Use of polymeric sub-micron ion-exchange resins for removal of lead, copper, zinc, and nickel from natural waters

This research investigated the removal capacity of polymeric sub-micron ion-exchange resins(SMR) for removal of lead, copper, zinc, and nickel from natural waters in competition with natural organic matter(NOM). Polymeric SMR particles were created and tested to ensure that they were adequately dispersed in the solution. They removed little NOM(10%or less) from river water and wastewater, indicating that competition from NOM was not a major concern. SMR were able to remove 82% ± 0.2% of lead, 46% ± 0.6% of copper, 55% ±20% of zinc, and 17% ± 2% of nickel from river water spiked with 500 μg/L of each. Similarly,in wastewater, they were able to remove 86% ± 0.1% of lead, 38% ± 0.8% of copper, 28% ± 1%of zinc, and 11% ± 1% of nickel.     

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

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 monitoring. In 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 matter. Multivariate linear regression was applied to components derived from parallel factors analysis. The 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 possible. Analyses of sucralose, a wastewater indicator, were conducted for treated wastewater as well as surface water collected at two intake locations on Lake Ontario. Results 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 results. Furthermore, 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.     

泉州市大气PM2.5中PAHs的污染特征、来源及其健康风险评价

为了解泉州市大气PM_(2.5)中PAHs的污染特征,明确关键污染源,于2016年2月～10月采集了清源山、涂山街、万安和东海四个站点的PM_(2.5)样品,采用前进样口直接热解析气相色谱-质谱联用仪(TD-GC/MS)定量分析了19种多环芳烃(PAHs)的浓度水平,并对其健康风险进行评价。结果表明,采样期间泉州市大气PM_(2.5)中∑PAHs质量浓度为1. 98±0. 75 ng/m~3,显著低于国内大多数城市;呈现冬季春季夏季秋季的季节变化特点,以及涂山街万安东海清源山的空间分布特征。其中,5环PAHs占比最大,为30%～38%,其次为3环,4环和6环,占比分别为18%～27%、22%～25%、和13%～19%。特征比值法分析发现,夏、秋季PAHs受生物质燃烧或煤燃烧的影响大于冬、春季;冬、春季化石燃料燃烧(如机动车排放)的影响较大。大气PM_(2.5)中PAHs对儿童和成人的超额终生致癌风险分别为0. 7×10~(-7)和1. 4×10~(-7),不具有致癌风险。     

大沽河麻湾桥饮用水源区现状及保护对策

在对大沽河麻湾桥饮用水源区进行调查研究的基础上,分析了饮用水源区的现状及饮用水主要超标污染物。研究表明污染主要来自农村生活、农业生产及工业生产,另外饮用水源保护地存在管理能力薄弱等问题。结合实际,提出了采取发展生态农业、河道综合整治、改进管理模式等对策和建议,确保水源地得到有效保护。     

云南省农业自然灾害区划指标之探讨

自然灾害区划是防灾减灾和灾害科学研究的重要内容，而正确地选取区划指标是进行区划工作的关键环节。本文作为《云南省农业自然灾害区划研究》课题的一部分，在探讨各单项灾害（干旱、洪涝、低温霜冻、风雹、水土流失）区划指标的基础上，提出了综合农业自然灾害区划的基本指标－即“综合农业自然灾害指数”，并对指标进行了分级，为区划工作提供了依据。     

Real-world gaseous emission characteristics of natural gas heavy-duty sanitation trucks

