Optimal operation of water supply systems with tanks based on genetic algorithm

In view of the poor water supply system’s network properties, the system’s complicated network hydraulic equations were replaced by macroscopic nodal pressure model and the model of relationship between supply flow and water source head. By using pump-station pressure head and initial tank water levels as decision variables, the model of optimal allocation of water supply between pump-sources was developed. Genetic algorithm was introduced to deal with the model of optimal allocation of water supply. Methods for handling each constraint condition were put forward, and overcome the shortcoming such as premature convergence of genetic algorithm; a solving method was brought forward in which genetic algorithm was combined with simulated annealing technology and self-adaptive crossover and mutation probabilities were adopted. An application example showed the feasibility of this algorithm.

Water hammer protection for diversion systems in front of pumps in long-distance water supply projects

For a water supply system with long-distance diversion pipelines, in addition to the water hammer problems that occur beyond pumps, the safety of the water diversion pipeline in front of pumps also deserves attention. In this study, a water hammer protection scheme combined with an overflow surge tank and a regulating valve was developed. A mathematical model of the overflow surge tank was developed, and an analytical formula for the height of the overflow surge tank was derived. Furthermore, a practical water supply project was used to evaluate the feasibility of the combined protection scheme and analyze the sensitivity of valve regulation rules. The results showed that the combined protection scheme effectively reduced the height of the surge tank, lessened the difficulties related to construction, and reduced the necessary financial investment for the project. The two-stage closing rule articulated as fast first and then slow could minimize the overflow volume of the surge tank when the power failure occurred, while the two-stage opening rule articulated as slow first and then fast could be more conducive to the safety of the water supply system when the pump started up.

Optimum combination of water drainage, water supply and eco-environment protection in coal-accumulated basin of North China

The conflict among water drainage, water supply and eco-environment protection is getting more and more serious due to the irrational drainage and exploitation of ground water resources in coal-accumulated basins of North China. Efficient solutions to the conflict are to maintain long-term dynamic balance between input and output of the ground water basins, and to try to improve resourcification of the mine water. All solutions must guarantee the eco-environment quality. This paper presents a new idea of optimum combination of water drainage, water supply and eco-environment protection so as to solve the problem of unstable mine water supply, which is caused by the changeable water drainage for the whole combination system. Both the management of hydraulic techniques and constraints in economy, society, ecology, environment, industrial structural adjustments and sustainable developments have been taken into account. Since the traditional and separate management of different departments of water drainage, water supply and eco-environment protection is broken up, these departments work together to avoid repeated geological survey and specific evaluation calculations so that large amount of national investment can be saved and precise calculation for the whole system can be obtained. In the light of the conflict of water drainage, water supply and eco-environment protection in a typical sector in Jiaozuo coal mine, a case study puts forward an optimum combination scheme, in which a maximum economic benefit objective is constrained by multiple factors. The scheme provides a very important scientific base for finding a sustainable development strategy.

Combination of drainage, water supply and environmental protection as well as rational distribution of water resource in Zhengzhou mining district

The geological condition of coalfield is much complex in China. With increasing in mining depth and drainage amount, the contradiction of drainage, water supply and environ-mental protection is becoming more and more serious. However, the contradiction can be solved by the scientific management of optimizing combination of drainage, water supply and environ-mental protection. The Philip multiple objectives simplex method used in this article has searched for a possible solution at the first step, and then it goes on searching to find out whether there is a weight number that can lead the solution to the biggest. It can reduce the randomness and diffi-culty of traditional weight method which determine the weight number artificially. Some beneficial coefficients are vague and the number is larger in the model of water resource dispatch. So the vague layer analysis method can consider these vague factors fully, combining the qualitative and quantitative analysis together. Especially, this method can quantify the experiential judge-ment of policy decider, and it will turn to be more suitable if the structure of objective factors is complex or the necessary data are absent. In the paper, the two methods above are used to solve the plans of drainage, water supply and optimizing distribution of water resource in the Zhengzhou mining district.

