浅谈水生植物在园林造景中的配置及应用

本文介绍了水生植物的概念及分类,分析了水生植物在园林中的作用及在园林造景中的配置,并对水生植物在园林中的应用进行探讨,以期通过本文的阐述让更多的人重视对水生植物研究与利用。     

分析植物修复在水环境污染治理中的应用

水生植物能够去除水体中的污染物质,且不会造成二次污染,有利于水生生态环境的重建与恢复,具有投资少、维修费用低廉、操作简便等优点。文章论述了水生植物治理水环境污染的作用,并结合水生植物的净化机理,分析水生植物对不同污染物的影响,提出了利用植物修复技术治理水环境的有效措施。     

城市水体净化中水生植物的选择及应用探析

在实际生活中,利用水生植物来进行水体净化已经得到了广泛应用。科学研究证明,部分水生植物具有极佳的治污能力,不但能够去除污水中的氮、磷等营养物,还能吸附污水中的金属离子、有机物等。本文对这些治污水生植物的类型进行了说明,并详细探讨了水生治污植物的作用、应用。     

水生植物修复富营养化水体的机理及影响因素综述

介绍了水生植物修复富营养化水体的机理及其影响因素。水生植物修复受多种因素制约,包括植物物种差异、水体富营养化程度差异、植物种植方式等,并提出了水生植物水体修复技术今后有待进一步研究的问题。     

水生植物在水质改善中应用探究

近年来,水体污染已经严重威胁人类健康,目前引起广泛的关注,鉴于传统物理化学法治理水污染成本高、易产生二次污染,人们将目光转向于水生植物治理污水上。本文介绍了以水生植物为核心的各种污水处理系统的研究进展与现状;探讨了用水生植物治理污水的机制及水生植物污水治理效果的影响因素。     

四种水生植物中无机元素和维生素C的研究

目的：水生植物中的无机元素和维生素是水生植物营养成分的组成部分,为了评价四种水生植物（芋头、荸荠、茭白、菱角）的品质。方法：用火焰原子吸收法和2,6-二氯酚靛酚滴定法[1]对它们中的无机元素和维生素C进行测定。结果表明：四种水生植物中各种营养素的含量均很高。结论：水生植物综合开发和使用前景广阔。     

水生植物在海绵城市构建中的应用研究

文章以滨州市海绵城市为例,滨州在其建设过程中使用了水生植物,文章对在其建设中植物的作用进行分析,以此明确水生植物在打造海绵城市,构建宜居生态环境的价值。研究为提高同领域水生植物防内涝、固土的应用,全面推广海绵城市景观构建,提供参考。     

大型水生植物在水污染治理中的应用研究进展

近年来随着将大型水生植物运用在水污染治理中,通过长时间研究发现,其可以通过自身生长代谢吸收氮、磷等水体营养物质,从而实现降解有机污染物。而进一步针对大型水生植物在水污染治理中应用研究进展展开分析,对于促进我国水污染治理会起到诸多帮助。基于此,本文首先将会针对大型水生植物及生态功能展开概述,而后针对大型水生植物在生态系统污水处理中应用研究进展与现状展开分析,进而针对大型水生植物种类选择及搭配展开研究,旨为相关人员提供参考帮助。     

莲藕汁饮料的研制

本文对莲藕汁饮料研制过程中防褐变方法、酶法处理原汁等关键工艺、技术进行了研究,确定了科学的生产工艺、较好地解决了藕汁饮料生产过程中沉淀、褐变、涩味等突出问题,最大程度地保持了莲藕中原有的营养成份和药理功能。利用扬州地区白花莲藕研制出的天然莲藕汁饮料清雅爽口,藕香浓郁,风味独特,不含色素、香精和防腐剂。本产品为利用水生植物资源开发饮料食品开辟了新路。     

水生植物在水环境治理中的作用

随着近些年水污染趋势的不断加剧,以及水资源紧缺现象的愈发严重,治理水环境已经成为了一项重要的社会问题。作为江河湖泊中最为常见的植物类型,水生植物经常被相关人员用来作为水塘和湿地的污水治理手段。将水生植物应用到治理水环境的工作中,其自身的新陈代谢行为可以促进水环境中微生物降解的速度,控制水污染。文章以水生植物为研究点,通过对其在水环境治理工作中的作用进行分析,从而对其在该项治理工作中具体的应用情况进行研究。     

