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| 1 | High-performance size exclusion chromatography with a multi-wavelength absorbance detector study on dissolved organic matter characterisation along a water distribution system显示文摘This study examined the associations between dissolved organic matter(DOM) characteristics and potential nitrification occurrence in the presence of chloramine along a drinking water distribution system. High-performance size exclusion chromatography(HPSEC) coupled with a multiple wavelength detector(200–280 nm) was employed to characterise DOM by molecular weight distribution, bacterial activity was analysed using flow cytometry, and a package of simple analytical tools, such as dissolved organic carbon, absorbance at 254 nm, nitrate,nitrite, ammonia and total disinfectant residual were also applied and their applicability to indicate water quality changes in distribution systems were also evaluated. Results showed that multi-wavelength HPSEC analysis was useful to provide information about DOM character while changes in molecule weight profiles at wavelengths less than 230 nm were also able to be related to other water quality parameters. Correct selection of the UV wavelengths can be an important factor for providing appropriate indicators associated with different DOM compositions. DOM molecular weight in the range of 0.2–0.5 k Da measured at210 nm correlated positively with oxidised nitrogen concentration(r = 0.99), and the concentrations of active bacterial cells in the distribution system(r = 0.85). Our study also showed that the changes of DOM character and bacterial cells were significant in those sampling points that had decreases in total disinfectant residual. HPSEC-UV measured at210 nm and flow cytometry can detect the changes of low molecular weight of DOM and bacterial levels, respectively, when nitrification occurred within the chloraminated distribution system. | Huiping Huang Emma Sawade David Cook Christopher W.K.Chow Mary Drikas Bo Jin | 2016 | Journal of Environmental Sciences2016，28，6： | 7 |
| 2 | Influence of coagulation mechanisms and floc formation on filterability显示文摘Minimizing particles in water is a key goal for improving drinking water quality and safety.The media filtration process,as the last step of the solid–liquid separation process,is largely influenced by the characteristics of flocs,which are formed and controlled within the coagulation process.In a laboratory-based study,the impacts of the physical characteristics of flocs formed using aluminum sulfate on the filtration treatment of two comparative water samples were investigated using a photometric dispersion analyzer and a filterability apparatus.In general,the optimum dosage for maximizing filterability was higher than that for minimizing turbidity under neutral p H conditions.For a monomeric aluminum-based coagulant,the charge neutralization mechanism produced better floc characteristics,including floc growth speed and size,than the sweep flocculation mechanism.In addition,the charge neutralization mechanism showed better performance compared to sweep flocculation in terms of DOC removal and floc filterability improvement for both waters,and showed superiority in turbidity removal only when the raw water had high turbidity.For the different mechanisms,the ways that floc characteristics impacted on floc filterability also differed.The low variation in floc size distribution obtained under the charge neutralization mechanism resulted in the flocs being amenable to removal by filtration processes.For the sweep flocculation mechanism,increasing the floc size improved the settling ability of flocs,resulting in higher filter efficiency. | Ruyuan Jiao Rolando Fabris Christopher W.K.Chow Mary Drikas John van Leeuwen Dongsheng Wang Zhizhen Xu | 2017 | Journal of Environmental Sciences2017，29，7： | 6 |
| 3 | Characterisation of dissolved organic matter in stormwater using high-performance size exclusion chromatography显示文摘Understanding the complexity of dissolved organic matter(DOM)in stormwater has drawn a lot of interest,since DOM from stormwater causes not only environmental impacts,but also worsens downstream aquatic quality associated with water supply and treatability.This study introduced and employed high-performance size exclusion chromatography(HPSEC)coupled with an ultraviolet–visible(UV–vis)diode array detector to assess changes in stormwater-associated DOM characteristics.Stormwater DOM was also analysed in relation to storm event characteristics,water quality and spectroscopic analysis.Statistical tools were used to determine the correlations within DOM and water quality measurements.Results showed that dissolved organic carbon(DOC)and UV absorbance at 254 nm(UV_(254))as conventional DOM parameters were found to be correlated well to the changes in stormwater quality