城市供水系统的节能与优化

介绍了供水系统节能的几种常见方式以及泵站优化运行中线性规划法，非线性规划法等基本方法，并针对管网优化中常用的非线性规划算法以及近几年出现的基因算法进行论述。在对各种方法进行论述的过程中，提出其适用条件及优，缺点，同时，在对城市给水系统的节能与优化进行综述的基础上，提出建议。通过本文希望达到确定已有方法，认清新发展方向的目的。     

考虑THM的管网水质服务水平多目标优化

针对供水管网中余氯及氯仿(THM)服务水平优化问题,提出了一种衡量THM服务水平的表达式,推导了THM-I/O模型,建立了以管网余氯服务水平最大化、THM服务水平最大化以及加氯费用最小化的多目标优化模型。考虑了主体水余氯衰减系数、基于余氯消耗的THM生成比例系数、出厂水THM浓度、加氯点数量4个影响因素对优化结果Pareto前沿面的影响。结合一管网算例,采用EPANET_MSX模拟余氯衰减和THM生成,利用实数编码的非支配排序遗传算法Ⅱ(NSGA-Ⅱ)进行优化,可得到各种情况下的Pareto前沿面。计算结果表明,随着主体水余氯衰减系数减小,加氯费用减少,THM服务水平增加。基于余氯消耗的THM生成比例系数和出厂水THM浓度的减小均能提高THM服务水平,但对加氯费用没有影响。增加加氯点虽然能减少余氯投加,但加氯站建设费用加大了总加氯费用。降低主体水余氯衰减系数是提高管网水质服务水平最经济有效的方法。     

Concentration and size distribution of bioaerosols in an outdoor environment in the Qingdao coastal region

Bioaerosol particles in the atmosphere were collected from the coastal region of Qingdao from Jul. 2009 to Jun. 2010. The concentrations of microorganisms (including culturable, nonculturable, terrestrial and marine microorganisms) were measured. Average concentrations of airborne terrestrial bacteria, marine bacteria, terrestrial fungi, marine fungi and total bioaerosol were in the ranges of 33-664 CFU/m³, 63-815 CFU/m³, 2-777 CFU/m³, 66-1128 CFU/m³ and 85,015-166,094 Cells/m³, respectively. The nonculturable microbes accounted for 99.13% of the total microbes. In addition, there were more culturable marine microbes than culturable terrestrial microbes, and more airborne fungi than bacteria. The concentration of airborne bacteria showed a skewed distribution pattern, while unimodal size distributions were observed for the concentrations of fungi and total microbes. The airborne microbes mainly existed in > 2.1 μm coarse particles. Pearson correlation analysis between the concentrations and meteorological parameters showed that the meteorological parameters had different effects on different kinds of microbes. Sandstorms increased the concentrations of both culturable microbes and total microbes in the bioaerosol.     

给水管网中细菌总数快速预测模型的建立与应用

对选定实际给水管网的水质进行了长期监测,研究了水质与细菌总数的相关关系,分析确定了与细菌总数相关性较高且易于测定的水温、自由余氯、总余氯、浊度及UV254等5项指标.应用多元线性回归分析建立了实际给水管网中细菌总数的快速预测模型.经验证,该模型预测的准确度为64.55%,能够用于实际给水管网中细菌总数的快速预测,可为保障供水管网水质微生物学指标的安全提供快速、可靠的技术支持.     

给水管网压力监测点的优化布置

以厦门市给水管网压力监测点的布置为例，根据给水管网压力监测系统的实际运行数据，综合利用变量相关系数和变量标准差等信息，建立了管网压力监测系统信息量的优化模型．并采用残差、信息损失比率及逐步回归方法，确定了给水管网压力监测点的优化布置方案。     

固定化菌种处理锈蚀管网出水的研究

发生内腐蚀的管道出水往往使出厂饮用水水质部分超标,遂进行了相关的深度净化技术研究。从除铁除锰滤池中的成熟滤砂洗脱下滤膜,以铁锰细菌的选择性培养基进行分离纯化,共培养出5株铁锰降解菌。通过试验发现,铁锰降解菌在铁、锰共存的培养基中的生长情况要好于只含铁基质的,而在只含有锰的基质中不生长。将降解有机物的工程菌和铁锰降解菌固定在同一个反应器的不同滤料上并处理管网出水(浊度为1.5NTU、色度≥25倍、有腥味),结果表明,一体式固定菌种反应器对铁、锰和高锰酸盐指数的去除率可达98%、96%和55%,处理出水的浊度<0.5NTU,色度<15倍,没有嗅味。     

