臭氧-生物活性炭对有机物分子量分布的影响

测定了南方某水厂中试规模的臭氧-生物活性炭工艺不同处理阶段(原水、沉淀水、砂滤水、臭氧化水、生物活性炭出水)有机物(TOC和UV254)的分子量(MW)分布.分析了原水中生物可同化有机碳(AOC)的分子量分布.结果表明,AOC主要属于天然有机物(NOM)中MW<1kDa的部分.MW<1kDa的部分占可溶解性有机碳(DOC)的53%～67%,而AOC只占DOC的2.65%～5.91%,表明去除大部分DOC的臭氧-生物活性炭工艺并不能有效去除AOC.     

强化混凝去除黄浦江水有机物的试验研究

强化混凝去除有机物的效果与水源的分子量分布特性有着密切的关系.由于黄浦江水中低分子量的溶解性有机物占多数,因此,强化混凝处理有机物效果有限.对于＜1k分子量区间的有机物.增加混凝剂投量可有效去除紫外吸光值(UV254),但去除溶解性有机碳(DOC)的效果很差.尽管增加混凝剂投量和降低pH都能有效地去除有机物,但决定强化混凝效果的主要因素是pH,去除黄浦江水有机物的最佳pH范围为6～5.     

原水碳源分子量分布及DPB效能对酸化时间的响应

采用超滤-纳滤膜法对污水中碳源分子量(MW)进行切割试验,并测定各区间总有机碳(TOC)浓度以了解污水碳源组成特性;同时采用污水酸化技术,研究在不同酸化时间,碳源分子量分布的变化及对厌氧-膜好氧-反硝化(A2N)工艺中反硝化聚磷菌(DPB)用碳和净污效能的影响.结果表明,试验原水TOC为(58.3±2.83) mg /L,其中颗粒有机碳(POC)为(38.05±1.65)mg /L,占65.27%,剩余溶解有机碳(DOC)在分子量0.5kDa以上区间呈现“W”型分布,其中 MW>100kDa、10k~5kDa、1k~0.5kDa、MW<0.5kDa区间碳源分别占36.20%、12.05%、13.68%和29.83%.在不同酸化时间下,POC含量与DOC分布存在显著差异,在12h内酸化,可以有效将POC转化为DOC,且在14mg/L左右趋于平衡;DOC在大于0.5kDa区间上的分布呈现随时间而整体后移的趋势,在8h时碳源质量最优,其中MW<1kDa的小分子有机物高达17.30mg/L;此时,DPB污泥在厌氧池与缺氧池中的碳源利用率分别为 83.48%、79.59%,比0h时分别提高了23.56%、18.03%;TN、TP去除率分别提高了14.63%、16.98%.     

废水处理系统中有机物分子量分布及其变化

采用超滤膜法对废水处理系统中有机物的分子量分布及其变化进行研究,分析有机物分子量分布特性及不同分子量分布区间有机物的相对含量。结果表明:厌氧、缺氧、好氧反应池出水中,小于1K分子量区间上的有机物所占比例最高。该分子量区间有机物TOC分别占总TOC的60.9%、58.5%、65.2%,UV254分别占总UV254的69.9%、67.9%、82.1%。传统工艺对小分子量有机物去除效率较低。     

臭氧预氧化对城市污水二级出水可生化性的影响

以臭氧预氧化强化后续曝气生物滤池对城市污水二级出水中难降解有机物净化效率为目的,研究了臭氧预氧化对二级出水可生化性的影响。臭氧投量为10mg/L、接触时间为4min时,臭氧氧化对COD和TOC去除率分别达到25.7%和16.5%;臭氧氧化使二级出水的生物可降解有机碳(BDOC)值提高为原来的2.45倍;臭氧氧化使二级出水中有机物的分子量分布发生了明显的变化:大分子有机物比例减少,小分子有机物比例增加,使分子量小于1kDalton的有机物的比例由原来的52.9%提高到72.6%;通过UV254值变化可知,臭氧氧化能将大多数含有C=C、C=O双键等活性基团破坏;臭氧氧化后,GC/MS检测到的有机物种类和数量明显增多,氧化前后烷烃种类明显增多,而环状结构、羧酸和醇类化合物明显减少。     

