传统加氯工艺的优化控制

加氯消毒是制水厂最基本且最重要的水处理单元,文章对某水厂现有加氯工艺进行研究探讨,并对该加氯工艺进行优化控制,以确保水质卫生学指标安全,降低氯消毒副产物(如THMs)的生成量。     

接触氧化与混凝沉淀在处理喷胶棉生产废水工程中的应用

广东某再生资源有限公司喷胶棉污水处理工程,设计处理能力为1000m3/d,污水分两部分:生活污水,生产废水。处理水量各为500m3/d,即20.8m3/h。生活污水采用接触氧化—沉淀—砂滤工艺;生产废水采用混凝沉淀—过滤—混凝沉淀—砂滤—活性炭吸附—消毒工艺。从2007年5月运行以来出水一直稳定达到并高于广东省《水污染物排放限值》(DB44/26-2001)第二时段一级标准。文章主要介绍该工程得工程概况,调试过程和运行效果。     

污水厂出水消毒效果影响因素的探讨

通过对污水处理厂出水加氯消毒各种因素的分析,并经实验研究确定影响消毒效果的因素为pH、有机氮、COD、氨氮、水温等,其中pH为最主要影响因素,同时得出加氯消毒最佳水质条件。在实际生产中,可根据在线仪表显示的水质情况,来调节最佳投氯量。     

Removal of particle-associated bacteriophages by dual-media filtration at different filter cycle stages and impacts on subsequent UV disinfection

This bench-scale study investigated the passage of particle-associated bacteriophage through a dual-media (anthracite-sand) filter over a complete filter cycle and the effect on subsequent ultraviolet (UV) disinfection. Two model viruses, bacteriophages MS2 and T4, were considered. The water matrix was de-chlorinated tap water with either kaolin or Aldrich humic acid (AHA) added and coagulated with alum to form floc before filtration. The turbidity of the influent flocculated water was 6.4+/-1.5 NTU. Influent and filter effluent turbidity and particle counts were measured as well as headloss across the filter media. Filter effluent samples were collected for phage enumeration during three filter cycle stages: (i) filter ripening; (ii) stable operation; and (iii) end of filter cycle. Stable filter operation was defined according to a filter effluent turbidity goal of <0.3 NTU. Influent and filter effluent samples were subsequently exposed to UV light (254 nm) at 40 mJ/cm(2) using a low pressure UV collimated beam. The study found statistically significant differences (alpha=0.05) in the quantity of particle-associated phage present in the filter effluent during the three stages of filtration. There was reduced UV disinfection efficiency due to the presence of particle-associated phage in the filter effluent in trials with bacteriophage MS2 and humic acid floc. Unfiltered influent water samples also resulted in reduced UV inactivation of phage relative to particle-free control conditions for both phages. Trends in filter effluent turbidity corresponded with breakthrough of particle-associated phage in the filter effluent. The results therefore suggest that maintenance of optimum filtration conditions upstream of UV disinfection is a critical barrier to particle-associated viruses.     

Impact of microparticles on UV disinfection of indigenous aerobic spores

Numerous studies have shown that the efficacy of ultraviolet (UV) disinfection can be hindered by the presence of particles that can shield microorganisms. The main objective of this study was to determine to what extent natural particulate matter can shield indigenous spores of aerobic spore-forming bacteria (ASFB) from UV rays. The extent of the protective shielding was assessed by comparing the inactivation rates in three water fractions (untreated, dispersed and filtered on an 8 microm membrane) using a collimated beam apparatus with a low-pressure lamp emitting at 254 nm. Levels of inactivation were then related to the distribution and abundance of particles as measured by microflow imaging. Disinfection assays were completed on two source waters of different quality and particle content. A protocol was developed to break down particles and disperse aggregates (addition of 100mg/L of Zwittergent 3-12 and blending at 8000 rpm for 4 min). Particle size distribution (PSD) analysis confirmed a statistically significant decrease in the number of particles for diameter ranges above 5 microm following the dispersion protocol and 8 microm filtration. The fluence required to reach 1-log inactivation of ASFB spores was independent of particle concentration, while that required to reach 2-log inactivation or more was correlated with the concentration of particles larger than 8 microm (R(2)>0.61). Results suggest that natural particulate matter can protect indigenous organisms from UV radiation in waters with elevated particle content, while source water with low particle counts may not be subject to this interference.     

