOM）的荧光成分、来源、组成、腐殖化程度与消毒副产物三卤甲烷（THMs）生成势的关系。结果表明：三维荧光光谱解析出水源地2条入库河流原水中共有类蛋白物质（C1）、紫外腐殖酸类物质（C2）、陆地/人造腐殖质类物质（C3）3个荧光峰;水源地的2条入库河流（Q河与X河）的3个荧光峰峰值分别为4.50、10.75、7.56和1.33、9.24、7.56;荧光源指数（FI）与生物源指数（BIX）均体现出水源地原水中的DOM主要为陆源输入;此外,水源地原水中的DOM化学分级之后,5个组分浓度表现为疏水性有机酸（HoA）>亲水物质（HiM）>疏水中性有机物（HoN）>疏水碱性有机物（HoB）>弱疏水酸性有机物（wHoA）;Q河原水氯化后产生CHCl₃、CHClBr₂和CHBrCl₂ 3种成分,X河氯化后产生CHCl₃和CHBrCl₂ 2种成分,说明河水并没未受到明显的工业污染。水源地2条入库河流原水的DOM各化学分级组分的THMs生成势的研究结果表明,THMs的主要前驱物为HoA和HiM,而HoA、HiM、wHoA 3种组分对THMs的生成能力均较强,与紫外吸收特性SUVA相一致,说明生成THMs的能力也很强,应选取工业聚合氯化铝进行强化混凝去除。     

融雪期城市河流中溶解性有机物的时空分布特征

以沈阳市新开河为研究对象,考察了河水中溶解性有机物(DOM)含量的月份变化,以及融雪期河水中DOM含量和特性的时空变化规律.利用XAD树脂将DOM分为5个部分:疏水性有机酸(HPO-A),疏水性中性有机物(HPO-N),过渡亲水性有机酸(TPI-A),过渡亲水性中性有机物(TPI-N)和亲水性有机物(HPI).结果表明,融雪期河水中的溶解性有机碳(DOC)浓度较高,HPO-N和TPI-N是融雪期河水中的主要DOM组分,并且DOM中的荧光物质主要为类芳香族蛋白质荧光物质和类腐植酸荧光物质.融雪期水体中的DOC、波长254nm处的紫外吸光度(UV-254)和三卤甲烷生成势(THMFP)呈先降低然后波动最后升高的变化趋势.特征紫外吸光度(SUVA)和三卤甲烷生成活性(STHMFP)与以上三者的变化规律相反.融雪期河水中的DOC受污水排放影响大,有排污口处的DOC含量明显大于其他区域.污水排放也使受纳水体中UV-254对THMFP的指示作用减弱.     

The effect of coupling coagulation and flocculation with membrane filtration in water treatment： A review

Water supply and sanitation demands are foreseen to face enormous challenges over the coming decades to meet the fast growing needs in a global perspective. Significant growth in the industry is predicted and membrane separation technologies have been identified as one of the possible solutions to meet future demands. Application and implementation of membrane technology is expected both in production of potable water as well as in treatment of wastewater. In potable water production membranes are substituting conventional separation technologies due the superior performance, potential for less chemical use and sludge production, as well as the potential to fulfill hygienic barrier requirements. Membrane Bio-Reactor (MBR) technology is probably the membrane process which has had most success and has the best prospects for the future in wastewater treatment. Trends and developments indicate that this technology is becoming accepted and is rapidly becoming the best available technology (BAT) for many wastewater treatment applications. A major drawback of MBR systems is membrane fouling. Studies have shown that fouling mitigation in MBR systems can potentially be done by coupling coagulation and flocculation to the process.     

