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1.
Kenneth R. Krach Benjamin R. Burns Baikun Li Alison Shuler Charles Cole Yuefeng Xie 《Water, Air, & Soil Pollution: Focus》2008,8(3-4):369-378
Over three million dry metric tons of biosolids produced in the United States are land applied as Class B. Lime stabilization
is employed for biosolids treatment at approximately 20% of the wastewater treatment plants because it is a simple and inexpensive
process. During lime stabilization, the pH of sewage sludge is raised above 12 for pathogen inactivation and odor reduction.
Lime dose and mixing have been found to greatly reduce odor generation from lime stabilized biosolids. A better quality biosolids
product is less likely to create public opposition to land application programs. In this study, land application tests using
Class B biosolids were conducted in order to determine whether better mixing can reduce odor generation during the land application
of lime stabilized biosolids. The mixing quality of a treatment plant’s lime stabilized biosolids was improved by relocating
the lime addition point, which prolonged the mixing time and produced a better mixed biosolids product. Based on field observations
of land application, the poorly mixed biosolids were more odorous and offensive prior to incorporation. However, once incorporated
into the soil, there was no appreciable odor difference between the biosolids. Another land application study was conducted
to assess the odor of unincorporated Class A biosolids and compare it with incorporated Class A biosolids with the soil. 相似文献
2.
混合气体爆炸性MFC图形分析 总被引:3,自引:2,他引:1
李唐山 《中国安全科学学报》2004,14(5):84-87
判断混合气体爆炸性常用 3种方法 ,即科瓦德爆炸三角形法、美国矿业局采用的爆炸三角形计算法和最小助燃氧浓度法 ,然而如何准确、快速、形象地得到分析结果在防灾救灾中是十分关键的。笔者的重点是提供一个图形分析方法解决上述问题。VC ++是方法的基本理论依据 ,用一个实例来验证方法的有效性。总之 ,研究表明 :图形分析法可提高安全管理效率。 相似文献
3.
脱卤球菌(Dehalococcoidia,Dia)纲是绿弯菌门下属八大纲之一.迄今为止,脱卤球菌纲中包含3个能进行严格厌氧有机卤化物呼吸的菌属:脱卤拟球菌(Dehalococcoides,Dhc)、脱卤单胞菌(Dehalogenimonas,Dhgm)及尚未正式命名的Candidatus"Dehalobium".当前关于脱卤拟球菌和脱卤单胞菌生理学、生物化学和生态学方面的研究,主要集中在从有机氯污染场地中富集或者分离出来的菌株方面.而越来越多的研究证据表明,能进行有机卤化物呼吸的脱卤球菌纲微生物不仅仅只存在于污染物产地,在各种环境(如海洋、淡水、陆地)中也能经常被检测和鉴定到.但脱卤球菌纲微生物在自然界生态系统中起到的重要作用尚未被完全揭示.本文旨在介绍和讨论被低估且未被充分研究的脱卤球菌纲微生物的生理生态特征及其潜在的生态学功能,从而引起研究人员更广泛的关注,鼓励跨学科研究来揭示这一类特殊微生物在有机卤化物生物地球化学循环中的重要作用. 相似文献
4.
从城市工业固体废物消纳和废弃采石场作为填埋处置场地的角度出发,对利用废弃采石场作为第Ⅰ类一般工业固体废物填埋场场址条件进行探讨,通过广州市地区实例说明利用废弃采石场选址作为第Ⅰ类一般工业固废填埋场址的可用性,这对未来废弃采石场的综合利用具有一定的借鉴意义。 相似文献
5.
Maud C. O. Ferrari Myles R. Brown Michael S. Pollock Douglas P. Chivers 《Chemoecology》2007,17(3):157-161
Summary. Many aquatic prey are known to use chemical alarm cues to assess their risk of predation. In fishes, such alarm cues can be
released either through damage of the epidermis during a predatory attack (capture-released) or through release from the predator
feces (diet-released). In our study, we compared the importance of capture- versus diet-released alarm cues in risk assessment
by fathead minnows (Pimephales promelas) that were na?ve to fish predators. We utilized two different fish predators: a specialized piscivore, the northern pike
(Esox lucius) and a generalist predator, the brook trout (Salvelinus fontinalis). Handling time of pike consuming minnows was much shorter than for trout consuming minnows, likely resulting in less epidermal
damage to the minnows during attacks by pike. In accordance with this, minnows showed a less intense antipredator response
to capture-released cues from pike than capture-released cues from trout. This represents a paradox in risk assessment for
the minnows as they respond to the specialized piscivore, the more dangerous predator, with a less intense antipredator response.
In contrast, the minnows showed a stronger antipredator response to the specialized piscivore than to the generalist when
given diet cues. This work highlights the need for researchers to carefully consider the nature of the information available
to prey in risk assessment. 相似文献
6.
