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为了研究管网腐蚀、管垢对供水管网水质的影响,以28aDN350无内衬灰口铸铁管为对象开展了腐蚀饮用水管道中水质变化规律的试验研究.研究表明:腐蚀管道中浊度、总铁等水质指标随水力停留时间的增长而增加,且总铁与浊度呈良好正相关关系,水中铁质量浓度升高取决于水中悬浮态铁的升高;且以上指标的变化均与水流速度有关,当水流速度大时,管中水质变化加速;用扫描电子显微镜(SEM)对C市供水管道腐蚀瘤结构进行微观形貌分析,可以将腐蚀瘤分为表面层、硬壳层和内核层3层;采用能量分散光谱法(EDS)和X荧光光谱仪(XRF)对腐蚀瘤化学成分进行分析,腐蚀瘤主要组成成分为铁的氧化物,即α-FeOOH,γ-FeOOH和Fe3O4.以上结果表明:管道腐蚀瘤的物理形态和力学强度易受水力条件的影响,其腐蚀成分在水流扰动下容易脱落释放,是导致管网水质二次污染的重要原因.
In order to study the influence of pipeline corrosion and tube scale on the water quality of the water supply pipe network, a 28a DN 350 non-lined gray cast iron pipe was used as the research object to study the variation of water quality in the pipeline of drinking water corrosion.The results show that the turbidity, Total iron and other water quality indicators increased with the increase of hydraulic retention time, and the total iron and turbidity showed a good positive correlation between the iron concentration in water depends on the rise of suspended iron in water; and the above indicators are changes with the water flow Speed. When the water velocity is high, the change of water quality in the pipe is accelerated. By scanning electron microscopy (SEM), the microstructure of the corroded tumor in C water supply pipelines can be divided into surface layer, hard shell and inner core Layer 3. The chemical composition of the corrosive tumor was analyzed by energy dispersive spectroscopy (EDS) and X-ray fluorescence spectrometer (XRF). The main constituents of the corrosive tumor were iron oxides, namely α-FeOOH, γ-FeOOH and Fe3O4. The results show that the physical morphology and mechanical strength of pipe corrosion are susceptible to the influence of hydraulic conditions, and the corrosion components are easily shed and released under the disturbance of water flow, which is the important reason for secondary pollution of pipe network water quality.