次氯酸钠发生器在电镀废水处理中的应用

通过一家电镀厂的实例分析，介绍了生产技术管理和使用次氯酸铜发生器前后的经济对比。     

次氯酸钠废液在污水处理厂消毒应用研究

为了确定次氯酸钠废液应用于城镇生活污水处理厂出水消毒的合理投加量,通过实验研究了采用次氯酸钠废液消毒后粪大肠菌群数、COD和p H的变化规律。研究结果显示,在实验条件下,次氯酸钠废液有效氯的合理投加量为5.0 mg/L~5.2mg/L,此时能使粪大肠菌群数达到GB18918-2002的一级A标,同时COD有一定的下降,p H也在排放限值内。     

次氯酸钠消毒在城市污水处理的应用探讨

近年来,随着国家对污水处理厂出水标准的提高,对城市污水处理厂出水中粪大肠杆菌要求也由一级B提高到一级A,消毒已成为污水处理环节的重要组成部分。对城市污水处理厂而言,不仅要确保出水达标还要考虑消毒工艺的经济性,本文以16.5万吨城市污水处理厂为例,探讨次氯酸钠消毒工艺运行的经济性和可行性。     

城镇污水处理厂次氯酸钠消毒实验与分析

本文通过次氯酸钠消毒在无锡市S厂的消毒实验,得出了次氯酸钠消毒用于城镇污水厂合适的投加量和接触时间,并通过成本测算,初步验证了次氯酸钠消毒在城镇污水处理厂应用的经济可行性。     

次氯酸钠用于自来水消毒效果分析

本文探讨了次氯酸钠消毒对自来水水质的影响,通过合理选择次氯酸钠处理参数优化了自来水消毒的效果。     

次氯酸钠与臭氧处理医院污水

从对铁路医院污水两种处理方法的比较，说明臭氧法投资大，运行费用高，管理难，而次氯酸钠法适合于中小型医院污水处理。     

液氯及次氯酸钠消毒对自来水中余氯及消毒副产物的影响

为避免液氯消毒带来的安全隐患,以江苏某国家级开发区水厂加氯消毒系统升级改造项目为研究对象,采用次氯酸钠代替液氯作为消毒剂,从消毒剂消耗量、余氯及消毒副产物含量等方面进行了对比研究。结果表明：采用两种消毒剂对降低浊度及去除余氯的效果无显著性差异;在同等处理效果下,次氯酸钠和液氯的耗氯量均值分别为14.71 kg/kt和1.47 kg/kt;在分别采用液氯消毒剂和次氯酸钠消毒剂的条件下,三卤甲烷出厂水均值分别为379μg/L和253μg/L;与液氯消毒相比,次氯酸钠消毒工艺在一定程度上降低了消毒副产物的产生。     

次氯酸钠、臭氧及其组合再生水消毒技术研究

以某城市污水处理厂二级出水为原水,采用次氯酸钠、臭氧以及臭氧/次氯酸钠组合工艺,研究了不同消毒方式对总大肠菌群、粪大肠菌群和色度的去除规律,消毒副产物中三卤甲烷(THMs)生成量随有效氯投加量变化的规律。试验结果表明:在次氯酸钠消毒过程中,有效氯投加量为5 mg/L时,总大肠菌群和粪大肠菌群去除率分别为99.91%和99.99%,色度去除率为26.00%;臭氧消毒过程中,当臭氧剂量为2.6 mg/L时,总大肠菌群和粪大肠菌群去除率分别为99.70%和99.73%,色度去除率为71.65%;在组合工艺中,当臭氧剂量为2 mg/L、有效氯投加量为0.5 mg/L时,出水总大肠菌群和粪大肠菌群总数去除率分别为99.94%和99.87%,色度去除率为70.60%;在相同有效氯投加量条件下,组合工艺较单独次氯酸钠消毒出水的总大肠菌群和粪大肠菌群更低,三氯甲烷生成量降低36.67%,一氯二溴甲烷未检出。     

