首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
我国污水处理的发展趋势   总被引:14,自引:2,他引:12  
目前我国污水处理的总体发展趋势;一是普及城市污水处理,二是提高工业废水排放达标率,三是推广污水回用。论文重点介绍了城市污水的强化一级处理、数学模型用于精确控制的技术,清洁生产在提高工业废水排放达标方面的作用,以及再生水作为环境用水的回用方式。  相似文献   

2.
以武汉市东西湖区园艺花城小区(3期)污水深度处理和中水回用系统建设为例,介绍和推广一套具有较强实用性的生活污水生化—物化—生态组合处理工艺。该项工艺特别适用于氮含量偏高情况下的离散型住宅小区生活污水深度处理与回用,具有占地省,处理效果稳定,易与周边环境协调等诸多优势。采用组合工艺,可使小区污水经处理后实现达标排放,中水处理系统的出水水质满足《城市污水再生利用(城市杂用水和景观环境用水)水质标准》;系统运行能耗低,污水处理和中水制水的总成本仅为0.69元/m~3。  相似文献   

3.
昆明市某森林公园污水回用工程处理规模1000t/d,于2007建成使用,水源为市政管网截污,使用一段时间后出水各项指标均超过回用水质标准33%~170%,针对出现问题采用MBR工艺进行了改造。改造后系统运行稳定,出水COD≤50mg/L、BOD≤6mg,/L、SS≤10mg/L、NH4-N≤5mg/L、TP≤0.5mg/L、TN≤15mg/L,均优于《城市污水再生利用景观环境用水水质》标准中观赏性景观环境用水水景类水质标准,同时运行费用较原工艺降低18%,为0.847元/m^3,实现了工程改造的预期目标。  相似文献   

4.
污水湿地处理工艺优化组合设计   总被引:8,自引:0,他引:8  
污水湿地处理系统是利用土壤、作物、微生物自然净化功能的生态工程技术。主要有水面湿地和渗滤湿地两种类型,在天津城市污水土地处理与利用系统研究的基础上,将两种工艺的优点进行优化组合,并应用于大港油田等污水湿地处理工程,运行结果表明:将水面湿地和渗滤湿地工艺优化组合设计的示范工程,具有提高水力负荷、减少运行费用、节省工程投资、处理效果稳定等特点,有利于处理工程的长期稳定运行。  相似文献   

5.
高效聚合氯化铝在石油化工污水回收处理中的应用   总被引:6,自引:0,他引:6  
许坤  沈茂铮 《环境化学》1996,15(4):356-359
通过絮凝性能比较以及中试规模的应用,表明高效聚合氯化铝具有用量少,污泥少,除浊率高,对出水pH影响小等优点,是石油化工污水回用处理中的理想絮凝剂。  相似文献   

6.
F-RNA噬菌体及其作为水中肠道病毒指示物的研究进展   总被引:7,自引:0,他引:7  
李梅  胡洪营 《生态环境》2005,14(4):585-589
城市污水的再生利用是缓解水资源紧张、减少水污染和改善生态环境的有效途径。污水及其回用水中的肠道病毒对人体健康的风险日益受到关注。直接检测水中肠道病毒的操作复杂、安全性差、时间长、需要专门的技术和设备,因此需要寻找合适的指示生物,以实现对水中肠道病毒的及时检测和风险评价。F-RNA噬菌体是通过性菌毛感染雄性大肠杆菌的一类RNA细菌病毒,在污水中普遍存在,在大小、形态结构及对环境条件和水处理过程的抗性与肠道病毒相似,被认为是水中肠道病毒的合适的指示生物。文章介绍了F-RNA噬菌体在环境及污水中的分布、存活和去除特性、检测方法及作为水中肠道病毒指示生物的研究进展。  相似文献   

7.
城市污水处理厂出水生态渠回用方案实证研究   总被引:3,自引:0,他引:3  
本文结合天津经济技术开发区(TEDA)污水回用,在研究回用规模、深度处理工艺以及生态渠的挖掘的基础上,从技术经济分析的角度对方案的可行性进行了探讨。结果表明该方案科学合理。  相似文献   

