A CASE STUDY FOR CONTROL STRUCTURE SELECTION: CHLORINATION STAGE IN THE BLEACHING PROCESS OF A PULP AND PAPER PLANT

The minimization of chlorinated organic compounds in the effluents of the chlorination unit of a pulp mill is proposed by the use of a control structure for the chlorination unit. Bleached pulp properties are related to the unbleached pulp properties: lignin content, brightness, and viscosity, as well as the amount of chlorinated organics in the bleachery effluent. The best feasible control pairings are studied by RGA and SVD methods. Kappa number of the bleached pulp (a measure of lignin content) and percent consistency of the pulp to be bleached; residual chlorine (which affects the amount of chlorinated organics discharged) and percent chlorine/pulp ratio adapted in the chlorination stage; and exit pulp viscosity (which directly affects strength and tear resistance of the paper) and residence time in the chlorinator are chosen to be the best pairings.     

Ozone Disinfection Of Urban Storm Drain Water

Concerns regarding bacteria in runoff entering Santa Monica Bay were validated by the isolation of human enteric virus in storm drain effluents. As an alternative to chlorination, ozonation was investigated for disinfection of dry-weather urban runoff. Ozone at 10-20 mg/L reduced coliform counts an average of 3.4-logs, with 6-log maximal disinfection. Although varying contaminant concentrations complicate the analyses, total organic carbon predicted ozone demand, and effluent coliform counts were correlated with ozone residuals.     

多管发酵法测定污水中粪大肠菌群结果不确定度的评定

目的：研究污水处理厂污水粪大肠菌群检测结果不确定度,找出影响检测结果的主要不确定因素.方法：通过现场采集污水进行粪大肠菌群检测,对检验结果的不确定度来源作出评定.结果：本次医院污水粪大肠菌群检测不确定度为0.1601.重复性限为1.5400.结论：不确定度的分析能有效掌握检测结果的可信程度和准确性,所建立的不确定度评定方法,适合于类似粪大肠菌群检验的不确定度评定.     

现代紫外C消毒技术在污水处理中的应用

本文介绍了紫外消毒技术的原理及系统组成等,并以福州经济技术开发区污水处理厂应用紫外消毒技术为例,探讨紫外消毒技术在污水处理中的应用,以杀菌效率及经济技术指标分析,表明紫外消毒技术具有高效广谱杀菌、运行稳定、安全可靠、占地面积小、成本低、大水量连续运行、无污染等特点.是其它传统的消毒手段所无法比拟的.     

Urban wastewater disinfection by filtration technologies

The microbiological quality of effluents from different macrofiltration systems (pressure sand filter and disc filter) used as pre-treatment and membrane technologies (microfiltration and ultrafiltration) was evaluated in order to determine their possible application as alternatives to disinfection of urban wastewater prior to reutilization. Microbiological quality was determined by reference to nematode egg content, fecal coliforms, E. coli and somatic coliphages. Pathogenic nematode eggs were efficiently retained by the macrofiltration systems. However, since other types of nematode eggs were present in the effluents treated by both systems, the possibility of such infective agents appearing after this type of treatment cannot be discounted. The membrane technologies proved highly efficient at retaining micro-organisms, achieving effluents of excellent microbiological quality. However, the effluents could not be classified as sterile, since contamination of permeation zones gave rise to the presence of micro-organisms. This result casts doubt on the validity of using the fecal coliform indicator to assess microbiological quality of effluents from these systems. Differences between the two membrane technologies were noted with regard to viral particle retention capacity, with only the ultrafiltration module achieving effluents with total absence of fecal contamination indicators. The macrofiltration systems may present problems when used as pre-treatments to standard disinfection systems (UV radiation, reactive oxidant disinfection). Such problems do not arise with the membrane technologies, which offer a valid alternative for the disinfection of urban wastewater prior to reutilization.     

