不同预氧化剂对长江原水氯(胺)化DBPs生成潜能的影响

以取自上海市杨树浦水厂的长江原水为研究对象,对比分析了3种常见预氧化剂二氧化氯(ClO2)、高锰酸钾(KMnO4)及氯(Cl2)预氧化对削减氯化和氯胺化消毒副产物(DBPs)生成潜能的效果情况.氯化培养实验结果表明,3种预氧化剂的处理对DBPs总量的去除效果均不显著,经ClO2、Cl2及KMnO4作用后可分别削减8.4%、5.7%及3.9%,效果为ClO2>Cl2>KMnO4.对于长江原水使用氯化消毒时,采用ClO2作为预氧化剂可取得对消毒副产物较好的去除效果.氯胺化培养实验结果表明,3种预氧化剂处理对长江原水氯胺化DBPs的生成潜能影响有较大差异,经ClO2和KMnO4作用后可分别削减18.1%及4.1%,而预氯化后则增高12.3%,对于长江原水使用氯胺化消毒时,采用ClO2作为预氧化剂可取得对消毒副产物较为明显的去除效果.同时,应尽量避免使用预氯化后加氯胺化的组合,以防止在水处理过程中生成更多的DBPs而影响出水水质.     

黄河原水中消毒副产物前体物的组成特征及其化学预氧化处理效果对比

以取自河南省郑州市石佛原水厂的黄河原水为研究对象,系统研究了原水中消毒副产物(DBPs)前体物的组成规律,对比分析了3种预氧化剂(高锰酸钾、自由氯和二氧化氯)对原水中DBPs生成潜能的消减规律.试验结果表明:原水中DBPs的前体物均以小分子有机物和疏水性组分(52.51%)为主;分子量小于1 k Da有机物组分是生成含氮消毒副产物(N-DBPs)和三卤甲烷(THMs)的主要前体物;疏水性有机物是生成THMs的主要前体物,亲水性有机物是生成N-DBPs的主要前体物.经Cl2预氧化后,直接生成的DBPs随着自由氯投加量的增加而增加,Cl O2和KMn O4预氧化直接增加DBPs产生量.经3种预氧化剂氧化后,原水中三卤甲烷生成潜能(THMFP)均呈现一定的下降,其降低量依次为Cl O2Cl2KMn O4;然而3种预氧化剂都不能有效的减少含氮消毒副产物生成潜能(N-DBPFP),Cl O2预氧化和Cl2预氧化可增加N-DBPs生成潜能,尤其在较高投加量下,Cl2预氧化将大大增加N-DBPs生成潜能.为有效消减总DBPs生成潜能,水厂可优先采用KMn O4或Cl O2作为预氧化剂处理引黄水库或沉砂池水.     

Characterization of chlorine dioxide as disinfectant for the removal of low concentration microcystins

Microcystins, which represents one kind of cancerogenic organic compounds, is abundant in eutrophication water. The effects of reaction factors on chlorine dioxide (ClO₂) for removal of low-concentration Microcystin-LR, Microcystin-RR, and Microcystin-YR in water as well as the reaction mechanisms was investigated by using enzyme-linked immunosorbent assay (ELISA) kit and gas chromatography-mass spectrometry (GC-MS). The results showed that MC-LR, MC-RR, and MC-YR could be efficiently decomposed by ClO₂. The degradation efficiency was shown positively correlated to the concentration of ClO₂ and reaction time; while the effect of reaction temperature and pH is slight. The kinetic constants and activation energies of the reaction of MC-LR, MC-RR, and MC-YR with ClO₂ are determined as 459.89, 583.15, 488.43 L·(mol·min)⁻¹ and 64.78, 53.01, 59.15 kJ·mol⁻¹, respectively. As indicated by high performance liquid chromatography mass spectrometer (HPLC-MS) analysis, degradation should be accomplished via destruction of Adda group by oxidation, with the formation of dihydroxy substituendums as end products. This study has provided a fundamental demonstration of ClO₂ serving as oxidizing disinfectant to eliminate microcystins from raw water source.     

