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1.
研究了粉末活性炭(PAC)作为载体的膜生物反应器(MBR)处理吹脱后垃圾渗滤液的硝化性能.在HRT=3 d、NH 4-N=200~500 mg/L条件下,进水pH>8.7时,PAC-MBR和没有添加PAC的普通MBR均只能将氨氮转化为NO-2;降低pH至7.6~8.2时,PAC-MBR中的亚硝酸盐氧化菌迅速恢复活性,将NO-2完全转化为硝酸盐,而普通MBR仍然停留在亚硝化阶段;当吹脱取消后,NO-2迅速消失,这可能与取消吹脱后,不再使用大量硫酸进行pH调节有关.研究发现,当SO2-4为3 g/L时,氨氮氧化速度出现了明显的下降,表明SO2-4对硝化菌具有抑制作用;同时,微生物代谢产物(SMP)分泌量越高,NO-2含量越低,但是SMP不是影响NO-2积累的主要原因. 相似文献
2.
应用由城市污水处理厂序批式间歇反应器(SBR)中筛选得到的4株特殊氨氧化菌,分别在SBR和有回流的生物膜与A/O工艺耦合体系培养中,考察其降解低碳高氨氮废水的功能。结果表明,自养硝化与异养氨氧化菌的混合菌群较单一自养硝化菌株降解氨氮速率快;在生物膜与A/O工艺耦合系统中,自养硝化与异养氨氧化菌协同代谢加速氨氮氧化脱除,氨氮脱除速率远比SBR系统快。对生物膜与A/O工艺耦合系统中氨氮脱除动力学进行了研究,模拟了NH4^+、NO2^-;质量浓度与氨氮脱除比速率之间的关系,模型得到了较好的验证。 相似文献
3.
亚硝酸盐对厌氧氨氧化的影响研究 总被引:12,自引:0,他引:12
以二沉池出水为原水,探讨了亚硝酸盐浓度对厌氧氨氧化生物膜滤池性能的影响。实验结果显示,亚硝酸盐浓度的提高有利于加快ANAMMOX反应速率,当NO2^-N=118.4mg/L时,氨氮转化速率达最高;此后,进一步提高进水中NO2^--N浓度,NO2^-—N对ANAMMOX反应产生了明显的抑制作用,ANAMMOX反应速率逐渐下降,但此时ANAMMOX细菌仍存在较高的活性。试验结果还显示,为获得良好的脱氮效果,进水中适宜的NO2^--N:NH4^+-*N应为1.3:1。 相似文献
4.
采用电极一SBBR系统去除Cu^2+,考察了电流强度,IA竞争离子(阴离子SO4^2-、NO3^-、CL^-和阳离子Zn^2+、Ph^2+)、初始含Cu^2+量及溶液pH值对除铜效除果的影响。结果表明,当电流强度为40mA时Cu^2+去除率最高为98%。投加阴(SO4^2-、NO3^-、Cl^-)、阳(Zn^2+、Pb^2+)离子均会引起出水Cu^2+浓度的增加,且Cl^-和Ph^2+含量分别为45mg/L和30mg/L时对Cu^2+去除的影响更为显著。进水Cu^2+浓度为30mg/L时,Cu^2+去除率最高为98.48%,当进水Cu^2+≥70mg/L时,出水Cu^2+浓度不能达标。酸性(pH4.0~4.5)与碱性(pH9.0~10.0)条件均不利于Cu^2+的去除,且酸性条件的负面影响更显著.当pH为4.5~7.5时.Cu^2+去除率最高为97.78%。 相似文献
5.
短程反硝化聚磷的反硝化特征研究 总被引:2,自引:0,他引:2
研究了温度、pH值、电子供体种类及电子受体种类对反硝化的影响。试验结果表明,(1)在相同试验条件下。亚硝酸型反硝化与硝酸型反硝化的速率与硝态氮的浓度有关。在温度为25℃、pH为7的条件下,基质浓度〈300mg/L时短程反硝化速率较快;基质浓度≥300mg/L时,以NO3^-为基质的反硝化速率较大。(2)具有大量碳源储存物(PHB)的细菌可实现快速的内源性反硝化脱氮,而处于饥饿状态的细菌的内源性反硝化效率极低。 相似文献
6.