城镇污水处理厂次氯酸钠消毒工艺对出水BOD_5测定影响探讨

本文研究了城镇污水处理厂次氯酸钠消毒工艺对BOD5测定结果的影响,并对污水杀菌工艺进行了初步研究。实验表明次氯酸钠的投加,会消耗水中的微生物,并且产生消毒副产物抑制微生物生长,从而对BOD5的测定产生干扰。反应时间30min时,3.0mg/L的加氯量可以使粪大肠菌群小于800个/L,达国标要求。增加反应时间可以减少氯的使用。当次氯酸钠投加量大于5mg/L时,此时余氯含量大于1.05mg/L,BOD5受到显著抑制,应在除氯后用非稀释接种法测定。污水处理厂可以采用增加停留时间等方式改善工艺,减少次氯酸钠投加量。     

Interactions of fluoroquinolone antibiotics with sodium hypochlorite in bromide-containing synthetic water: Reaction kinetics and transformation pathways

Seven popular fluoroquinolone antibiotics (FQs) in synthetic marine aquaculture water were subject to sodium hypochlorite (NaClO) disinfection scenario to investigate their reaction kinetics and transformation during chlorination. Reactivity of each FQ to NaClO was following the order of ofloxacin (OFL) > enrofloxacin (ENR) > lomefloxacin (LOM) > ciprofloxacin (CIP) ~ norfloxacin (NOR) >> pipemedic acid (PIP), while flumequine did not exhibit reactivity. The coexisting chlorine ions and sulfate ions in the water slightly facilitated the oxidation of FQs by NaClO, while humic acid was inhibitable to their degradation. The bromide ions promoted degradation of CIP and LOM, but restrained oxidation of OFL and ENR. By analysis of liquid chromatography with tandem mass spectrometry (LC-MS/MS), eight kinds of emerging brominated disinfection byproducts (Br-DBPs) caused by FQ_S were primarily identified in the chlorinated synthetic marine culture water. Through density functional theory calculation, the highest-occupied molecular orbital (HOMO) and the lowest-unoccupied molecular orbital (LUMO) characteristic as well as the charge distribution of the FQs were obtained to clarify transformation mechanisms. Their formation involved decarboxylation, ring-opening/closure, dealkylation and halogenation. Chlorine substitution occurred on the ortho-position of FQs's N4 and bromine substitution occurred on C8 position. The piperazine ring containing tertiary amine was comparatively stable, while this moiety with a secondary amine structure would break down during chlorination. Additionally, logK_ow and logBAF of transformation products were calculated by EPI-Suite^TM to analyze their bioaccumulation. The values indicated that Br-DBPs are easier to accumulate in the aquatic organism relative to their chloro-analogues and parent compounds.     

Impacts of sodium hydroxide and sodium hypochlorite aging on polyvinylidene fluoride membranes fabricated with different methods

This study compared the effects of chemical aging on the polyvinylidene fluoride(PVDF)membranes fabricated with the methods of non-solvent induced phase separation(NIPS)(named NIPS-PVDF) and thermally induced phase separation(TIPS)(named TIPS-PVDF). The chemical solutions of sodium hypochlorite(NaClO) and sodium hydroxide(NaOH) were chosen at the concentration of 5000 mg/L. The equivalence of 5 and 10 years was respectively selected as the time of aging. The physicochemical evolutions of membrane aging are characterized on the base of morphology analysis, chemical components, permeation ability and mechanical properties. The aging of NIPS-PVDF membrane led to the elimination of surface hydrophilic additives, while NaO H focused on the dehydrofluorination process resulting in the formation of conjugated chains of polyene on the skeleton structure. The chemical components of the surface of TIPS-PVDF membrane were removed continuously during the aging processes of both NaClO and NaOH, which was caused by the saponification of surface additives and the chain scissions of skeleton structure, but without producing any obvious conjugated chains of polyene. All the aging processes led to the increase of contact angle and the decrease of mechanical properties, and the permeability was reduced first and increased later due to the enlargement of surface membrane pores and membrane block. With the influence of membrane aging, selectivity of membrane was decreased(except coliform bacteria). At the beginning of filtration, the turbidity and particle count were at relatively high levels and declined with the filtration process.     