ClO2消毒工艺对污水处理厂出水超级耐药基因的影响

为了研究二氧化氯（chlorine dioxide,ClO₂）消毒工艺对污水处理厂出水中超级耐药基因（super antibiotic resistance genes,SARGs）的去除效果,对污水处理厂出水消毒前后的水样进行了全年采集,并采用微孔滤膜正压过滤法及核酸吸附柱-洗脱法分别富集水中细菌和胞外核酸后,利用荧光定量PCR技术对其中的9种SARGs进行定量检测.结果表明,无论是胞内还是胞外核酸,均有NDM-1、MCR-1 和MEC-A被检测出;同时,ClO₂消毒后上述3种SARGs的胞内相对总浓度明显上升（P<0.05）,且ClO₂消毒对胞内SARGs相对浓度的影响与季节有关,其中春季、夏季和秋季均发生上升,且春季升高最为明显,达2倍,而冬季出水在消毒前后均未测出胞内SARGs;胞外SARGs则在ClO₂消毒前后没有明显浓度变化.因此,ClO₂消毒不能有效去除污水处理厂出水中胞内和胞外SARGs污染.     

The contribution of mediated oxidation mechanisms in the electrolytic degradation of cyanuric acid using diamond anodes

In this work, the contribution of mediated oxidation mechanisms in the electrolytic degradation of cyanuric acid using boron-doped diamond(BDD) anodes was investigated in different electrolytes. A complete mineralization of cyanuric acid was obtained in Na Cl;however lower degrees of mineralization of 70% and 40% were obtained in Na2SO4 and Na Cl O4, respectively. This can be explained by the nature of the oxidants electrogenerated in each electrolyte. It is clear that the contribution of active chlorine(Cl2, HCl O, Cl O-)electrogenerated from oxidation of chlorides on BDD is much more important in the electrolytic degradation of cyanuric acid than the persulfate and hydroxyl radicals produced by electro-oxidation of sulfate and water on BDD anodes. This could be explained by the high affinity of active chlorine towards nitrogen compounds. No organic intermediates were detected during the electrolytic degradation of cyanuric acid in any the electrolytes, which can be explained by their immediate depletion by hydroxyl radicals produced on the BDD surface. Nitrates and ammonium were the final products of electrolytic degradation of cyanuric acid on BDD anodes in all electrolytes. In addition, small amounts of chloramines were formed in the chloride medium. Low current density(≤ 10 m A/cm2) and neutral medium(p H in the range 6–9) should be used for high efficiency electrolytic degradation and negligible formation of hazardous chlorate and perchlorate.     

Biomass-based carbon capture and utilization in kraft pulp mills

Corporate image, European Emission Trading System and Environmental Regulations, encourage pulp industry to reduce carbon dioxide (CO₂) emissions. Kraft pulp mills produce CO₂ mainly in combustion processes. The largest sources are the recovery boiler, the biomass boiler, and the lime kiln. Due to utilizing mostly biomass-based fuels, the CO₂ is largely biogenic. Capture and storage of CO₂ (CCS) could offer pulp and paper industry the possibility to act as site for negative CO₂ emissions. In addition, captured biogenic CO₂ can be used as a raw material for bioproducts. Possibilities for CO₂ utilization include tall oil manufacturing, lignin extraction, and production of precipitated calcium carbonate (PCC), depending on local conditions and mill-specific details. In this study, total biomass-based CO₂ capture and storage potential (BECCS) and potential to implement capture and utilization of biomass-based CO₂ (BECCU) in kraft pulp mills were estimated by analyzing the impacts of the processes on the operation of two modern reference mills, a Nordic softwood kraft pulp mill with integrated paper production and a Southern eucalyptus kraft pulp mill. CO₂ capture is energy-intensive, and thus the effects on the energy balances of the mills were estimated. When papermaking is integrated in the mill operations, energy adequacy can be a limiting factor for carbon capture implementation. Global carbon capture potential was estimated based on pulp production data. Kraft pulp mills have notable CO₂ capture potential, while the on-site utilization potential using currently available technologies is lower. The future of these processes depends on technology development, desire to reuse CO₂, and prospective changes in legislation.

