Effect of a seasonal di use pollution migration on natural organic matter behavior in a stratified dam reservoir

This article aims to describe the influence of di use pollution on the temporal and spatial characteristics of natural organic matter (NOM) in a stratified dam reservoir, the Daecheong Dam, on the basis of intensive observation results and the dynamic water quality simulation using CE-QUAL-W2. Turbidity is regarded as a comprehensive representation of allochothonous organic matter from di use sources in storm season because the turbidity concentration showed reasonable significance in a statistical correlation with the UV absorbance at 254 nm and total phosphorus. CE-QUAL-W2 simulation results showed good consistency with the observed data in terms of dissolved organic matter (DOM) including refractory dissolved organic carbon (RDOC) and labile DOC and also well explained the internal movement of constituents and stratification phenomenon in the reservoir. Instead turbidity and NOM were related well in the upper region of the reservoir according to flow distance, gradually as changing to dissolved form of organic matter, RDOM a ected organic matter concentration of reservoir water quality compared to turbidity. To control the increase of soluble organic matters in the dam reservoir, appropriate dam water discharge gate operation provided e ective measurement. Because of the gate operation let avoid the accumulation of organic matter within a dam reservoir by shorten of turbid regime retention time.     

臭氧预氧化对芘在天然有机物中分配行为的影响

以疏水性有机物——芘为代表,考察了臭氧预氧化处理对高稳定性有机污染物在天然有机物(NOM)中分配行为的影响.结果表明,芘在不同性质NOM中分配系数(K_oc)的大小与NOM中芳香结构和疏水基团含量有关,芘在液相、吸附相NOM中的分配行为受NOM自身特性、吸附性能及吸附剂表面有机碳覆盖率(f_oc)大小的影响.臭氧预氧化能够破坏NOM中的芳香结构和疏水结构,削弱NOM与芘之间的相互作用,降低芘的Koc,臭氧预氧化对吸附相NOM疏水结构的破坏是造成芘在吸附相NOM中分配能力降低的主要原因.     

Characteristics of natural organic matter affect sorption of organic contaminants

Several soil samples were used to study how the characteristics of natural organic matter (NOM) affect sorption of organic compounds. These soils contains different amounts and types of NOM. Aromaticity of NOM (percentage of aromatic carbons) was determined from solid-state CPMAS 13C NMR spectra and the soil effective polarity was computed from the equation developed by Xing et al. Naphthalene was used to examine the sorption characteristics of NOM. Both aromaticity and polarity of NOM strongly affected sorption of naphthalene. Old NOM showed higher affinity than that in the surface, young soils. Sorption increased with increasing aromaticity and decreasing polarity. Thus, the sorption coefficients of organic contaminants cannot be accurately predicted without some consideration of NOM characteristics.     

Effects of artificially induced complete mixing on dissolved organic matter in a stratified source water reservoir

Naturally complete mixing promotes the spontaneous redistribution of dissolved oxygen(DO), representing an ideal state for maintaining good water quality, and conducive to the biomineralization of organic matter. Water lifting aerators(WLAs) can extend the periods of complete mixing and increase the initial mixing temperature. To evaluate the influence of artificial-induced continuously mixing on dissolved organic matter(DOM) removal performance, the variations of DOM concentrations, optical cha...     

Characteristics of the natural organic matter sorption affects of organic contaminants

Several soil samples were used to study how the characteristics of natural organic matter(NOM)affect sorption of organic compounds.These soils contains different amounts and types of NOM.Aromaticity of NOM(percentage of aromatic carbons)was determined from solid-state CPMAS^13 C NMR spectra and the soil effective polarity was computed from the equation developed by Xing et al.Naphthalene was used to examine the sorption characteristics of NOM.Both aromaticity and polarity of NOM strongly affected sorption of naphthalene.Old NOM showed higher affinity than that in the surface,young soils.Sorption increased with increasing aromaticity and decreasing polarity.Thus,the sorption coefficients of organic contaminants cannot be accurately predicted without some considerstion of NOM characteristics.     

Characteristics of the natural organic matter sorption affects of organic contaminants

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水中天然有机物的臭氧强化光催化降解研究

研究了饮用水源中大分子天然有机物（NOM）的臭氧强化光催化降解,考察了臭氧投加量、反应时间和HCO3^-浓度对NOM降解速率的影响;分析了臭氧强化光催化过程中NOM相对分子质量的变化,并比较不同相对分子质量大小NOM的降解速率.研究结果表明,臭氧强化光催化比单独臭氧氧化、光催化能更有效地降解NOM,同时增加臭氧投加量和反应时间才能有效提高臭氧强化光催化对TOC的去除率,而单独增加臭氧投加量可显著提高生物可降解性;HCO3^-显著降低光催化的降解效果,臭氧强化光催化能有效地减弱HCO3^-的不利影响;臭氧强化光催化过程中大分子NOM分解为小分子,SUVA值迅速下降,且相对分子质量越大矿化速度越快.     