韧性城市建筑“平急结合”设计给排水应对关键措施探索

简介韧性城市建筑中适用于临时隔离收治点的建筑类型,提出建立临时隔离收治点“平急结合”设计的标准体系构想,解析作为临时隔离收治点的新建建筑、既有建筑在设计或改造中的给排水应对措施,重点就条件预留、用水定额、系统定型、管道布设、设备选用、污水处理等方面进行深入探索。

广西农村水柜供水保障研究与实践

水柜供水作为广西大石山区农村供水工程体系的重要组成,目前在水量、水质、用户3个层面仍存在水资源匮乏、水质亟待提升、村民供水保障意识能力欠缺等问题。文章提出通过借助山泉水、河水、地下水和塘坝蓄水等手段,保障水源充足;通过强化水源保护、配套水处理设施和加强水质监测等方法,保证水质合格;通过加强宣传和培训工作,提升村民供水保障意识能力等解决对策。其中,强化水源保护主要从为水柜设置盖板、增加初雨弃流装置以及降低水源污染风险等途径出发,配套的水处理设施则需要根据水柜供水规模来选取,家庭水柜可选取以慢滤技术为主的水处理设施,集体水柜可选取以快滤技术为主的水处理设施。课题研究团队在上述调查研究的基础上,开展水源保障项目、水质提升项目、跟踪服务活动等探索实践,为水柜供水保障工作的实施提供了借鉴,助力广西农村供水高质量发展。

联合收获机发动机风冷系统优化设计

为了减少联合收获机收获过程中水箱“开锅”现象的发生,延长收获机的无故障工作时长,对4LXZ-8F型联合收获机的发动机风冷系统散热量进行了计算,并基于计算结果对防尘罩、散热器进行了优化设计,对冷却风扇进行了匹配选型。利用SolidWorks对优化前后风冷系统进行了三维建模,利用Fluent软件对发动机风冷系统优化前和优化后散热器散热性能分别进行仿真分析。仿真结果表明:优化前的冷却水入口温度为90℃,出口温度为72.3℃,进出口温差为17.7℃;优化后的冷却水入口温度为90℃,出口温度为71.1℃,进出口温差为18.9℃,表明优化后散热器散热性能提升了6.78%。研究成果可为提高发动机风冷系统的散热性能,延长无故障收获时长提供理论指导。

基于串级LSTM深度学习模型的二次供水余氯预测方法

伴随着城市高层住宅的增多,住宅区内二次供水泵房数量迅速增加。由于二次供水水箱位于城市供水系统末端,水质安全引起社会广泛关注。为提升水箱水质,一些泵房引入自动补氯装置,然而传统自动控制方法在应对二次供水系统中长时间延迟和非线性特性的补氯系统时存在局限性,仅能在线监测水箱余氯水平,过多的余氯可能对人体健康有害,因此,确保自动补氯系统安全运行成为亟待解决的问题。研究提出基于串级LSTM深度学习的神经网络模型,用于分析水箱余氯数据、准确预测水箱出水余氯浓度,并制定相应监测和控制策略。试验验证和实际应用结果表明,该深度学习模型能有效智能预测水箱余氯,为自动补氯系统提供重要的智能控制手段,具有实用意义。

MSBR+高效沉淀池组合工艺在高排放标准下污水厂的应用

广西某污水处理厂设计能力为5×10^(4)m^(3)/d,采用10格MSBR+高效沉淀池处理工艺,出水作为环境综合整治后河道的生态补水。通过对处理水量达设计规模后的运行工况变化较大情况下的运行效果总结分析,并对超负荷运行、污泥浓度控制、出水带泥等问题提出了调控建议;实际运行数据表明,该组合工艺出水NH_(3)-N、TN、TP、SS平均消减效率分别达到99.6%、76%、97%、98.9%,主要指标甚至满足《地表水环境质量标准(GB3838-2002)》Ⅳ类水标准,具有污水处理效果稳定,耐冲击负荷强等特点,在南方丰水、雨污合流城市高排放标准污水处理方面有着较高的推广应用价值。

基于Flowmaster的小流量供水设备调节性能模拟

现有的二次供水研究对小流量工况关注较少,小流量工况下主泵低效运行、频繁启停问题正成为制约城市供水“最后一公里”低能耗、高质量发展的痛点。为此,建立Flowmaster仿真模型对“工频辅泵+气压罐”小流量供水模式进行模拟,探究了需求侧不同小流量下气压罐的调节性能。结果表明,“工频辅泵+气压罐”可很好减少水泵启停次数,保持系统稳定。进一步研究了气压罐预充压力对调节性能的影响,阐明了预充气泄漏带来的负面影响,并提出相关工程建议。