8.
城市污水成分复杂,含有多种有毒有害物质,使其能对生物体产生各种不良生物效应,其中,内分泌干扰物,尤其是雌激素类物质以及具有雌激素活性的污染物,因能影响生物的生殖系统并造成受纳水体鱼类性别转变等危害而备受关注,城市污水的雌激素活性也一直是污水处理领域的研究热点.当前,城市污水回用是缓解全球水资源危机的重要途径之一,在此背景下开展污水雌激素活性毒性评估、致毒物解析及毒性削减研究对于保障其回用过程中的安全性至关重要.笔者围绕这一条研究主线,以城市污水为研究对象,对污水雌激素活性表征方法、雌激素活性关键致毒物解析以及污水处理过程中雌激素活性削减的相关研究成果进行回顾和总结,为今后城市污水安全排放和回用提供参考.  相似文献   

9.
天津市东郊污水处理厂是新建投产的一座大型城市污水处理厂,其设计处理能力为400000m ̄3/d。该厂引进了国外先进设备和技术,60000m ̄3/d污水采用前置缺氧脱氮的A/O工艺进行了深化处理。本文全面论述了A/O工艺曝气他的设计,并就设计参数取值、池型设计、进出水形式,回流方式和缺氧区与好氧区的容积比等进行了分析探讨。  相似文献   

10.
城市污水回用健康风险评价   总被引:5,自引:0,他引:5  
随污水回用量增加,其对人体健康可能产生的危害日益受到重视。利用风险评价技术对回用水的健康风险进行评估成为保证安全回用的关键。主要论述了污水回用健康风险评价的基本概念和方法。  相似文献   

11.
Invasive non-native species are important drivers of ecosystem change, yet the driving forces of biological invasions themselves are poorly understood. Such information is essential to ensure policies focus on the most relevant drivers, and that future scenarios capture the full range of potential outcomes for invasive non-native species. I carried out a bibliometric analysis of articles published from 2000 to 2020 that address either invasive non-native species or biodiversity and ecosystem services and that also mention 1 or more drivers of ecosystem change. I examined 5 indirect drivers (demographic, economic, governance, sociocultural, and technological) and 6 direct drivers (climate change, invasive non-native species, land-use or sea-use change, natural hazards, pollution, and resource extraction). Using the Web of Science core collection of citation indexes, I undertook searches of article titles and keywords and retrieved 27,462 articles addressing invasive non-native species and 110,087 articles dealing with biodiversity or ecosystem services. Most research to date on biological invasions as well as on biodiversity and ecosystem services has focused on anthropogenic direct drivers of ecosystem change rather than indirect drivers. Yet currently, less than 18% of articles addressing biological invasions examined drivers of ecosystem change, a similar level to that found over 20 years ago for biodiversity or ecosystem services. Knowledge of the drivers of biological invasions is limited, emphasizes tractable drivers over those that require an interdisciplinary approach, and is biased toward developed economies. Drivers generally deemed important for biological invasions, such as governance and resource extraction, accounted for less than 2% of research effort. The absence of a systematic understanding of the forces that drive invasive non-native species and how they interact means that attempts to mitigate or forecast biological invasions are likely to fail. To address biological invasions requires a much better orientation of national and international research on drivers in relation to both their actual importance as well as their policy relevance.  相似文献   

12.
For sea turtles, like many oviparous species, increasing temperatures during development threaten to increase embryonic mortality, alter offspring quality, and potentially create suboptimal primary sex ratios. Various methods are being implemented to mitigate the effects of climate change on reproductive success, but these methods, such as breeding programs, translocations, and shading, are often invasive and expensive. Irrigation is an alternative strategy for cooling nests that, depending on location, can be implemented relatively quickly and cheaply. However, multiple factors, including ambient conditions, nest substrate, and species characteristics, can influence irrigation success. Additionally, irrigation can vary in duration, frequency, and the volume of water applied to nests, which influences the cooling achieved and embryonic survival. Thus, it is critical to understand how to maximize cooling and manage risks before implementing irrigation as a nest-cooling strategy. We reviewed the literature on nest irrigation to examine whether artificial irrigation is feasible as a population management tool. Key factors that affected cooling were the volume of water applied and the frequency of applications. Embryonic responses varied with species, ambient conditions, and the timing of irrigation during development. Nest inundation was the key risk to a successful irrigation regime. Future irrigation regimes must identify clear targets, either primary or adult sex ratios, that maximize population viability. Monitoring population responses and adjusting the irrigation regime in response to population characteristics will be critical. Most studies reported on the manipulation of only one or two variables, further research is required to understand how altering multiple factors in an irrigation regime influences the cooling achieved and embryonic responses.  相似文献   

