我国人工湿地标准中潜流湿地设计分析

人工湿地污水处理技术是一种处理污水的生态处理方法,近年来在我国得到快速发展和推广应用。2009年起,国家和部分省份的职能部门颁布实施了一系列人工湿地标准,用于指导并规范人工湿地设计建设,内容主要包括人工湿地构筑物设计、污染负荷设计和水力负荷设计等3方面的参数。比较了各个标准中潜流人工湿地的设计参数,发现不同标准的污染负荷和水力负荷差异明显。人工湿地设计面积计算结果表明,对于不同性质的废水,设计时应核算不同的设计参数,不应只根据水力负荷或仅采用污染负荷进行人工湿地设计。同时,需要考虑气候、湿地填料、深度、植物等其他因素对人工湿地处理效果的影响。     

人工湿地处理污水的实践

分析了胶南市的城区排污现状及人工湿地污水处理工艺的特点。运行效果表明，该工艺投资省、运行费用低、处理效果好，适于沿海小城市的污水处理。     

人工湿地废水处理中氮、磷去除机理研究

人工湿地是由基质、植物、微生物和水体组成污水处理生态系统,在脱氮除磷方面有着很好的效果。文中比较全面的总结了近几年来在人工湿地氮磷去除机理研究方面所取得的一些成果,着重讨论了基质、植物、微生物、水力负荷、温度、溶解氧等因素对人工湿地氮磷去除效果的影响。并提出了为了提高人工湿地脱氮除磷效果、扩大人工湿地应用范围,今后需要开展3方面工作：（1）进一步的深入研究氮磷去除机理;（2）考察更多环境因素对氮磷去除的影响;（3）研发、改进工艺。     

水力负荷对湖滨带人工湿地除磷效果的影响

分析了湖滨带复合人工湿地的各单元在旱季和雨季的除磷效果。结果表明，在进水TP浓度较高时，沉淀池对TP的去除效果较明显，旱、雨季的不同水力负荷对处理效果几乎没有影响。雨季时潜流人工湿地内发生了不溶性磷的吸附和沉积，实现了对磷的去除；旱季时由于水力负荷极小，水体流动性差，系统内处于厌氧状态，出现了磷的释放。雨季时，表面流人工湿地对磷的去除效果没有沉淀池和潜流人工湿地的理想，旱季的低水力负荷对除磷效果没有显著的影响。     

人工湿地植物的研究进展

人工湿地因其去污效果好、运行费用低而被广泛应用于污水处理中。湿地植物在其中起着重要作用。论述了人工湿地植物的作用、去污机理及植物资源,展望了今后的发展重点,以期为类似研究提供参考。     

序批式垂直潜流人工湿地处理农村生活污水

通过改进人工湿地的运行方式设计研发了一种序批式垂直潜流人工湿地(CBW),并将其与传统潜流人工湿地低浸润线和高浸润线运行方式的处理效果进行了对比。CBW对TN和TP的去除率最高,分别为30.85%和52.59%;对氨氮和COD的去除率仅次于低浸润线运行方式的,分别为80.75%和70.14%。CBW处理低碳高氮农村污水的最佳水力负荷为0.1 m3/(m2·d),并且在连续两个月的运行中处理效果较稳定,出水COD和NH4+-N浓度均能达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)的二级标准,为CBW在农村地区的推广应用提供了理论依据。     

人工湿地技术处理油田含油污水的应用

与传统污水处理工艺相比,人工湿地技术具有高效低耗、运行维护简便、对复杂含油污水净化效果良好等特点。文章综述了人工湿地技术处理油田含油污水的净化机理、净化效果、工艺流程及其工艺优势,为含油污水处理技术的研究提供借鉴和参考,对深入认识人工湿地净化机制亦具有一定意义。     

人工湿地污水处理技术简介

人工湿地是20世纪70年代发展起来的一种污水处理技术,具有氮磷去除能力强、投资低、处理效果好、操作简单、维护和运行费用低等优点,以其为基础的生态工程技术费用低廉、实用有效,在治理城镇生活污水方面有较好的效果,适宜在我国推广应用。     

人工湿地用于污水深度处理的反应动力学

比较3种不同形式人工湿地(潜流、表面流和组合流)对城市污水厂二级生物处理出水中污染物的去除效果,并采用一级反应动力学模型进行模拟.结果表明,潜流湿地对有机物、总氮、总磷的去除效率高于其它2种湿地,其标准温度下反应动力学常数( KA20)分别为0.29、0.20和0.28 m/d;表流湿地对氨氮的去除效率最高,其KA20值为0.12 m/d.温度变化对3种人工湿地中有机物和总磷去除的影响不明显,对氨氮和总氮的去除有明显影响,尤其对表面流湿地影响最为显著.3种人工湿地对污染物的去除效率均随着水力负荷的增大而显著下降,污染物的面积去除量将随着面积负荷的不断提高逐渐趋于定值,因此人工湿地宜在低负荷工况下运行.     