MIEX~预处理对水源水中藻源DON的去除效能及机理

利用小试试验研究了磁性离子交换树脂预处理(MIEX~)对高藻水源水中的溶解性有机氮(DON)的去除效能,并通过分子量分布测定、双向电泳等手段初步分析了其作用机理.结果表明,MIEX~预处理对DON具有较好地去除效果,并可有效强化混凝工艺的处理效能.投加量为15m L/L时,MIEX~预处理可提升DON去除率20%;以铜绿微囊藻为主要种属的高藻水源水中藻类蛋白种类不低于230种,且大多数处于酸性端,分子量区间主要分布于15~40Ku、65~75Ku,处于MIEX~预处理可去除的分子量区间,从而具有较好的去除效果.综上所述,MIEX~预处理可以作为强化去除高藻水源水中DON的一种方法.     

市政污水A/DAT-IAT系统中溶解性有机物表征与生态安全

为了解决市政污水处理出水水质安全与无害化问题,以改良的SBR——A/DAT-IAT工艺为依托,对A/DAT-IAT工艺进水,连续曝气池(DAT)上清液及间歇曝气池(IAT)出水的溶解性有机物(dissolved organic matter,DOM)采用超滤膜法进行了相对分子质量分级,并进行了TOC、UV254、3D-EEM及发光菌毒性测试,探索市政污水毒性的主要物质来源.结果表明,实验室规模的A/DAT-IAT工艺对市政污水各分子量区间的有机物均有较好的去除效果.腐殖质是污水处理厂出水中主要物质,且天然水体中难去除的腐殖质及处理过程中形成的腐殖质成分是二级出水中主要的荧光物质.沿污水处理流程,DOM的组成呈现出由低分子量向高分子量转化的趋势,相对分子质量<1×103区间的物质芳香性显著增加,导致IAT出水与氯的反应活性增高,产生消毒副产物的风险增加.与进水毒性主要来源于原水中相对分子质量<1×103的小分子物质相同,IAT出水的毒性也主要来源于相对分子质量<1×103的小分子物质,但与原水中的小分子物质不同,主要是生物处理过程中产生的类腐殖质.结合对TOC、UV254、3D-EEM及毒性的分析,小分子的类腐殖质是二级出水有机物含量达标、氯化消毒副产物控制及毒性控制应该重点考虑去除的对象.在之后的研究中,应该根据这部分物质进行工艺调节及针对性处理单元的添加.     

生物活性炭内吸附与生物降解协同去除有机污染物

本研究建立了一个确定BAC内2种机理去除有机物分配比例的试验方法.该方法以BAC进出水中溶解性有机碳（DOC）与可生物降解有机碳（BDOC）浓度变化作为评价参数,并利用此方法确定了臭氧投加量对2种去除机理的影响.臭氧化可以使BDOC浓度增加,臭氧投量为2～8mg/L时,BDOC增加0.12～0.54mg/L;BAC过滤使出水BDOC浓度降低为0.23～0.31mg/L.随着臭氧投量增加（2～8mg/L）,在BAC内生物降解作用去除有机物比例从46%增加到89%.     

