城市污水二级生化出水中溶解性有机物的特性及其深度处理研究

在对某城市污水二级生化出水中溶解性有机物(DOM)特性进行深入分析的基础上,对比了混凝、活性炭吸附、树脂吸附等深度处理工艺对DOM的处理效果。结果表明,水样中溶解性有机碳(DOC)为12.32mg/L,其中疏水性组分占46.65%,亲水性有机物(HPI)占33.33%,过渡亲水性组分占20.02%;酸碱滴定结果表明,HPI的总酸度最强;MIEX树脂对所有组分尤其是疏水性组分的去除效果都较好,它在城市污水二级生化出水(尤其是富含疏水性物质的水体)的深度处理中具有更广阔的应用前景;凝胶渗透色谱分析结果表明,水样中DOM的分子量呈宽分布特征,主要包含平均分子量为230~750u的低分子量小分子有机物,也包含12 000u左右的中等分子量有机物,而经MIEX树脂吸附处理后,分子量在12 000u左右的组分基本去除,分子量在230~750u的组分也有显著的减少。     

臭氧氧化对二级出水有机物(EfOM)特性机制的影响

开展了臭氧氧化对二级出水有机物(effluent organic matter,Ef OM)的去除效能研究,并进一步采用超滤分离、三维荧光光谱等方法,系统研究了不同臭氧投加量下,Ef OM的分子量分布、亲疏水特性以及荧光特性的变化规律。结果表明,臭氧化去除Ef OM的效果有限,但能够有效分解二级出水中具有强烈紫外吸收的有机物。此外,臭氧能优先氧化分解二级出水中大分子有机物,有效提高二级出水的可生化性。臭氧氧化过程中,分子质量(molecular weight,MW)100 k Da的有机物组分被完全氧化分解,10 k DaMW100 k Da和1 k DaMW10 k D的有机物组分含量总体呈下降趋势,而MW1k Da的有机物组分随臭氧投加时间的延长含量不断上升。臭氧化后,Ef OM中疏水组分减少,亲水组分升高;酸性组分减少。随着臭氧投量的增加,蛋白质与腐殖酸类物质的荧光吸收强度迅速下降。     

石化综合污水处理厂出水溶解性微生物产物的特性

溶解性微生物产物(soluble microbial products,SMP)是生化系统出水残留COD的主要组成部分,通过采用分子量截留超滤分离、有机物树脂分离等方法对某石化综合污水处理厂出水SMP的分子量分布、亲水特性进行了分析研究.结果表明,水样中的SMP占出水残留COD的85%左右。SMP中主要成分是蛋白质,出水中小于1 kDa的有机物是SMP中的主要物质。树脂分离实验表明,亲水性有机物和疏水酸性有机物分别约占出水SMP的50%和20%,是需要进一步处理削减的主要物质类别。     

印染废水生化出水中各类有机物在小型活性炭床吸附过程中的去除效果

采用连续流活性炭炭床处理印染废水生化出水,通过XAD-8/XAD-4吸附树脂将印染废水生化出水中的溶解性有机物分为4类:疏水酸、非酸疏水物质、弱疏水物质和亲水物质,采用超滤膜法测定水样的分子量分布,对印染废水生化出水中不同种类以及不同分子量大小的有机物在煤质炭、椰壳炭2种活性炭动态实验处理过程中的去除特性进行研究。实验结果表明,2种活性炭对该水样中的有机物均有明显的去除效果,其中以煤质炭的处理效果较优。煤质炭吸附疏水性和亲水性有机物均有明显的处理效果,对非酸疏水物质和弱疏水有机物的吸附效果较差。煤质炭对分子量<10 k的小分子有机物的吸附效果对实验结果的贡献较大。     

管网末梢水中DOM分布特征及影响因素

为探明长期运行的供水管网末梢出水的溶解性有机物(DOM)分布特征及影响因素,采用三维荧光技术结合平行因子分析法(PARAFAC)对西北某高校管网水质进行了研究,并利用荧光区域积分(FRI)法得到各类DOM占比,通过实验揭示了加氯与DOM的相互关系。结果表明:该区域管网水中DOM主要为溶解性微生物副产物(SMP)、富里酸类(fulvic acid-like)和腐殖酸类(humic acid-like)有机物;DOM平均相对浓度约为2.0×106AU·nm2,其中类蛋白有机物较少,SMP占30%~34%、富里酸类占23%~25%、腐殖酸类占25%~28%;铸铁管出水中SMP总量(80 643 AU·nm2)和占比(34%)比不锈钢管出水中的SMP总量(72 420 AU·nm2)和占比(30%)有所升高;加氯对腐殖质类有机物具有一定的去除效果,且在前10 min内去除率最高。研究结果可为供水管网水质维护和加氯机制提供理论依据。     

