紫外/臭氧复合杀灭水中细菌性能研究

为开发一种高效灭菌方法,研究了UV/O3的复合灭菌性能,对紫外辐射、臭氧和羟基自由基等在体系中的各自作用进行探讨,同时考察pH值、温度等对灭菌效果的影响.结果表明,UV/O3较单独紫外或臭氧灭菌时效果有所提高,在初始臭氧质量浓度为5.02mg·L-1,液面紫外辐射强度为6.5mW·cm-2,灭菌时间1.5～9.0s时,UV/O3对细菌总数灭菌率达3.6～6.4,单独紫外时为1.8～4.7,单独臭氧时仅为1.6～3.0.羟基自由基的产生是复合灭菌效果增加的主要原因.随紫外辐射强度和臭氧投加量的增加,复合灭菌作用得到提高.pH值在5.5～8.5变化时,UV/O3灭菌效果随原水pH值的增加略有提高.温度由10℃上升到27℃时,灭菌效果稍有下降.由此可见,UV/O3是一种高效可行的水体灭菌技术。     

氯和氯胺冲击消毒对二次供水管道生物膜的控制作用

针对建筑二次供水管壁生物膜对饮用水的生物安全性构成的潜在威胁,采用生物膜反应器(BAR)模拟二次供水管道,研究氯和氯胺冲击消毒过程对管壁生物膜的细菌总数、大肠杆菌和异养菌(HPC)灭活效果以及对生物膜结构的影响.结果表明,在第80天时生物膜中生物量达到最大,生物膜宏基因组分析表明,厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)和拟杆菌(Bacteroidetes)为优势菌种.冲击消毒对生物膜的灭活效能与氯和氯胺的质量浓度以及CT值有关,在相同CT值条件下,高质量浓度氯和氯胺的灭活效果更佳.氯和氯胺的生物膜灭活效果对比可以看出,在低投量条件下,氯的细菌总数和大肠杆菌灭活效果好于氯胺,但氯的HPC灭活效果弱于氯胺;在高投量条件下,消毒剂质量浓度和CT值与生物膜的灭活效果无明显相关性,可以达到快速消毒的效果.在氯和氯胺的投加质量浓度为3.0 mg/L、CT值300~400 mg·min/L的最佳冲击消毒条件下,生物膜中细菌总数、大肠杆菌和HPC的灭活率均达到95%以上.从生物膜的表面特性分析可以看出,冲击消毒后生物膜结构破坏明显,生物膜变薄或脱落;氯冲击消毒对生物膜的破坏和削减程度优于氯胺,更有利于管道生物膜的控制.     

不锈钢尖角面板拉伸模设计

通过对消毒柜面板的工艺分析 ,设计了1副在单动液压机上工作的拉伸复合模 ,既满足了面板零件的工艺要求 ,又解决了尖角工件拉伸的难题 ,给纯平面板的拉伸提供了设计参考     

臭氧消毒技术研究进展

主要综述了臭氧消毒技术的研究现状,包括消毒机理以及主要影响因素,如温度、pH、有机物、颗粒物和无机离子等对消毒效果的影响,并介绍了消毒联合工艺研究进展。总体而言,臭氧具有较强的杀菌能力,是有较好前景的消毒技术。     

Application of partial mutual information variable selection to ANN forecasting of water quality in water distribution systems

Recent trends in the management of water supply have increased the need for modelling techniques that can provide reliable, efficient, and accurate representation of the complex, non-linear dynamics of water quality within water distribution systems. Statistical models based on artificial neural networks (ANNs) have been found to be highly suited to this application, and offer distinct advantages over more conventional modelling techniques. However, many practitioners utilise somewhat heuristic or ad hoc methods for input variable selection (IVS) during ANN development.This paper describes the application of a newly proposed non-linear IVS algorithm to the development of ANN models to forecast water quality within two water distribution systems. The intention is to reduce the need for arbitrary judgement and extensive trial-and-error during model development. The algorithm utilises the concept of partial mutual information (PMI) to select inputs based on the analysis of relationship strength between inputs and outputs, and between redundant inputs. In comparison with an existing approach, the ANN models developed using the IVS algorithm are found to provide optimal prediction with significantly greater parsimony. Furthermore, the results obtained from the IVS procedure are useful for developing additional insight into the important relationships that exist between water distribution system variables.     

游泳池池水消毒药剂的探讨

综评了消毒游泳池池水的各种消毒剂,结合我国国情和实际工作提出消毒效果好,经济、简单易行的液氯消毒法。     

管道分质供水TCCA消毒方法

对三氯异氰尿酸(TCCA)消毒法在管道分质供水中的应用进行了研究。结果表明,利用TCCA消毒管道分质供水,只要控制管网水中余氯质量分数>3.0×10-8,就能起到良好的消毒效果,并能有效的控制消毒副产物,使管道分质供水具有较好的口感。采用的TCCA消毒法在管道分质供水工程具有广泛应用前景。     

水厂消毒副产物的变化规律

三卤甲烷（THMs）和卤乙酸（HAAs）是给水厂中具有代表性的消毒副产物（DBPs）,如果水厂中消毒副产物生成量过高,将会影响到管网中水质安全。通过比较水厂2种不同处理工艺中各单元出水口的三卤甲烷、卤乙酸浓度变化,分析了消毒副产物DBPs浓度变化情况,讨论比较2套处理工艺水质处理效果。结果表明,水体经过折板反应池—斜板沉淀池—移动冲洗罩滤池处理后,出厂水中消毒副产物量的增加量相对水体经过机械搅拌澄清池—双阀滤池—处理后较小。     

Regional variability of disinfection by-products in Canadian drinking water

The chlorination of drinking water forms various disinfection by-products (DBPs), some of which present potential risks to humans. This study investigates occurrences, trends, and regional and seasonal variability of DPBs in two Canadian provinces: Ontario and Quebec. The findings demonstrate that trihalomethanes (THMs) and haloacetic acids (HAAs) can be represented better by region-based analysis than by province-based analysis. THMs in summer months are much higher than in cold months, while HAAs show variable results. The seasonal and regional variability of DBPs can have implications for the selection of DBP sampling locations, sampling frequency, regulatory limitations of DBPs, exposure analysis and risk characterization.     

氯、二氧化氯对氯胺消毒管网硝化作用控制效果对比

采用2台串联BAR模拟给水管网系统,通过对余氯、NH4+-N、N02-N、NO3--N、DO、HPC及AOB等指标检测,评价氯和二氧化氯2种消毒剂对氯胺消毒管网中硝化作用的控制效果.研究结果表明:二氧化氯比等量氯更易提高管网中余氯质量浓度和DO质量浓度;氯消毒阶段NH4+-N降解,NO2--N和NO3--N积累,而投加二氧化氯后可有效控制硝化作用;与投加氯消毒相比,投加等质量浓度(0.6 mg/L)二氧化氯时,第1台BAR中悬浮和生物膜中HPC分别降低了2.54 log和1.63 log,悬浮及生物膜中AOB降低约1 log;二氧化氯能对AOB起到控制灭活效果而等量氯对其几乎没有灭活效果,在控制供水管网硝化作用方面,二氧化氯与氯胺联用的消毒效果优于氯与氯胺.