     

Genotoxicity of drinking water treated with different disinfectants and effects of disinfection conditions detected by umu-test

The genotoxicity of drinking water treated with 6 disinfection methods and the effects of disinfection conditions were investigated using the umu-test. The pretreatment procedure of samples for the umu-test was optimized for drinking water analysis. The results of the umu-test were in good correlation with those of the Ames-test. The genotoxicity and production of haloacetic acids (HAAs) were the highest for chlorinated samples. UV + chloramination is the safest disinfection method from the aspects of genotoxicity, HAA production and inactivation effects. For chloramination, the effects of the mass ratio of Cl₂ to N of chloramine on genotoxicity were also studied. The changes of genotoxicity were different from those of HAA production, which implied that HAA production cannot represent the genotoxic potential of water. The genotoxicity per chlorine decay of chlorination and chloramination had similar trends, indicating that the reaction of organic matters and chlorine made a great contribution to the genotoxicity. The results of this study are of engineering significance for optimizing the operation of waterworks.     

漂白废水中有机氯在湿地土壤中的环境行为

在实验室模拟条件下,研究了漂白废水中有机氯在土壤中的吸附平衡规律和土柱中的迁移特性,同时分析了某造纸废水长期灌溉湿地土壤的可提取有机氯分布特征.结果表明,可吸附有机氯在土壤中的吸附规律符合Freundlich等温式,且在未受灌溉土壤和已灌溉2a土壤中的吸附常数分别为7.341 0和4.950 1,非线性程度常数分别为0.502 4和0.610 8;经漂白废水淋溶的土柱渗滤液中有较多的可吸附有机氯(AOCl)检出,废水中的有机氯被土壤大量的吸附,且在表层中含量最高.经过造纸废水灌溉1、2和3a后的土壤表层可提取有机氯(EOCl)的平均含量分别为4.48、10.35和10.07μg/g,与土壤背景值相比有明显的提高.     

Minimizing Bias in Virally Seeded Water Treatment Studies: Evaluation of Optimal Bacteriophage and Mammalian Virus Preparation Methodologies

One key assumption impacting data quality in viral inactivation studies is that reduction estimates are not altered by the virus seeding process. However, seeding viruses often involves the inadvertent addition of co-constituents such as cell culture components or additives used during preparation steps which can impact viral reduction estimates by inducing non-representative oxidant demand in disinfection studies and fouling in membrane assessments. The objective of this study was therefore to characterize a mammalian norovirus surrogate, murine norovirus (MNV), and bacteriophage MS2 at sequential stages of viral purification and to quantify their potential contribution to artificial oxidant demand and non-representative membrane fouling. Our results demonstrate that seeding solvent extracted and 0.1 micron filtered MNV to ~10⁵ PFU/mL in an experimental water matrix will result in additional total organic carbon (TOC) and 30 min chlorine demand of 39.2 mg/L and 53.5 mg/L as Cl₂, respectively. Performing sucrose cushion purification on the MNV stock prior to seeding reduces the impacts of TOC and chlorine demand to 1.6 and 0.15 mg/L as Cl₂, respectively. The findings for MNV are likely relevant for other mammalian viruses propagated in serum-based media. Thus, advanced purification of mammalian virus stocks by sucrose cushion purification (or equivalent density-based separation approach) is warranted prior to seeding in water treatment assessments. Studies employing bacteriophage MS2 as a surrogate virus may not need virus purification, since seeding MS2 at a concentration of ~10⁶ PFU/mL will introduce only ~1 mg/L of TOC and ~1 mg/L as Cl₂ of chlorine demand to experimental water matrices.     

