单片机监测余氯和自动加药系统

在对一些回用水和高层建筑二次供水的处理工艺中,需要对出水进行杀菌消毒处理,使其达到国家标准中规定的水致传染病指标.例如,宾馆饭店的中水,游泳池循环水、饮用水二次供水消毒等处理,通常需要监测水中的总游离氯(Total Free Chlorine,TFC),并且按照水质标准投加消毒剂.在这一过程中,精确地测定水中的即时TFC含量,适量地投加消毒剂是一个关键问题.因为水中余氯含量和消毒剂的投药量直接影响水质的消毒效果、出水水质、处理成本和人体健康.目前,中水回用和饮用水二次供水消毒,尚未有在线TFC监测仪器,多数水处理消毒剂投药仍停留在传统的定量加药、定期水质分析判断出水水质,当消毒剂配制浓度和处理水量发生变化后,难于实现准确投药使之达到所需要的水中TFC含量.由于游泳池循环水和饮用水二次供水中本身含有余氯,补药量取决于水中余氯的含量.因此,我们研制了应用单片机监测余氯和自动加药系统,用于监测水中TFC,井可以设定水中TFC含量的上下阀值以控制加药泵的启停实现自动投药.     

紫外-氯联合消毒处理及副产物生成特征研究进展

消毒处理是杀灭水中病原微生物的最关键环节,经过上百年的发展,已研发出几十种消毒处理技术.紫外-氯联合消毒技术在杀灭病原微生物方面兼具紫外线消毒和氯消毒的优点,但因水中存在为数众多的化学物质,紫外线和氯的联合处理可能导致该过程比单独的紫外处理或氯化处理发生更加复杂的化学反应,生成种类更多、毒性较强的消毒副产物.本文在大量文献资料调研的基础上,对紫外-氯联合消毒的原理、主要毒性消毒副产物的生成机制、影响因素及消毒处理方法的优化等方面进行了比较全面的综述,并分析了当前紫外-氯联合消毒处理中存在的问题和面临的挑战.     

饮用水中消毒副产物的消减措施

为了去除水中的病毒和细菌等有毒物质,在饮用水中添加氯是最常用的一种消毒方法.但是由于加入的氯会与水中的天然有机物(NOM)反应,产生包括三卤甲烷(THMs)和卤乙酸(HAAs)在内的各种氯化消毒副产物.这些消毒副产物的去除对饮用水的安全是一个值得关注的问题.     

饮用水细菌内毒素污染的风险识别与分析研究进展

细菌内毒素,又称脂多糖分子或者热原,是革兰氏阴性细菌和某些蓝藻细胞壁组分,主要由菌体死亡解体后释放.内毒素是常见的外源性致热原,属于强免疫刺激剂,与多种人类疾病密切相关.由于饮用水中会滋长微生物,因此内毒素污染在饮用水中普遍存在.近年来,国外研究中饮用水的细菌内毒素污染开始受到关注,成为饮用水微生物安全领域新兴的研究方向.本文概述了细菌内毒素的物化性质和生物活性,分析了细菌内毒素在饮用水中的存在形态,综述了国内外关于地表水源、地下水源、管网末梢水和深度处理水的内毒素污染调查状况,分析了传统水处理技术、深度处理技术和饮用水消毒技术对内毒素的控制效果,探讨了饮用水中内毒素的血液暴露、呼吸暴露和胃肠暴露途径导致机体潜在的健康风险、安全阈值和相关标准,并对饮用水细菌内毒素污染研究方向进行了展望.     