Positive effects of wastewater ozonation displayed by in situ bioassays in the receiving stream

Tertiary treatment methods, like ozonation, are currently under discussion to improve removal efficiencies of micropollutants by municipal wastewater treatment plants (WWTPs). In order to assess the effects of a full-scale wastewater ozonation at WWTP Wu?eri, Switzerland, on the receiving stream, a total of seven in situ bioassays with Gammarus fossarum that lasted 7-days were conducted during an overall period of 33 months. Caged gammarids were exposed between 150 m up- and 400 m downstream of a WWTP effluent before, during and following the operation of the full-scale wastewater ozonation. During the release of nonozone treated wastewater, gammarid feeding was significantly reduced by up to 90% 50 and 150 m downstream of the WWTP effluent. In contrast, during the operation period of the ozonation, no significant alterations in feeding were observed downstream. The results of these bioassays were incorporated into a mathematical simulation of the release of nonozone treated wastewater in a Central European region, suggesting a 40% reduction in leaf litter breakdown and hence in energy provision for the remaining aquatic food web downstream of WWTP effluents, while the release of ozone treated wastewater did not affect this important ecosystem function.     

水环境中纤维微塑料去除技术研究展望

微塑料作为一种水环境中大量存在的新兴污染物已引起学者和公众的重视,而且目前常用的污水处理工艺无法实现对微塑料的完全去除,导致大量的小尺寸微塑料和纤维微塑料在水环境中积累,对生物体造成持续危害。为减少环境中的微塑料污染,通过对现有的水环境微塑料去除技术相关工作的综述,探讨了各项技术的去除机制、效率和可行性。并针对目前传统水处理工艺对去除纤维微塑料的低效和纤维微塑料去除相关研究工作的匮乏,从传统水处理工艺的改革、纤维微塑料的重视程度、纤维微塑料无害化去除手段的探索、纤维微塑料的资源化利用4个方面对未来纤维微塑料去除技术的发展趋势进行展望。     

Algal uptake of hydrophobic and hydrophilic dissolved organic nitrogen in effluent from biological nutrient removal municipal wastewater treatment systems

Dissolved organic nitrogen (DON) accounts for a large fraction of the total nitrogen discharged to surface waters by municipal wastewater treatment plants designed for biological nutrient removal (BNR). Previous research indicates that some but not all of the DON in wastewater effluent is available to bacteria and algae over time scales that are relevant to rivers and estuaries. To separate bioavailable DON from nitrate and less reactive DON species, an XAD-8 resin coupled with an anion exchange treatment was employed prior to chemical analysis and algal bioassays. Analysis of effluent samples from a range of municipal BNR plants (total DON concentrations ranging from 0.7 to 1.8 mg N/L) employing a range of technologies indicated that hydrophilic DON, which typically accounted for approximately 80% of the total DON, stimulated algal growth, whereas hydrophobic DON, which accounted for the remaining DON, remained at nearly constant concentrations and had little or no effect on algal growth during a 14-day incubation period. The hydrophobic DON exhibits characteristics of humic substances, and is likely to persist for long periods in the aquatic environment. The distinct differences between these two classes of DON may provide a basis for considering them separately in water quality models and effluent discharge regulations.     

Applications of fluorescence spectroscopy for predicting percent wastewater in an urban stream

Dissolved organic carbon (DOC) is a significant organic carbon reservoir in many ecosystems, and its characteristics and sources determine many aspects of ecosystem health and water quality. Fluorescence spectroscopy methods can quantify and characterize the subset of the DOC pool that can absorb and re-emit electromagnetic energy as fluorescence and thus provide a rapid technique for environmental monitoring of DOC in lakes and rivers. Using high resolution fluorescence techniques, we characterized DOC in the Tualatin River watershed near Portland, Oregon, and identified fluorescence parameters associated with effluent from two wastewater treatment plants and samples from sites within and outside the urban region. Using a variety of statistical approaches, we developed and validated a multivariate linear regression model to predict the amount of wastewater in the river as a function of the relative abundance of specific fluorescence excitation/emission pairs. The model was tested with independent data and predicts the percentage of wastewater in a sample within 80% confidence. Model results can be used to develop in situ instrumentation, inform monitoring programs, and develop additional water quality indicators for aquatic systems.     