空气源-水蓄热-水源组合式热泵系统在西北沙漠地区供暖运行分析

针对西北沙漠地区冬季环境温度较低问题,为了满足现场生活区供暖需求,设计了一套组合式热泵系统:空气源热泵为第一级,结合水箱储热;水源热泵为第二级,提温的组合式热泵供暖系统,替代原燃气加热炉。通过对该系统在供暖季和极端工况下的运行参数统计、性能分析,系统供暖季平均COP为2.342,相较于常规热泵系统COP小于1.8,效率提升显著,能耗降低明显,年减少燃料气消耗19.66×10^(4)m^(3),减少碳排放量134.15 t,兼顾低温环境适应性和较高效率;同时每年减少运行费11.84万元。试验表明,组合式热泵系统可成为油田供暖技术经济均可行的选择之一。

三级AO+深度处理组合工艺在中小型城镇污水厂中的应用

由于排放标准的提高和进水水质的变化,成都市某污水厂需提标改造。改造后,处理规模为2 500 m^(3)/d不变,出水水质需达到《四川省岷江、沱江流域水污染物排放标准》(DB 51/2311—2016)。本工程采用充分利用原有的生化池,改建为三级AO池并新建深度处理设施的改造方式,该改造方式节省投资、不新征用土地、抗冲击负荷强,仅需约30 min短时间碰管停水,改造后工艺运行稳定可靠,达到DB 51/2311—2016的要求(CODCr≤30 mg/L,氨氮≤1.5 mg/L,总氮≤10 mg/L,总磷≤0.3 mg/L)。项目可为中小型城镇污水厂提标改造提供借鉴经验。

基于组合赋权-集对分析的城市供水安全评价

为更精准地评价城市供水安全,将集对分析法与主客观组合赋权法相结合,建立区域城市供水安全评价模型,即用最小相对信息熵原理确定指标综合权重并耦合到指标联系度中,构建出城市供水安全的组合赋权-集对分析的评价体系,通过五元减法集对势确定城市供水安全等级,并对昆明市2011~2020年的供水安全评价划分安全等级。结果表明,2011~2013年昆明市供水处于安全等级,其中2011、2012年更倾向于基本安全等级;2014~2020年昆明市供水处于非常安全等级但更倾向于安全等级,供水状态相对安全和稳定。所提方法一定程度上解决了城市供水安全评价等级中的不确定性和多指标性问题,为城市供水安全评价提供了一种新思路。

A survey on heavy metal concentrations in residential neighborhoods: The influence of secondary water supply systems

Water quality deterioration often occurs in secondary water supply systems(SWSSs), and increased heavy metal concentrations can be a serious problem. In this survey, twelve residential neighborhoods were selected to investigate the influence of SWSSs on the seasonal changes in heavy metal concentrations from input water to tank and tap water. The concentrations of nine evaluated heavy metals in all groups of water samples were found to be far below the specified standard levels in China. The concentrations of Fe, Mn, and Zn increased significantly from the input water samples to the tank and tap water samples in spring and summer( p < 0.05), especially for the water samples that had been stagnant for a long time. Negative correlations were found between most of the heavy metals and residual chlorine(Fe, Cu, Zn, and As, r =-0.186 to-0.519, p < 0.05). In particular, a high negative correlation was observed between Fe and residual chlorine( r =-0.489 to-0.519, p < 0.01) in spring and summer. Fe and Mn displayed positive correlations with turbidity( r = 0.672 and 0.328, respectively;p < 0.05). In addition, Cr and As were found to be positively associated with some nutrients(NO, TN, and SO;r = 0.420-0.786, p < 0.01). The material of the storage tanks had little influence on the difference in heavy metal concentrations. Overall, this survey illustrated that SWSSs may pose a chronic threat to water quality and could provide useful information for practitioners.