天然有机质模型化合物分子结构对碳纳米管分散性的影响

研究了不同分子结构的天然有机物质（NOM）模型化合物单宁酸（TA）、没食子酸（GA）和十二烷基苯磺酸钠（SDBS）对碳纳米管（CNTs）分散性的影响.通过计算得出,TA的临界胶束浓度（CMC）为1.12mmol/L,SDBS的CMC为0.24mmol/L,GA在所测试的浓度范围内没有形成胶束.比较NOM在CNTs表面的吸附过程和CNTs的分散过程,表明空间位阻和胶束包裹是2个促进CNTs分散的主要机理.借助透射电子显微镜（TEM）和测量悬浮的CNTs的平均流体动力学直径（DLS）结果表明,TA在较少的固相吸附量（S_e ≈ 0.01mmol/g）就能使CNTs分散,归因于其吸附后刚性芳香三维结构的TA能形成的较大空间位阻;同样具有芳香平面结构的GA分子在CNTs表面的吸附需要达到一定的厚度（S_e > 0.2mmol/g）,才能有效地分散CNTs;具有烷基脂肪链的SDBS,需要在形成半胶束或胶束后（S_e > 0.13mmol/g） CNTs才能有效地被分散.芳香族刚性结构和脂肪族柔性结构的模型化合物对CNTs的分散效果和机理存在较大的差别.     

天然太阳辐射作用下冰体中溶解性有机物组分的光降解

利用XAD树脂对沈阳市细河河水中的溶解性有机物(DOM)进行分级分离.按照DOM在XAD树脂上的吸附特性将其分为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).研究了天然太阳辐射作用下冰体中DOM组分的光降解特性.结果表明:太阳辐射作用下,冰体中的5种DOM组分均会发生光降解,其中HPO-A的光降解程度最高.光照80 h后,冰体中HPO-A、HPO-N、TPI-A、TPI-N和HPI的UV-254去除率分别为43.4%、44.15%、45.9%、55.0%和58.8%.光降解作用对冰体中的荧光物质具有显著的去除效果.除了HPO-A中的类芳香族蛋白质荧光物质(Ⅰ)之外,DOM组分中的各类荧光物质的光降解程度均高于以DOC表征的整体有机物的光降解程度.光降解对DOM组分中类富里酸荧光物质和类腐殖酸荧光物质的去除效果优于对类溶解性微生物代谢产物荧光物质和类芳香族蛋白质荧光物质的去除效果.在冰体中DOM组分的光降解过程中,既发生THMs前体物的去除,也发生THMs前体物的生成.光降解使HPO-A中THMs前体物的量减少,使TPI-N中THMs前体物的量增加,而其他3种组分中THMs前体物的量的变化与光照时间有关.     

有机质和阳离子对氧化石墨烯团聚行为的影响

利用动态光散射技术分别考察了3种天然有机质（NOM）及其浓度和阳离子对纳米氧化石墨烯（GO）在水环境中团聚动力学的影响.无NOM存在时,GO团聚行为符合经典的Derjaguin-Landau-Verwey-Overbeek（DLVO）理论和舒尔采-哈迪准则.Na⁺溶液中,NOM显著增强GO稳定性,顺序为腐殖酸（HA） > 富里酸（FA） > 海藻酸钠（SA）,这主要是由于HA在GO之间产生了更强的空间位阻斥力.以HA为代表性有机质,2mg/L HA对GO在水溶液中的稳定性还受阳离子种类的影响：HA增强了GO在Na⁺和Mg²⁺溶液中的稳定性,然而对GO在Ca²⁺溶液中的稳定性几乎没有影响.提高HA浓度为5mg/L时：高浓度Mg²⁺溶液中,HA的盐析效应使得其未促进GO稳定性;Ca²⁺溶液中,HA与Ca²⁺发生了较强的桥联作用,使得HA促进了GO的团聚.     

分层水库温度梯度对扬水曝气原位控藻效果的影响

基于计算流体力学(CFD)方法,数值模拟了不同温度梯度条件下扬水曝气器外围流场及藻类浓度场,并与实际工程运行数据进行对比.当水深为80m、水面下30m内的温度梯度从0.17℃/m增加到0.73℃/m时,核心控藻区域的半径从100m增加到150m,控藻区域百分比从25.16%增大到28.60%,藻类完全混合的时间分别从16d增加到24d.在稳定条件下,藻类在补偿点以下的停留时间均大于48h,基本不受温度梯度的影响,藻类生长受抑制.藻类浓度模拟结果与实际工程运行结果吻合良好.推荐水库中扬水曝气器合理设计间距为250m.     