Effect of THMs concentrations on the redesigning of Bani Suef water distribution system

Controlling trihalomethanes (THMs) formed in water distribution systems (WDS) is an important issue for producing safe drinking water in the last decades. The main objective of this study is to design WDS to minimize THMs formation. Implemented case of Bani Suef water distribution system (BSWDS), Egypt, was modeled and studied for operating scenarios 2020 and 2040 (case study) using WaterCAD software, alternative [1]. Drinking water samples were collected from fifteen points located on BSWDS according to monthly sampling program performed between February and September 2015. Laboratory analysis showed that the total growth rate coefficient was 1.157 day^?1, used in THMs prediction by WaterCAD. Three design alternatives [2, 3, 4] were prepared to reduce the formed THMs based on WaterCAD results. Alternative [2] represented new design of alternative [1] through using decreased pipes diameters to study the effect of reducing travel time on minimizing THMs. Alternative [3] was prepared by redesigning alternative [1] using extending new pipelines from dead ends. Alternative [4] was prepared by redesigning alternative [1] through replacing asbestos cement pipes with new UPVC ones. Predicted THMs from alternatives [2, 3, 4] are lower about 27.85, 21.82 and 11.4% than alternative [1], respectively, for 2020. While, for 2040, are lower about 26.41, 20.2 and 11.4%, respectively.     

A model of the filling process of an intermittent distribution network

In many countries, private tanks are acquired by users to reduce their vulnerability to intermittent supply. The presence of these local reservoirs modifies the user demand pattern and usually increases user water demand at the beginning of the service period depending on the tank filling process. This practice is thus responsible for the inequality that occurs among users: those located in advantaged positions of the network are able to obtain water resources soon after the service period begins, while disadvantaged users have to wait much longer, after the network is full. This dynamic process requires the development of ad hoc models in order to obtain reliable results. This paper discusses a numerical model used for evaluating this complex process as well as the application of model to an Italian case study. The model agreed with calibration data and provided interesting insights into the network filling process.     

谱聚类在给水管网分区优化中的应用

利用图划分技术和图论算法实现给水管网分区。根据给水管网分析,确定分区数量,建立权重邻接矩阵并计算图拉普拉斯矩阵及其特征向量,通过多路图划分对隐藏在特征向量中的聚类信息进行数据挖掘,采用遗传算法和K均值方法实现最佳节点聚类。利用PageRank和最短路径算法确定水表和阀门位置,最终实现给水管网优化分区。实际给水管网模型分区实例表明所提方法在给水管网分区的有效性。     

开式蒸发冷却中央空调水质分析及研究

对开式蒸发冷却中央空调冷却水的水质进行分析,并提出杀菌灭藻、缓蚀、阻垢的水处理方法机理。     

The effect of advanced treatment on chlorine decay in metallic pipes

Experiments were run to measure what effect advanced treatment might have on the kinetics of chlorine and chloramine decay in metallic pipes that comprise many drinking water distribution systems. A recirculating loop of 6-in diameter unlined ductile iron pipe was used to simulate turbulent flow conditions in a pipe with significant corrosion and tubercle buildup. Conventionally treated test water was subjected to either ozonation, carbon adsorption (GAC), reverse osmosis (RO) or no further treatment before being chlorinated and introduced into the pipeline simulator. Results showed that overall chlorine decay in the simulator was consistently dominated by wall reactions whose first-order rate constants were an order of magnitude higher than those for the bulk water. With free chlorine, the wall rate constants for ozonated and GAC-treated water were about twice those of conventional or RO-treated water. This behavior is believed due to the effect that changes in the organic content of water have on its ability to complex iron and the effect that changes in water conductivity have on pipe wall corrosion. Tests run with chloraminated water showed no statistically significant effect of treatment type and had wall rate constants that were only 40 to 70% as high as those using free chlorine.     

防止直饮供水水质污染的技术措施

对某些小区直饮水终端的水质检测结果和用户投诉水质问题的统计资料表明,在供水过程中存在水质污染。针对产生污染的原因,提出了经济可行的防止水质污染的技术措施。     

Ecological succession of the microbial communities of an air‐conditioning cooling coil in the tropics

Air‐conditioning systems harbor microorganisms, potentially spreading them to indoor environments. While air and surfaces in air‐conditioning systems are periodically sampled as potential sources of indoor microbes, little is known about the dynamics of cooling coil‐associated communities and their effect on the downstream airflow. Here, we conducted a 4‐week time series sampling to characterize the succession of an air‐conditioning duct and cooling coil after cleaning. Using an universal primer pair targeting hypervariable regions of the 16S/18S ribosomal RNA, we observed a community succession for the condensed water, with the most abundant airborne taxon Agaricomycetes fungi dominating the initial phase and Sphingomonas bacteria becoming the most prevalent taxa toward the end of the experiment. Duplicate air samples collected upstream and downstream of the coil suggest that the system does not act as ecological filter or source/sink for specific microbial taxa during the duration of the experiment.     