黄浦江原水中各类有机物在铝盐混凝过程中的去除效果

通过XAD-8/XAD-4吸附树脂联用技术将黄浦江微污染原水中溶解性有机物分为疏水酸、非酸疏水物质、弱疏水物质及亲水物质4类有机物,研究了铝盐混凝工艺对黄浦江水中4类有机物的去除效果.硫酸铝在最佳混凝条件下,即投加量为8 mg·l~(-1)(以Al计),pH=5.5时,水中的DOC和UV_(254)的去除率分别达到23%和32%.有机物的亲疏水性对混凝工艺有较大影响,混凝法倾向于优先去除水中疏水性有机物,而疏水性有机物的酸碱性对混凝工艺没有明显影响,酸性和非酸类疏水物质均能破混凝工艺所去除.疏水酸是水中最主要的三氯甲烷类消毒副产物的前体物质,混凝工艺对于三氯甲烷类消毒副产物有良好的控制作用,总体减少了 39%的生成量.而不同类的有机物之间,混凝工艺对消毒副产物控制效果不同,其中对疏水酸的控制三氯甲烷消毒副产物的效果最好,减少了63%的生成量,亲水物质的控制效果最差,三氯甲烷生成量仪减少了3%.疏水酸表现出比亲水物质更强的生物毒性,混凝工艺能明显降低原水的毒性.     

室内泳池水中8种芳香族氯/溴代消毒副产物的生成

消毒是泳池水处理过程中一项重要的工艺,而在消毒过程中消毒剂会与水中的有机质和无机离子发生反应生成消毒副产物(DBPs).近年来泳池水DBPs引起人们越来越多的关注.本研究以8种高毒性芳香族氯/溴代DBPs(2,4,6-三氯苯酚、2,4,6-三溴苯酚、3,5-二氯水杨酸、3,5-二溴水杨酸、3,5-二氯-4-羟基苯甲醛、3,5-二溴-4-羟基苯甲醛、2,6-二氯-4-硝基苯酚、2,6-二溴-4-硝基苯酚)为研究对象,评估了它们在5个室内泳池水及其消毒源水自来水中的浓度水平,测定了各类水质参数,并对水质参数与8种芳香族氯/溴代DBPs的浓度进行了相关性分析.结果表明,泳池水中自由余氯、氯胺、Br~-、I~-、各形态氮(总氮、氨氮、硝态氮、亚硝态氮)、DOC及UV_(254)等指标均普遍高于其源头自来水,且不同消毒方式的泳池水在这些水质参数上也呈现出一定的差异.在5个泳池水中,8种芳香族氯/溴代DBPs均有检出(检出限在0.08—0.64 ng·L~(-1)之间),且各泳池水中芳香族Cl-DBPs浓度明显高于Br-DBPs.无论是芳香族Cl-DBPs还是Br-DBPs,在臭氧和氯联合消毒的泳池水中的浓度均要低于只用氯消毒的泳池水.不同月份8种芳香族氯/溴代DBPs浓度差异较大,但它们在泳池水中的浓度均低于自来水中的浓度.水质参数中Br~-和I~-浓度与多种芳香族氯/溴代DBPs的生成呈显著正相关.     

UV/H_2O_2技术对上海青草沙水源水砂滤后溴酸根和三卤甲烷的生成控制

针对含溴离子(Br-)的上海某水厂滤后水的高级氧化处理,考察了紫外/过氧化氢(UV/H_2O_2)技术对UV254和总有机碳(TOC)的削减效率、控制消毒副产物溴酸根(Br O-3)和三卤甲烷(THMs)的生成情况,同时研究了水中溴离子(Br-)浓度的改变对UV/H_2O_2处理效果的影响.结果表明,UV/H_2O_2处理工艺不产生Br O-3;500 m J·cm-2的UV剂量和5 mg·L-1H_2O_2投加量下,出水UV254和TOC分别降低了35%和21%;后续氯消毒过程中的THMs生成势随H_2O_2投加量的增加显著降低,500 m J·cm-2的UV剂量下,H_2O_2投加量为5 mg·L-1和10 mg·L-1时,THMs生成势的削减率分别为49.4%和79.9%;水中Br-浓度的改变不影响UV/H_2O_2工艺的运行效果;相比UV,UV/H_2O_2还可使9种农药的降解率提高50%—85%.因此,UV/H_2O_2在含Br-水源水深度处理方面有着较好的应用前景.     