某污染场地地下水中溶解性有机质组成特征及其自然衰减指示作用

溶解性有机质（DOM）影响着地下水中污染物的降解转化行为,其结构组成的变化可以反映外来污染物的迁移转化过程。以山东某污染场地地下水为研究对象,利用三维荧光光谱（EEM）、同步荧光光谱（SFS）和荧光区域体积积分法（FRI）分析研究区地下水DOM的组成及结构变化规律,并结合自然衰减能力评估方法——水文地球化学指标分析方法和微生物学分析方法探讨DOM光谱信息对地下水有机污染自然衰减效果的指示作用。结果表明：在地下水有机污染持续存在和长期的微生物作用下,地下水DOM中类腐殖质和类蛋白物质组分含量均增加,随着生物降解作用越来越强烈,DOM中类蛋白物质占比逐渐升高。基于FRI分区理论,提出可用特定荧光分区相对含量比〔P_(Ⅰ+Ⅱ)/P_Ⅴ〕,即类蛋白物质与类腐殖质物质的相对含量比,作为快速判断地下水有机污染自然衰减生物作用效果的代替表征指标,P_(Ⅰ+Ⅱ)/P_Ⅴ越大,表明自然衰减中的生物降解作用越强。

     

有机物对ANAMMOX反应器运行性能的影响

研究了有机物对ANAMMOX反应器运行性能的影响.在没有有机物的条件下,进水基质(氨氮和亚硝氮)浓度为70～280 mg·L-1,容积总氮负荷为0.29～0.72 kg·m-3·d-1,氨氮去除率86.0%～99.7%,亚硝氮去除率88.7%～99.3%.添加有机物(酵母膏100 mg·L-1)后,ANAMMOX反应器运行性能与容积总氮负荷有关.容积总氮负荷低于0.43 kg·m-3·d-1时,有机物对ANAMMOX反应器运行性能的影响较小,氨氮和亚硝氮去除率保持在94%以上;但当容积总氮负荷为0.72 kg·m-3·d-1时,有机物对ANAMMOX反应器运行性能产生严重影响,氨氮和亚硝氮去除率降至75%以下.停止添加有机物并降低容积总氮负荷,可在短期内消除有机物对ANAMMOX反应器运行性能的影响.     

Molecular characterization of effluent organic matter in secondary effluent and reclaimed water: Comparison to natural organic matter in source water

Municipal wastewater reclamation is becoming of increasing importance in the world to solve the problem of water scarcity. A better understanding of the molecular composition of effluent organic matter(Ef OM) in the treated effluents of municipal wastewater treatment plants(WWTPs) is crucial for ensuring the safety of water reuse. In this study, the molecular composition of Ef OM in the secondary effluent of a WWTP in Beijing and the reclaimed water further treated with a coagulation–sedimentation–ozonation process were characterized using a non-target Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS) method and compared to that of natural organic matter(NOM) in the local source water from a reservoir. It was found that the molecular composition of Ef OM in the secondary effluent and reclaimed water was dominated by CHOS formulas, while NOM in the source water was dominated by CHO formulas. The CHO formulas of the three samples had similar origins. Anthropogenic surfactants were responsible for the CHOS formulas in Ef OM of the secondary effluent and were not well removed by the coagulation-sedimentation-ozonation treatment process adopted.     

Membrane flux dynamics in the submerged ultrafiltration hybrid treatment process during particle and natural organic matter removal

Exponential relationship was developed to quantify the normalized membrane flux dynamics during the filtration period and fitted the results well.     

Natural organic matter quantification in the waters of a semiarid freshwater wetland (Tablas de Daimiel, Spain)

Dissolved organic matter (DOM) concentrations have been measured in the waters of a semiarid freshwater wetland, the Tablas de Daimiel, Spain, when the system-characterised by variable hydroperiodicity conditions, was completely flooded (February 2011). Fluxes of DOM from the wetland soils to the overlying waters were measured by using a passive diffusion sampler (peeper). Not only dissolved organic carbon (DOC) concentrations were measured but refractory organic matter (ROM, usually known as humic substances) was also quantified using a novel voltammetric method. Fluorescence spectra were recorded to help in selecting the appropriate standard for ROM quantification, test the homogeneity of DOM in the waters and get an indication of their source. The results obtained show a 7-fold increase in measured ROM concentrations from the Gigu¨ela River to the outlet, which points to a net exportation of ROM from the wetland and to the existence of an internal source of ROM in the system, probably diffusion from the wetland soils. This hypothesis is confirmed by the flux of ROM from the soils to the water column measured with the peeper and by the common fluorescence characteristics of column and interstitial waters. The smaller increase in DOC concentrations along the wetland, in spite of the higher DOC fluxes from soils, suggests that there is significant turnover of organic carbon (OC) in the water column. The system acts as a major carbon sink but, when flooded, exports OC as DOM.     