不同水体溶解性有机物的混凝去除特性

采用硫酸铝、工业氯化铁、无机高分子絮凝剂(PAC)3种无机混凝剂,对广州珠江、北京密云、天津滦河不同原水进行了混凝实验,分析了不同混凝剂去除水体有机物的特性以及不同水体溶解性有机物(DOM)的内在分级特征与其混凝去除率的关系.实验结果表明,①珠江水体由于碱度低,pH较易下降,高投药浓度下此水体DOM更易被氯化铁去除;中低投药下,在南方水体中,PAC与盐类絮凝剂对去除DOM的混凝性能差别不如在北方水体中明显,表明南北方水体DOM的内在特性存在一定差异,即北方水体DOM中可混凝去除部分的有机物易发生电中和作用,带有较多负电基团,南方珠江水体DOM含带电基团的有机物相对较少,而中性有机物含量相对较高,这与进一步分级结果一致.②所有水体从混凝收敛点看,总溶解性有机碳(DOC)去除率都是工业PAC最高,显示电中和(憎水化)-沉淀(吸附)可能为这些水体DOM的主要去除机理.③从不同水体的DOC平均去除率看,珠江水体高于密云水体,它们又明显高于滦河水体.对水体DOM进一步的化学分级研究结果表明,DOC去除率越高的水体,其中的憎水中性物质(HoN)含量也越高.这表明,除了碱度、总有机碳(TOC)外,原水DOM的内在化学分级特征也是影响水体DOC混凝去除率的重要因素.     

城镇化河流DOM组成结构及与水质相关性研究

应用三维荧光技术和多元统计方法,分析城镇化河流水溶性有机物(DOM)组成结构特征,研究其与河水水质的相关性.根据人类活动对沈阳市白塔堡河影响程度的不同,分别在农村、城镇与城市河段设置3个采样点,采集水样.结果发现,河水营养水平由高到低的顺序为城市河段城镇河段农村河段,而水质由好变差的顺序为农村河段城镇河段城市河段.河水DOM由类酪氨酸、类色氨酸、类糖化蛋白、微生物代谢产物、类富里酸和类胡敏酸组成,主要成分为类蛋白,类蛋白含量由高到低的顺序为城市河段城镇河段农村河段.从源头到入浑河口,类蛋白丰度增长最大,类胡敏酸丰度增长最小,类富里酸介于两者之间.DOM的腐殖化程度由强到弱的顺序为城市河段城镇河段农村河段.影响河水营养状态的潜在因子包括COD、NH3-N、BOD5、DO和类蛋白,农村河段主要污染物来源于农村生活污水及养殖废水,城镇河段污染物来源于生活废水与工业园排水,城市河段污染物来源于处理和未处理的生活污水及工业废水.河水受人类活动影响由大到小的顺序为城市河段城镇河段农村河段.     

KMnO4-PAC对高原喀斯特湖库DOM的DBPsFP控制

以云贵高原典型喀斯特湖库红枫湖取水口溶解性有机质（DOM）为研究对象,调查不同组合方式下高锰酸钾-聚合氯化铝（KMnO₄-PAC）对消毒副产物的生成潜能（DBPsFP）变化和平均组成分布,并通过红外光谱（FTIR）和三维荧光光谱（3D-EEM）对部分样品进行化学表征,推断其影响机制.结果表明：在0.1,0.2,0.4mg/L KMnO₄投加量下,DBPsFP降低17.5~73%,DOM的卤代活性化学结构和官能团部分被有效钝化;PAC的网捕和卷扫效应使DBPsFP进一步减少27.9~86.1%,组合工艺对DBPs的生成潜能影响大小为：三卤甲烷（THM₄） > 卤乙酸（HAA₉） > 卤乙腈（HAN₄）/卤代酮（HK₂）/三氯硝基甲烷（TCNM）.FTIR的结果表明预氧化后3300cm^-1处的透过率降低,指纹区1000~1300cm^-1处的峰频提升,表明分子中的O-H、COOH和C-O官能团增加,共轭不饱和结构在KMnO₄作用下部分消失.3D-EEM验证了外源有机物（腐殖酸）在DOM中占比随KMnO₄浓度梯度升高而下降,同时类蛋白结构的吸收峰强度增加,说明最终DBPs贡献可能源于DOM中剩余的小分子类蛋白（氨基酸）.     