离子色谱法测定饮用水中亚氯酸盐、氯酸盐、溴酸盐、二氯乙酸及三氯乙酸

消毒副产物(Disinfection by-products,DBPs)是指用消毒剂对饮用水消毒时,消毒剂与水中含有的天然有机物反应生成的化合物.随着水处理技术的发展,对水处理中产生的各类消毒副产物的研究也日益关注.氯气、漂白粉和臭氧在消毒过程会产生少量对人体健康不利的副产物,如亚氯酸盐、溴酸盐和氯酸盐等.其中溴酸盐是饮用水中臭氧消毒的副产物,已被世界卫生组织和美国EPA列为潜在的致癌物,甚至在含量低至1μg.L-1也有致癌的作用.美国环境保护署(USEPA)和世界卫生组织(WHO)在最新的饮用水法规中规定饮用水中溴酸盐的含量不得超过10μg.L-1.我国最新的饮用水规范中也建议生活饮用水中溴酸盐的最高含量不允许超过10μg.L-1.卤代乙酸(haloacetic acids,HAAs)是饮用水加氯消毒时氯与水中存在的天然有机物反应生成的一类消毒副产物,通     

一种测定水中总磷的简易方法

我们根据日本1983年公布的水中总磷测定方法以及Junko Ebiua等人创立的“用过硫酸盐氧化的方法同时测定水中的总氮和总磷”的方法介绍,结合具体情况和条件,通过大量的实验,得出了一种能适应大批量采样分析的测定水中总磷的方法。通过与其它方法的对比,认为本方法具有以下最基本的两大优点:其一,由于样品的加热分解操作是在120℃的高压消毒器中进行,因而操作简易、省时省力。并且一次能处理较多的样品。使用25毫升     

水体中盐单胞菌属(Halomonas)细菌实时荧光定量PCR检测方法的建立及应用

通过制备标准曲线模板,针对一株盐单胞属细菌X3(经鉴定为Halomonas alkaliphila)的16S r DNA序列设计和筛选特异性引物,建立水体中盐单胞菌属细菌的实时荧光定量PCR检测方法,并将该法用于检测莱州人工鱼礁海域Halomonas属细菌数量.结果表明,引物X3-3F和X3-3R能够对Halomonas属的细菌进行特异性检测,对细菌浓度为6.75×10~1-6.75×10~7 CFU/m L检测重复性和稳定性较好,最低检出浓度为67.5 CFU/m L.运用建立的方法对莱州人工鱼礁海域水体样品的检测结果表明,在未投礁海域2011年5月和7月水体样品中Halomonas细菌数量分别为8.71×10~3 CFU/m L和2.37×10~3 CFU/m L,而投礁区5月份水样也检出了该属细菌,但荧光信号较弱,7月份水样未检出该属细菌.本研究可为Halomonas属细菌的快速检测及其在海水养殖水质净化方面的推广应用提供有力的技术支撑.     

E. coli and bacteriophage MS2 disinfection by UV,ozone and the combined UV and ozone processes

The combination of low-dose ozone with ultraviolet （UV） irradiation should be an option to give benefit to disinfection and reduce drawbacks of UV and ozone disinfection. However, less is known about the disinfection performance of UV and ozone （UV/ozone） coexposure and sequential UV-followed-by-ozone （UV- ozone） and ozone-followed-by-UV （ozone-UV） expo- sures. In this study, inactivation of E. coli and bacterioph- age MS2 by UV, ozone, UV/ozone coexposure, and sequential UV-ozone and ozone-UV exposures was investigated and compared. Synergistic effects of 0.5-0.9 log kill on E. coli inactivation, including increases in the rate and efficiency, were observed after the UV/ozone coexposure at ozone concentrations as low as 0.05 mg-L-1 in ultrapure water. The coexposure with 0.02-mg.L-1 ozone did not enhance the inactivation but repressed E. coli photoreactivation. Little enhancement on E. coli inactivation was found after the sequential UV-ozone or ozone-UV exposures. The synergistic effect on MS2 inactivation was less significant after the UV/ozone coexposure, and more significant after the sequential ozone-UV and UV-ozone exposures, which was 0.2 log kill for the former and 0.8 log kill for the latter two processes, at ozone dose of 0.1 mg. t-1 and UV dose of 8.55 mJ. cm 2 in ultrapure water. The synergistic effects on disinfection were also observed in tap water. These results show that the combination of UV and low-dose ozone is a promising technology for securing microbiological quality of water.     