液氯消毒和紫外线消毒在实践中的应用比较

为了有效保护水体,防止传染性病原菌对人们的危害,降低水源的总大肠菌群数和粪大肠菌群数,对污水处理厂出水进行消毒是十分必要的,文章通过介绍液氯消毒和紫外线消毒,并针对这两种消毒方式在广州污水厂的应用实践的比较,提出对于污水处理厂出水消毒的建议。     

Studies on chlorination of greywater

In view of the growing implementation of systems for treated greywater reuse, and as chlorination is an eventual step of the treatment to assure disinfection, a study of variables affecting the residual chlorine decay in greywater are reported in this paper. The investigation was carried out at laboratory scale with chlorinated samples, and the residual chlorine was measured spectrophotometrically with o-tolidine. To discuss the effects of these variables, decay curves were compared, or alternatively, fitted to a parallel first order decay model. Studied variables were: pH, surfactants, coliform bacteria, ammonia concentration, coagulant agents, potassium permanganate concentration, filtration and storage time. The obtained results showed that residual chlorine can be stabilized by: ammonia, by preoxidation with potassium permanganate or by treatment with coagulanting-flocculanting agents. Surfactants and bacteria were shown to favoured chlorine consumption. Results from this study can be useful to define the working conditions of full-scale systems where the reduction of chlorination dose is a matter of great interest to minimize the environmental impact of the systems.     

氯化酶解木质素的合成与性能研究

以酶解木质素为原料,在水相条件下通入氯气合成氯化木质素。考察了木质素与水的配比、有无紫外光催化、反应温度和通氯量对产物得率和氯含量的影响,并对产物进行了红外光谱和热重分析。结果表明,在氯气过量的情况下,产物氯含量达到29.8%,有紫外光催化时产物氯含量比较低,不加热时的产物氯含量更高,产物氯含量随氯气的增加而增大。氯化木质素的红外光谱图在1720cm-1处羰基强度明显增强,680cm-1附近出现C-Cl的特征吸收峰,说明Cl2与酶解木质素发生了取代反应。热重分析结果表明,氯化木质素的耐热性比酶解木质素稍差。与PVC共混改性的结果表明,氯化木质素改善了原有木质素分子的极性,有望作为极性高聚物共混改性的相容剂使用。     

氯化熔盐体系黏度特性研究现状

中国钛原料钙镁含量高,主要采用熔盐氯化法处理,会产生大量废盐难以处理。研究氯化熔盐体系的黏度特性对于开发该工艺产生的大量废盐利用新方法具有重要意义。综述了国内外对氯化熔盐体系黏度影响规律的研究：从氯化熔盐体系的熔盐离子出发,探讨了Ca²⁺、Mg²⁺、Na⁺及K⁺等对氯化熔盐黏度的影响;从反应条件出发,探讨了温度、气氛和添加剂对氯化熔盐黏度的影响。结合当前对氯化熔盐体系黏度的研究,针对NaCl-KCl-CaCl₂-MgCl₂四元氯化熔盐体系,在不同温度条件下改变气氛或者添加剂,对体系黏度的变化规律进行了考察。通过改变氯化熔盐体系的黏度,寻求适合高温相转化渣高效分离的手段和方法,对高温相转化法高效循环处理熔盐氯化废渣具有重要意义,并能有效推动中国熔盐氯化法的发展。     

Residual disinfection with N-halamine based antimicrobial paints

An N-halamine acrylamide monomer was copolymerized with the sodium salt of 2-acrylamido-2-methylpropane sulfonic acid to produce water-dispersible/soluble polymers. The polymers were added into a water-based latex paint and the treated paints were rendered antimicrobial upon chlorination with dilute household bleach. The chlorinated paints were exposed to fluorescent and ultraviolet light for several periods of time. The bound chlorine on the polymers was remarkably stable and the remaining chlorine on the treated paints after several weeks of light exposure was sufficient to provide 6-log inactivations of both Gram-positive and Gram-negative bacteria within 5–10 min of contact time. The samples exposed light could be rechlorinated to their initial chlorine loadings, indicating that the polymers were also very stable toward light irradiation. This study describes an effective approach to prepare antimicrobial surfaces providing long-term disinfection.     

粪大肠菌群检测方法研究进展

粪大肠菌群是水体粪便污染的指示菌。详细介绍了多管发酵法、滤膜法、纸片法、酶底物法及分子生物学方法检测粪大肠菌群的优缺点及主要应用实例。     

三氯异氰尿酸参与的水-甲醇可重复利用体系中的氯代反应

以水为主要反应介质,以甲醇为助溶剂,以低毒的三氯异氰尿酸(TCCA)为氯代试剂,以对甲苯磺酸为催化剂,发展了在室温下的氯代反应,对于部分苯乙酮类化合物和含有强供电子基的芳香族化合物取得了良好的反应效果,氯代产物产率为82.0%～95.2%。水-醇的反应体系可以重复利用5次,氯代产物产率没有明显降低。该反应体系低毒、温和、廉价、可重复利用,比较接近绿色化学的要求。     

氯蜡-70市场与应用及生产技术概述

系统介绍了氯蜡-70的用途和国内外市场状况.其目前的生产技术有溶剂法(光催化氯化法、催化氯化法)、本体法、改良本体法、水相法(一步水相法、二步水相法),分析了各种工艺的生产技术要点,指出水相法是最经济、产品性能最好的方法,代表着国内氯蜡-70今后的发展方向,但应加快研究解决腐蚀问题的办法,促进该产品的快速发展,满足市场对氯蜡-70需求的不断增长.     

