共查询到20条相似文献,搜索用时 203 毫秒
1.
2.
3.
沉水植物占据着水体生态系统的关键界面,是水-沉积物环境质量及其界面物质迁移转化的重要调节器,对水体生产力及生物地球化学循环具有十分重要的影响。沉水植物在生长发育、衰亡过程中,通过直接或间接作用影响沉积物磷的迁移转换。针对已有研究成果存在的问题,提出了今后的研究方向:研究方法的改进与创新,拓展研究范围,开展生物相磷的相互迁移转化研究,深化不同类型沉水植物对沉积物磷影响机制的研究等。 相似文献
4.
5.
典型盐碱地改良区农田排水沟水体与底泥界面氧通量研究 总被引:2,自引:0,他引:2
农田排水沟水体与底泥中的氧含量决定了底泥中各种生源要素的最终归趋,对维持农田排水沟的水环境至关重要。本论文以陕西富平县卤泊滩盐碱地改良区农田排水沟水体与底泥为研究对象,从环境微界面角度出发,根据多年监测数据构建室内试验,采用高分辨率微环境固液剖面传感系统(丹麦Unisense微电极系统),探究了研究区农田排水沟水体与底泥界面氧通量变化规律。研究结果表明:底泥中的溶解氧随深度的增加逐渐减小,直至溶解氧浓度为零,到达厌氧层;溶解氧剖面浓度的实测值与Profile模型模拟值的相关系数均在0.995以上,表明该模型能客观地描述溶解氧在农田排水沟水体与底泥扩散边界层和底泥中的分布;农田排水沟上游不同监测点位的底泥含氧层厚度在3.5~6 mm之间,而下游监测点位的底泥含氧层厚度约为1.5 mm,差异显著;通过氧浓度线性分布、剖面拐点法得到氧气扩散边界厚度,上游监测点位的氧气扩散边界层厚度基本在1 mm,而下游监测点位的氧气扩散边界层厚度减少至0.2 mm。农田排水沟水体与底泥界面氧通量的测定,对于认识农田排水沟底泥的地球化学过程及水环境作用机理具有重要意义,可为农田排水沟水环境治理提供参考依据。 相似文献
6.
《人民黄河》2021,43(10)
遴选地表水环境中常见的聚乙烯(PE)微塑料为目标污染物,开展絮凝试验,研究絮凝剂种类、pH值及助凝剂阴离子聚丙烯酰胺(APAM)对水体中PE微塑料去除的影响,分析絮凝机制。结果表明:相同絮凝剂投加量时,硫酸铝对PE微塑料的去除率高于三氯化铁的;水体pH值为中性、硫酸铝投加量为50 mg/L,室温下PE微塑料去除率约为40%,同样的水质条件及硫酸铝投加量下,加入5 mg/L APAM强化絮凝反应,PE微塑料的去除率提升至53.19%,当APAM投加量大于10 mg/L时,PE微塑料的去除率提升至60%;在助凝剂APAM强化硫酸铝对PE微塑料的絮凝去除过程中,吸附电中和、吸附架桥作用是絮凝去除微塑料的主要机制。 相似文献
7.
通过对三峡库区中部典型支流梅溪河库湾水动力参数及水体温度、浊度数据进行分析,研究水库运行各时期梅溪河河口干支流界面水流特性,探讨其影响因素以及水交换对库湾的影响。结果表明:梅溪河河口双向水流特征明显,在温差异重流、干流惯性作用以及库区水位变动等因素影响下,干支流界面水流强度、进出水体间界面结构及形态在不同运行期有显著差异;由于双向水流结构的存在,尽管梅溪河河口干支流界面净流量较小(多小于100 m~3/s),但是干支流水体的交换量相对显著,介于314.17~535.26 m~3/s之间,可达净流量的4~40倍;在净流量最小的低水位运行期,干流倒灌水体基本能到达支流库湾常年回水区的末端。 相似文献
8.