不同聚合铝对水中有机物的去除研究

强化混凝是去除水中消毒副产物的最佳方法之一。文章针对强化混凝技术,从去除水中有机物的角度出发,对不同聚合铝的处理效果进行了研究。结果表明,酸性条件、加大投药量有利于水中TOC及UV254的去除,且酸性条件更为有利。在pH=6.3,工业PAC投药量为1.5×10-4mo(l有效铝)时去除效果最佳,水中总有机碳(TOC)及紫外吸光度(UV25)4的去除率分别可达到46%及57%,实验室制备的聚合铝碱化度越高越有利于水中有机物的去除。     

绍兴市富营养化水源水中有机物特性研究

采用超滤法对绍兴富营养化水源水中有机物进行了分子量的测定,继而考察了不同分子量区间的有机物对色度,紫外吸收的影响,并与淮河（蚌埠段）水及密云水库水中的有机物特性作了比较,发现密云水库水以小分子有机物为主,分子量小３０００的有机物占总ＢＯＣ的９６．７％,而绍兴水及淮河水（蚌埠段）中有机物相对分子质量分布相对较为均匀,分子量大于３０００的有机物占总ＤＯＣ的比例分别为２８．３７％和３８．２８％,水中有机     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

Removal of cadmium using MnO2 loaded D301 resin

MnO2 loaded weak basic anion exchange resin D301 （Anion exchange resin, macroreticular weak basic styrene） as adsorbent has been prepared and applied to the removal of cadmium. The adsorption characteristics have been investigated with respect to effect of pH, equilibrium isotherms, removal kinetic data, and interference of the coexisting ions. The results indicated that the Cd^2＋ could be efficiently removed using MnO2 loaded D301 resin in the pH range of 3-8 from aqueous solutions with the co-existence of high concentration of alkali and alkaline-earth metals ions. The saturate adsorption capacity of the Cd^2＋ was 77.88 mg/g. The adsorption process followed the pseudo first-order kinetics. The equilibrium data obtained in this study accorded excellently with the Langmuir adsorption isotherm.     

Effect of coagulation pretreatment on the fouling of ultrafiltration membrane

The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）. A relatively higher molecular weight （MW） of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.     

Penetration analysis of elements and bioleaching treatment of spent refractory for recycling

Acidithiobacillus ferrooxidans ATCC23270 and Acidithiobacillus thiooxidans TM-32 were used for bioleaching of spent refractories of aluminium and copper melting furnaces for their recycling.Firstly,penetration of elements into aluminium melting furnace refractory was investigated and it was found that up to 7 cm from surface was contaminated.Comparison on leaching efficiency by the strains ATCC23270 and TM-32 found that the strain ATCC23270 could treat larger amount of the refractories than the strain TM-32 could do.In the experiment of bioleaching of spent refractory aluminium melting furnace by the strain ATCC23270,high leaching efficiency were obtained on Al,Si,and Ca,and extremely low leaching performance was,however,shown on the rest of elements i.e.,Na,Mn,and Zn.Under the strain TM-32 use,relatively high leaching performance was recognized on Al,Si,Ca,Na,Mn,and Zn.In the experiment of bioleaching for spent refractory copper melting furnace,almost the same leaching trends were shown on Cu,Zn,Al,and Si under the strains ACTT23270 and TM-32 uses.     

Simultaneous removal of ammonium and phosphate by zeolite synthesized from coal fly ash as influenced by acid treatment

Zeolite synthesized from fly ash （ZFA） without modification is not efficient for the purification of NH4＋ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacity. To develop an effective technique to enhance the removal efficiency of ammonium and phosphate at low concentrations, ZFA was modified with acid treatment and the simultaneous removal of ammonium and phosphate in a wide range of concentration was investigated. It was seen that when compared with untreated ZFA, only the treatment by 0.01 mol/L of H2SO4 significantly improved the removal efficiency of ammonium at low initial concentrations. The behavior was well explained by the pH effect. Treatment by more concentrated H2SO4 led to the deterioration of the ZFA structure and a decrease in the cation exchange capacity. Treatment by 0.01 mol/L H2SO4 improved the removal efficiency of phosphate by ZFA at all initial P concentrations, while the treatment by concentrated H2SO4 （≥0.9 mol/L） resulted in a limited maximum phosphate immobilization capacity （PIC）. It was concluded that through a previous mild acid treatment （e.g. 0.01 mol/L of H2SO4）, ZFA can be used in the simultaneous removal of NH4＋ and P at low concentrations simulating real effluent.