Characterization of Pseudomonas mendocina LR capable of removing nitrogen from various nitrogen-contaminated water samples when cultivated with Cyperus alternifolius L

A new strain of denitrifying bacterium, Pseudomonas mendocina LR, was isolated from rhizosphere soil of aquatic plants living in a river contaminated with industrial wastewater and domestic sewage. The isolate was found to fully remove as much as 613.2 mg nitrate in 60 h under stationary culture conditions. The effects of carbon sources and nitrogen sources on nitrogen removal were investigated using a modified denitrification medium (DM). Sodium citrate was identified as the most effective source of carbon. The ability of LR to adapt to different nitrogen sources, including nitrite, indicated that LR could be used in the purification of wastewater containing different forms of nitrogen. The optimal C/N ratio was 7 for LR, and it was resistant to antibiotics Amp, Chl, Ery, and Str. Plant-microbe bioaugmentation was performed to remove nitrogen dissolved in Hoagland medium and natural wastewater. An increased rate of nitrogen removal was observed when root exudates of Cyperus alternifolius L. were added simultaneously with LR. LR was not able to survive in the natural wastewater unless root exudates from umbrella grass were added. LR cultured with umbrella grass exhibited a maximal nitrogen reduction rate of 95.9% and 97.3% in Hoagland medium and wastewater, respectively. This shows that bioaugmentation utilizing plant-microbe interactions can be an effective and exhaustive means of removing nitrogen and may be an attractive approach to nitrogen reduction in natural environments and wastewater treatment factories.     

Fate, transport, and biodegradation of natural estrogens in the environment and engineered systems

Natural steroidal estrogen hormones, e.g., estrone (E1), 17beta-estradiol (E2), estriol (E3), and 17alpha-estradiol (17alpha), are released by humans and livestock in the environment and are the most potent endocrine disrupters even at nanogram per liter levels. Published studies broadly conclude that conventional wastewater treatment is efficient in the removal of 17beta-estradiol (85-99%), but estrone removal is relatively poor (25-80%). The removal occurs mainly through sorption by sludge and subsequent biodegradation. The long solids retention time in wastewater treatment systems enhances estrogen removal due to longer exposure and the presence of a diverse microbial community, particularly nitrifiers. In spite of the treatment, the effluent from conventional biological wastewater treatment systems still contains estrogenic compounds at a level that may cause disruption of endocrine systems in some species. Advanced wastewater treatment systems such as membrane processes remove the estrogen compounds mainly through physical straining of particle-bound estrogens. Another major source, which accounts for 90% of the estrogen load, is animal manure from concentrated animal-feeding operations (CAFOs). Manure is not required to be treated in the United States as long as it is not discharged directly into water bodies. Thus, there is an urgent need to study the fate of animal-borne estrogens from these facilities into the environment. A number of studies have reported the feminization of male aquatic species in water bodies receiving the effluents from wastewater treatment plants (WWTPs) or surface runoff from fields amended with livestock manure and municipal biosolids. Estrogenicity monitoring studies have been conducted in more than 30 countries, and abundant research articles are now available in refereed journals. This review paper focuses on estrogen contributions by wastewater and livestock manure, their removal rate and mechanisms in an engineered system, and their transport and ultimate fate in an engineered system and the environment. The review aims to advance our understanding of fate, transport, and biodegradation of estrogen compounds and outlines some directions for future research.     