DO和pH值在短程硝化中的作用 总被引:16,自引:0,他引:16
在SBR反应器中对DO和pH值在短程硝化和半亚硝化过程中的作用进行试验研究,结果表明,控制低DO和适宜的pH值在短程硝化过程中起着重要的作用。本试验条件下。当DO为0.5~1.0mg/L、pH值为7.5—8.0时。在SBR反应器中很容易实现短程硝化;当DO〉0.3mg/L时,DO越低,出水NO2^-N积累率越高;当pH值〉6.8时,不会影响系统NO2^-N积累的稳定性。另外,研究结果还表明,通过控制DO和pH值可以实现半亚硝化。本试验条件下,当进水氨氮浓度为120mg/L时,控制DO为0.3—0.4mg/L可实现出水半亚硝化;当进水氨氮浓度为200mg/L时,控制DO为0.5—0.6mg/L或pH值为6.8也可以实现出水半亚硝化。 相似文献
7.
多孔碳表面自养硝化生物膜的培养及其性能研究 总被引:1,自引:0,他引:1
在pH值7.5~7.8、温度28℃、DO≥3mg/L的条件下,分别以NaNO2和K2HPO4为氮源和磷源,按N:P=50:1的比例混合,对自养硝化菌进行液相培养并在一种新型材料多孔碳的表面挂膜,进而对其特征、性能等进行了研究。实验得到了稳定的自养硝化生物膜;当NO2^-浓度为206.82mg/L时,生物膜的稳定硝化速率可达260mg/L·d;经鉴定,硝化速率最高的N-20菌株属硝化杆菌属(Nitrobacter sp.)。 相似文献
8.
采用聚合羟基铝交联剂对蒙脱土进行撑柱,合成铝交联黏土(Al-PILC),并以其为载体,制备了应用于C3H6选择还原NO的催化剂Cu/Al-PILE。考察了制备工艺条件及La2O3助剂对催化剂性能的影响,并采用DTA、IR技术对Al-PILC进行表征。研究结果表明,Al-PILE热稳定性随Al/clay比增加逐步提高,SO4^2-改性Al-PILE上SO4^2-与铝氧化柱形成了具有超强酸性的结构,催化活性得到显著提高;当Al/clay比为10mmol/g,浸渍SO4^2-量为20%(wt),Cu担载量为3%(wt),空速20000h^-1时,Cu/Al-PILE在350℃NO转化率达到最大值52.02%;浸渍0.5%La2O3提高了Cu/Al-PILE催化剂的活性和热稳定性。 相似文献
9.
采用气体扩散电极为阴极,钛基氧化物(Ti/SnO2-Sb2O5-IrO2)和金属铁构成组合阳极,构建了新型电化学氧化体系用于降解有机污染物。利用该氧化体系,在不同实验条件下考察了苯胺降解的效果与降解过程的相关规律。结果表明,阴极电位、铁阳极通电时间以及苯胺初始浓度均显著影响苯胺的降解效果。当阴极电位为-0.7V,pH3.0,铁阳极通电时间20min时,电化学处理200mg/L苯胺480min,TOC的去除效率达到80.4%,矿化电流效率(MCE)为8.6%,显示了该氧化体系具有良好的有机物降解能力。此外,苯胺降解过程中氨氮和硝态氮浓度的变化表明,苯胺分子中的氮主要转化为NH4和NO3^-。 相似文献
10.
水体中常见无机阴离子对TiO2薄膜光催化降解甲醛的影响 总被引:4,自引:0,他引:4
选择了5种水体中常见的阴离子(Cl^-,SO4^2-,HPO4^2-/HPO4^2-,HCO3^-/CO3^2-和NO3^-),分别考查了其对TiO2薄膜光催化降解模拟甲醛废水的反应速率的影响;从上述离子的光吸收,对.OH的捕获及其生成的相应的无机自由基的氧化作用以及与甲醛的竞争吸附3个方面讨论了上述离子影响TiO2薄膜光催化降解模拟甲醛废水的反应速率的原因。结果表明,HCO3^-/CO3^2-对TiO2薄膜光催化降解甲醛具有抑制作用,Cl^-和SO4^2-的影响不大,H2PO4^-/HPO4^2-和NO3-具有促进作用。造成上述结果的主要原因是HCO3^-/CO2^3-具有很强的.OH捕获作用;Cl^-,SO4^2-对.OH捕获作用以及竞争吸附都较弱;H2PO4^-/HPO4^2-在TiO2表面具有较强的吸附能力,释放出的H+起到了酸催化剂的作用;NO3^-在紫外光的照射下可以产生.OH,此外NO3^-作为电子受体而降低了TiO2表面光生电子和空穴的复合几率。 相似文献
11.
