PREDICTIVE MODEL FOR NITRATE LOAD IN THE BULL RUN WATERSHED,OREGON1

ABSTRACT: Predictive models for nitrate in four streams in the Bull Run Watershed in the Cascade Mountains of Oregon were developed from a record of 17 years of nitrate samples. The models are time series regression models written in terms of Log(nitrate load). The independent variables are logarithm of 14-day mean daily stream discharge, current day's precipitation, logarithm of the previous day's precipitation, total precipitation for the previous seven days, a hydrograph position variable that indicates rising or falling limb, and average maximum air temperature for the preceding 14 days. The models describe annual cycle and seasonable trends and variations in nitrate load, but are unable to describe large day to day variations like those associated with hydrograph peaks.     

EFFECTS OF ADVANCED WASTEWATER TREATMENT ON THE QUALITY OF WHITE RIVER,INDIANA1

ABSTRACT: In 1983, the City of Indianapolis, Indiana, completed construction of advanced wastewater treatment (AWT) systems to enlarge and upgrade its existing Belmont Road and South port Road secondary treatment plants. A nonparametric statistical procedure, a modified form of the Wilcoxon-Mann-Whitney rank-sum test, was used to test for trends in water quality at two upstream and two downstream sites on White River and at the two treatment plants. Results comparing the pre- (1978–1980) and post- (1983–1986) AWT periods show statistically significant improvements in the quality of the treated effluent and of the White River downstream from the plants. Water quality at sites upstream from the city was relatively constant during the period of study. Total ammonia (as N) decreased 14.6 mg/L and BOD₅ (five-day biochemical oxygen demand) decreased 10 to 19 mg/L in the two effluents. Total ammonia in the river downstream from the plants decreased 0.8 to 1.9 mg/L and BOD₅ decreased 2.3 to 2.5 mg/L. Nitrate (as N) increased 14.5 mg/L in the plant effluents and 2.0 to 2.4 mg/L in the river because of in-plant nitrification. Dissolved oxygen concentration in the river increased about 3 mg/L because of reduced oxygen demand for nitrification and biochemical oxidation processes.     

TA-FTIR/MS用于硝酸铵及其混合物的热化学行为研究

为评价物料混合对危险化学品热化学行为的影响,采用热分析-红外/质谱联用技术(TA-FTIR/MS)研究硝酸铵、柠檬酸和蔗糖的混合物的热化学行为。通过对硝酸铵及其混合物的分解温度和分解过程中逸出气体的分析,发现硝酸铵、柠檬酸和蔗糖的混合物热分解温度分别降低至135℃和153℃,而硝酸铵与甲基纤维素的混合物分解温度与硝酸铵基本相同为201℃,且各混合体系的气相分解产物均有氮氧化物(NOX),H2O和CO2。结果表明,混合物受热后其中的硝酸铵首先分解为硝酸和氨气;酸性物质和还原性物质由于对硝酸的分解反应有催化作用,使得混合物的热稳定性下降。     

Ammonium nitrate thermal decomposition with additives

Runaway reactions present a potentially serious threat to the chemical process industry and the community; such reactions occur time and time again often with devastating consequences. The main objective of this research is to study the root causes associated with ammonium nitrate (AN) explosions during storage. The research focuses on AN fertilizers and studies the effects of different types of fertilizer compatible additives on AN thermal decomposition. Reactive Systems Screening Tool (RSST) has been used for reactivity evaluation and to better understand the mechanisms that result in explosion hazards. The results obtained from this tool have been reported in terms of parameters such as “onset” temperature, rate of temperature and pressure rise and maximum temperature. The runaway behavior of AN has been studied as a solid and solution in water. The effect of additives such as sodium sulfate (Na₂SO₄) and potassium chloride (KCl) has also been studied. Multiple tests have been conducted to determine the characteristics of AN decomposition accurately. The results show that the presence of sodium sulfate can increase the “onset” temperature of AN decomposition thus acting as AN thermal decomposition inhibitor, while potassium chloride tends to decrease the “onset” temperature thus acting as AN thermal decomposition promoter.     

不同收获时期和控氮条件对水培小白菜硝酸盐含量的影响

在水培中采用收获前降低营养液浓度、完全停止供氮以及在不同时期采收等方法来研究小白菜硝酸盐含量的控制方式及其效果,结果表明:适时采收和收获前适当控氮可以降低小白菜的硝酸盐含量。在小白菜生长第26d左右硝酸盐含量最低,此后l~2d产量增长较快,此时采收品质较好;小白菜硝酸盐含量呈明显的日变化,并且与硝酸还原酶活性呈正相关,在下午16:00时左右采收硝酸盐含量最低,仅为894mg.kg-1;完全断氮7d后,小白菜硝酸盐含量显著降低,但产量也受到明显的影响。而采用低浓度营养液控氮4d左右采收既可控制硝酸盐含量又不会使产量过低。     

