城镇污水处理厂次氯酸钠消毒实验与分析

本文通过次氯酸钠消毒在无锡市S厂的消毒实验,得出了次氯酸钠消毒用于城镇污水厂合适的投加量和接触时间,并通过成本测算,初步验证了次氯酸钠消毒在城镇污水处理厂应用的经济可行性。     

城镇污水处理厂次氯酸钠消毒工艺对出水BOD_5测定影响探讨

本文研究了城镇污水处理厂次氯酸钠消毒工艺对BOD5测定结果的影响,并对污水杀菌工艺进行了初步研究。实验表明次氯酸钠的投加,会消耗水中的微生物,并且产生消毒副产物抑制微生物生长,从而对BOD5的测定产生干扰。反应时间30min时,3.0mg/L的加氯量可以使粪大肠菌群小于800个/L,达国标要求。增加反应时间可以减少氯的使用。当次氯酸钠投加量大于5mg/L时,此时余氯含量大于1.05mg/L,BOD5受到显著抑制,应在除氯后用非稀释接种法测定。污水处理厂可以采用增加停留时间等方式改善工艺,减少次氯酸钠投加量。     

浓盐水排海对渤海湾盐度分布的影响预测

利用MIKE21模型进行浓海水排放对渤海湾海水盐度分布影响的研究,分别以天津大港和河北黄骅两地建设海水淡化工程所排放的浓海水量为输入条件,模拟预测了渤海湾不同潮期和工程规模浓海水排放的扩散状况。结果显示,浓海水的稀释扩散受潮流的影响较大,总体来讲小潮低潮时排海的浓海水稀释扩散效果最差,大潮低潮和小潮高潮时次之,大潮高潮时扩散效果最好;建设10×104 t/d以下的海水淡化工程浓海水排海对周围海区的盐度影响不显著,建设50×104 t/d以上的大型海水淡化工程时,小潮低潮时盐度升高波及面积最大,高于背景值1.5 PSU的面积为31 km2,最远离岸距离为6.74 km,所以大规模海水淡化工程的选址、浓海水排海方式均要进行合理规划、选择,尽可能降低其对海洋环境的不利影响。     

次氯酸钠废液在污水处理厂消毒应用研究

为了确定次氯酸钠废液应用于城镇生活污水处理厂出水消毒的合理投加量,通过实验研究了采用次氯酸钠废液消毒后粪大肠菌群数、COD和p H的变化规律。研究结果显示,在实验条件下,次氯酸钠废液有效氯的合理投加量为5.0 mg/L~5.2mg/L,此时能使粪大肠菌群数达到GB18918-2002的一级A标,同时COD有一定的下降,p H也在排放限值内。     

不同方式污水排海对海水水质的影响

污水排海主要有岸边直排和深海排放两种方式，本文以深圳下沙海域为例，采用数值模拟的方法，对污水岸边排放和在500m及1000m不同距离的深海排放进行了计算和分析，结果表明，在一般水动力条件下，污水排放距岸越远，对海水水质的影响越水，岸边直排以近岸海域影响最大。     

生物制药（品）废水的灭活与处理

介绍采用物理加热消毒灭菌及好氧接触氧化法在昆明某医学生物学研究所处理生物制药（疫苗）生产废水及生活污水应用情况。在生物制药（特别是减毒活疫苗）生产废水中通常含有病原性微生物,如细菌、病毒等,须经消毒灭菌处理后才能排入污水处理系统。首先,根据相关病毒的致死温度,采用加热法将减毒活疫苗生产废水中的病毒杀死;然后,灭活后的废水排入生物接触氧化处理系统与生活污水混合后进行处理;最后,氯消毒后达标排放或进行中水回用。本文为生物制药废水的处理提供了一定参考价值。     

医疗机构消毒对粪大肠菌群的影响

医疗机构污水有传染、放射、有毒及耐药等特点,随着我国医疗机构就医人数的增长,污水排水量也急剧增长。就医疗机构消毒剂次氯酸钠和过氧乙酸在时间及浓度上对消毒效果的影响做出分析,指出医疗机构消毒对粪大肠菌群的影响。     

城市污水资源化(续)

4、再用于城市建设 (1)回灌地下再生后的城市污水,回灌地下的目的有二:一是补给水源,二是防止海水侵入。荷兰多德雷赫特试验厂研究了两种污水深度处理路线。一种以物理化学法为主,包括石灰处理、CO_2再碳酸化、石英砂和无烟煤双层过滤池过滤、臭氧氧化、生物滤池处理和离子交换法脱氨。另一种以反渗透法为主,包括投加次氯酸钠、氯化铁和高分子絮凝剂的化学预处理、上流式接触滤池和下流式快滤池、添加HCl酸化后进入反渗透器、活性炭吸附、白云石过滤和次氯酸钠消毒。两种方法均能获得高质量的饮用水。美国污水回收厂基本上也采取了与上述路线相类似的方法。纽约州纳珊县西达港水回收     

宜昌市选用“次氯酸钠发生器”处理医疗污水装置投入运行

宜昌市拥有30张病床以上的医院共19家,已有4家选用液氯消毒法处理医疗污水。六七一医院是全市首家选用“次氯酸钠发生器”装置处理医疗污水的医院。为了鉴定该装置的处理效果及摸索最佳操作条件,市环保局、监测站和六七一医院污水处理站的同志对处理前后的污水进行了系统的检测分析。根据不同的排污量调试工艺参数,控制投氯量和余氯量。     

污水排海扩散器的数值模拟与模型试验

在污水排海工程的设计工作中,采用数值模拟与模型试验相结合的方法是一种有效的设计手段。本文结合某污水排海整治工程,首先采用HydroInfo-1D管网模型对该工程排污扩散器进行数值模拟,得到相应各喷口的流量、流速和弗劳德数,然后设计水工模型试验对数值模拟结果进行验证。模拟结果显示,两种排放流量工况下该扩散器各喷口出流均具有很好的均匀性,且弗劳德数均大于1,满足设计规范的要求。此外,通过将实验结果与计算结果对比,发现两种工况下流量的计算值与实验值的最大误差分别为2.18%和2.42%,流速的最大误差分别为2.19%和2.43%,说明该模型的计算结果具有较高的精度。研究结果表明:该模型可以准确的对污水排海扩散器进行模拟,且管道的设计结构参数满足实际运行要求。     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

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.     

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.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

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.     

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.     

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.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

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 heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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