Mirosław Mleczek Marek Siwulski Patrycja Mikołajczak Monika Gąsecka Iwona Rissmann Piotr Goliński 《Journal of environmental science and health. Part. B》2013,48(9):659-666
The aim of the study was to estimate copper (Cu) accumulation efficiency in whole-fruiting bodies of 18 edible and non-edible wild growing mushrooms collected from 27 places in the Wielkopolska Voivodeship. Mushrooms were collected each time from the same places to estimate the diversity in Cu accumulation between tested mushroom species within 3 consecutive years of study (2011–2013). The study results revealed various accumulation of Cu in the whole-tested mushroom fruiting bodies. The highest mean accumulation of Cu was observed in Macrolepiota procera (119.4 ± 20.0 mg kg?1 dm), while the lowest was in Suillus luteus and Russula fellea fruiting bodies (16.1 ± 3.0 and 18.8 ± 4.6 mg kg?1 dm, respectively). Significant differences in Cu accumulation between mushroom species collected in 2011 and in the two following years (2012 and 2013) were observed. The results indicated that sporadic consumption of these mushrooms was not related to excessive intake of Cu for the human body (no toxic influence on health). 相似文献
12.
B.G. Arends J.H. Baard H.M. Ten Brink 《Atmospheric environment (Oxford, England : 1994)》1997,31(24):4063-4072
A trend analysis of the sulphate concentration in Europe in the summer half-year was performed. Data from various measuring networks were analysed, but only stations with quality assured sampling methods and a record of more than 10 years were included in the study. 1978 served as the reference year for the trend, because in that year most stations started operation. The relatively dense network in Belgium provided the most valuable data, as evidenced by the fact that two sites at a distance of only 10 km apart correlated better than 95% over a month. The two sites also show a correlation of better than 90% over a season with two other stations at distances of 45 and 95 km. The relative decrease in summer-sulphate at the four stations in Belgium, as analysed by linear regression, was 3.3% per year which corresponds to an absolute decrease of 0.42 μgm−3 per year. In the Netherlands the average yearly decrease in summer-sulphate at two stations was 3.5% (−0.34 μgm−3). In other countries stations were further apart or only a single site wits in use, which limits the representativeness of the data. In northwestern Germany, a region with several monitoring stations, a yearly averaged decrease of 3.0% occurred. The lower absolute decrease (0.25 μgm−3) per year compared to that in the two neighbouring countries reflects the lower summer-time sulphate concentrations. In the remainder of Germany the average decrease was 1.6%. In South-Scandinavia the yearly relative decrease at two sites was 2.6% (0.13 μgm−3 absolute). There was no significant trend in the U.K. Al the Polish station the levels increased, it decreased at the Hungarian and Austrian station and remained constant at the Czechoslovakian site. Reasons for omission of the data from France from the trend analysis are discussed. 相似文献
13.
Pesticides in rainfall in Europe 总被引:1,自引:0,他引:1
Papers and published reports investigating the presence of pesticides in rainfall in Europe were reviewed. Approximately half of the compounds that were analysed for were detected. For those detected, most concentrations were below about 100 ng/l, but larger concentrations, up to a few thousand nanograms per litre, were detected occasionally at most monitoring sites. The most frequently detected compounds were lindane (gamma-HCH) and its isomer (alpha-HCH), which were detected on 90-100% of sampling occasions at most of the sites where they were monitored. For compounds developed more recently, detection was usually limited to the spraying season. A classification of pesticides according to their deposition pattern is proposed. 相似文献
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15.
G. A. El Zorgani 《Journal of environmental science and health. Part. B》2013,48(6):1091-1098
Abstract Cotton‐producing areas of the Centrol Sudan, bordered by the Blue and the White Nile, have been subjected to repeated applications of pesticides. This region is irrigated by a series of canals, the Gezira canals, which hold large amounts of fresh water. Lake Nubia at the Sudan‐Egypt border is another important fresh water reservoir and fisheries ground. Fish from both the Gezira and Lake Nubia showed elevated concentrations of pesticides, suggesting that continued pesticides application would endanger the equatic fauna of this region and the proposed fresh water fishery. 相似文献
16.