两个水库型湖泊中溶解性有机质三维荧光特征差异

应用三维荧光光谱技术(3D-EEM),研究了两个典型水库型湖泊(长寿湖和大洪海)水体中溶解性有机质(DOM)的荧光光谱特征,结合沿岸生态系统差异,讨论其对两个湖泊中DOM性质及来源的影响.结果表明,沿岸生态系统的差异性(尤其是人为干扰)是导致两个水体DOM地球化学特征存在明显差异的重要原因.两湖水体中DOM均存在4个荧光峰,且长寿湖样本中类蛋白物质含量更高;而大洪海水体中腐殖化程度较高的组分(C峰)含量较高.相关性分析表明,两湖DOM样本中类蛋白和类腐殖组分来源不同,而A、C峰代表的类腐殖组分存在共源性.通过荧光参数分析显示,沿岸以森林系统为主的大洪海水体DOM陆源性更强,腐殖化程度高;而长寿湖受两岸农田、果园的输入以及人为排放影响,其水体DOM具有明显的自生源特征,新生DOM含量较高,其荧光特征也反映了该区域水体受人为干扰较大.与其他不同湖泊对比,进一步表明沿岸生态系统类型及人为土地利用是决定水体DOM来源和特性的关键因素.     

Effects of pre-ozonation on organic matter removal by coagulation with IPF-PACI

Ozone plays an important role as a disinfectant and oxidant in potable water treatment practice and is increasingly being used as a pre-oxidant before coagulation. The purpose of this study is to obtain insight into the mechanisms that are operative in pre-ozonized coagulation. Effects ofpre-ozonation on organic matter removal during coagulation with IPF-PAC1 were investigated by using PDA （photometric disperse analysis）, apparent molecular weight distribution and chemical fractionation. The dynamic formation of flocs during coagulation process was detected. Changes of aquatic organic matter （AOM） structure resulted from the influence of pre-ozonation were evaluated. Results show that dosage of O3 and characteristics of AOM are two of the major factors influencing the performance of O3 on coagulation. No significant coagulation-aid effect of O3 was observed for all experiments using either A1C13 or PAC1. On the contrary, with the application of pre-ozonation, the coagulation efficiency of A1C13 was significantly deteriorated, reflected by the retardation of floc formation, and the removal decreases of turbidity, DOC, and UV254. However, if PACl was used instead of AlCl3, the adverse effects of pre-ozonation were mitigated obviously, particularly when the O3 dosage was less than 0.69 （mg O3/mg TOC）. The difference between removals of UV254, and DOC indicated that pre-ozonation greatly changed the molecular structure of AOM, but its capability of mineralization was not remarkable. Only 5% or so DOC was removed by pre-ozonation at 0.6--0.8 mg/L alone. Fractionation results showed that the organic products of pre-ozonation exhibited lower molecular weight and more hydrophilicity, which impaired the removal of DOC in the following coagulation process.     

Atomic force microscopy study on the microtopography of natural organic matter and newly formed hydrous MnO2

To understand the water purification mechanism of potassium permanganate as a coagulation-aid during the preoxidation process, the microtopography of its reductive products, the newly formed hydrous manganese dioxide and the aged hydrous manganese dioxide, was investigated. The morphology of natural organic matter (NOM) adsorbed by the newly formed hydrous manganese dioxide was also compared with that of NOM alone. By using the tapping mode atomic force microscopy (AFM), the observation results show that the newly formed hydrous manganese dioxide possess a perforated sheet (with a thickness of 0–1.75 nm) as well as some spherical particle structures compared with the hydrous manganese dioxide with 2 h aging time, which demonstrated that the newly formed hydrous manganese dioxide had a large surface area and adsorption capacity. When 1 mmol/L newly formed hydrous manganese dioxide was added, the microtopography of NOM molecules shifted from a loosely dispersed pancake shape (with adsorption height of 5–8.5 nm) to a densely dispersed and uniform spherical structure. These results provide a valid proof that it is the perfect adsorption capability of the newly formed hydrous manganese dioxide that might result in the coagulation aid effect of potassium permanganate preoxidation. Translated from Environmental Science, 2006, 27(5): 945–949 [译自: 环境科学]     

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.