铁盐和铝盐混凝对印染废水生化出水中溶解性有机污染物的去除特性

以三氯化铁和硫酸铝为混凝剂,印染废水二级生化出水为研究对象,并利用XAD-8/XAD-4吸附树脂联用技术将印染废水生化出水中溶解性有机物分为疏水酸、非酸疏水物质、弱疏水物质及亲水物质4类有机物,通过小试实验探讨了2种混凝剂对生化出水中各类溶解性有机物的去除效果及特点。实验结果表明,对于该印染废水的生化出水,溶解性有机物的主要成分是疏水性物质,以DOC表征时占总DOC的75%,其中疏水酸约占41%,疏水性物质也是引起色度的主要物质,所占比例以ADMI7.6表征时为89%,其中以非酸疏水物质的贡献最大,达到52%,并且非酸疏水物质中不饱和双键或芳香环有机物的含量较高。在三氯化铁和硫酸铝各自最佳的混凝条件下,均能够有效去除由疏水性物质（疏水酸和非酸疏水物质）引起的色度,但三氯化铁对弱疏水性物质以及亲水物质的去除率高于硫酸铝,这使得三氯化铁对印染废水生化出水中的溶解性有机物的去除效果优于硫酸铝。并且三氯化铁和硫酸铝混凝工艺均能明显降低生化出水的毒性。     

臭氧对化工园区废水厂二级出水的选择性氧化

以化工园区废水厂二级出水作为实验废水,采用臭氧氧化工艺对其进行处理,采用分子量分级、亲疏水性分离和傅里叶红外等手段对臭氧氧化前后水质进行了系统分析。结果表明,在进水COD为126 mg/L,臭氧氧化60 min的条件下,COD和UV254的去除率分别为37.9%和55%;臭氧氧化对水中疏水性物质去除效率高于亲水性物质,部分疏水性物质氧化成亲水性小分子有机物。臭氧氧化可以改变废水中有机物的分子结构,使水中分子量小于1×103k Da的有机物比例从56.3%提高至71.2%,分子量大于1×105k Da的有机物比例由原来的24.2%下降至9.6%。红外光谱分析表明,臭氧氧化具有一定的选择性,可显著去除水中含不饱和键、酚类、醇类等有机物,但对饱和烷烃基本无降解效果。     

臭氧对超滤膜处理钱塘江水中有机物的影响研究

钱塘江水经臭氧化后过超滤膜,考察臭氧对超滤膜过滤地表水中有机物的作用,进而考察其对膜过滤特性的影响。结果表明,钱塘江水中的有机物以小分子、亲水组分为主;臭氧接触时间为20.0min时,膜出水中DOC和UV254的总去除率分别达到39.3%、73.1%;随着臭氧接触时间的增加,膜出水DOC中分子量3ku的有机物所占比例下降,分子量3ku的有机物所占比例几乎不变或稍有升高,膜出水UV_(254)中不同分子量有机物的比例变化与DOC相反;总体看来,投加臭氧使膜出水中强疏水组分的比例下降,弱疏水及亲水组分的比例则有增加趋势。臭氧化可有效缓解膜污染,臭氧接触时间为5.0min时膜污染下降率最大,为75.4%。     

水解酸化+A/O工艺对石化废水不同分子量有机物去除效果评价

对某典型石化企业综合污水处理厂"水解酸化+A/O"处理工艺各单元出水不同分子量区间的有机物含量及光谱特性进行了表征。研究表明,石化企业综合污水处理厂各处理单元出水DOC以分子量1 kDa的有机物为主;处理工艺对废水COD、DOC和UV254的总去除率分别为84.58%、86.22%和72.92%,分子量1 kDa、3~5 kDa、10~30 kDa、30~100 kDa的DOC去除率达90%左右,分子量5~10 kDa和100 kDa的DOC增加了28.57%和43.90%;分子量1 kDa的UV254的去除率为76.27%;水解酸化池对分子量30~100 kDa的有机物去除率达90.87%,缺氧段对分子量1~3 kDa的DOC去除率达92.86%,缺氧出水分子量3~10 kDa和30~100 kDa的DOC浓度较水解酸化出水有较大增加,好氧段对缺氧段出水中分子量30~100 kDa、5~10 kDa和3~5 kDa的有机物有很好的去除作用,去除率分别为80.85%、43.46%和72.32%,而分子量1~3 kDa的DOC浓度有所增加。各出水在260~270 nm有紫外吸收峰。各分子量区间DOC的SUVA值随处理工艺沿程增大,废水有机物芳香度提高,UV253/UV203呈减小趋势。     