13.
Species that are strong interactors play disproportionately important roles in the dynamics of natural ecosystems. It has been proposed that their presence is necessary for positively shaping the structure and functioning of ecosystems. We evaluated this hypothesis using the case of the world's largest parrotfish (Bolbometopon muricatum), a globally imperiled species. We used direct observation, animal tracking, and computer simulations to examine the diverse routes through which B. muricatum affects the diversity, dispersal, relative abundance, and survival of the corals that comprise the foundation of reef ecosystems. Our results suggest that this species can influence reef building corals in both positive and negative ways. Field observation and simulation outputs indicated that B. muricatum reduced the abundance of macroalgae that can outcompete corals, but they also feed directly on corals, decreasing coral abundance, diversity, and colony size. B. muricatum appeared to facilitate coral advancement by mechanically dispersing coral fragments and opening up bare space for coral settlement, but they also damaged adult corals and remobilized a large volume of potentially stressful carbonate sediment. The impacts this species has on reefs appears to be regulated in part by its abundance—the effects of B. muricatum were more intense in simulation scenarios populated with high densities of these fish. Observations conducted in regions with high and low predator (e.g., sharks) abundance generated results that are consistent with the hypothesis that these predators of B. muricatum may play a role in governing their abundance; thus, predation may modulate the intensity of the effects they have on reef dynamics. Overall our results illustrate that functionally unique and threatened species may not have universally positive impacts on ecosystems and that it may be necessary for environmental managers to consider the diverse effects of such species and the forces that mediate the strength of their influence. Efectos Positivos y Negativos de un Pez Loro Amenazado Sobre Ecosistemas Arrecifales  相似文献   

14.
Two closely related forms ofOphrys insectifera were observed in the field to attract different pollinator species selectively.O. i. ssp.insectifera attracted males of two species ofArgogorytes (Sphecidae, Hymenoptera Aculeata) andO. i. ssp.aymoninii attractedAndrena combinata males (Andrenidae, Apoidea, Hymenoptera Aculeata). A third form,O. aff.i. ssp.insectifera, attracted none of these three species. Volatile compounds from flowers and inflorescences of the three forms (originating from Öland, Sweden, and Aveyron, France) were collected, using entrainment, enfleurage, and solvent extraction techniques, and identified by gas chromatography — mass spectrometry. Scent differences between the three forms were confirmed in the amounts of aliphatic hydrocarbons (C11–C19), methyl esters (C14–C18), short chain aliphatic 1-alcohols (C6–C12), and monoterpene alcohols (C10).  相似文献   

15.
A method is developed to estimate the stress at the surface in a portable wind tunnel for wind erosion studies. The boundary layer height and the pressure gradient are used in a simple expression from the Kármán Integral Momentum Equation. Values of friction velocity u * are within 10% of experimental values obtained through correlation techniques, including measurements of differential pressures with the Murdoch Turbulence Probe MTP and the X-wire, hot-wire anemometer XWA. Wind velocity and stress profiles reveal logarithmic trends and a constant stress layer near the surface in the DAWA portable wind tunnel. Realignment of the statistics with the mean wind is essential.  相似文献   

