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531.
基于PPI的河段水体潜在污染研究 总被引:4,自引:3,他引:1
提出了一种预报河段水体潜在污染的方法——河段潜在污染指数法(riversection potential pollution index,R-PPI),并在北京市山区3个典型小流域进行应用.河流水体污染是我国目前最为突出的水环境问题,在治理工作开展前需要确定重点污染河段、区域和污染源,而基于河流水质监测的水质评价方法难以确定重点污染源.因此引入了潜在非点源污染指数(potential non-point pollution index,PNPI)法,进行了土地利用类型扩展、土地利用分类比对和土壤渗透性分级3个方面改进,得到潜在污染指数(potential pollution index,PPI),并在此基础上建立了河段潜在污染指数法.通过在3个小流域的应用研究可知,该方法具有所需监测资料少、操作简单、便于确定重点污染源、综合性强等特点,可为流域污染治理提供科学指导. 相似文献
532.
在长期运行的序批式生物反应器(SBR)中,考察了以葡萄糖和2,4-二氯苯氧乙酸(2,4-D)为混合碳源培养的好氧颗粒污泥在转换为2,4-D唯一碳源废水后,其形态、结构及对目标污染物去除功能的变化.结果表明,基质转换为2,4-D单一碳源后,好氧颗粒污泥仍保持了对目标污染物高效的去除能力.当进水2,4-D浓度为361~564mg/L,其去除率为99.2%~100%,COD平均去除率达到85.6%.混合碳源向2,4-D单一碳源转换对原好氧颗粒结构产生一定破坏作用,使其发生部分解体,粒径由513μm下降到302μm.但好氧颗粒污泥良好的耐负荷冲击使其保持了颗粒主体,通过一段时间适应调整后能够重新聚集生长,最终获得能够利用2,4-D为唯一碳源生长并具有良好沉降性(SVI20~40mL/g)的好氧颗粒污泥,粒径为489μm.扫描电子显微镜(SEM)观察结果表明,混合碳源转向单一碳源使好氧颗粒生物相丰富度降低. 相似文献
533.
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针对大蒜废水特点,采用了铁屑微电解-UASB-接触氧化工艺进行处理.运行结果表明:在设计进水水质、水量范围内,COD、BOD5、氨氮和ss去除率分别为98%、99%、70%和98%,出水各项指标均达到GB 8978--1996<污水综合排放标准>中的一级排放标准,系统运行费用为1.19元/m3. 相似文献
536.
印钞废水属高浓度难降解有机废水,对环境污染严重。鉴于现有处理工艺出水普遍不达标的情况,通过对比实验确定了改进方案:超滤浓缩液离心出水在进入接触氧化池前,增加新的处理单元(Fenton氧化-混凝)。Fenton氧化最佳条件:FeSO4.7H2O投加量14 g/L,H2O2的投加量34 mL/L,初始pH值6.0,氧化反应时间1.5h,温度18.8℃;混凝过程最佳条件:PAC投加量4 g/L,PAM(5‰)投加量10 mg/L,pH值7。新增单元对废水中COD去除率接近80%,可生化性提高1.6倍,色度降低36%。 相似文献
537.
This work was designed to explore the characteristics of photodegradation of herbicides in the copper-polluted water body. The
results showed that Cu(II) alone could induce a photo Fenton-like reaction to enhance the degradation of atrazine, in which hydroxyl
radical ( OH) was a main active species. Humic acids restrained atrazine degradation, nevertheless, when introducing Cu(II), the
photodegradation was accelerated, in which singlet oxygen (1O2) replaced OH acting as the prevailing species. A feasible mechanism
for the photochemical process was also proposed, which is helpful for better understanding the environmental photochemistry of
atrazine in the copper-polluted water. 相似文献
538.
Aged refuse from waste landfills closed for eight years was examined and found to contain rich methanotrophs capable of biooxidation
for methane. Specially, community structure and methane oxidation capability of methanotrophs in the aged refuse were
studied. The amount of methanotrophs ranged 61.97 103–632.91 103 cells/g (in dry basis) in aged refuse from Shanghai Laogang
Landfill. Type I and II methanotrophs were found in the aged refuse in the presence of sterilized sewage sludge and only Type I
methanotrophs were detected in the presence of nitrate minimal salt medium (NMS). The clone sequences of the pmoA gene obtained
from the aged refuse were similar to the pmoA gene of Methylobacter, Methylocaldum, and Methylocystis, and two clones were distinct
with known genera of Type I methanotrophs according to phylogenetic analysis. Aged refuse enriched with NMS was used for methane
biological oxidation and over 93% conversions were obtained. 相似文献
539.
Meeta Lavani Priyangshu M. Sarm Ajoy K. Man Simrita Cheem Banwari La 《环境科学学报(英文版)》2011,23(8):1394-1402
We compared the efficacy of a natural biocide with four chemical tetrakishydroxymethyl phosphonium sulfonate, benzyl trimethyl
ammonium chloride, and formaldehyde, glutaraldehyde, to control microbial induced corrosion in oil pipelines. The efficacy of biocides
were monitored against Desulfovibrio vulgaris and Desulfovibrio gigas in experimental pipes by measuring cell counts, H2S production,
Fe(II) production, production of extracellular polymeric substances and structure of biofilm. The treatment with cow urine had minimum
planktonic cell counts of 3 102 CFU/mL as well as biofilm cell counts of 9 101 CFU/mL as compared with tetrakishydroxyl methyl
phosphonium sulfonate, benzyl trimethyl ammonium chloride, formaldehyde and glutaraldehyde. Sulfide production was the lowest
with cow urine (0.08 mmol/L), followed by tetrakishydroxymethyl phosphonium sulfonate 0.72 mmol/L. On day 90 of treatment,
Fe(II) production was also found to be the lowest with cow urine. The scanning electron microscopic studies indicated that the biofilm
bacteria were killed by cow urine. These results demonstrate the cow urine mediated control of microbially induced corrosion, and this
is indicative of its potential as a viable substitute of toxic biocides. To the best of our knowledge, this seems to be the first report which
screens possible biocidal activity by cow urine as compared to the most common biocides which oil industry is currently using. 相似文献
540.
The activities of CeO2 nanocubes calcined at different temperatures were tested for catalytic oxidation of o-xylene. Using CeO2 nanocubes as catalysts, complete catalytic oxidation of o-xylene was achieved below 210℃. The CeO2 nanomaterials were characterized by means of BET, X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). From the TEM images, all Ce02 nanocubes displayed cubic morphology irrespective of calcination temperature. The HRTEM images revealed that these nanocubes were enclosed by reactive {001}planes, which may contribute to the intrinsically catalytic property of o-xylene oxidation. The higher activity of Ce02 nanocubes calcined at 550℃ than those calcined at above 550℃ was attributed to their smaller crystallite size and larger surface area. The influences of reaction conditions were also studied, which found that a higher reaction temperature was necessary for complete catalytic oxidation of o-xylene at higher weight hourly space velocity (WHSV) and o-xylene concentration. 相似文献