生活污水的臭氧深度处理及其急性毒性

以生活污水处理厂二级生物处理出水为研究对象,利用固相萃取、吸附树脂层析等手段,研究了臭氧氧化过程中进出水及不同分级组分的发光细菌急性毒性的变化,揭示了无机离子浓度对臭氧氧化出水急性毒性的影响,并采用三维荧光光谱对急性毒性相关的物质组分进行了解析。结果表明,在反应时间为15 min,臭氧投加速率为2.1 mg·(L·min)-1,臭氧氧化出水的急性毒性明显下降,出水的急性毒性仅为进水的24.7%。水样不同分级组分的生物毒性测试结果显示,生物处理出水中的亲水性物质和疏水中性物质分别贡献了44.6%和27.8%的毒性当量。当生物处理出水的氯离子含量为75~400 mg·L~(-1)时,经臭氧氧化后,出水的急性生物毒性与氯离子浓度成正相关关系,当生物处理出水的硫酸根离子和硝酸根离子含量分别在150~300 mg·L~(-1)和20~110 mg·L~(-1)变化时,经臭氧氧化后,出水的急性生物毒性变化不大,结合三维荧光光谱的分析结果,臭氧氧化出水中急性毒性物质可能主要存在于芳香族蛋白质类似物(Ⅱ区)和类腐殖酸类物质(Ⅴ区)中。     

硅藻土强化混凝去除微污染原水中的有机物

研究了联用硅藻土与聚合氯化铝（PAC）强化混凝对有机微污染原水中不同性质溶解性有机物的去除效果。采用超滤膜和XAD系列树脂对微污染原水中溶解性有机物进行分级表征,物理分级表明分子量〈4 kD的溶解性有机物占50%以上,化学分级表明原水中以憎水酸（HoA）和亲水物质（HiM）为主。硅藻土助凝去除溶解性有机物,实验结果表明,当PAC投加量30 mg/L,硅藻土投加量0.5 g/L时,溶解性有机碳去除率由22.5%提高到26.3%。     

Isolation and characterization of dissolved organic matter fractions from antialgal products of Microcystis aeruginosa

An antialgal bacterium, Streptomyces sp. HJC-D1, was applied for the biodegradation of cyanobacterium Microcystis aeruginosa, and the isolation and characterization of dissolved organic matter (DOM) fractions in antialgal products were studied. Results showed the the growth of M. aeruginosa was significantly inhibited by the cell-free filtrate of Streptomyces sp. HJC-D1 with the growth inhibition of 86?±?7 %. The antialgal products were divided using resin adsorbents into the hydrophilic fraction (HPI), hydrophobic acid (HPO-A), transphilic acid (TPI-A), hydrophobic neutral and transphilic neutral, and then the five fractions were analyzed by the 3-D fluorescence spectroscopy, gel permeation chromatography, and Fourier transform infrared spectroscopy. The results indicated that the HPI component was the most abundant DOM fraction in the antialgal products, and its concentration was increased with the increase of cell-free filtrate concentration. The fluorescence peak location and intensity analysis showed that the protein-, fulvic-, and humic-like substances were dominant in the HPI, HPO-A, and TPI-A fractions, and intensities of the relevant fluorescence peaks were stronger in the experimental groups than those of the control groups. It was also found that the number-average molecular weight of DOM fractions ranged from 245 to 1,452 g mol^?1, and thereinto organic acids such as HPO-A and TPI-A exhibited lower molecular weights.     