9.
环境微界面对湖泊内源磷释放的影响研究 总被引:1,自引:0,他引:1
为揭示湖泊内源污染的微界面环境行为及机制,从环境微界面角度出发,研究湖泊水-沉积物界面三相结构模式中磷的界面反应过程。利用微电极系统获取了微界面溶氧浓度剖面,结合Profile模型进行了分析计算。结果发现,玄武湖湖心区沉积柱含氧层厚度达5mm,而湖口区则不到3mm,湖心区微界面上氧气消耗主要以自由扩散为主,而湖口区受微界面上微生物活动影响较大。利用梯度扩散薄膜技术(DGT)获取了水-沉积物界面上分辨率高达1mm的可溶性活性磷DRP剖面浓度分布,结果发现在湖口区沉积物表层2cm处有强烈磷释放现象,而在湖心区则未发现,这可能与含氧层厚度有着密切的联系,这一重要现象在常规尺度下可能被掩盖。 相似文献
10.
在对扬州市江阳中路路面雨后积水的多次采样,分析其COD、电导率、pH等水质参数及降雨历时特征,悬浮颗粒物对COD的贡献的基础上,运用环境扫描电子显微镜和X射线能谱仪,观测悬浮颗粒物的微形貌和元素组成,获得了公路路面降雨一径流非点源污染状况和影响因子等重要信息,为南水北调东线源头区域地表水质量决策提供支持。 相似文献
11.
Wastewater treatment plants (WWTPs) represent a significant source for the input of micro pollutants as endocrine disruptors (EDs) or pharmaceutically active compounds (PhACs) into the aquatic environment. Treatment efficiency of WWTPs often is reported, taking into account only inflow and effluent concentrations without further specification of the WWTP investigated. In order to allow comparison and evaluation of the removal efficiency of different layouts and concepts in wastewater treatment, additional information like the sludge retention time (SRT) and sludge load (F/M ratio) are necessary. Presented results from different WWTPs show correlation of removal of EDs and PhACs to the SRT. Compared to WWTPs with high F/M ratio implementation of the nitrification process on WWTPs results in a significant increase of the removal efficiency for EDs and PhACs. This paper describes an approach to determine comparable removal rates for different activated sludge systems based on mass balance and SRT. 相似文献
12.
The behaviour of nine pharmaceutically active compounds (PhACs) of different diagnostic groups is studied during a nitrifying-denitrifying process in an activated sludge system. The compounds selected cover a wide range of frequently used substances such as anti-epileptics (carbamazepine), tranquillisers (diazepam), anti-depressants (fluoxetine and citalopram), anti-inflammatories (ibuprofen, naproxen and diclofenac) and estrogens (estradiol and ethinylestradiol). The main objective of this research is to investigate the effect of acclimation of biomass on the removal rates of these compounds, either by maintaining a high sludge retention time or at long-term operation. The removal rates achieved for nitrogen and carbon in the experimental unit exceed 90% and were not affected by the addition of PhACs. Carbamazepine, diazepam and diclofenac were only removed to a small extent. On the other hand, higher removal rates have been observed for naproxen and ibuprofen (68% and 82%), respectively. 相似文献
13.
对环境水对混凝土静力强度影响的一系列试验研究成果进行了综述,分析了湿态混凝土静力强度降低的物理机理;指出现有的研究大多为定性的解释,定量的研究较少;提出应研究多因素相互作用对混凝土静力强度产生的影响,并采用有限元法来模拟湿态混凝土各个界面的连接耦合。 相似文献
14.
以4种药理活性化合物(PhACs)为目标物,运用UPLC/MS为检测方法,针对其在城市污水处理厂工艺流程中的分布迁移进行了研究,并进一步实验研究了其迁移机理。所有PhACs在城市污水厂进出水中均被检出,进水中浓度为0.11μg/L(氯贝酸)-0.46μg/L(卡马西平),出水中50μg/L((氯贝酸)-0.45μg/L(卡马西平)。卡马西平几乎不能被去除,除此之外,在生物处理阶段可较有效去除其它PhACs,其迁移机理主要是生物降解,生物降解速率与化合物种类及污泥类型有关。 相似文献
15.