Cu2+在混凝中对富里酸氯化消毒副产物的影响

混凝实验采用硫酸铝作为混凝剂,以富里酸（FA）为目标物,考察Cu²⁺对浊度、溶解性有机碳（DOC）去除效果和氯化消毒副产物生成势（DBPsFP）的影响,并采用三维荧光光谱（3DEEM）和超滤膜分级对混凝出水进行表征.结果表明,Cu²⁺可以通过络合反应提高混凝过程对FA中亲水性组分和芳香结构DBPs前驱体的去除效果.在pH> 7时,可以使二氯乙酸生成势（DCAAFP）和三氯甲烷生成势（TCMFP）明显降低.Cu²⁺-混凝的作用更倾向于影响FA中分子量级分处于10~30kDa的物质,提高其对DOC和DBPs生成势的去除效果.     

辽河保护区水体溶解性有机质空间分布与来源解析

以辽河保护区水体为研究对象,使用三维荧光光谱技术(EEMs)结合平行因子模型(PARAFAC)探究辽河保护区水体溶解性有机质(DOM)的组成成分、主要来源及DOM的空间分布特征.同时,结合水体理化性质指标,运用统计学分析方法研究影响DOM的主要因素.结果表明,辽河保护区表层水中DOM含有3种荧光组分,分别为陆源及海洋源...     

臭氧/陶瓷膜对生物活性炭工艺性能和微生物群落结构影响

利用处理量为120m3/d的臭氧/陶瓷膜-生物活性炭(BAC)组合工艺处理微污染原水, 对工艺性能和BAC中的微生物多样性和种群结构进行了研究.结果显示,组合工艺可有效去除微污染原水中的有机物和氨氮.臭氧曝气提高了溶解氧浓度,改善了后续BAC工艺对氨氮的去除效果.组合工艺对氨氮和CODMn的总去除率分别约为90%和84%,其中BAC在污染物的去除中发挥了重要作用.组合工艺和传统工艺中BAC床层共检测到36个门类的细菌.与传统BAC工艺相比,臭氧/陶瓷膜降低了后续BAC中微生物群落结构的多样性和均匀度.组合工艺BAC中存在丰度较高的亚硝化单胞菌属和硝化螺旋菌属,可能对氨氮的去除具有重要的作用.臭氧/陶瓷膜对后续BAC中致病菌和条件致病菌有很好的预处理和抑制作用,显著降低了其相对丰度,提高了饮用水的生物安全性.     

制药废水二级出水中溶解性有机物混凝去除特性研究

制药废水二级出水中溶解性有机物(DOM)由于组成复杂、难去除、具有多异质性和分散性,是污水深度处理与回用的主要去除对象和关键限制因子.本论文以发酵制药废水二级出水的DOM为研究对象,采用投加聚合氯化铝(PAC)混凝剂去除DOM,考察混凝剂投加量和混凝pH值对去除效果的影响,并结合分子量分级、亲疏水性分级以及三维荧光光谱-平行因子分析方法等对DOM进行了系统表征和分析,进一步阐述混凝过程DOM的去除特征.结果表明,PAC投加量为250 mg·L~(-1)、pH=7时,混凝沉淀30 min对DOC、UV_(254)、色度和浊度的去除率分别为13.05%±0.29%、23.65%±0.75%、12.66%±1.34%、63.67%±0.89%;混凝对分子量10 kDa的组分和疏水中性(HON)组分去除效果分别为50.33%±0.98%、21.56%±0.42%,而对分子量1 kDa组分去除率较低为2.26%±0.12%;三维荧光光谱-平行因子分析将制药废水二级出水分为2个类腐殖质组分(C1、C3)和1个类蛋白组分(C2),混凝对类腐殖酸组分(C1)最大荧光强度去除率(F_(max))最高为46.22%,而亲水性的小分子和蛋白类物质混凝去除效果较差.     