during each of the three storm events studied.Both detector wavelengths(210and 254 nm)and their ratio(A_(210)/A_(254))were found to provide additional information on the physiochemical properties of stormwater-associated DOM.This study indicated that A_(210)/A_(254) is an important parameter which could be used to estimate the DOM proportions of functional groups and conjugated carbon species.This study provided also an understanding of stormwater quality constituents through assessing variability and sensitivity for various parameters,and the additional information of rainfall characteristics on runoff quality data for a better understanding of parameter correlations and influences. | Huiping Huang Christopher W.K.Chow Bo Jin | 2016 | Journal of Environmental Sciences2016，28，4： | 3 |
| 4 | Developing a chloramine decay index to understand nitrification:A case study of two chloraminated drinking water distribution systems显示文摘The management of chloramine decay and the prevention of nitrification are some of the critical issues faced by water utilities that use chloramine as a disinfectant.In this study,potential association between high performance size exclusion chromatography(HPSEC)data obtained with multiple wavelength Ultraviolet(UV) detection from two drinking water distribution systems in Australia and nitrification occurrence was investigated.An increase in the absorbance signal of HPSEC profiles with UV detection at λ = 230 nm between apparent molecular weights of 200 to 1000 Da was observed at sampling sites that experienced rapid chloramine decay and nitrification while its absorbance signal at λ =254 nm decreased.A chloramine decay index(C.D.I) defined as the ratio of area beneath the HPSEC spectra at two different wavelengths of 230 and 254 nm,was used in assessing chloramine decay occurrences.The C.D.Is of waters at locations that experienced nitrification were consistently higher than locations not experiencing nitrification.A simulated laboratory study showed that the formation of nitrite/nitrate and/or soluble microbial products and/or the release of extracellular polymeric substances(EPS) during nitrification may contribute to the C.D.I.increase.These findings suggest that C.D.I derived from HPSEC with multiple wavelength UV detection could be an informative index to track the occurrence of rapid chloramine decay and nitrification. | Sina Moradi Sanly Liu Christopher W.K.Chow John van Leeuwen David Cook Mary Drikas Rose Amal | 2017 | Journal of Environmental Sciences2017，29，7： | 1 |
| 5 | Chloramine demand estimation using surrogate chemical and microbiological parameters显示文摘A model is developed to enable estimation of chloramine demand in full scale drinking water supplies based on chemical and microbiological factors that affect chloramine decay rate via nonlinear regression analysis method.The model is based on organic character(specific ultraviolet absorbance(SUVA)) of the water samples and a laboratory measure of the microbiological(Fm) decay of chloramine.The applicability of the model for estimation of chloramine residual(and hence chloramine demand) was tested on several waters from different water treatment plants in Australia through statistical test analysis between the experimental and predicted data.Results showed that the model was able to simulate and estimate chloramine demand at various times in real drinking water systems.To elucidate the loss of chloramine over the wide variation of water quality used in this study,the model incorporates both the fast and slow chloramine decay pathways.The significance of estimated fast and slow decay rate constants as the kinetic parameters of the model for three water sources in Australia was discussed.It was found that with the same water source,the kinetic parameters remain the same.This modelling approach has the potential to be used by water treatment operators as a decision support tool in order to manage chloramine disinfection. | Sina Moradi Sanly Liu Christopher W.K.Chow John van Leeuwen David Cook Mary Drikas Rose Amal | 2017 | Journal of Environmental Sciences2017，29，7： | 0 |
| 6 | Effects of carbonation on mechanical properties of CAC‑GGBFS blended strain hardening cementitious composites显示文摘基于铝酸盐水泥(CAC)的应变硬化水泥基复合材料(SHCC)已成功应用于污水管道的修复。除了微生物引起的腐蚀外,污水环境中的高浓度CO_(2)也会导致管道严重碳化。因此,本文旨在研究碳化对基于CAC的SHCC力学性能的影响。制备了两种不同强度等级的基于CAC的SHCC试样和一种基于普通硅酸盐水泥(OPC)的SHCC试样作为参照。加速碳化试验在CO_(2)浓度为5%的碳化室中进行。首先进行SHCC的抗压和抗拉强度测试,然后利用X射线衍射和扫描电子显微镜等进行微观结构分析。结果表明,由于纤维桥接效应,基于CAC的SHCC试样表现出稳健的应变硬化性能及较大的拉伸变形能力。此外,与基于OPC的SHCC相比,CAC的SHCC抗压和抗拉强度显著提高,并且在碳化后得到更高的拉伸应变能力。微观结构分析表明,碳化后的基于CAC的SHCC试样中的亚稳相转变为稳定相和碳酸钙多晶型,使胶凝基体更致密。本文的研究为利用碳化避免CAC水化产物的不稳定转变提供了新的见解。 | Wei Fan Yan Zhuge Xing Ma Christopher W.K.Chow Yue Liu Guangtong Huang Nima Gorjian | 2023 | Low-carbon Materials and Green Construction2023，1，1： | 0 |
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