生物吸附作用对漂白废水中AOX去除作用的研究

研究了CEH三段漂白废水二级生物处理中好氧及厌氧生物污泥对AOX吸附作用。结果表明,污泥生物吸附符合Langmuir吸附等温式,好氧污泥对AOX的吸附量大于厌氧污泥,污泥对废水中低分子量AOX的吸附量大于高分子量AOX。污泥的解吸实验则表明污泥的生物吸附是一不可逆过程;活性和受抑制的2种污泥的吸附量没有明显差别,其好氧、厌氧污泥的AOX单位碳原子的吸附能仅为0.37和0.38 kJ/mol,表明生物吸附仅是与生物代谢无关的而与分子间爱德华力有关的物理吸附。      

上海食用鱼中短链氯化石蜡的污染特征

为了解长三角地区食用鱼中短链氯化石蜡(SCCPs)的污染特征,根据当地人的食鱼习惯,在上海采集了不同营养级的食用鱼8种,共计68尾,测定了肌肉中SCCPs含量并分析了其同族体的分布模式.结果表明,食用鱼肌肉中SCCPs的含量(干重,dw)范围为36～801 ng.g-1;同族体分布以C10-和C11-SCCPs为主,随着碳链长度的增加,SCCPs同族体含量所占比例随之降低,并且均以低氯(Cl6～Cl8)取代的SCCPs为主要组成部分,相对丰度之和占总丰度的61.46%～82.50%.上海食用鱼中SCCPs的含量在世界范围内处于中等水平,其分布模式与国内外研究一致.     

Fenton氧化去除制药企业活性污泥中AOX的效果研究

用Fenton氧化处理合成制药企业活性污泥混合液,考察了不同Fe~(2+)、H_2O_2投加量和不同反应时间下污泥与上清液中AOX(可吸附有机卤代物)的去除效果,优化了反应条件,探讨了氧化机制.结果表明,Fenton氧化的最佳条件为H_2O_2投加量0.90 mol·L~(-1),Fe~(2+)投加量0.045 mol·L~(-1)[物质的量比为:n(Fe~(2+))∶n(H_2O_2)=1∶20],反应2 h,污泥和上清液中AOX可分别去除70.7%和78.5%.GC-MS分析结果显示,污泥中含有11种有机卤代物,Fenton氧化后有8种不再检出;3种仍有检出,但浓度有所降低,去除率约为40%~50%.与此同时,污泥中对二甲苯、邻苯二甲酸二异丁酯等非有机卤代物类有毒有害有机物也得到有效去除.     

造纸漂白废水中多氯联苯的测定

介绍了造纸氯化漂白废水中痕量多氯联苯的测定方法,采用国产ＧＤＸ－５０１树脂进行富集,经素氏提取,浓硫酸洗涤和去活化的氧化铝－硝酸银硅胶层析柱净化后,用毛细管气相色谱法测定,实验结果表明,造纸氯化漂白废水中产生的ＰＣＢｓ为１０＾－９级,且以低氯取代产物为主,方法回收率在６０％以上。     