Presence,dissemination and removal of antibiotic resistant bacteria and antibiotic resistance genes in urban drinking water system: A review

Reviewed the change of ARGs and ARB in full-scale urban drinking water systems. Conventional processes are more promising than BAC process in ARGs removal. Mechanisms of ARGs enrichment and spread in BAC filter and DWDSs are discussed. Raise the need of future research on ARGs and ARB change in building plumbing systems. Antibiotic resistance in aquatic environment has become an important pollution problem worldwide. In recent years, much attention was paid to antibiotic resistance in urban drinking water systems due to its close relationship with the biosafety of drinking water. This review was focused on the mechanisms of antibiotic resistance, as well as the presence, dissemination and removal of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in the urban drinking water system. First, the presence of ARB and ARGs in the drinking water source was discussed. The variation of concentration of ARGs and ARB during coagulation, sedimentation and filtration process were provided subsequently, in which filtration was proved to be a promising technology to remove ARGs. However, biological activated carbon (BAC) process and drinking water distribution systems (DWDSs) could be incubators which promote the antibiotic resistance, due to the enrichment of ARGs and ARB in the biofilms attached to the active carbon and pipe wall. Besides, as for disinfection process, mechanisms of the inactivation of ARB and the promotion of conjugative transfer of ARGs under chlorine, ozone and UV disinfection were described in detail. Here we provide some theoretical support for future researches which aim at antibiotic resistance controlling in drinking water.     

Bacterial inactivation,DNA damage,and faster ATP degradation induced by ultraviolet disinfection

• Long amplicon is more effective to test DNA damage induced by UV. • ATP in bacteria does not degrade instantly but does eventually after UV exposure. • After medium pressure UV exposure, ATP degraded faster. The efficacy of ultraviolet (UV) disinfection has been validated in numerous studies by using culture-based methods. However, the discovery of viable but non-culturable bacteria has necessitated the investigation of UV disinfection based on bacterial viability parameters. We used quantitative polymerase chain reaction (qPCR) to investigate DNA damage and evaluated adenosine triphosphate (ATP) to indicate bacterial viability. The results of qPCR effectively showed the DNA damage induced by UV when using longer gene amplicons, in that sufficiently long amplicons of both 16S and gadA indicated that the UV induced DNA damages. The copy concentrations of the long amplicons of 16S and gadA decreased by 2.38 log/mL and 1.88 log/mL, respectively, after exposure to 40 mJ/cm² low-pressure UV. After UV exposure, the ATP level in the bacteria did not decrease instantly. Instead it decreased gradually at a rate that was positively related to the UV fluence. For low-pressure UV, this rate of decrease was slow, but for medium pressure UV, this rate of decrease was relatively high when the UV fluence reached 40 mJ/cm². At the same UV fluence, the ATP level in the bacteria decreased at a faster rate after exposure to medium-pressure UV.     

