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31.
海水异养硝化-好氧反硝化芽孢杆菌SLWX2的筛选及脱氮特性 总被引:4,自引:3,他引:1
从分离自刺参养殖环境的7株候选菌株中筛选出1株具有较强异养硝化和好氧反硝化能力的菌株SLWX_2,通过形态学特征、生理生化特性和16S rRNA基因测序分析鉴定其为花津滩芽孢杆菌(Bacillus hwajinpoensis).该菌株脱氮特性研究结果表明,SLWX_224 h对氨氮、亚硝酸氮和硝酸氮的去除率分别达到100%、99.5%和85.6%;当3种无机氮源同时存在时,菌株优先利用氨氮,再利用NO_2~--N和NO_3~--N,72 h 3种无机氮的质量浓度均降至0.013 mg·L~(-1)以下,表明该菌株能同时进行异养硝化和好氧反硝化完成脱氮;在氨氮负荷500 mg·L~(-1)、亚硝酸氮负荷100 mg·L·~(-1)和硝酸氮负荷200 mg·L~(-1)范围内,该菌的脱氮能力不受明显抑制,对3种形态的氮均有良好去除效果,96 h最多可去除180 mg NH_4~+-N、30 mg NO_2~--N和120 mg NO_3~--N,并且在硝化过程中没有亚硝酸氮积累.该菌株在海水养殖和高盐高氮工业废水的脱氮处理方面具有更大潜力. 相似文献
32.
本文首先介绍公路项目施工期环评的现实意义,之后阐述公路项目施工期环评要点,以此强化公路项目施工期环评水平及其环保效益。 相似文献
33.
This work represents an attempt to define a simple method to classify the relative degree of disturbance of sites in lotic
systems on the basis of comparison of their faunistic composition with reference sites. Two ecotypes were selected in northern
Portugal where benthic invertebrates were sampled in reaches with different levels of contamination. As a first stage, previous
Geographic Information System information was used to define reference sites in each ecotype. Afterwards, multivariate techniques
and non linear estimation models were combined to assess biological quality. This method allowed us to quantify sites according
to increasing levels of contamination, after the probabilities of occurrence of taxa along a gradient of contamination taking
into account the reference condition. The results suggest that this method is sensitive to organic pollution, easy to interpret,
namely the species tolerance, and could be a good framework to establish regional rankings depending on the ecological impact
of river sites. 相似文献
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36.
Simo Sarkki Jari Niemelä Rob Tinch Jukka-Pekka Jäppinen Matti Nummelin Heikki Toivonen 《Journal of Environmental Planning and Management》2016,59(8):1377-1396
The Convention on Biological Diversity's national biodiversity strategies and action plans (NBSAPs) are major mechanisms for mainstreaming biodiversity into national policies. This article examines whether and how the NBSAPs contribute to mainstreaming biodiversity across policy sectors in Finland in order to halt biodiversity loss. We have developed an innovative analytical framework where the concept of responsibility addresses how motivations for mainstreaming can be built, and the concept of social learning outcomes addresses the extent of institutional changes for biodiversity. The Finnish NBSAP processes have been able to build diverse forms of responsibility (liability, accountability, responsiveness and care) in different policy sectors by providing new knowledge, careful process design and developing institutional linkages. Despite pro-biodiversity outcomes in the targeted policy sectors, the responsibilities do not diffuse from the environmental administration to other policy sectors to a sufficient extent. Closing this ‘responsibility gap’ is a key challenge for building effective environmental policies. 相似文献
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38.
Ted R. Angradi David W. Bolgrien Matt A. Starry Brian H. Hill 《Journal of the American Water Resources Association》2012,48(5):1054-1070
Angradi, Ted R., David W. Bolgrien, Matt A. Starry, and Brian H. Hill, 2012. Modeled Summer Background Concentration of Nutrients and Suspended Sediment in the Mid‐Continent (USA) Great Rivers. Journal of the American Water Resources Association (JAWRA) 48(5): 1054‐1070. DOI: 10.1111/j.1752‐1688.2012.00669.x Abstract: We used regression models to predict summer background concentration of total nitrogen (N), total phosphorus (P), and total suspended solids (TSS), in the mid‐continent great rivers: the Upper Mississippi, the Lower Missouri, and the Ohio. From multiple linear regressions of water quality indicators with land use and other stressor variables, we determined the concentration of the indicators when the predictor variables were all set to zero — the y‐intercept. Except for total P on the Upper Mississippi River, we could predict background concentration using regression models. Predicted background concentration of total N was about the same on the Upper Mississippi and Lower Missouri Rivers (430 μg l?1), which was lower than percentile‐based values, but was similar to concentrations derived from the response of sestonic chlorophyll a to great river total N concentration. Background concentration of total P on the Lower Missouri (65 μg l?1) was also lower than published and percentile‐based concentrations. Background TSS concentration was higher on the Lower Missouri (40 mg l?1) than the other rivers. Background TSS concentration on the Upper Mississippi (16 mg l?1) was below a threshold (30 mg l?1) designed to protect aquatic vegetation. Our model‐predicted concentrations for the great rivers are an attempt to estimate background concentrations for water quality indicators independent from thresholds based on percentiles or derived from stressor‐response relationships. 相似文献
39.
Increasing antibacterial resistance and pathogenicity in the environment is of growing concern due to its potential human risk. In the present study, 236 Escherichia coli isolates were collected from Wenyu River in China on drugless (48 isolates) and quinolone-containing plates (189 isolates). Their minimum inhibitory concentrations (MICs) were determined ranging from 0.125 μg mL−1 to 128 μg mL−1. Mutation points related to fluoroquinolone resistance were observed at S83 to L and D87 to N or Y in the GyrA subunit and S80 to R or I and E84 to G in the ParC subunit. Generally, MICs of LEV and GAT are dependent on the patterns of these mutation points. The profile with three mutation points was related to LEV-resistant E. coli isolates, and the (S83L, D87N + S80I) mutation profile was most prevalent (65.7%) in LEV-resistant isolates, while a large proportion of isolates, even those with three mutation points, were susceptive to GAT. The incidence of virulence factors in LEV-resistant isolates (44.7%, 59/132) was much higher than in nonresistant isolates (23.1%, 24/104) (χ2 = 11.925, 1° of freedom, p < 0.001) indicating that fluoroquinolone-resistant E. coli would pose a potential risk. A similar distribution was also found in isolates resistant to GAT (χ2 = 7.843, 1° of freedom, p = 0.0079). 相似文献
40.
VFAs、TOC及COD作为生物除磷能力指标的探讨 总被引:3,自引:0,他引:3
在实际生活污水的处理中,研究了通过A/O运行模式对生物除磷过程中磷的变化情况及在厌氧释磷过程中COD、TOC与VFAs变化之间的关系。结果表明,在厌氧释磷过程中VFAs的变化更能准确地反映系统内释磷进程,实际生活污水中能直接用于磷释放的有机物含量占COD的13.33%,并且释放1 mg P所需VFAs为1.401 mg,此值明显低于前期研究结果。通过对COD、TOC和VFAs 3种组分的分析,可将实际生活污水中的有机底物分为3类:易生物降解含碳有机物、难降解的含碳有机物和水中存在的无机性还原物质,含量分别占COD的13.33%、31.7%和54.97%,其中只有13.33%的含量对生物释磷有直接作用,并可对实际生活污水除磷有指导意义。 相似文献