消毒技术处理废水的研究与应用进展

阐述了污水消毒的必要性,消毒已成为污水回用技术中必须的处理单元,介绍了液氯、二氧化氯、臭氧、紫外线消毒等各种污水消毒技术的消毒原理及优缺点,指出了紫外线消毒技术将会取代化学消毒在给排水处理中得到广泛应用。     

预氧化消毒方式对三卤甲烷控制的生产性试验

以高温高藻期原水为处理对象,在天津某净水厂选择预臭氧—紫外线加单点加氯消毒、预臭氧—紫外线加两点加氯消毒、预加氯—紫外线加两点加氯消毒3种不同预氧化消毒方式进行生产性试验,考察3种工况下滤后水、出厂水及管网水中三卤甲烷(THMs)生成量、余氯、浊度等相关水质指标。结果表明,控制出厂水和管网水THMs最低的最佳预氧化消毒方式为预臭氧—紫外线加两点加氯消毒,在每年7月—9月采用预臭氧—紫外线加两点加氯的预氧化消毒方式,预加氯—紫外线加单点加氯的预氧化消毒方式可用于7月—9月之外的时段,当7月—9月之间在应急情况下必须启动预加氯时,必须采取两点加氯的消毒方式。     

紫外线（UV）消毒的一些特点

水处理的消毒方法包括物理法(如加热、紫外线和超声波杀菌等)和化学法(如氯热、臭氧和二氧化氯等)。以往给水处理及污水处理中常用的消毒方法为加氯消毒，近几年来，紫外线消毒以其灭菌的广泛性、产生副产物最少等优点而迅速发展起来。本文对紫外线消毒技术的一些特点进行了讨论。     

认识高温消毒柜——家用消毒柜消毒方式（二）

目前市场上的家用消毒柜主要的消毒方式为：高温、紫外线、臭氧。三种方式的消毒原理是不同的，上期我们介绍了“臭氧 紫外线”消毒方式，那是属于低温消毒，消毒温度一般在60oc以下，特别适合不耐高温的塑料、玻璃制品。这期我们将着重介绍高温消毒柜，包括高温和臭氧、紫外线组合消毒柜(目前单一消毒方式的消毒柜已经不能满足人们的需求，很少生产了)。     

紫外线技术在给水深度处理中的应用

在现代的城市给水排水消毒中,通常可以采用物理消毒法和化学消毒法。通常情况下化学消毒法主要是应用化学理论,采用化学材料与水中的杂质进行反应,从而达到净水的目的,而就目前化学消毒法应用的实际情况而言,通常采用的是氯消毒好臭氧消毒。采用氯消毒和臭氧消毒都是利用了其化学特性也就是强氧化性。然而化学消毒通常都会伴随着一些副作用,因此,人们迫切的需要一种无副作用的消毒方法。在这一背景下,紫外线消毒技术应运而生,其不仅具有极强的杀菌消毒能力,而且还不会产生对水体产生负面影响,从而使得其在现代的消毒处理中备受青睐。本文通过对紫外线消毒技术的深入研究,然后对其在给水深度处理中的应用进行了详细的产生,以供同行探讨。     

健康“卫士”——品评两款家用消毒柜

随着人们生活水平的逐步提高，消毒柜已进入千家万户。目前市场上的家用消毒电器主要的消毒方式为：高温、紫外线、臭氧。其中紫外线、臭氧由于其卓越的杀菌效果和低能耗、低成本，加上技术成熟，得到了广泛使用。     

给排水消毒技术发展趋势探讨

介绍了氯、臭氧、二氧化氯和紫外线消毒技术的特点,探讨了消毒技术的发展趋势,认为各种消毒方式应取长补短,从传统、单一的消毒工艺向组合式消毒工艺发展.     

浅议城市污水处理中的几种消毒技术

随着对污水处理尾水消毒的重视,消毒成为污水处理的一个重要环节。本文详细介绍了液氯、二氧化氯、臭氧和紫外线消毒技术的特点,分析了各自的优缺点,指出了污水处理消毒技术的发展方向。     

浅析“紫外线＋臭氧”消毒——家用消毒柜消毒方式（一）

“紫外线 臭氧”消毒方式由于消毒效果显，加上低能耗、低成本、技术成熟，得到了广泛使用。     

饮用水预臭氧化与预氯化工艺处理效果对比

对比了预臭氧化与预氯化工艺对高温高藻原水的处理效果。结果表明,与传统的预氯化工艺相比,"预臭氧化—紫外线+氯联合消毒"工艺对浊度、UV_(254)、藻类和叶绿素的去除效果更佳,平均去除率分别为99. 06%、55. 29%、87. 54%和99. 23%。     