不同超滤膜过滤天然有机物的膜污染特性研究

超滤膜的截留分子量、天然有机物的分子量分布以及两者之间的相对关系对于膜污染以及过滤阻力的组成有很大的影响。MWCO140kDa、70kDa、30kDa、10kDa、4kDa和1kDa的超滤膜过滤10mg/L腐殖酸溶液和未名湖湖水的试验结果表明,在过滤初始时刻就发生了膜污染,膜的截留分子量越大,膜污染越显著。在长期过滤的过程中,截留分子量>10kDa的超滤膜的过滤阻力受到膜污染的控制,膜孔堵塞和膜面形成凝胶层是造成膜污染的主要原因;当膜的截留分子量≤10kDa时,过滤阻力主要由膜本身固有的阻力决定,膜污染影响较小。不同浓度、类型的腐殖酸溶液和不同种类的超滤膜过滤试验数据分析表明,当膜对腐殖酸分子的截留率超过40%时,膜污染的程度会逐渐减小,过滤阻力将由膜本身固有的阻力控制。     

Removal of humic acid using TiO2 photocatalytic process--fractionation and molecular weight characterisation studies

The photocatalytic removal of humic acid (HA) using TiO₂ under UVA irradiation was examined by monitoring changes in the UV₂₅₄ absorbance, dissolved organic carbon (DOC) concentration, apparent molecular weight distribution, and trihalomethane formation potentials (THMFPs) over treatment time. A resin fractionation technique in which the samples were fractionated into four components: very hydrophobic acids (VHA), slightly hydrophobic acids, hydrophilic charged (CHA) and hydrophilic neutral (NEU) was also employed to elucidate the changes in the chemical nature of the HA components during treatment. The UVA/TiO₂ process was found to be effective in removing more than 80% DOC and 90% UV₂₅₄ absorbance. The THMFPs of samples were decreased to below 20 μg l⁻¹ after treatments, which demonstrate the potential to meet increasingly stringent regulatory level of trihalomethanes in water. Resin fractionation analysis showed that the VHA fraction was decreased considerably as a result of photocatalytic treatments, forming CHA intermediates which were further degraded with increased irradiation time. The NEU fraction, which comprised of non-UV-absorbing low molecular weight compounds, was found to be the most persistent component.     

A fingerprint analysis method for characterization of dissolved organic matter in secondary effluents of municipal wastewater treatment plant

Dissolved organic matter (DOM) in wastewater and reclaimed water is related to water quality, safety, and treatability. In this study, DOM was characterized through a fingerprint analysis method for DOM characterization using resin fractionation followed by size exclusion chromatography (SEC). Resin fractionation was used in the first step to divide the DOM in water samples into six resin fractions, namely, hydrophobic acids (HOA), hydrophobic bases (HOB), hydrophobic neutrals (HON), hydrophilic acids (HIA), hydrophilic bases (HIB), and hydrophilic neutrals (HIN). SEC analysis was then performed to separate each resin fraction into several (n) subfractions with different molecular weights (MW). Thus, the total DOM in the water sample was fractionated into 6n subfractions. After quantification of each subfraction by dissolved organic carbon (DOC), a fingerprint graph was constructed to express the distribution of DOM in the subfractions. The fingerprint analysis method was applied to a secondary effluent sample during ozonation. Ozonation (dose of 10 mg L^?1) removed the DOC only by 8 % and reduced UV₂₅₄ of the sample by 36 %. Fingerprint graphs also revealed that the resin fractions changed quite limitedly but transformation of subfractions occurred notably.     

Fluorescence spectroscopic characterization of DOM fractions isolated from a filtered river water after ozonation and catalytic ozonation

Fluorescence spectra were applied to investigate the structural changes of four dominant dissolved natural organic matter (DOM) fractions of a filtered river water before and after ozonation and catalytic ozonation. The ozonation and catalytic ozonation with synthetic goethite (FeOOH) and cerium dioxide (CeO(2)) were carried out under normal conditions, i.e. pH 7, reaction time of 10 min, and ozone/DOC ratio of about 1. The fluorescence spectra were recorded at both excitation-emission matrix (EEM) and synchronous scanning modes. EEM results reveal that ozonation of these DOM fractions causes a significant decrease of the aromaticity of humic-like structures and an increase of electron withdrawing groups, e.g., carboxylic groups. The catalysts can further improve the destruction of the humic-like structures in catalytic ozonation. Synchronous spectra reveal that ozonation of hydrophobic acid and hydrophilic acid (HIA) yields a significant amount of by-products with low aromaticity and low molecular weight. Catalytic ozonation enhances substantially the formation of these by-products from HIA and improves the destruction of highly polycyclic aromatic structures for all examined DOM fractions.     