Locally enhanced electric field treatment (LEEFT) for water disinfection

• Nanowire-assisted LEEFT is applied for water disinfection with low voltages. • LEEFT inactivates bacteria by disrupting cell membrane through electroporation. • Multiple electrodes and device configurations have been developed for LEEFT. • The LEEFT is low-cost, highly efficient, and produces no DBPs. • The LEEFT can potentially be applicable for water disinfection at all scales. Water disinfection is a critical step in water and wastewater treatment. The most widely used chlorination suffers from the formation of carcinogenic disinfection by-products (DBPs) while alternative methods (e.g., UV, O₃, and membrane filtration) are limited by microbial regrowth, no residual disinfectant, and high operation cost. Here, a nanowire-enabled disinfection method, locally enhanced electric field treatment (LEEFT), is introduced with advantages of no chemical addition, no DBP formation, low energy consumption, and efficient microbial inactivation. Attributed to the lightning rod effect, the electric field near the tip area of the nanowires on the electrode is significantly enhanced to inactivate microbes, even though a small external voltage (usually<5 V) is applied. In this review, after emphasizing the significance of water disinfection, the theory of the LEEFT is explained. Subsequently, the recent development of the LEEFT technology on electrode materials and device configurations are summarized. The disinfection performance is analyzed, with respect to the operating parameters, universality against different microorganisms, electrode durability, and energy consumption. The studies on the inactivation mechanisms during the LEEFT are also reviewed. Lastly, the challenges and future research of LEEFT disinfection are discussed.     

Potential shift of bacterial community structure and corrosion-related bacteria in drinking water distribution pipeline driven by water source switching

• Bacterial release from aged pipe sections under extreme conditions was quantified. • Released bacterial community structure exhibited large variation after transition. • Risks from transition reduced significantly with cleaner source. As a result of pollution in the present water sources, cities have been forced to utilize cleaner water sources. There are few reports regarding the potential shift of bacterial community structure driven by water source switching, especially that of corrosion-related bacteria. Three types of finished water were used for simulation, the polluted source water from the Qiantang and Dongtiaoxi Rivers (China) was replaced by cleaner water from Qiandao Lake (China). Here, we discussed the transition effects through three simulated reactors. The bacterial characteristics were identified using the high-throughput sequencing and heterotrophic plate count method. It was observed that the level of culturable bacteria declined by 2–3 orders of magnitude after water source switching. The bacterial community released from the pipeline reactor was significantly different under different finished water, and it exhibited large variation at the genus level. Porphyrobacter (58.2%) and Phreatobacter (14.5%) clearly replaced Novosphingobium, Aquabacterium, and Cupriavidus as new dominant genera in system A, which could be attributed to the lower carbon and nitrogen content of the new water source. Although corrosion-inhibiting bacteria decreased after switching, they still maintained dominant in three reactors (6.6%, 15.9%, and 19.7%). Furthermore, potential opportunistic pathogens such as Sphingomonas were detected. Our study shows that after transition to a high quality water source, the total culturable bacteria released was in a downtrend, which leads to a great reduction in the risk of bacterial leakage in the produced drinking water.     

Removal efficiencies of natural and synthetic progesterones in hospital wastewater treated by different disinfection processes

● The concentrations of 61 progesterones in HWW, PFTE, SBTE were evaluated. ● The removal efficiencies of progesterones by PFT and SBT were identified. ● Compared the removal efficiencies of progeste rones in five disinfection processes. Progesterones are ubiquitous in hospital wastewater (HWW) with concentrations much higher than those of estrogens and androgens. To ensure that these water systems are safe to use, disinfection is crucial during HWW treatment by providing “front line” defense against biological contaminations. Here, five disinfection processes, namely, chlorine (Cl₂), chlorine dioxide (ClO₂), ozone (O₃), ultraviolet (UV)), and UV/chlorine (UV/Cl₂), were selected to investigate their removal efficiencies for progesterones in primary filtration and secondary biological treatment effluents. There were 61 natural and synthetic progesterones detected in HWW, with the natural progesterones being the main components with a concentration of 845.51 ng/L and contributing to 75.08% of the total progesterones. The primary filtration treatment presented insignificant removal effects on the progesterones, while the secondary biological treatment significantly reduced the progesterone content by biodegradation. The order of removal efficiencies of total progesterones by different disinfection processes was UV/Cl₂ > Cl ₂ > O ₃ > ClO ₂ > UV. UV/Cl ₂ showed the highest removal efficiency against progesterones mainly due to the activation of Cl₂ by ultraviolet (UV) photolysis, which helps open the heterocyclic, aromatic, and phenolic rings, thus accelerating progesterone degradation. In addition, the removal efficiencies of natural progesterones in the five disinfection processes were higher than those of synthetic progesterones (progesterone derivatives, 19-nortestosterone derivatives, and 17α-hydroxyprogesterone derivatives).     