As compared to conventional diesel heavy-duty vehicles, natural gas vehicles have been proved to be more eco-friendly due to their lower production of greenhouse gas and pollutant emissions, which are causing enormous adverse effects on global warming and air pollution. However, natural gas vehicles were rarely studied before, especially through on-road measurements. In this study, a portable emission measurement system (PEMS) was employed to investigate the real-world emissions of nitrogen oxides (NOx) (nitrogen monoxide (NO), nitrogen dioxide (NO₂)), total hydrocarbons (THC), carbon monoxide (CO), and carbon dioxide (CO₂) from two liquified natural gas (LNG) China V heavy-duty cleaning sanitation trucks with different weight. Associated with the more aggressive driving behaviors, the vehicle with lower weight exhibited higher CO₂ (3%) but lower NOx (48.3%) (NO₂ (78.2%) and NO (29.4%)), CO (44.8%), and THC (3.7%) emission factors. Aggressive driving behaviors were also favorable to the production of THC, especially those in the medium-speed range but significantly negative to the production of CO and NO₂, especially those in the low-speed range with high engine load. In particular, the emission rate ratio of NO₂/NO decreased with the increase of speed/scaled tractive power in different speed ranges.     

Unignited High-Pressure Methane Jet Impinging a Pipe Rack: Practical Tools for Risk Assessment

Although the diffusion of its storage and transport under liquefied conditions, nowadays it is common to have methane in gaseous form in several industrial applications. This leads to safety implications to be considered: hazards are linked to both the high-pressure at which the gas is kept and to its flammability. Scenarios where flammable jets impact an obstacle are of paramount importance because of their possible occurrence. Following a numerical approach, literature shows up that their assessment can be reliably performed by means of only Computational Fluid Dynamics tools. However, despite the improvements of computing power, Computational Fluid Dynamics costs still limit its use in daily risk analysts’ activities. Therefore, considering an accidental jet-obstacle scenario of industrial interest, the present work investigates how a pipe rack can influence the development of a high-pressure methane jet. Based on a Computational Fluid Dynamics analysis, main achievements of this work are a simple criterion able to identify the situations where the pipe rack does not influence the high-pressure methane jet behavior, therefore allowing to identify the scenarios where simpler models can be used (i.e., analytical correlations known for the free jet situation), and, if present, a simple analytical relationship that roughly predicts the influence of the pipe rack without the need of performing complex Computational Fluid Dynamics simulations.     

Study on leak-acoustics generation mechanism for natural gas pipelines

In order to figure out the principles of acoustic leak detection for natural gas pipelines, a study on the leak-acoustics generation mechanism is carried out. The aero-acoustics generation mechanism is analyzed and when leakage occurs the wave equations of sonic sources are developed. The leak-acoustics generated by the quadrupole and dipole sonic sources are then simulated to obtain the laws of the acoustic characteristics. The simulation data are compared with the experimental data to verify the simulation accuracy under variable operating conditions. The results show that the quadrupoles and the dipoles generated by turbulent fluctuations cause leak-acoustics; the main component of pressure perturbations acquired by the dynamic pressure sensor is acoustic perturbations; both the simulation method and the experimental method can be applied to study the leak-acoustics generation mechanism of natural gas pipelines.     

Qualitative risk assessment of a Dual Fuel (LNG-Diesel) system for heavy-duty trucks

A Dual Fuel (LNG-Diesel) system can be applied to heavy-duty diesel trucks for achieving environmental benefits in comparison to existing diesel vehicles. Because of lack of reports about risk assessment of this technology, we performed a qualitative assessment based on a framework of some literature techniques for risk identification, analysis and evaluation. After constructing a Reliability Block Diagram (RBD) to establish the context, we conducted bow-tie analysis, Fault Tree Analysis (FTA), Failure Mode and Effects Analysis (FMEA), likelihood and consequence analysis, and used a risk matrix. We applied these methods and techniques qualitatively to identify causes (e.g. collisions), critical events (e.g. releases of natural gas), related consequences (e.g. fires and explosions), and different possible pathways from a specific cause to its consequence, and to assess some negative accident scenarios related to use and parking of the vehicle. The bow-tie analysis also allowed to make explicit barriers and controls that prevent critical events and/or mitigate consequences. Therefore, we identified a set of safety measures, including design, technical, management, and emergency actions, which shall be implemented in each step of the system's life cycle.Our risk assessment showed that the risk level of the Dual Fuel (LNG-Diesel) system is similar to the risk level of a traditional diesel system. Future research will overcome current lack of data and, therefore, permit a quantitative rating of the risk of the Dual Fuel (LNG-Diesel) system.