Nicotine derivatives in wastewater and surface waters: application as chemical markers for domestic wastewater

Nicotine is extensively metabolized in the human body to a number of compounds, which may enter natural waters via discharge of domestic wastewater. However, little is known on exposure of and potential effects on the aquatic environment. In this study, two major urinary metabolites, cotinine and 3'-hydroxycotinine, as well as a further tobacco alkaloid, N-formylnornicotine, were measured in wastewater and water from Swiss lakes using an analytical procedure based on SPE and LC-MS/MS SRM with cotinine-d3 as internal standard (LOQs, 1.0-1.5 ng/L). Typical concentrations of cotinine and 3'-hydroxycotinine were approximately 1-10 microg/L in untreated wastewater, but clearly less in treated wastewater (approximately 0.01-0.6 microg/L), corresponding to elimination efficiencies of 90-99%. N-Formylnornicotine, however,was found at similar concentrations in untreated and treated wastewater (0.02-0.15 microg/L). Its apparent persistence during wastewater treatment was further confirmed by incubation experiments with activated sludge. In lakes, cotinine, 3'-hydroxycotinine, and N-formylnornicotine were detected at concentrations up to 15, 80, and 6 ng/L, respectively. Concentrations in lakes correlated with the expected anthropogenic burden by domestic wastewater (ratio population per water throughflow), demonstrating the suitability of these nicotine derivatives as hydrophilic, anthropogenic markers. In small receiving waters with significant wastewater discharges, concentrations of a few hundred ng/L may be expected. Possible ecotoxicological risks associated with such environmental concentrations, can, however, not be assessed at present as data on effects on aquatic organisms are very limited, in particular on long-term effects.     

Occurrence and mass flows of fluorochemicals in the Glatt Valley watershed, Switzerland

Fluorochemicals are persistent contaminants that are globally distributed in air, water, sediments, and biota. Wastewater treatment plants (WWTPs) play an important role in mitigating pollutant releases from municipalities to aquatic and terrestrial environments. However, because WWTPs are point sources of fluorochemicals, it is important to understand their contribution to fluorochemical burdens in the greater context of watersheds. To this end, over a 1 week period, the mass flows of 11 fluorochemicals from seven WWTPs that discharge effluent into the Glatt River in Switzerland were measured and compared to the measured mass flows within the Glatt River. Overall, the fluorochemicals were not removed efficiently during wastewater treatment. Effluents from WWTPs and Glatt River water were dominated by perfluorooctane sulfonate, which was detected in all samples, followed by perfluorohexane sulfonate and perfluorooctanoate. The mass flows of fluorochemicals emanating from WWTPs were found to be conserved within the 35 km Glatt River, which indicates that input from the WWTPs is additive and that removal within the Glatt River is not significant. Per capita discharges of fluorochemicals were calculated from the populations served by the WWTPs studied; the values determined also account for the fluorochemical content of Lake Greifen (Greifensee), which is a lake at the headwaters of the Glatt River that also receives treated wastewater.     

Occurrence and fate of macrolide antibiotics in wastewater treatment plants and in the Glatt Valley watershed, Switzerland

An analytical method was developed for determining macrolide antibiotics in treated wastewater effluents and in ambient water based on solid-phase extraction and LC/MS analysis as well as on LC/MS/MS for structural confirmation. In wastewater treatment plants (WWTPs) macrolides are only partly eliminated and can therefore reach the aquatic environment. In treated effluents from three WWTPs in Switzerland, clarithromycin, roxithromycin, and erythromycin-H2O, the main degradation product of erythromycin, were found. The most abundant, clarithromycin, reflects the consumption pattern of macrolide antibiotics. Summer concentrations of clarithromycin varied between 57 and 330 ng/L in treated WWTP effluents. In the WWTP Kloten-Opfikon seasonal differences revealed a load two times higher in winter than in summer. The higher abundance of erythromycin-H2O in the effluent of WWTP Kloten-Opfikon can be explained by distinct consumption patterns due to the main international airport of Switzerland in the catchment area. In the Glatt River clarithromycin reached concentrations of up to 75 ng/L. Mass flux determinations in treated effluents and in river water in the Glatt Valley watershed showed that elimination of clarithromycin along the river stretch of 36 km is insignificant (<20%). Investigations in the Glatt River before and after the diversion of the largest WWTP revealed an observable decrease in clarithromycin loads.