Dispersion of exhaled droplet nuclei in a two-bed hospital ward with three different ventilation systems

Effective ventilation in general hospital wards is important for controlling the airborne transmission of infectious respiratory diseases. Experiments have been carried out to increase our understanding of the interaction of the breathing flows of two individuals in a full-scale experimental hospital ward with three ventilation systems, i.e. mixing, downward and displacement ventilation. Two life-size breathing thermal manikins were used to simulate a source patient and a receiving patient. The exhalation jet from a bed-lying manikin was visualized using smoke. N2O was used as tracer gas to simulate the droplet nuclei exhaled by patients; and the spatial distribution of its concentrations was measured. Our experimental results show that for both mixing and downward ventilation, the exhaled jet penetrates a short distance and is diluted quickly by ventilation air. The exhaled droplet nuclei are well mixed in the ward. Bed distance does not affect the personal exposure of the receiving patient. For displacement ventilation, the exhaled jet can penetrate a long distance. A high concentration layer of exhaled droplet nuclei because of thermal stratification locking has also been observed with displacement ventilation. This work is useful for identifying an appropriate ventilation method that can remove droplet nuclei more effectively and minimize the risk of cross-infections in a hospital ward environment. PRACTICAL IMPLICATIONS: As one of the major potential sources for infectious droplet nuclei in a hospital environment, exhalation flows of an infected patient can interact with the respiratory activities of other close individuals and with the room ventilation systems. Our latest results provide information on the penetration of exhalation jets into the ambient environment in different ventilation systems. This work is useful in identifying an appropriate and effective ventilation method for removing droplet nuclei more effectively, and thus minimizing the risk of cross-infections in hospital wards with multiple beds.     

Role of air distribution in SARS transmission during the largest nosocomial outbreak in Hong Kong

Severe acute respiratory syndrome (SARS) is primarily transmitted by bio-aerosol droplets or direct personal contacts. This paper presents a detailed study of environmental evidence of possible airborne transmission in a hospital ward during the largest nosocomial SARS outbreak in Hong Kong in March 2003. Retrospective on-site inspections and measurements of the ventilation design and air distribution system were carried out on July 17, 2003. Limited on-site measurements of bio-aerosol dispersion were also carried out on July 22. Computational fluid dynamics simulations were performed to analyze the bio-aerosol dispersion in the hospital ward. We attempted to predict the air distribution during the time of measurement in July 2003 and the time of exposure in March 2003. The predicted bio-aerosol concentration distribution in the ward seemed to agree fairly well with the spatial infection pattern of SARS cases. Possible improvement to air distribution in the hospital ward was also considered. PRACTICAL IMPLICATIONS: Our study revealed the need for the development of improved ventilation and air-conditioning systems in an isolation ward or a general hospital ward for infectious respiratory diseases. The outbreak in Ward 8A, which was in a general hospital and could house nearly 40 patients, demonstrated the cross-infection risks of respiratory infectious diseases in hospitals if a potential highly infectious patient was not identified and isolated. Our example simulation, which extended the SARS Busters' design for an isolation room to Ward 8A, demonstrated that there was room for improvement to minimize cross-infection in large general hospital wards.     

美国传染性隔离病房的通风空调系统设计

回顾了美国传染病医院的发展历程,介绍了美国不同时期医院在应对传染性疾病传播方面所采取的一些措施。介绍了美国隔离病房通风空调系统设计方面的一些经验,包括空调系统、气流流向、房间气流组织、房间压力控制、换气次数等方面。     

室内生物污染治理方法研究述评与展望

介绍了目前室内生物污染治理的一些方法,包括通风、过滤、紫外线灭菌、臭氧灭菌、等离子体灭菌和光催化灭菌,分析了各自的特点和局限,从应用角度指出了需进一步研究的问题。     

Framework for Evaluating Measures to Control Nosocomial Tuberculosis Transmission

Abstract Diverse control measures can be applied to reduce tuberculosis infection risk in health-care facilities. Selecting optimal controls requires methods for predicting the dependence of infections risk on underlying parameters. A common model for infection risk only explicitly accounts for control by ventilation. This paper proposes a more complete model for evaluating tuberculosis infection control methods in health-care settings. An infection risk parameter is defined as the probable number of infectious droplet nuclei inhaled by all susceptible persons from a single infectious person. Algebraic model equations are presented for two exposure cases. In one, the susceptible and infectious persons are together in a well-mixed indoor environment; in the socond, the infectious person is in respiratory isolation. Model equations are used to explore many common tuberculosis control measures: identification, isolation and treatment of tuberculosis cases; surgical masks and treatment booths applied at the source; environmental controls such as ventilation, air filtration, and ultraviolet germicidal irradiation; and respiratory protection for susceptible persons. Experimental data are limited or lacking on some key variables, such as emissions of infectious droplet nuclei by contagious persons and air leakage rates from isolation rooms. Methods are outlined for collecting additional data.     