氯化聚丙烯熔点与氯化度的关系研究

以甲苯为溶剂,过氧化二苯甲酰(BPO)为引发剂,通过自由基聚合,对聚丙烯(PP)进行氯化改性;研究了PP氯化改性熔点与氯化度的关系,模拟出了氯化聚丙烯(CPP)氯化度与熔点之间的关系模型,该模型为CPP的氯化度的测定提供了一种较为简便的方法     

污泥中粪大肠菌群菌值检测方法的改进

对污泥中粪大肠菌群菌值目前通用的多管发酵法进行优化。将污泥接种到乳糖胆盐发酵管,(44.5±0.5)℃培养24 h,阳性发酵管转种到EC培养液,(44.5±0.5)℃培养24 h,查MPN检索表,求倒数算出粪大肠菌群菌值,并与优化前的国标方法进行比对。结果表明,改进后的方法比国标方法减少了平板分离和染色镜检过程,缩短了检测时间,提高了检测结果的重现性,但两者在结果上无统计学意义上的差异。改进后的多管发酵法可以用于污泥中粪大肠菌群菌值的检测。     

氯化石蜡-52光引发氯化工艺条件的研究

建立了1套光引发氯化制备氯化石蜡-52的小试实验装置及对反应过程进行分析测试的方法，运用正交设计实验方法，系统地考察了各工艺条件如光强度，光引发时间，氯气流量，反应温度对氯化反应的影响。确定了较佳的工艺参数，为开发万吨级连续化生产装置提供了依据。     

固相法氯化聚乙烯增韧聚氯乙烯的研究──氯化聚乙烯的氯含量、制备条件与增韧聚乙烯性能的关系

本文研究了固相氯化法制备的氯化聚乙烯（ＣＰＥ）和ＰＶＣ／ＣＰＥ共混物的机械特性。氏考察了ＣＰＥ氯含量、氯化条件如聚乙烯晶区与非晶区氯化程度比、氯化过程中热处理条件、氯化温度等对聚氯乙烯（ＰＶＣ）增韧效果的影响。共混前后的物理力学性能变化表明，不仅氯含量、而且氯化聚乙烯的制备条件对ＰＶＧ的增韧效果有着很大的影响，而分子量对性能影响不大。因相法ＣＰＥ与悬浮法ＣＰＥ对ＰＶＣ的增韧效果相当，ＣＰＥ用量为７—１５ｐｈｒ时，增韧效果尤为突出。形态结构的表征结果说明共混物是微观上的相分离，具有优良增韧效果的体系为ＣＰＥ是均匀连续同分布于ＰＶＣ粒子表面。     

低温等离子体气相法制备氯化聚氯乙烯

介绍了氯化聚氯乙烯树脂的生产方法,研究了低温等离子体气相法制备氯化聚氯乙烯的新方法;试验结果表明:低温等离子体氯化工艺能够使聚氯乙烯快速氯化。     

现场电解制次氯酸钠在污水处理厂出水消毒的应用研究

随着污水厂出水排放标准日益提高,对排水中粪大肠菌群的控制也越来越严格。现场电解制次氯酸钠发生系统是一种较为理想的环境友好型氯消毒技术,能够有效杀灭城镇污水处理厂出水中的粪大肠杆菌。因原水水质不同,次氯酸钠的杀菌效果会有差异。次氯酸钠对原水中的氨氮有一定的去除作用,但是有可能氧化原水中残留的有机氮,从而使得氨氮含量重新升高。现场连续投加试验中,反应池次氯酸钠浓度为1．2mg／L,出水中的粪大肠菌群始终稳定达到GB18918-2002一级A标准的要求,且其他水质指标（如氨氮、COD等）良好。     

关于改善水相法氯化石蜡-70产品色泽的探讨

从原料、生产过程(主要包括氯化、中和、水洗、干燥)等方面分析了水相悬浮氯化法生产的氯化石蜡-70产品色泽深的原因.通过实验确定了生产色泽佳的产品的操作方法.