水泥窑协同处置医疗废物工艺

笔者参与设计了某水泥窑协同处置医疗废物项目,通过“微波消毒预处理+水泥窑窑尾投加”的工艺设计思路,解决了医疗废物在水泥窑停窑、窑况异常调整期间的进场储存时间限制,延长了医疗废物的储存时效。同时,利用水泥窑协同处置的方法,通过利用水泥窑处置的诸多优点,也为医疗废物最终处置提供了一种安全、可靠的途径。     

消除鲜食生菜中细菌污染的研究进展

随着营养均衡的饮食观念不断深入人心,人们对于鲜食蔬果的消费量不断上升。生菜这种广受中西方民众欢迎的蔬菜在日常鲜食食品中具有重要的地位。但是,生菜在种植、采摘、流通、销售等环节都可能会被细菌污染,这些细菌甚至包括金黄色葡萄球菌、沙门氏菌、蜡样芽孢杆菌、大肠杆菌O157:H7等致病菌。一方面,细菌性腐败菌的大量污染会对生菜货架期造成影响;另一方面,致病菌的污染会造成消费者食物中毒。目前,已有大量消除生菜中细菌污染方法的研究,包括物理清洗、消毒剂杀菌、物理杀菌等。本文对这些细菌消除方法的使用以及优缺点进行系统综述,以期为后续研究或应用提供理论参考。     

Antiviral effect of multipurpose contact lens disinfecting solutions against coronavirus

PurposeTo evaluate the antiviral potential of five multipurpose disinfecting solutions against coronavirus (mouse hepatitis virus, a surrogate for SARS-CoV-2 human corona virus).MethodsTest solutions (Biotrue, renu Advanced [Bausch and Lomb], ACUVUE RevitaLens [Johnson and Johnson Vision], cleadew [Ophtecs corp.] or AOSept Plus [Alcon]) were mixed with the coronavirus mouse hepatitis virus at 10⁴ plaque forming units (PFU)/mL as the final concentration and incubated at room temperature for the specified disinfection time. Surviving virus from each sample was then quantified by standard plaque forming unit assay and the reduction of PFU for each disinfectant was compared to the phosphate buffer saline (PBS) treated negative control. A regimen test was also conducted using Biotrue.ResultsThe three multipurpose disinfecting solutions Biotrue (containing PHMB and polyquaternium-1), renu Advanced (PHMB, polyquaternium-1 and alexidine) and ACUVUE RevitaLens (polyquaternium-1 and alexidine) did not kill the coronavirus at the manufacturers recommended disinfection time in the stand alone test. After treatment, the virus’s titer (3.8 ± 0.2 log₁₀ for Biotrue, 3.7 ± 0.1 log₁₀ for renu and 3.7 ± 0.2 log₁₀ for RevitaLens) was similar to the negative control (3.7 ± 0.1 log₁₀; p ≥ 0.996). AOSept Plus (hydrogen peroxide) and cleadew (povidone iodine) significantly (p < 0.001) reduced the numbers of coronaviruses to below the detection limit (i.e. killed 3.7 ± 0.1 log₁₀ viruses compared to control). However, there was a significant reduction (p = 0.028) in numbers of coronaviruses attached to lenses when using the regimen test with Biotrue.ConclusionsThis study shows that oxidative contact lens disinfecting solutions (i.e. those containing povidone-iodine or hydrogen peroxide) provide superior antiviral activity against a coronavirus surrogate of SARS-CoV-2, unless the full regimen test (rub, rinse, disinfect) is used.     

用于医疗器械快速灭菌的低温等离子体装置研究

现有低温等离子体技术存在放电范围小、放电电压高等局限性,不适用于大尺寸医疗器械的消毒灭菌。 本文研制了一 种灭菌装置,在较低击穿电压下(大气压氦气 325 V,大气压空气 585 V)产生了大面积等离子体,且创新性地在印刷电路板上实 现了气体放电。 通过 COMSOL 等离子体仿真以及实际放电实验,同时实现了低气压与大气压环境下的均匀辉光放电,放电实 验结果表明:相对气压在-70~ -50 kPa 范围内,击穿电压值最低。 通过灭菌实验,验证了此灭菌装置产生等离子体的灭菌效 能,并对影响灭菌效果的因素进行了探究,灭菌实验结果表明:电源频率是影响灭菌效果的最关键因素,灭菌时间其次,氦气气 压对灭菌效果影响最小。 对于一定浓度的大肠杆菌,6 min 即可达到完全灭菌。     

A Study on the Removal of Humic Acid Using Advanced Oxidation Processes

Abstract

Humic acid (HA) removal using advanced oxidation processes (AOPs) was investigated, particularly UVA/H₂O₂ and photo Fenton‐like process (UVA/Fe(III)/H₂O₂). Changes in the UV₂₅₄ absorbance, dissolved organic carbon (DOC), apparent molecular weight (AMW) distribution, and the Trihalomethane formation potential (THMFP) of the organics were monitored. UVA/Fe(III)/H₂O₂ based process was found to be effective in removing more than 80% DOC and 90% UV₂₅₄ absorbance. Differences in the reduction profiles of AMW distributions for UVA/Fe(III)/H₂O₂ based process and UVA/H₂O₂ process were observed, with the latter showing preferential removal of a certain molecular weight range. Selected samples were then fractionated into four components: very hydrophobic acids (VHA), slightly hydrophobic acids (SHA), hydrophilic charged (CHA), and hydrophilic neutral (NEU). The HA used is found to consist mostly of VHA fraction that is very susceptible to AOP treatments. The results illustrate that the degradation process occurred via the fragmentation of VHA fraction to form SHA, CHA, and NEU fractions.