A unique long term, 49-year record (divided into three time periods 1961–1976, 1977–1992, and 1993–2009) of snow profile stratigraphy
from the Swedish sub Arctic, was analyzed with a focus on changes in snow characteristics. The data set contained grain size,
snow layer hardness, grain compactness, and snow layer dryness, observed every second week during the winter season. The results
showed an increase in very hard snow layers, with harder snow in early winter and more moist snow during spring. There was
a striking increase in the number of observations with very hard snow at ground level over time. More than twice as many occasions
with hard snow at ground level were observed between 1993 and 2009 compared to previous years, which may have a significant
effect on plants and animals. The changes in snow characteristics are most likely a result of the increasing temperatures
during the start and the end of the snow season. 相似文献
17.
Mercury in fish in Swedish lakes 总被引:5,自引:0,他引:5
Håkanson L Nilsson A Andersson T 《Environmental pollution (Barking, Essex : 1987)》1988,49(2):145-162
The aim of this work has been to try to obtain a picture of the past, present and future mercury situation in fish in Swedish lakes, to make an estimate of the number of lakes threatened by 'blacklisting', and to see if the data can be used to reveal anything about the impact of liming on the Hg content in pike. The register contains a broad set of data from 1456 lakes. The main results are as follows. Trend analyses indicate that the Hg content in 1-kg pike seems to increase with time. This is interesting since there has been a significant decrease in mercury emissions from Swedish industries during the last two decades. High Hg contents in 1-kg pike appear in a very characteristic pattern, linked to specific sources of Hg emission. The data indicate that old Swedish 'sins' are still causing a lot of problems. The factors governing the leakage of Hg from soils to water ought to be a very important topic for further studies. The Hg content in pike shows the highest correlation with the following parameters: Hg in surficial sediments, pH, distance from point source and water hardness, lake water alkalinity and conductivity, water retention time, size of drainage area and lake surface. A formula which provides the best possible degree of explanation (r2 = 0.78) has been derived. At present there are about 250 lakes 'blacklisted' in Sweden due to high Hg content in fish. Our data show that there are at least 9400 lakes that ought to be 'blacklisted' today. A successful liming operation will alter the chemical conditions in lakes and also decrease the Hg content in fish. 相似文献
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We investigated the occurrence, source and exposure time of lead poisoning in whooper swans (Cygnus cygnus cygnus) and Bewick's swans (Cygnus columbianus bewickii) in Japan during the winters of 1984-1987. Concentrations of lead in various tissues and physiological evidence of lead shot in some birds indicated that lead shotgun pellets were the source of lead, and exposure occurred after the birds arrived in Japan. Mortality probably occurred within 30 days after exposure to, and retention of, lead shot in the gizzard. 相似文献
20.
Decamethylcyclopentasiloxane (D5), a high production volume chemical used in personal care products, enters the environment both via air and sewage treatment plant (STP) recipients. It has been found in fish, and there is concern that it may be a bioaccumulative substance. In this work D5 was analyzed in perch from six Swedish lakes that did not receive STP effluent, and in perch and sediment from six lakes that received STP effluent. In the lakes receiving the STP effluent, the D5 concentrations in sediment varied over three orders of magnitude and were correlated with the number of persons connected to the STP normalized to the surface area of the receiving body. In the lakes not receiving effluent, the D5 levels in perch were all below the LOQ, while D5 was above the LOQ in almost all perch from lakes that received effluent. The D5 concentrations in perch and sediment from the lakes receiving STP effluent were correlated. This shows that STP effluent is a much more important source of D5 to aquatic ecosystems than atmospheric deposition, and that the risk of adverse effects of D5 on aquatic life will be greatest in small recipients receiving large amounts of STP effluent. The bioaccumulation of D5 was compared to that of PCB 180 on the basis of multimedia bioaccumulation factors (mmBAFs), which describe the fraction of the contaminant present in the whole aquatic environment (i.e. water and surface sediment) that is transferred to the fish. In four of the six lakes the mmBAF of D5 was >0.3 of the mmBAF of PCB 180. Given that PCB 180 is a known highly bioaccumulative chemical, this indicates that the bioaccumulation of D5 in perch is considerable. 相似文献