南京市郊主要蔬菜硝酸盐污染现状评价

以ＷＨＯ／ＦＡＯ规定的日允许摄入量换算得到的标准评价了南京市郊主要蔬菜品种的ＮＯ－３污染状况。结果表明，双闸镇蔬菜基地的大白菜和青菜样品属重污染，菠菜属轻污染，萝卜污染程度居中，因而有必要采取有效的污染防治措施     

水分和氮素供应对菠菜硝酸盐累积和钾素吸收的影响

研究了水分和氮素供应对露地秋菠菜的硝酸盐累积和钾、氮吸收的影响。结果表明：与传统的水氮管理措施相比，采用水分平衡法和氮素专家系统进行的水氮供应并没有造成作物减产，但对钾、氮元素的吸收却有明显的影响，同氮素吸收相比，作物对钾素的吸收数量更高；并且作物对钾、氮的吸收比例随氮素供应水平的增加而降低，试验还动态监测了菠菜最新展开叶的叶柄汁液中的硝酸盐和K^ 浓度在一天内的变化情况。结果表明，不同水氮处理的菠菜叶柄汁液的硝酸盐浓度在白天均没有发生显著变化；叶柄汁液中的K^ 浓度和NO3^-／K^ 的浓度比在白天受氮素供应水平的影响很大，供氮量高，K^ 浓度和NO3^-／K^ 浓度比的变化也大，但受灌水量影响不大。图3表2参17。     

王哥庄湾陆源硝酸盐氮输送通量研究

以汇水区域相对独立的崂山王哥庄地区为例 ,通过研究该区的水文地质条件、分析地表水和地下水中的硝酸盐氮 (NO3 N) ,采用流量法和断面法分别对河流和地下水向王哥庄湾的NO3 N输送量进行了计算。结果表明 ,1999年 5月下旬地下水向海洋输送的NO3 N占整个陆源输入量的 30 .0 6 % ,说明地下水向海洋的营养盐输送量是海洋环境评估的重要边界条件。     

Aerosol light-scattering in The Netherlands

The relation between the (midday) aerosol light-scattering and the concentrations of nitrate and sulfate has been assessed at a site near the coast of the North Sea in The Netherlands. Midday was selected for the measurements because this is the time at which the aerosol is most effective in the scattering of solar radiation. Automated thermodenuders were used for the hourly measurement of the concentration of nitrate and sulfate with a lower detection limit of 0.1 μ m⁻³. The site is operational since October 1993. The first-year average dry aerosol light-scattering (measured with an integrating nephelometer at a wavelength of 525 nm) was 0.71 × 10⁻⁴ m^1̄. In arctic marine air the aerosol light-scattering was a factor of 10 lower than the average value, in polluted continental air it was up to a factor of 10 higher. The ratio of the total aerosol light-scattering to the concentration of sulfate was 20 m² g⁻¹. The contribution of nitrate to the aerosol light-scattering was higher than that of sulfate in the winter and of about equal magnitude in the summer period. In November and December of 1993, the humidity dependence of the aerosol light-scattering was investigated. Two types of (continental) aerosol were found with respect to the humidity behavior. One type showed a significant increase in light-scattering at the deliquescence points of ammonium nitrate and ammonium sulfate, with that of ammonium nitrate the most pronounced. The second type of continental aerosol did not show deliquescence, but followed the typical humidity dependence of aerosol in a supersaturated droplet state. In this latter aerosol type, nitrate dominated over sulfate. It was concluded from the study that the aerosol light-scattering in The Netherlands, in particular its humidity dependence, is governed by (ammonium) nitrate.     

Investigative consequence analysis: A case study research of beirut explosion accident

Around 15:00 GMT on August 4th, an explosion occurred in the warehouse facility storing Ammonium Nitrate (AN) at Beirut port, Lebanon. The explosion resulted in more than 178 fatalities and injured more than 6500 people, and also left an estimated 300,000 people homeless and registered as an equivalent to a 3.3 magnitude earth quake. The accident was considered to be the largest of its kind and the most severe anthropological disaster of the decade, the financial loss the nation was subjected to post the explosion was estimated to be around $ 15 billion as informed by the governor. The storage conditions of ammonium nitrate at Beirut port is not definitively known to anyone, and there is no documentation provided so far from the authorities regarding the same. This work focuses on the investigation & consequence analysis of the explosion using TNT equivalent approach. The overpressure and the impulse obtained from TNT calculations are used in probit models to assess the damages caused on human beings and structures. The results obtained in this investigative approach are then utilized to provide an analytical inference relative to the damage proxy map reported by the advance rapid imaging analysis team from NASA. Also, this work examines the existing standards, fire safety measures and legal regulations for ammonium nitrate facilities in the region. AN explosion during storage like other fire and explosion accidents are definitely preventable owing to the technological advancements and developments to prevent or extinguish controllable fires. The significance of this work relates to the methods for calculation of consequences of explosion that are happening due to the storage of highly hazardous explosive materials in excessive quantities and insists the necessity of incorporating adequate safety measures while storing such reactive and hazardous materials.