上海地区大气中氯化氢和颗粒氯排放源清单初步研究

氯自由基对于臭氧和二次气溶胶的生成贡献不容忽视.夜间颗粒相氯(Cl~-)可以通过与N_2O_5的复杂反应转化生成ClNO_2,其光解产生的氯自由基将显著影响大气污染的形成机制.本文以上海地区为案例,以2017年为基准年,收集了人为源活动水平数据,采用排放系数估算方法,首次建立了上海地区人为源氯化氢(HCl)和颗粒氯(Cl~-)的排放清单;并进一步结合模型计算海盐气溶胶排放的颗粒氯(Cl~-).结果表明,2017年上海市人为源和天然源排放的HCl和Cl~-分别为1207 t和820 t,其中,燃煤、工业、垃圾焚烧和秸秆燃烧产生的HCl排放量分别为327、134、722和24 t.燃煤源中的燃煤电厂和其它行业燃烧约占燃煤源排放的80%;工业源中水泥为HCl的最大排放源,约占工业源排放的51%;垃圾焚烧厂排放约占总HCl排放的60%,为最大的HCl排放源.燃煤、工业源、垃圾焚烧、秸秆焚烧、烹饪源和海盐的颗粒Cl~-排放量分别为82、153、498、47、39和0.6 t,燃煤源中的燃煤电厂占燃煤Cl~-排放的40%,供热、其他行业和家庭燃烧分别占燃煤Cl~-排放的24%、22%和14%;钢铁行业为工业源的主要Cl~-排放源,约占工业源排放的90%,垃圾焚烧厂占全部Cl~-排放的61%,烹饪源中餐饮企业为最主要排放源,占烹饪源的70%;天然源海盐的排放量极少,未占到总排放的1%.从空间分布来看,浦东新区、宝山、普陀、松江和金山排放的HCl和Cl~-占到全市人为源总排放的80%,为主要的HCl和Cl~-排放区域.本文研究建立的上海地区大气中氯化氢和颗粒氯排放源清单,对于深入研究氯化学机制对二次污染的影响提供了重要的数据参考.     

给水管网中耐氯性细菌的灭活特性研究

使用4种常见消毒剂对从实际管网中分离出来的7株耐氯性细菌进行消毒实验.结果表明,这7株细菌均具有较高的耐氯性,其中1株耐氯性最高的类龟分支杆菌自由氯99.9%灭活的CT值为120 mg.(L.min)-1,另外2株血红鞘氨醇单胞菌和甲基杆菌99.9%灭活的CT值分别为7 mg.(L.min)-1和4 mg.(L.min)-1.比较4种消毒剂的消毒效果发现,二氧化氯和单过硫酸氢钾的消毒效果较好,能够在30 min内使分支杆菌的灭活率达到5个数量级.自由氯由于衰减较快,消毒效果不佳.一氯胺能够维持一定的消毒剂浓度,但由于其氧化性较弱,因此需要提高浓度,才能满足消毒要求.能在1 h内灭活3个数量级以上分支杆菌的消毒剂投加量为:3.0 mg/L一氯胺、1.0 mg/L二氧化氯(以Cl2计)和1.0 mg/L单过硫酸氢钾(以Cl2计).考虑到我国水厂消毒的实际情况,建议采用间歇性提高一氯胺浓度或改换二氧化氯消毒的方法,提高对耐氯性细菌的灭活效果.     

絮凝法处理纸浆漂白废水的研究

研究了无机絮凝剂ＰＡＣ，ＰＳＡ，ＰＥＳ，ＭｇＣｌ２，ＣａＯ及其与有机高分子絮凝剂ＣＧＡ复全使用对两种不同工艺漂白废水的混凝处理特性，结果表明，水质１ＣＯＤｃｒ，ＡＯＸ去除率分别为６３．２％，４５．３％，水质２ＣＯＤｃｒ，ＡＯＸ去除率达７３．１￥％，５３．４％。化钙与碳酸钠具有相同的降解ＡＯＸ能力，硫离子在中性ｐＨ条件下可显著提高ＡＯＸ的去除率。     

Effects of disinfection efficiency on microbial communities and corrosion processes in drinking water distribution systems simulated with actual running conditions

The effects of disinfection efficiency on microbial communities and the corrosion of cast iron pipes in drinking water distribution systems (DWDSs) were studied. Two annular reactors (ARs) that simulated actual running conditions with UV/Cl₂ disinfection and chlorination alone were used. High chlorine consumption and corrosion rate were found in the AR with UV/Cl₂. According to functional genes and pyrosequencing tests, a high percentage of iron recycling bacteria was detected within the biofilm of the AR with Cl₂ at early running stage, whereas siderophore-producing bacteria were dominant in the biofilm of the AR with UV/Cl_2. At the early running stage, the sequential use of UV light and an initial high chlorine dosage suppressed the biomass and iron-recycling bacteria in both bulk water and biofilms, thereby forming less protective scales against further corrosion, which enhanced chlorine consumption. Non-metric multidimensional scaling analysis showed that the bacterial communities in the ARs shaped from within rather than being imported by influents. These results indicate that the initial high disinfection efficiency within the distribution system had not contributed to the accumulation of iron-recycling bacteria at the early running stages. This study offer certain implications for controlling corrosion and water quality in DWDSs.     