Carbamazepine, diclofenac, ibuprofen and bezafibrate--investigations on the behaviour of selected pharmaceuticals during wastewater treatment. 总被引:1,自引:0,他引:1
Numerous investigations in different European countries observed various pharmaceutically active compounds (PhACs) in notable concentrations in the aquatic environment. Further determinations found the effluents of sewage treatment plants (STPs) to be significant sources for the entry of pharmaceutical residuals to rivers, streams and surface waters. Due to those pathways the knowledge about the elimination of these substances and their behaviour in wastewater treatment plants (WWTP) is elementary for protection of an intact aquatic environment. Since the sludge retention time (SRT) is the most important parameter for the design of STPs, its influence on the reduction rate of these PhACs in the wastewater treatment process was investigated. To study this influence of the SRT on the elimination of PhACs, lab scale plants have been operated with different sludge retention times. The results of the laboratory experiments have been validated analysing various STPs within a wide capacity range and operating at different SRTs. This report describes the determinations observed on the antiepileptic drug Carbamazepine, the two antiphlogistics and analgesics Diclofenac and Ibuprofen and the lipid regulator Bezafibrate. 相似文献
16.
桩-土动力相互作用接触面研究综述 总被引:1,自引:0,他引:1
桩-土动力相互作用的问题是岩土工程、地震工程和结构工程的重要研究内容,其复杂性源于土动力性能和桩-土接触面的动力接触行为的复杂性,因而接触面的研究是桩-土动力相互作用的主要课题之一。回顾了接触面的研究历程和现状,介绍了接触面的变形机理和接触面数值计算方法,阐述了桩-土接触面分离和滑移的判断方法,并对今后的研究提出了几点看法。 相似文献
17.
桩-土界面剪切性状制约着桩基受力特性,对研究桩-土相互作用机理具有重要意义。利用改进后的直剪仪,进行海洋黏土与钢板、混凝土板的界面剪切试验,研究不同含水率、不同固结时间的海洋黏土与钢、混凝土界面的剪切应力-剪切位移关系。结果表明:界面剪切应力-剪切位移关系表现出较好的弹塑性关系,可用双曲线模型表示;随着法向应力增大、含水率减小和固结时间增长,界面峰值剪切应力增大,所需峰值剪切位移增加,峰值剪应力的增加集中在固结开始后的14 d内;界面摩擦角和界面黏聚力随含水率增加而减小,界面摩擦角受固结时间影响不大,集中在20°~23°范围内,界面黏聚力随固结时间增加而增大,且集中在固结开始后的14 d内。研究成果可为海洋桩基工程沉桩阶段阻力估算及数值模拟提供参考。 相似文献
18.
19.
本文用边界元方法定量计算了混凝土非均匀性对断裂特性的影响,特别是在计算中,把骨料增强和微裂纹削弱两种互相制约因素区别开来处理,实例表明,骨料离主裂缝的距离和交界面微裂纹的长度对断裂影响具有最为重要的作用。 相似文献
20.
ABSTRACTResearch at the interface between terrestrial, riverine, estuarine and marine environments is frequently constrained by significant disciplinary and geographical boundaries. This article outlines an international initiative, DANUBIUS-RI, which aims to address these problems by facilitating biogeochemical monitoring and interdisciplinary research on river–sea systems. The scope of the project spans the environmental, social and economic sciences and was accepted into the European Strategy Forum on Research Infrastructures roadmap in 2016. When operational, DANUBIUS-RI will offer researchers access to interdisciplinary expertise, facilities and European river–sea systems, providing a comprehensive platform for multidisciplinary research and training. 相似文献