Technical feasibility study of an onshore ballast water treatment system

To fulfill the requirements of Guidelines for approval of ballast water management system (G8), a set of onshore ballast water treatment equipment utilizing micro-pore ceramic filtration (MPCF) and UV radiation (MPCF&UV) system was designed and set up with a maximum flow rate of 80 m³·h^-1. Technical feasibilities of MPCF&UV system were evaluated in three areas: removal efficiencies of indicator organism and oceanic bacteria, perdurability of a ceramic filter, and application on native seawater. The results showed that no indicator organism (Dunaliella) or oceanic bacteria was detected after treatment of 20 L MPCF and UV radiation at 1.3× 10⁴ μW·s·cm^-2. A 20 L ceramic filter can run continuously for 5.3 h at the flow rate of 15 m³·h^-1 before its pressure drop up to 0.195 MPa. The removal percentage of total plankton amounts were 91.9% at a flow rate of 70 m³·h^-1 by 80 L MPCF and UV radiation at 1.3× 10⁴ μW·s·cm^-2.     

新型污染物及其生态和环境健康效应

近年来,随着现代分析手段的改进和发展,各种污染物检测能力的提高,以及新的毒作用模式的发现、新合成化合物的制造和使用等,一些物质成为广受国内外关注的新型污染物.新型污染物已在世界范围内对环境和生态系统造成了污染,对生态系统中包括人类在内的各种生物均构成了潜在的危害.目前,人们关注较多的新型污染物主要有全氟有机化合物、人用与兽用药物、饮用水消毒副产物、遮光剂/滤紫外线剂、人造纳米材料、汽油添加剂、溴化阻燃剂等.论文在总结国内外相关研究基础上,对一些重点新型污染物的生态效应及其潜在健康影响进行了简要综述,为我国开展这方面的研究提供了一定的参考.     

Bactericidal effects of adsorbent on Escherichia coli for use in disinfection of drinking water

A synergistic action of silver (Ag) and groundnut husk carbon was shown, which markedly enhanced inactivation of Escherichia coli. The purpose of this study was to assess the feasibility of using a silver-impregnated groundnut husk carbon adsorbent (AdSG) for drinking water disinfection and evaluate % disinfection of E. coli. The results showed that contact of bacterial cells with AdSG resulted in a transfer of Ag ion to the cell, as evidenced by bactericidal activity. It is also possible that Ag produced generation of reactive oxygen species in the cell that led to bactericidal activity of the adsorbent. Data indicated that AdSG was effective as a bactericidal agent and may prove to be economically beneficial in drinking water disinfection.     

Intergrated approach for microbiological impact assessment of public wastewater treatment plants

Wastewaters are a source of pathogenic micro-organisms in the environment. The microbial load and residues found in the final effluents of wastewater-treatment plants (WWTPs) depend on the WWTPs' abatement capacity and the final disinfection treatment systems applied to wastewaters before discharge into water. A historical database with data on surface and marine-coastal water quality and on the characterization of WWTP effluents was made using data from 1997 to 2004 to assess the microbiologic impact along the coast of the Venice province (Italy, northern Adriatic sea). The monitoring of river and sea discharges along the coast is integrated with the application of the Synthetic Pluriennal Faecalization Index (ISPF). The experimental study was conducted in the period from November 2002 to April 2004 by the Veneto Regional Environmental Prevention and Protection Agency. The results of this investigation on faecal contamination together with previous data are presented with a preliminary performance characterization of the WWTPs' disinfection technologies (sodium hypochlorite, peracetic acid, UV rays, and ozone).