微絮凝直接过滤工艺处理低浊度原水试验研究

采用微絮凝直接过滤对低浊度原水进行试验研究，试验结果表明：当原水浊度小于20NTU时，采用聚合氯化铝（PAC）作为絮凝剂，控制投药量为3～5mg／L，絮凝时间3～5min，可保证出水浊度小于0．5NTU，符合国家饮用水卫生标准．     

Evaluation of data driven models for pipe burst prediction in urban water distribution systems

ABSTRACT

The water distribution network is one of the most expensive parts of a water supply system. The fundamental variables of a network, material, diameter, length, age, and the hydraulic pressure of pipes are the factors that affect the pipe burst rate (PBR). Establishing a relationship among the burst rate and these factors is an important step to assess the conditions governing the network and preventing significant water leakage. Implementing the data-driven approach in PBR prediction is an effective method to find the relationship. In the present study, Grasshopper Optimization Algorithm-based Support Vector Regression (GOA-SVR), Gaussian Process Regression (GPR), and Artificial Neural Network (ANN) have been developed to predict PBR in an urban area. The results show that the GPR model outperforms other methods. Furthermore, the sensitivity analysis indicates that the pipe age has a negative effect on PBR modeling while the pipe length is the most relevant variable.     

施工网络计划资源有限的直接和动态综合优化方法

结合实例,探讨了建筑工程施工网络计划资源有限、工期最短的直接优化方法,并由此推导出资源有限的动态优化方法和资源、工期、费用的综合优化方法。     

SARS诊疗室内的气流分布优化研究

本文分析了SARS病毒特性及其传播机理,结合相关标准并借鉴生物安全技术归纳出SARS诊疗室内的气流分布要求,给出了相关的评价指标。模拟和实验结果表明尽管都采用单侧顶送异侧下回的风口布局方式,但是未必所有的送风口均能形成理想的气流定向流动,满足SARS诊疗室的气流分布要求。通过对多种气流分布方式的比较和总结,本文提出了适合SARS诊疗室的最佳气流分布方式。     

SARS隔离病房内的气流组织优化研究

本文分析了SARS病毒特性及其传播机理,结合相关标准并借鉴生物安全技术提出了SARS隔离病房内的气流组织要求,给出了相应的气流组织评价指标。针对SARS隔离病房的特点,提出了多种较为合理的气流组织方案,采用数值模拟的方法比较了各气流组织方案的综合性能,从而得到了适用于SARS隔离病房内的最优气流组织方案。模拟和实验结果表明尽管都采用单侧顶送异侧下回的风口布局方式,未必所有的送风口都能满足隔离病房内气流形成合理定向流动的要求。本文为SARS隔离病房推荐了所应采用的送风口形式及其布局方案。     

吹填软土地基上砂桩工艺与轻型井点降水效果分析

作为沉管砂桩与预排水动力固结法联合加固软土地基的关键技术之一,本文对吹填软土地基上砂桩工艺以及轻型井点降水效果进行分析。现场测试表明,在降水过程中,地下水位呈不断下降趋势,最后当抽水时间达到150h后趋于稳定。此外,由孔隙水压力计测定的孔隙水压力下降值小于地下水位下降引起的静水压力值,这与土层的滞水性和土层的透水性有关。     

A review of methods for leakage management in pipe networks

Leakage in water distribution systems is an important issue which is affecting water companies and their customers worldwide. It is therefore no surprise that it has attracted a lot of attention by both practitioners and researchers over the past years. Most of the leakage management related methods developed so far can be broadly classified as follows: (1) leakage assessment methods which are focusing on quantifying the amount of water lost; (2) leakage detection methods which are primarily concerned with the detection of leakage hotspots and (3) leakage control models which are focused on the effective control of current and future leakage levels. This paper provides a comprehensive review of the above methods with the objective to identify the current state-of-the-art in the field and to then make recommendations for future work. The review ends with the main conclusion that despite all the advancements made in the past, there is still a lot of scope and need for further work, especially in area of real-time models for pipe networks which should enable fusion of leakage detection, assessment and control methods.