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Disinfection byproduct regulatory compliance surrogates and bromide-associated risk

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Journal of environmental Sciences 2017年第8期29卷 191-207页

作者： Chelsea Kolb Royce A.Francis Jeanne M.VanBriesen department of ciuil and environmental engineering Carnegie Mellon Uniuersity Pittsburgh PA 15213 USA department of engineering Management and Systems engineering The George Washington University Washington DC 20052 USA department of engineering and Public Policy Carnegie Mellon University Pittsburgh PA 15213 USA

Natural and anthropogenic factors can alter bromide concentrations in drinking water sources. Increasing source water bromide concentrations increases the formation and alters the speciation of disinfection byproducts（DBPs） formed during drinking water *** DBPs are more toxic than their chlorinated analogs, and thus have a greater impact on human health. However, DBPs are regulated based on the mass sum of DBPs within a given class（e.g., trihalomethanes and haloacetic acids）, not based on species-specific risk or extent of bromine incorporation. The regulated surrogate measures are intended to protect against not only the species they directly represent, but also against unregulated DBPs that are not routinely measured. Surrogates that do not incorporate effects of increasing bromide may not adequately capture human health risk associated with drinking water when source water bromide is elevated. The present study analyzes trihalomethanes（THMs）, measured as TTHM,with varying source water bromide concentrations, and assesses its correlation with brominated THM, TTHM risk and species-specific THM concentrations and associated *** potential surrogates are evaluated to assess their ability to capture THM risk under different source water bromide concentration conditions. The results of the present study indicate that TTHM does not adequately capture risk of the regulated species when source water bromide concentrations are elevated, and thus would also likely be an inadequate surrogate for many unregulated brominated species. Alternative surrogate measures,including THM3 and the bromodichloromethane concentration, are more robust surrogates for species-specific THM risk at varying source water bromide concentrations.

关键词： Disinfection byproducts Bromide Disinfection byproduct regulation Trihalomethanes Disinfection byproduct risk

Towards real-time detection of wastewater in surface waters using fluorescence spectroscopy

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Journal of environmental Sciences 2019年第12期31卷 195-202页

作者： Ye Z.Yang Nicolas M.Peleato Raymond L.Legge Robert C.Andrews department of ciuil and Mineral engineering University of Toronto35 St.George St.TorontoOntario M5S 1A4Canada School of engineering Uniuersity of British Columbia Okanagan1137 Alwmni AueKeloiunaBritish Columbia V1V 1V7Canada department of Chemical engineering University of Waterloo200 University Ave.WWaterlooOntario N2L 3G1Canada

The presence of municipal wastewater at the intake of a major drinking water treatment facility located on Lake Ontario was examined using fluorescence data collected during a period of continuous *** addition,controlled mixing of lake water and wastewater sampled from a local treatment facility were conducted using a bench-scale fluorescence system to quantify observed changes in natural organic *** linear regression was applied to components derived from parallel factors *** resulting mean absolute error for predicted wastewater level was 0.22%(V/V,wastewater/lake water),indicating that wastewater detection at below 1.0%(V/V)was *** of sucralose,a wastewater indicator,were conducted for treated wastewater as well as surface water collected at two intake locations on Lake *** suggested minimal wastewater contribution at the drinking water intake.A wastewater detection model using a moving baseline was developed and applied to continuous fluorescence data collected at one of the drinking water intakes,which agreed well with sucralose ***,the simulated addition of 1.0%(V/V)of wastewater/wastewater was detectable in 89%of samples analyzed,demonstrating the utility of fluorescence-based wastewater monitoring.

关键词： Excitation emission matrices Parallel factors analysis Natural organic matter Source water monitoring Wastewater impact Water quality assessment

Comparative study of aeroacoustic performance of 1/8 and 1/1 pantographs coupled with cavity

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Railway engineering Science 2024年第4期32卷 551-572页

作者： Xiaoming Tan Huifang Liu Zhigang Yang Hong Chen Baojun Fu Linli Gong Key Laboratory of Intelligent Manufacturing and Service Performance Optimization of Laser and Grinding in Mechanical Industry Hunan Institute of Science and TechnologyYueyang 414006China department of Civil and environmental engineering The Hong Kong Polytechnic UniversityHong KongChina Key Laboratory of Traffic Safety On Track Ministry of EducationCentral South UniversityChangsha 410075China The State Key Laboratory of Heavy-Duty and Express High-Power Electric Locomotive CRRC Zhuzhou Locomotive Co.LtdZhuzhou 412001China

The technology of pantograph sinking in the cavity is generally adopted in the new generation of high-speed trains in China for aerodynamic noise reduction in this region. This study takes a high-speed train with a 4-car formation and a pantograph as the research object and compares the aerodynamic acoustic performance of two scale models, 1/8 and 1/1, using large eddy simulation and Ffowcs Williams–Hawkings integral equation. It is found that there is no direct scale similarity between their aeroacoustic performance. The 1/1 model airflow is separated at the leading edge of the panhead and reattached to the panhead, and its vortex shedding Strouhal number(St) is 0.17. However, the 1/8 model airflow is separated directly at the leading edge of the panhead, and its St is 0.13. The cavity's vortex shedding frequency is in agreement with that calculated by the Rooster empirical formula. The two scale models exhibit some similar characteristics in distribution of sound source energy, but the energy distribution of the 1/8 model is more concentrated in the middle and lower regions. The contribution rates of their middle and lower regions to the radiated noise in the two models are 27.3% and 87.2%, respectively. The peak frequencies of the radiated noise from the 1/1 model are 307 and 571 Hz. The 307 Hz is consistent with the frequency of panhead vortex shedding, and the 571 Hz is more likely to be the result of the superposition of various components. In contrast, the peak frequencies of the radiated noise from the 1/8 scale model are 280 and 1970 Hz. The 280 Hz comes from the shear layer oscillation between the cavity and the bottom frame, and the 1970 Hz is close to the frequency at which the panhead vortex sheds. This shows that the scaled model results need to be corrected before applying to the full-scale model.

关键词： Pantograph cavity coupling Aerodynamic noise Scale effect Large eddy simulation