人工湿地生态系统在城镇污水治理中的应用研究

城镇污水处理工作要求不断提高,既需要保证污水得到有效处理,同时还要做到生态环保,积极推广人工湿地技术,提升污水治理水平,有着重要的意义。本文现针对人工湿地在城镇污水治理中的应用相关问题,展开具体的论述,提出人工湿地运用的策略。     

虹口港、杨浦港地区旱流污水截流工程设计水量的论证

对虹口港、杨浦港地区近几年来产业结构调整 ,污染大户的外迁 ,工业废水量明显减少的情况进行调研 ,通过对现状污水量的采集 ,规划、现状水量的测定等进行了详细的分析和论述 ,比较客观合理确定虹口港、杨浦港地区旱流污水截流工程的设计污水量     

工作流设计案例分析——房产管理系统中的工作流设计

工作流的设计概念应用到软件系统中,将工作过程分解成任务、角色,按照一定的规则来执行这些任务并对它们进行监控,可以提高办事效率、降低房产管理成本,提升企业经营管理水平和企业市场竞争力。房产管理系统中借鉴工作流的概念,可有效地提高管理人员的技术水平。     

变频调速与管网叠压供水系统小流量工况分析与对策探讨

在用水低谷期出现的生活给水系统小流量是造戍水泵运行效率低下、影响变频供水系统节能效果的重要因素之一.通过实测数据分析验证了变频调速供水系统在小流量工况下的高能耗现象;在分析变频调速泵特性曲线的基础上分别推求出满足水泵高效运行和变频可调速的最小流量,为水泵的选取提供理论依据;结合实例阐述了克服小流量不利影响的技术措施.     

An analysis of compartment fire doorway flows

A mathematical study is made to compute the doorway flow behavior due to fire in a room. Two approaches were taken, first a model attempting to include the effect of fire entrainment and vent mixing; second was a model based on an ideal point source plume fire—both in the zone model concept. Limiting analytic results were found for the latter to give insight into the physics. The results were compared to available flow data, and an approximate formula was developed to predict the doorway mass flow rate to within 20% for a wide range of fire conditions. CFD computations were also explored using FDS. Results are compared from FDS and the zone model with experimental data for a wide range of variables.     

水利工程明渠均匀流水力计算探讨

结合工程实例,阐述了水利工程明渠均匀流的计算方法及计算注意事项,对其中的有关水力专业名词及计算作出详细解释.     

Characterization of two-phase flow in a single rock joint

An experimental study using a triaxial apparatus was used to analyze the two-phase flow patterns in jointed rock specimens. Rock specimens having a single natural fracture were tested for two-phase flow of water and air. Triaxial tests were conducted to characterize the two-phase flow through fractured granite specimens at low confining pressures. It was found that for a relatively smooth joint (JRC<6), bubble flow pattern occurred within the rock joint when the gas velocity is below 15 m/s. The average velocity of water usually varied between 0.1 and 0.5 m/s for bubble flow patterns. In this velocity range, air bubbles were able to form along the joint walls or to be randomly displaced within the water phase. When the gas velocity inside the rock joint exceeded 22 m/s, the flow patterns took annular form for non-zero capillary pressures (i.e., injected gas pressure is not equal to injected water pressure). At elevated (>0.25 MPa) gas injection pressures, the gas occupied the main part of the fracture and the liquid was able to flow as an unstable film forming an annular flow along the joint. When the annular flow developed, the mixture flow pattern was independent of the air flow velocity. This was due to the fact that once the injected air velocity reached a critical value (i.e., 20 m/s), water velocity inside the joint was negligible for a given confining pressure and injected water pressure. Further increase in inlet air pressures developed a single-phase air flow with no water flow.     

供热系统中调节阀的研究与应用

依据调节阀流量特性的数学方程，导出了流量特性分别为直线型和等百分比型调节阀流通截面积的计算公式，指出了现有调节阀阀芯形状设计中存在的问题，分析了供热系统中调节阀的选用原则，认为应根据流通能力来计算选择调节阀的口径，而不是由连接管的管径来确定，并认为调节阀的安装地点不同，其计算公式中的系数有差别。     

Study on performance of horizontal single pass shell and multi-tube heat exchanger with baffles by air bubble injection

ABSTRACT

The single pass shell and multi-tube heat exchanger with double segmental baffles'’ performance improvement were experimentally investigated by two methods of air injection into shell side when an increase in air bubble created an effect in the corresponding values of shell and tube heat exchanger such as the overall heat transfer coefficient, effectiveness, NTU and the pressure loss. In the first method, air bubble injection into shell side was parallel to the cold water flow; also in the second method, air bubble injection into shell side was cross flow to the cold water with different air flow rates to calculate approximately the most favourable performance conditions. 1–6?LPM of air flow rates and 10–20?LPM shell side water flow rates were transformed with constant tube side hot water flow rate.     

The importance of gully flow modelling to urban flood simulation

ABSTRACT

Urban flood simulation often ignores or simplifies the function of underground gully systems due to data and computational limitations. To discover the influence of gullies on urban flooding, a novel approach is proposed in this study, by fully-coupling a 1D gully flow model (GFM), a 1D sewer flow model (SFM), and a 2D overland flow model (OFM) to simultaneously simulate the flow exchanges between surface, gullies and sewer pipes. This fully-coupled approach is compared with a simplified approach which directly introduces surface water into sewer pipes without being via gullies. The validation results show that the fully-coupled approach considerably reduces the underestimation of flood extent by 27% compared with the simplified approach. Without considering the capacity of lateral tubes between gullies and sewer pipes, the simplified approach over-drains the surface water into sewer pipes. The modelling of gully flow is crucial for correctly evaluating the efficiency of drainage systems.     

水环热泵空调水系统变流量节能控制探讨

针对传统空调系统设计负荷偏大、系统运行过程中水系统输送流量不能随室内负荷变化而变化的情况,在引入流量差异系数的基础上,认为对水环路采用流量控制可以达到节能的目的.