长江沿线城市水源氯(胺)化消毒副产物生成潜能研究

以长江上游重庆、中游武汉、下游上海等大城市的长江饮用水源为研究对象,在对溶解性有机物分子量和亲疏水性分离的基础上,分别采用氯和氯胺两种方式消毒,对比分析了相同时期沿江这些城市原水中氯(胺)化常规和新兴含氮消毒副产物生成潜能的分子组成规律.研究表明,重庆、武汉、上海三地的溶解性有机物均以小分子前体物为主,主要分布在<1kDa的区间内,且以强疏水性成分和亲水性成分为主,原水经氯(胺)化可产生三卤甲烷、卤乙酸、卤乙腈、三氯硝基甲烷等类型的消毒副产物;三地的氯(胺)化主要的含碳消毒副产物(C-DBPs)和含氮消毒副产物(N-DBPs)生成潜能均在<1kDa的区间内最大,从上游到下游,在<1kDa的区间内的生成潜能占各自总潜能比例逐渐增加.三地的氯(胺)化的C-DBPs和N-DBPs生成潜能均以强疏水性组分或亲水性组分为主,且氯胺化可导致亲水性组分C-DBPs和N-DBPs生成潜能所占总量比例增加.     

阿哈水库DOM的分离及其对消毒副产物的贡献

为研究高原喀斯特湖库DOM（dissolved organic matter,溶解性有机质）的组成及其化学特征对DBPs（disinfection by-products,消毒副产物）生成路径的影响,以西南喀斯特地区贵阳市阿哈水库的DOM为研究对象,结合XAD大孔树脂分离技术,通过化学表征〔包括UV-Vis（紫外-可见光光谱）、FTIR（红外光谱）和3D-EEM（三维荧光光谱）〕手段来研究各组分对C-DBPs（含碳消毒副产物）和N-DBPs（含氮消毒副产物）的生成贡献.不同组分芳香性的大小依次为HON（憎水中性物）> HIB（亲水碱）> HOA（憎水酸）> HIN（亲水中性物）≈HIA（亲水酸）> HOB（憎水碱）.憎水与亲水DOM的DBPs生成潜能相近.其中,HON最高,其次为HIB和HOA.HIB和HOA的主要卤代反应位分别来源于藻类有机物的蛋白质和富里酸,而HON的DBPs生成潜能的贡献主要为分子中的芳香和共轭不饱和结构.HIA和HIN的构成主要为脂肪烃,贡献较低的DBPs的生成潜能.对于C-DBPs,THMs和HAAs的生成潜能总体相近,不同组分的差异明显.对于N-DBPs,卤乙腈的生成潜能占80%以上,憎水DOM的贡献较高.DBPs的生成路径从UV-Vis、FTIR和3D-EEM的官能团和特征峰解析结果中均得到了较好的响应.      

济源市疫情防控期间VOCs的变化特征、臭氧生成潜势及来源解析

采用挥发性有机物(VOCs)在线监测仪(EXPEC 2000-MS)于2020年1月1日-2月11日对济源市环境空气中VOCs进行监测,分析了疫情防控前和期间TVOCs及其组分的变化特征、臭氧生成潜势(OFP)及来源解析.结果表明,疫情防控期间济源市TVOCs浓度均值为121.7×10-9,比疫情防控前增加了61.2％...     

天津中心城区夏季非甲烷有机化合物组成特征及其臭氧产生潜力分析

大气中非甲烷有机化合物(NMOCs)作为臭氧产生前体物之一,其浓度与组成特征研究对于研究地面臭氧形成的机制有重要的科学意义.选择夏季时段从2009年8月6日到13日在天津中心城区气象局铁塔站位对NMOCs进行采样分析,采样频次为每日5次,采样时间从7:30am到23:00pm间隔2～3h采样1次.天津城区NMOCs的含...