Chemical characteristics of chromophoric dissolved organic matter in rainwater

Proton nuclear magnetic resonance (¹H-NMR), UV absorbance and excitation-emission matrix (EEM) fluorescence spectroscopy were used to define the chemical characteristics of chromophoric dissolved organic matter (CDOM) in whole and C₁₈ extracted rainwater. The average total recovery of fluorescence determined from the sum of extract and filtrate fractions relative to the whole was 86% suggesting that 14% of fluorescent CDOM in rainwater is comprised of very hydrophobic material that cannot be eluted from the column. Half the fluorescence of rainwater was recovered in the filtrate fraction which is important because it suggests that 50% of the chromophoric material present in precipitation is relatively hydrophilic. The average spectral slope coefficient was smaller in extracted samples (16.3 ± 9.0 μm^?1) relative to whole samples (18.9 ± 2.8 μm^?1) suggesting that the extracted material contains larger molecular weight material. Approximately one-third of the total dissolved organic carbon (DOC) in rainwater exists in the extract fraction suggesting that a large percentage of the uncharacterized DOC in rainwater can be accounted for by these hydrophobic macromolecular species. The fluorescence of extracted samples is strongly correlated with total NMR integration and is most sensitive to aromatic protons suggesting that molecules in this region are the most important in controlling the optical properties of rainwater. The lower removal efficiency of CDOM in rainwater relative to surface waters or the water-soluble fraction of aerosols during solid phase extraction (SPE) suggests that rainwater contains significantly more hydrophilic chromophoric compounds which are compositionally different than found in these other aquatic matrices.     

不同工艺对含高浓度腐殖酸地下水处理的可行性

针对内蒙古农村地区高腐殖酸地下水的处理问题,分别对（pH调节）-PAC强化混凝、高锰酸钾预氧化／混凝、活性炭吸附／混凝、Fenton氧化等技术处理的可行性进行了研究,同时利用三维荧光和高效体积排阻色谱分析处理前后水中有机物的组成变化特征。有机分析结果显示,水中的有机物为腐殖酸类物质,分子量分别为1600和3500,腐殖酸类物质为水中色度的主要贡献者。原水PAC强化混凝、高锰酸钾预氧化／PAC混凝对有机物的去除效果不佳,处理前后水样DOC浓度无明显变化,而pH调节．PAC强化混凝、微米活性炭吸附和Fenton氧化均能有效去除有机物。将原水pH调节至6．5,经300mg／LPAC混凝后出水DOC降至5．99mg／L。活性炭投加量为0．6g／L时,DOC降至7．6mg／L,然后采用60mg／LPAC混凝出去高度分散而不易沉降的小颗粒活性炭。此外,当反应初始pH值为3,过氧化氢投加量为0．5％（v／v）,亚铁和双氧水摩尔比为0．05时,出水DOC降至5．6mg／L,氧化后有小分子有机物生成。     

Comprehensive characterization of oil refinery effluent-derived humic substances using various spectroscopic approaches

Refinery effluent-derived humic substances (HS) are important for developing refinery effluent reclamation techniques and studying the environmental chemistry of wastewater effluents. In this study, dissolved organic matter (DOM) from refinery effluent was concentrated using a portable reverse osmosis (RO) system. HS were isolated from RO retentates with XAD-8 resin. A variety of approaches such as specific UV absorbance at 254nm (SUV(254)), elemental analysis, size exclusion chromatography (SEC), solid-state cross polarization magic angle spinning (13)C nuclear magnetic resonance spectrometry ((13)C CPMAS NMR), Fourier transform infrared spectrometry (FTIR), and electrospray ionization/ion trap/mass spectrometry (ESI/ion trap/MS) were employed for characterization of HS. The portable RO system exhibited high yield and recovery of DOM for concentrating refinery effluent. The concentration of dissolved organic carbon (DOC) in the refinery effluent was 9.9mg/l, in which humic acids (HA) and fulvic acids (FA) accounted for 2.3% and 34.6%, respectively. Elemental and SUV(254) analyses indicated relative high amounts of aliphatic structures and low amounts of aromatic structures in refinery effluent-derived HS. Refinery effluent-derived HS displayed lower molecular weight than natural HS. The number-average molecular weight (M(n)) and the weight-average molecular weight (M(w)) of HA were 1069 and 2934, and those of FA were 679 and 1212 by SEC, respectively. By ESI/ion trap/MS, the M(n) and the M(w) of FA were 330 and 383. Four kinds of carbon structures (aliphatic, aromatic, heteroaliphatic, and carboxylic carbons) were found in refinery effluent-derived HS by (13)C NMR analysis. The quantitative results support the interpretation that these HS are rich in aliphatic carbons and poor in aromatic carbons. Proteinaceous materials were identified by FTIR analysis in refinery effluent-derived HS.