次氯酸钠与亚铁对污泥破解及脱水效果的影响

采用次氯酸钠（NaClO）与亚铁（Fe（II））结合处理污泥以提高污泥破解和脱水效能,考察了NaClO和Fe（II）投加量的影响,并通过定量和定性分析污泥中胞外聚合物质（EPS）的迁移转化,确定NaClO和Fe（II）对污泥脱水和破解的机制.试验结果表明,NaClO和Fe（II）投加量（以干泥固体计）分别为44 mg·g^-1和66 mg·g^-1时,污泥毛细吸吮时间（CST）从原泥的112 s下降到66.3 s.同时,NaClO/Fe（II）处理污泥能够使上清液中化学需氧量（COD）显著升高,并使污泥中紧密束缚型EPS（TB-EPS）和松散束缚型EPS（LB-EPS）转化成溶解性EPS（S-EPS）,导致S-EPS的溶解性有机碳（DOC）含量升高,而LB-EPS和TB-EPS的DOC含量降低.此外,NaClO/Fe（II）还能使污泥中有机物质矿化,使3种EPS中蛋白质类和腐殖酸类物质减少.NaClO和Fe（II）能够改善污泥脱水性能,强化污泥破解效果,利于污泥后续的处理处置.     

亚甲基蓝与次氯酸钠对塔胞藻胁迫作用的比较

实验选取养殖生产常用消毒药品亚甲基蓝C16H18ClN3S.3H2O和NaClO作为外源物质,探讨二者对塔胞藻(Pyramimimonas.sp)的毒理学影响及塔胞藻在逆境状态下的适应性变化。结果表明:NaClO对塔胞藻的胁迫表现为低浓度的刺激效应,细胞生理指标变化反映出明显的氧化毒害症状;C16H18ClN3S.3H2O对塔胞藻的胁迫表现为明显的抑制作用,塔胞藻对C16H18ClN3S.3H2O的降解作用显著,细胞所受到的氧化损伤轻微。胁迫作用下叶绿素含量、叶绿素a/b值降低,SOD活力、MDA含量升高;SOD在塔胞藻的氧化抗性机制起着重要作用。     

次氯酸钠对水中腐殖酸结构及光学特性的影响

以腐殖酸（HA）作为溶解性有机质模型化合物,采用高压排阻色谱、有机元素分析、傅里叶红外光谱、紫外-可见光谱、荧光光谱及光降解动力学等手段研究了NaOCl对HA元素组成、结构特征、抗氧化性及光学特性等的影响.结果显示,当NaOCl与HA的浓度比由0增至20.0μmol/mg时,HA的分子量逐渐减小,并趋于集中分布;HA中的芳香酸、脂肪酸、酚和醇等含氧组分先增多后减少,使得HA的极性呈现出先增大后减小的变化趋势.值得注意的是,尽管实验浓度范围内的NaOCl不改变HA的腐殖特性,但其能显著减小HA的吸光能力、抗氧化能力和芳香度,并增大HA的荧光发光强度和表观光敏化活性.研究结果能促进对深度氧化处理改变溶解性有机质结构的认识,并为污水处理厂出水中溶解性有机质的环境效应评估提供基础信息.     

Emergency membrane contactor based absorption system for ammonia leaks in water treatment plants

Because of the suspected health risks of trihalomethanes (THMs), more and more water treatment plants have replaced traditionalchlorine disinfection process with chloramines but often without the proper absorption system installed in the case of ammonia leaksin the storage room. A pilot plant membrane absorption system was developed and installed in a water treatment plant for this purpose.Experimentally determined contact angle, surface tension, and corrosion tests indicated that the sulfuric acid was the proper choice as the absorbent for leaking ammonia using polypropylene hollow fiber membrane contactor. Effects of several operating conditionson the mass transfer coefficient, ammonia absorption, and removal efficiency were examined, including the liquid concentration,liquid velocity, and feed gas concentration. Under the operation conditions investigated, the gas absorption efficiency over 99.9%was achieved. This indicated that the designed pilot plant membrane absorption system was effective to absorb the leaking ammonia in the model storage room. The removal rate of the ammonia in the model storage room was also experimentally and theoretically foundto be primarily determined by the ammonia suction flow rate from the ammonia storage room to the membrane contactor. The ammoniaremoval rate of 99.9% was expected to be achieved within 1.3 h at the ammonia gas flow rate of 500 m3/h. The success of the pilot plantmembrane absorption system developed in this study illustrated the potential of this technology for ammonia leaks in water treatmentplant, also paved the way towards a larger scale application.     