Natural ventilation for reducing airborne infection in hospitals

High ventilation rate is shown to be effective for reducing cross-infection risk of airborne diseases in hospitals and isolation rooms. Natural ventilation can deliver much higher ventilation rate than mechanical ventilation in an energy-efficient manner. This paper reports a field measurement of naturally ventilated hospital wards in Hong Kong and presents a possibility of using natural ventilation for infection control in hospital wards. Our measurements showed that natural ventilation could achieve high ventilation rates especially when both the windows and the doors were open in a ward. The highest ventilation rate recorded in our study was 69.0 ACH. The airflow pattern and the airflow direction were found to be unstable in some measurements with large openings. Mechanical fans were installed in a ward window to create a negative pressure difference. Measurements showed that the negative pressure difference was negligible with large openings but the overall airflow was controlled in the expected direction. When all the openings were closed and the exhaust fans were turned on, a reasonable negative pressure was created although the air temperature was uncontrolled.     

Role of ventilation in airborne transmission of infectious agents in the built environment - a multidisciplinary systematic review

There have been few recent studies demonstrating a definitive association between the transmission of airborne infections and the ventilation of buildings. The severe acute respiratory syndrome (SARS) epidemic in 2003 and current concerns about the risk of an avian influenza (H5N1) pandemic, have made a review of this area timely. We searched the major literature databases between 1960 and 2005, and then screened titles and abstracts, and finally selected 40 original studies based on a set of criteria. We established a review panel comprising medical and engineering experts in the fields of microbiology, medicine, epidemiology, indoor air quality, building ventilation, etc. Most panel members had experience with research into the 2003 SARS epidemic. The panel systematically assessed 40 original studies through both individual assessment and a 2-day face-to-face consensus meeting. Ten of 40 studies reviewed were considered to be conclusive with regard to the association between building ventilation and the transmission of airborne infection. There is strong and sufficient evidence to demonstrate the association between ventilation, air movements in buildings and the transmission/spread of infectious diseases such as measles, tuberculosis, chickenpox, influenza, smallpox and SARS. There is insufficient data to specify and quantify the minimum ventilation requirements in hospitals, schools, offices, homes and isolation rooms in relation to spread of infectious diseases via the airborne route. PRACTICAL IMPLICATION: The strong and sufficient evidence of the association between ventilation, the control of airflow direction in buildings, and the transmission and spread of infectious diseases supports the use of negatively pressurized isolation rooms for patients with these diseases in hospitals, in addition to the use of other engineering control methods. However, the lack of sufficient data on the specification and quantification of the minimum ventilation requirements in hospitals, schools and offices in relation to the spread of airborne infectious diseases, suggest the existence of a knowledge gap. Our study reveals a strong need for a multidisciplinary study in investigating disease outbreaks, and the impact of indoor air environments on the spread of airborne infectious diseases.     

传染性隔离病房气流组织设计研究

国外对于传染性隔离病房气流组织设计的建议基本上是针对单人病房提出的,然而在相当多国家和地区,为了减少病房建设初投资以及建成后的运行费用,大多采用多病床隔离病房。采用实验和数值模拟相结合的方法研究了不同气流组织形式对病人污染物扩散的影响,并就合理设计传染性隔离病房气流组织提出了建议。     

Method to evaluate UV dose of upper-room UVGI system using the concept of ventilation efficiency

Several countermeasures against the prevalence of infectious diseases have recently been issued, and one of them, the ultraviolet germicidal irradiation (UVGI) system, has been carefully considered for building environments especially. Besides experimental methods to evaluate the germicidal performance of upper air UVGI systems, this research introduces two numerical methods using the concept of ventilation performance, and illustrates the methods with a ward model. The first calculates the average residence time of air using the concept of local purging flow rate (L-PFR) which is multiplied by the average UV intensity of the upper area to obtain a UV dose. The other calculates the UV dose with the distributional UV intensity and deals with UV intensities as contaminant sources. The results of the illustrative cases with a ward model show that the method using the L-PFR concept could not clearly identify the difference in UV doses for each case with different exhaust opening setups, although the other could. The results from the method using the distributional UV intensity indicated the layout of ventilation openings and upper-room UVGI systems are important to optimize the germicidal performance.     

二氧化氯应用于水处理消毒的探讨

介绍了二氧化氯水处理原理和特点,并就消毒的效果、使用范围、建设费用、用地等方面与液氯、臭氧、紫外线作了比较,说明二氧化氯是一种新型高效多功能的水处理消毒剂。