轨道交通工程中消火栓系统设计关键技术探讨

为设计出更加安全可靠、经济合理的轨道交通工程,介绍南京—马鞍山城际铁路(简称宁马线)消火栓系统设计中的一些关键技术及其相对于常规传统设计的优点。首先,在对规范解读及工程经验分析的基础上,首次提出“轨道交通工程中,为了保证消防安全,消防泵房保护距离尽量控制在2000 m以内”的原则。为了将此理念落实到具体设计中,在本工程中提出一种新的消防供水方案,即“消防供水多方案组合模式”,具体内容为:1)优先选用一站带左右各半个相邻区间的方案;2)当区间长度小于2000 m时,也可以采用一站带一相邻区间方案;3)当区间长度大于4000 m时,在一站带左右各半个相邻区间方案的基础上,在区间风井处设置独立的消防泵房,以保证所有消防泵房的保护距离控制在2000 m以内;4)将各消防泵房的供水单元完全独立。其次,在车站给水水压制式方面,提出2种单路水源高架站的消防供水方案及其适用范围,即:1)室外低压、室内临时高压系统,适用范围为“高架站布置在市政道路一侧,并且车站离市区较近、消防基础设施条件较好,能保证足量消防车及时赶到火灾现场”或“条件特别困难的既有高架车站改造”;2)室内外共用临时高压消防系统,适用范围为“高架站布置在市政道路中央”或“车站离市区较远、消防基础设施条件比较不利,不能保证足量消防车及时赶到火灾现场”。最后,在消防设施布置方面,提出“高架车站室外消防水池、扑救类室外消火栓”的布置原则,其中最重要的2条为:1)室外低压、室内临时高压系统中,当高架站超出消防水池150 m保护半径时,应增设相应的消防水池取水井;2)车站扑救面上布置室外消火栓时,应优先布置在每个高架站出入口附近。

长距离泵站水锤分析及管线布置对水锤的影响

针对长距离供水工程中泵站事故停泵后管线后段负压成常态的问题,以甘肃某水库临库取水泵站为背景,建立了水锤基本方程、液控止回偏心半球阀和空气罐等数学模型.采用特征线法分析了泵后工作阀关闭规律以及增设空气罐和改变管线布置形式对水锤的影响.实例分析表明:泵后工作阀的关闭规律对管线负压的影响较小;管线出现“瞬时负压”在一些情况下可以忽略其对管道的危害;空气罐能够较好地解决长距离供水工程中泵站后段管线在设置一定数量的空气阀后依然无法消除“瞬时负压”的缺陷;改变管线布置形式对管线负压极值的影响较小,呈直线形式的水锤最大压力明显大于高低起伏形式的管线,采用先缓后陡的管线布置形式能够缩短负压发生的区域.研究结果可为长距离供水工程水锤防护设计提供一定参考.

某丙类生产厂区消防给水系统设计

某新建丙类加工生产厂区在进行消防给水系统设计时,需对生产厂区各单体建筑进行分析,根据其建筑高度、建筑体积、生产产品性质、仓库货物堆放方式等因素,按现行相关消防规范确定厂区所需消防给水系统,以及各消防给水系统的消防设计用水量。同时,消防设施的设置也需考虑厂区的建设开发顺序,以保证在开发周期内的建筑均满足消防使用要求,并在满足规范要求的前提下尽量考虑消防给水系统的经济性。

合流制箱涵末端水质净化站设计及运行分析

随着国家长江大保护行动计划的实施,长江流域一级支流黑臭水体河道亟需进行整治,以实现“清水绿岸,鱼翔浅底”的治理目标。重庆市花溪河为长江的一级支流,在其综合整治项目中,针对合流制箱涵溢流污染,提出了“源头雨污分流改造+末端新建水质净化站”的治理思路。其中土桥水质净化站的设计规模为1.0万m^(3)/d,调蓄池设计容积为11000 m^(3),出水执行准Ⅳ类标准。建成后的运行结果表明:在土桥箱涵排出的合流污水水量不同的工况下,通过采取末端截流、调蓄、净化等治理措施,土桥水质净化站运行正常,所排污水均达到排放标准并外排至花溪河。

《建筑给水排水与节水通用规范》条文浅议

GB 55020—2021《建筑给水排水与节水通用规范》颁布实施后,在业内反响很大,通过对规范的学习和思考,论文就该规范中的一些条文提出了某些看法和建议,如生活水箱露天设置、排水管敷设、源头减排措施、室外给水干管环状布置等问题。