16.
Global biodiversity indices are used to measure environmental change and progress toward conservation goals, yet few indices have been evaluated comprehensively for their capacity to detect trends of interest, such as declines in threatened species or ecosystem function. Using a structured approach based on decision science, we qualitatively evaluated 9 indices commonly used to track biodiversity at global and regional scales against 5 criteria relating to objectives, design, behavior, incorporation of uncertainty, and constraints (e.g., costs and data availability). Evaluation was based on reference literature for indices available at the time of assessment. We identified 4 key gaps in indices assessed: pathways to achieving goals (means objectives) were not always clear or relevant to desired outcomes (fundamental objectives); index testing and understanding of expected behavior was often lacking; uncertainty was seldom acknowledged or accounted for; and costs of implementation were seldom considered. These gaps may render indices inadequate in certain decision-making contexts and are problematic for indices linked with biodiversity targets and sustainability goals. Ensuring that index objectives are clear and their design is underpinned by a model of relevant processes are crucial in addressing the gaps identified by our assessment. Uptake and productive use of indices will be improved if index performance is tested rigorously and assumptions and uncertainties are clearly communicated to end users. This will increase index accuracy and value in tracking biodiversity change and supporting national and global policy decisions, such as the post-2020 global biodiversity framework of the Convention on Biological Diversity.  相似文献   

17.
Use of the internet as a trade platform has resulted in a shift in the illegal wildlife trade. Increased scrutiny of illegal wildlife trade has led to concerns that online trade of wildlife will move onto the dark web. To provide a baseline of illegal wildlife trade on the dark web, we downloaded and archived 9852 items (individual posts) from the dark web, then searched these based on a list of 121 keywords associated with illegal online wildlife trade, including 30 keywords associated with illegally traded elephant ivory on the surface web. Results were compared with items known to be illegally traded on the dark web, specifically cannabis, cocaine, and heroin, to compare the extent of the trade. Of these 121 keywords, 4 resulted in hits, of which only one was potentially linked to illegal wildlife trade. This sole case was the sale and discussion of Echinopsis pachanoi (San Pedro cactus), which has hallucinogenic properties. This negligible level of activity related to the illegal trade of wildlife on the dark web relative to the open and increasing trade on the surface web may indicate a lack of successful enforcement against illegal wildlife trade on the surface web.  相似文献   

18.
Freshwater turtle populations are susceptible to declines following small increases in the mortality of adults, making it essential to identify and understand potential threats. Freshwater turtles ingest fish hooks associated with recreational angling, and this is likely a problem because hook ingestion is a source of additive mortality for sea turtles. We used a Bayesian‐modeling framework, observed rates of hook ingestion by freshwater turtles, and mortality of sea turtles from hook ingestion to examine the probability that a freshwater turtle in a given population ingests a hook and subsequently dies from it. We used the results of these analyses and previously published life‐history data to simulate the effects of hook ingestion on population growth for 3 species of freshwater turtle. In our simulation, the probability that an individual turtle ingests a hook and dies as a result was 1.2–11%. Our simulation results suggest that this rate of mortality from hook ingestion is sufficient to cause population declines. We believe we have identified fish‐hook ingestion as a serious yet generally overlooked threat to the viability of freshwater turtle populations.  相似文献   

19.
20.
Content analysis of newspaper coverage of the Florida panther   总被引:1,自引:0,他引:1  
Populations of large carnivores are declining globally, and analysis of public discourse about carnivores is useful for understanding public opinion and influences on management and policy. Portrayal of carnivores in the media affects public perceptions and support for their conservation. We conducted a content analysis of 513 articles about Florida panthers (Puma concolor coryi) published from 2003 to 2006 in newspapers with local circulation in core panther habitat in southwest Florida and papers with statewide circulation to compare the differences in the amount of coverage and portrayals of panther risks to people and property on the basis of proximity of human communities to panthers. Local papers published significantly more news articles and significantly longer news articles primarily about panthers. Articles in local and statewide papers used both episodic frames, which focus on specific occurrences (e.g., a panther sighting or predation) and thematic frames, which focus on general trends (e.g., abundance of panthers over time). Local articles more often emphasized risks that panthers might harm people, pets, or livestock than statewide papers. Our results are consistent with theory that proximity to human-carnivore conflict influences perceptions and salience of risks posed by large carnivores. Most articles mentioned panthers as a secondary topic, which we believe was a result of the relevance an endangered carnivore has in discussions of public land management, development, and regulations in Florida. Claims made by sources quoted in each article had a neutral to positive depiction of panthers, and most quotations were from federal and state agency scientists. We suggest continued use by the media of agency sources provides the opportunity for clear, concordant messages about panther management. Content analysis provides a way to monitor media portrayal of carnivores for consistency with agency outreach goals.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号