铁刨花-Fenton-絮凝工艺对染料生产废水中AOX、色度和TOC的去除效果研究

采用铁刨花-Fenton-絮凝工艺处理染料生产废水,考察了不同Fe~(2+)与H_2O_2摩尔比(1∶3~1∶15)、铁刨花反应时间(2~5h)、Fenton氧化反应时间(20~80 min)下可吸附性有机卤代物(AOX)、色度和总有机碳(TOC)的去除效果.结果表明,AOX、色度和TOC去除率随Fe~(2+)与H_2O_2摩尔比的降低先升高后减少,随铁刨花和Fenton反应时间的增加而持续升高.最优化条件为Fe~(2+)与H_2O_2摩尔比1∶8、铁刨花反应时间4 h和Fenton反应时间60 min,该条件下AOX、色度和TOC的去除率分别为94.2%、93.7%和27.2%.比较实验结果表明,铁刨花-Fenton-絮凝组合工艺对废水AOX、色度和TOC的去除效果远优于铁刨花处理、Fenton氧化、絮凝沉淀的单个技术或两两技术组合效果.GC-MS分析表明,废水中的有机卤代物和苯胺类污染物得到高效去除,此外硝基苯类、苯酚类、苯甲醛类、醚类、腈类和杂环化合物等有毒有害物质也均得到高效去除.叔丁醇捕获·OH实验表明·OH在Fenton反应中的主导作用.     

纳米Ni/Fe用于去除染料生产废水二级生物处理出水中AOX和色度的研究

用纳米Ni/Fe材料深度处理染料生产废水的生物处理出水,考察了不同Ni负载量(质量分数0~5%)、废水初始p H值(4.1~10.0)、Ni/Fe投加量(1~5 g·L-1)、反应时间(0.5~96 h)下对可吸附性有机卤代物(absorbable organic halogens,AOX)的去除率和脱色率.结果表明,AOX和色度去除率随Ni负载量的增加先升高后减少,随废水初始p H值的降低和Ni/Fe投加量的增加而持续提高.最优化条件为Ni负载量1%、废水初始p H 4.1和Ni/Fe投加量3 g·L-1,该条件下AOX和色度的24 h去除率分别为29.2%和79.6%,96 h去除率分别为50.6%和80.7%.GC-MS分析表明经材料处理后废水中氯代苯胺类、对硝基苯胺、4-甲氧基-2-硝基苯胺及卤代烷烃等有毒有害物质得到高效去除.     

预氯化对铝盐混凝铜绿微囊藻过程中溶解性有机物和残余铝的影响

以铜绿微囊藻为对象,研究了预氯化过程中藻胞内代谢物释放及铝盐混凝除藻过程中残留铝的变化规律.结果表明,氯投量对胞内物质释放量和释放有机物特征有重要影响.与未投加氯的对照体系相比,在较低氯投量时(1~2 mg·L-1),水中有机物浓度升高26%~31%,UV254值升高46%~49%,且有机物主要为中等分子量(2191、2830和3168 Da)和高芳香度的有机物.增大氯投量至3~4 mg·L-1,水中有机物浓度和UV254值有所下降;就不同分子量有机物而言,大分子量有机物(16304 Da)浓度升高而中等分子量有机物(2830、3168和6163 Da)浓度下降,且出现少量小分子量有机物(180 Da).分子量较大或芳香度较高的溶解性有机物在铝盐混凝中可被优先去除.释放到水中的蛋白质能与铝盐形成可溶性蛋白质-混凝剂复合物,从而导致出水铝浓度升高,但增大铝投量可在一定程度上降低残留铝浓度.