In this paper, a toxicity study for a series of anilides of Naphthol-AS type is presented. The toxicity of the model compounds was determined by using the Hydractinia echinata (Hydrozoa) test system. Conformational analysis of Naphthol-AS derivatives was performed to elucidate the possible enzymatic hydrolysis mechanism of these compounds. This mechanism occurs with different rates and always leads to a stoichiometric mixture of reaction products, consisting in the substituted amine and the corresponding α-hydroxy-carboxylic acid. With one exception, the toxicities of the reaction products are subadditive. Quite similar measured toxicity values, log(1/MRC50), led to their average calculated values, and thus to the establishment of class isotoxicity. This method represents a practical alternative useful for the reduction of experimental tests on animals to the lowest possible level, in accordance to the ‘3Rs’ (reduction, refinement and replacement) concept. 相似文献
7.
Ning Zhang Xiang Liu Rui Liu Tao Zhang Miao Li Zhuoran Zhang Zitao Qu Ziting Yuan Hechun Yu 《Frontiers of Environmental Science & Engineering》2019,13(1):8
8.
9.
The emergence and prevalence of antibiotic resistance genes(ARGs) and pathogens in the environment are serious global health concern. However, information about the occurrence of ARGs and pathogens in recreational water is still limited. Accordingly, we investigated the occurrence of six ARGs and human pathogens in three recreational lakes, and the correlations between ARGs and one mobile genetic element(intI1) were analyzed. The quantitative PCR results showed that the concentration of ARGs ranged from 4.58 × 10~0 to 5.0 × 10~5 copies/mL in water and from 5.78 × 10~3 to 5.89 × 10~8 copies/g dry weight(dw)in sediment. Sul1 exhibited the highest level among the five quantifiable ARGs. The concentrations of sul1, bla_(-TEM), and tetX exhibited significant positive correlations with intI1(p 0.05), indicating that intI1 may be involved in their proliferation. The detection frequencies of ARGs ranged from 75%–10~0%, indicating the prevalence of these risks in this region. The concentration of Escherichia coli, Aeromonas spp., Mycobacterium avium,Pseudomonas aeruginosa, and Salmonella enterica ranged from 10~3 to 10~5 copies/10~0 mL in water and 10~4–10~6 copies/g dw in sediment. In total, 25% of the samples harbored all pathogen genes, indicating the prevalence of these pathogens in recreational lakes.Furthermore, the next-generation sequencing results showed that 68 genera of pathogens were present, among which Aeromonas, Mycobacterium, and Pseudomonas were the dominant ones in this region, posing a considerable potential health risk to public health. Overall, the widespread distribution of ARGs and pathogens underscores the need to better monitor and mitigate their propagation in recreational lakes and the associated risks to human health. 相似文献
10.
A growing number of scientific studies in recent years have investigated disparate exposure to ecological hazards in American society. Working from an environmental justice perspective, this body of research consistently reveals that poor communities of color are most likely to bear a disproportionate burden of negative externalities. These studies utilize a wide range of research methodologies, including various indicators of ecological hazards (e.g., proximity to waste sites, industrial emissions, ambient air quality), but few, if any, utilize composite measures to approximate cumulative environmental impact. Consequently, the environmental justice (EJ) literature is characterized by a failure to effectively measure overall impact from an extensive range of ecological hazards. Limitations on available data make this a serious problem for present and future studies. We argue that cumulative measures of environmental impact can play an important role in furthering our understanding of environmental injustices in the United States. In this study of Massachusetts, we develop and implement such a cumulative measure of negative environmental impacts. By controlling for the density and severity of ecological hazardous sites and facilities within every community in the state, we demonstrate that exposure patterns take a generally linear distribution when analyzed by race and class. So, while our results reaffirm previous findings that low-income communities and communities of color bear significantly greater ecological burdens than predominantly White and more affluent communities, our findings also suggest that environmental injustices exist on a remarkably consistent continuum for nearly all communities. In other words, as the minority population and lower-income composition of a community increases, correspondingly, so does cumulative exposure to environmental hazards. In this respect, communities which are more racially mixed and of moderate income status that are not typically identified as meeting EJ criteria (in demographic terms) also face more significant ecological hazards. Thus, the strict bifurcation of communities into categories of Environmental Justice and Non-Environmental Justice is problematic, and poses a serious dilemma for policy makers, public health officials, and community activists. To overcome this challenge requires the adoption of a cumulative environmental justice impact assessment (CEJIA), which in addition to the demographic characteristics of a community, also takes into account the total environmental burden and related health impacts upon residents. Furthermore, through the adoption of the precautionary principle, source reduction, and alternative forms of “cleaner” production, environmental justice advocates must work for policies which reduce the environmental threat for the full range of communities, as well as their own. 相似文献