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821.
因畜禽废水除了含有大量的有机物,还含有一定量的氨基酸,因此,研究利用UASB处理畜禽废水,在不同环境条件和工况条件下对氨化率的影响,结果表明:氨化菌适应的pH值范围较宽,在6.5—8.0范围均可以较好的生存,其中以7.0为最佳;温度与氨化率基本成正相关关系,从经济等多种角度考虑,中温阶段38%为最适宜;氨化率随进水浓度的增加而增加;进水有机负荷越大,氨化率越小。  相似文献   
822.
We consider the results of a recent paper in this journal [Zeru, A. and Schäfer, G., 2005. Analysis of groundwater contamination using concentration–time series recorded during an integral pumping test: Bias introduced by strong concentration gradients within the plume. Journal of Contaminant Hydrology 81 (2005) 106–124], which addresses the field-scale characterisation of contaminant plumes in groundwater. There, it is concluded that contaminant concentration gradients can bias Integral Pumping Test (IPT) interpretations considerably, in particular if IPTs are conducted in advective fronts of contaminant plumes. We discuss implications of this setting and also argue that the longitudinal and transverse dispersivities used in the examples of Zeru and Schäfer (2005) of up to 30 m and 3 m, respectively, are generally very high for the here relevant capture zone scale (< 20 m). However, regardless of both longitudinal and transverse concentration gradients, we further show through a counter-example that IPT results are unbiased as long as the concentration attenuation along the flow direction is linear over the capture zone extent.  相似文献   
823.
针对海洋柴油溢油,采用破乳剂对油水快速分离进行了研究.分别对油水比、温度、破乳剂量及存在Ca2 、Mg2 的影响因素,进行了系列油水快速分离试验,并测定了破乳剂作用下乳液的界面张力.试验结果表明,柴油溢油形成的乳液稳定性较差,油水分离较容易,但分离后的水中含油量较高.加入聚醚类非离子型破乳剂FA、FB、FC和FD,可达到油水低温、快速分离的目的,且分离后的水中含油量较低.随着破乳剂浓度的增加,界面张力降低,当破乳剂浓度达到临界胶束浓度(CMC)时,界面张力最小,脱水效果最好.Ca2 、Mg2 对聚醚类非离子型破乳剂的影响很小.  相似文献   
824.
不同功能区空气负离子的监测分析   总被引:9,自引:0,他引:9  
监测了西宁地区不同功能区空气负离子状况,以公园游览区空气负离子浓度最高,平均358个/cm^3;工业区最低,平均浓度259个/cm^3。各功能区空气负离子浓度明显不同,P〈0.01。用空气负离子浓度、空气离子单级系数和安培空气质量评价指数评价各功能区空气质量,从好到差依次为:公园游览区、生活居住区、商业交通繁忙区、工业区。3种评价指标结果相同,符合一般规律。  相似文献   
825.
焚烧秸秆对城市空气质量的影响及对策   总被引:10,自引:0,他引:10  
通过夏收季节农民焚烧秸秆的烟尘,引起对城市环境空气质量变化的分析,结果表明:焚烧秸秆对城市环境空气质量有很大影响,使环境空气质量明显下降,而主要污染物为可吸入颗粒物PM10。有关部门应采取有效措施,禁止焚烧秸秆,同时应积极为农民寻找合理利用秸秆的途径,减少对城市空气的烟尘污染。  相似文献   
826.
EuroBionet, the 'European Network for the Assessment of Air Quality by the Use of Bioindicator Plants', is an EU-funded cooperative project currently consisting of public authorities and scientific institutes from 12 cities in 8 countries. In 2000, the bioindicator plants tobacco (Nicotiana tabacum Bel W3), poplar (Populus nigra 'Brandaris'), spiderwort (Tradescantia sp. clone 4430), Italian rye grass (Lolium multiflorum italicum) and curly kale (Brassica oleracea acephala) were exposed to ambient air at 90 monitoring sites according to standardised methods. Visible injuries and growth parameters were assessed and the accumulation of toxic substances in leaves determined. The exposure of tobacco resulted in a gradient with low levels of ozone-induced foliar injury in N and NW Europe, and medium to high values in the southern and central regions. The results of heavy metal and sulphur analyses in rye grass samples generally showed low to very low sulphur and low to medium heavy metal concentrations in leaves. In some cities, however, local hot spots of heavy metal contamination were detected. Analyses of the PAH contents in curly kale leaves gave low to medium values, with locally elevated levels at traffic-exposed sites.  相似文献   
827.
The EMAP model (Eulerian Model for Air Pollution) is applied for calculating the sulfur concentration and deposition fields for 1995 as based upon Bulgarian and Greek sources. The country-to-country budgets show that about 4% of the sulfur oxides emitted by Bulgaria are deposited over Greek territory, estimated at 28 kt S. Only 2% of sulfur compounds emitted by Greece are deposited over Bulgaria, estimated at 6.2 kt S for 1995. This data is in agreement with EMEP/MSC-W estimates and provides more details concerning time and space. The results can be used in decision-making, negotiating and the development of contamination strategies.  相似文献   
828.
概述了高速微涡活性污泥法的工艺特点,并对该法提高氧的转移及利用效率进行了研究和机理分析。  相似文献   
829.
煤气发生站洗冷废水治理研究   总被引:2,自引:0,他引:2  
研究了以活性炭作为吸附剂处理煤气发生站废水工艺,并摸索出一整套的工艺参数。实验结果表明,采用活性炭吸附工艺使出水水质得到明显改观,硫化物、氰化物和挥发酚的去除效率均达90%以上,对CODcr、氨氮的去除也收到了明显的效果。  相似文献   
830.
The Southern California Air Quality Study database provides a valuable resource with which to test urban-scale photochemical models and to achieve a better understanding of the atmospheric dynamics of pollutant formation. The CIT model was evaluated using the SCAQS database according to traditional model performance guidelines. A first application, reported previously, focused on model enhancement and application of the model to the 27–29 August 1987 episode. This study evaluates the CIT model using the 24–25 June SCAQS episode, providing further evaluation of the model. Results show that the CIT airshed model can follow the diurnal variations of reactive species and the transport for relatively unreactive species. The normalized gross error for ozone was 31 % in June compared to 38% in August. However, to fully judge model performance in proper perspective, a question arises: “How well do the measurements reflect the air quality surrounding the monitoring station, not just in that location?” This is an important but seldom quantitatively considered factor, not only in model evaluation but in the study of health effects as well. Analyses indicate that individual concentration measurements only approximately represent the true volume-averaged concentrations within a computational grid cell and that significant spatial variations exist. Thus any evaluation of models using these data sets should take these local variations into consideration. A series of tests found that the local inhomogeneities had a normalized gross error in the range of 25–45% depending on the pollutant. In this context, the performance of the CIT model is consistent with known modeling limitations such as emissions inventories and sub-grid scale variation of observations.  相似文献   
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