Aging of PVDF and PES ultrafiltration membranes by sodium hypochlorite: Effect of solution pH

Sodium hypochlorite (NaClO) is a commonly applied cleaning agent for ultrafiltration membranes in water and wastewater treatment. Long-term exposure to NaClO might change the properties and performance of polymeric membranes, and ultimately shorten membrane lifespan. Active species in NaClO solution vary with solution pH, and the aging effects can change depending on the membrane material. In this study, the aging of polyvinylidene fluoride (PVDF) and polyethersulfone (PES) membranes by NaClO at pH 3–11 was investigated by examining variations in chemical composition, surface charge, surface morphology, mechanical strength, permeability, and retention ability. Polyvinyl pyrrolidone (PVP), which was blended in both membranes, was oxidized and dislodged due to NaClO aging at all investigated pH values, but the oxidation products and dislodgement ratio of PVP varied with solution pH. For the PVDF membrane, NaClO aging at pH 3–11 caused a moderate increase in permeability and decreased retention due to the oxidation and release of PVP. The tensile strength decreased only at pH 11 because of the defluorination of PVDF molecules. For the PES membrane, NaClO aging at all investigated pH resulted in chain scission of PES molecules, which was favored at pH 7 and 9, potentially due to the formation of free radicals. Therefore, a decrease in tensile strength and retention ability, as well as an increase in permeability, occurred in the PES membrane for NaClO aging at pH 3–11. Overall, the results can provide a basis for selecting chemical cleaning conditions for PVDF and PES membranes.     

Removal of hydrophobic volatile organic compounds with sodium hypochlorite and surfactant in a co-current rotating packed bed

A co-current flow rotating packed bed was applied to remove volatile organic compounds(VOCs) by sodium hypochlorite(Na Cl O) and surfactant(sodium dodecyl benzene sulfonate,SDBS) from air stream. Xylene was used as a model VOC herein. The effect of p H,concentration of Na Cl O and SDBS solution, liquid flow rate, gas flow rate and rotational speed on xylene removal efficiency and overall mass transfer coefficient(KGa) were discussed. Then, a correlation for KGa of the co-current rotating packed bed was proposed by fitting the experimental data of KGa and independent variables of liquid/gas ratio,rotational speed, p H, Na Cl O concentration and treatment time, which was in good agreement with the experimental data(the deviation ≤± 30%).     

次氯酸钠对剑水蚤灭活动力学及紫外强化灭活

水源水体富营养化导致剑水蚤孳生,进入供水系统后威胁供水安全.为高效控制剑水蚤污染风险,通过适当增加NaClO灭活CT值（NaClO浓度与接触时间乘积）范围,系统研究了NaClO对剑水蚤灭活动力学过程,同时探讨了紫外照射对灭活效果的强化作用.结果表明：NaClO对剑水蚤的灭活动力学过程符合迟滞型两阶段准一级动力学过程,灭活反应活化能为3774J/mol;pH值对灭活动力学过程的影响,主要通过改变溶液中HOCl和ClO^-物质的量及其化学稳定性来实现.当灭活CT值超出70mg min/L时,中性条件下NaClO对剑水蚤的灭活效率最高,碱性次之,酸性最差;浊度物质会削弱NaClO对剑水蚤的灭活效果,浊度物质会迟滞NaClO从液相主体向剑水蚤体表边界层的传质过程,被剑水蚤体表吸附后也会阻碍NaClO向剑水蚤体内的渗透过程.紫外照射尽管无法实现对剑水蚤的灭活,但可以强化NaClO对剑水蚤的灭活效果,经紫外照射后,剑水蚤灭活迟滞期消失或缩短,同时灭活反应速率常数增加.当pH值为6、7和8时,紫外照射预处理后,各自灭活反应速率常数分别由0.0093、0.02185和0.0206提高至0.0105、0.02673和0.0286.     

The effect of sodium hypochlorite solutions on in vitro seedling growth and shoot regeneration of flax (Linum usitatissimum)

The aim of this study was to determine the effect of concentration (40, 60, and 80%) and temperature (0, 10, 20, and 30°C) of sodium hypochlorite (NaOCl) solutions on seed germination, in vitro viability and growth of flax seedlings and regeneration capacity of hypocotyl explants. Results showed that seed germination, seedling growth and shoot regeneration were negatively affected by increasing concentration and temperature of disinfectant. The best results in seedling growth and shoot regeneration were obtained when 40% disinfectant concentration at 10°C was used.