嗜热微生物在废水处理中的应用

利用嗜热微生物处理高温排放废水是一项很有前任的废水处理技术，文章对嗜热微生物好氧处理废水及厌氧处理废水的发展进程和研究现状做了综述，例举了嗜热微生物在废水处理中的应用，并论证了一定工艺条件下高温废水处理的可行性和优越性；最后对嗜热微生物在废水处理中的应用前景作了展望。     

高速微涡活性污泥法提高氧利用效率的研究

概述了高速微涡活性污泥法的工艺特点，并对该法提高氧的转移及利用效率进行了研究和机理分析。     

废水厌氧处理研究前沿和趋势探讨

废水厌氧处理作为一种有竞争力的、经济的、日益成熟的生物处理工艺,是一种集环境保护、能源回收和生态良性循环于一体的技术,具有良好的社会、经济、环境效益,其研究和应用日益受到重视,工程化推广应用极其广泛。本文讨论了废水厌氧反应器的发展历程、厌氧氨氧化生物脱氮技术、两相生物反应器、高硫酸盐有机废水厌氧处理技术,并对目前废水厌氧处理的热点问题及发展趋势进行了展望。     

基于厌氧氨氧化和中温亚硝化的可持续生物脱氮工艺

通过介绍厌氧氨氧化技术（ANAMMOX）和亚硝化技术（SHARON）在污水脱氯处理中的原理,着重从工艺特性分析以及控制因数方面介绍SHARON—ANAMMOX联合工艺,并通过与传统工艺的比较,指出SHARON—ANAMMOX联合工艺是可持续性处理工艺。     

冲激式湿式除尘器在燃用高挥发份煤锅炉除尘的应用

本文总结了各种类型除尘器在使用当地含挥发份较高的长焰煤种过程中的除尘效率,及其性能特点,详细阐述了冲击式湿式除尘器在燃用高挥发份煤锅炉除尘中的应用效果。     

The Effects of Irrigation and Climate on the High Plains Aquifer: A County‐Level Econometric Analysis

The High Plains Aquifer (HPA) underlies parts of eight states and 208 counties in the central area of the United States (U.S.). This region produces more than 9% of U.S. crops sales and relies on the aquifer for irrigation. However, these withdrawals have diminished the stock of water in the aquifer. In this paper, we investigate the aggregate county‐level effect on the HPA of groundwater withdrawal for irrigation, of climate variables, and of energy price changes. We merge economic theory and hydrological characteristics to jointly estimate equations describing irrigation behavior and a generalized water balance equation for the HPA. Our simple water balance model predicts, at average values for irrigation and precipitation, an HPA‐wide average decrease in the groundwater table of 0.47 feet per year, compared to 0.48 feet per year observed on average across the HPA during this 1985–2005 period. The observed distribution and predicted change across counties is in the (?3.22, 1.59) and (?2.24, 0.60) feet per year range, respectively. The estimated impact of irrigation is to decrease the water table by an average of 1.24 feet per year, whereas rainfall recharges the level by an average of 0.76 feet per year. Relative to the past several decades, if groundwater use is unconstrained, groundwater depletion would increase 50% in a scenario where precipitation falls by 25% and the number of degree days above 36°C doubles. Editor’s note : This paper is part of the featured series on Optimizing Ogallala Aquifer Water Use to Sustain Food Systems. See the February 2019 issue for the introduction and background to the series.     

Simulating Soil Water Content,Evapotranspiration, and Yield of Variably Irrigated Grain Sorghum Using AquaCrop

Use of models to simulate crop production has become important in optimizing irrigation management in arid and semiarid regions. However, applicability and performance of these models differ across regions, due to differences in environmental and management factors. The AquaCrop model was used to simulate soil water content (SWC), evapotranspiration (ET), and yield for grain sorghum under different irrigation regimes and dryland conditions at two sites in Central and Southern High Plains. Prediction error (P_e), estimated as the difference between simulated and measured divided by measured, for SWC ranged from ?17% to 4% in fully irrigated, ?3% to ?10% in limited irrigated, and ?16% to 25% in dryland treatments. The P_e within ±4%, ?5%, and ?17% to 24% were attained for seasonal ET under fully irrigated, limited irrigated, and dryland conditions, respectively. P_e values for grain yield were within those previously reported and ranged from ?10% to 12%, ?12% to 7%, and 9% to 17% for fully irrigated, limited irrigated and dryland conditions, respectively. Overall performance of the AquaCrop model showed it could be used as an effective tool for evaluating the impacts of variable crop and irrigation managements on the production of grain sorghum in the study area. Finally, the application of the model in the study area revealed planting date has a significant impact on sorghum yield and irrigation requirements, but the impact of planting density was negligible. Editor's note : This paper is part of the featured series on Optimizing Ogallala Aquifer Water Use to Sustain Food Systems. See the February 2019 issue for the introduction and background to the series.     

输电线路山火跳闸机理的模拟实验研究

山火发生时植被燃烧产生的高温火焰及烟羽流使架空输电线路的空气绝缘性能大幅降低,可能引发导线之间或导线对地面间的击穿放电现象,导致输电线路发生跳闸事故。选取正庚烷与木垛为代表性火源,模拟研究直流高压电在火焰中的击穿放电现象,测量了火焰温度和电阻参数,获得了不同火源条件下放电间隙的击穿电压,分析了火焰参数对间隙击穿场强的影响。实验结果表明,正庚烷和木垛火焰放电实验中,火焰高温和电导率是导致击穿场强下降的主要因素。此外,烟颗粒也会导致击穿场强下降。     

高压低流电化学深度处理砷氟废水技术研究

为解决企业外排生产废水砷氟超标问题,采用高压低流电化学技术对某矿山企业外排的含砷氟废水进行深度处理,研究考察进水pH值,电流密度,电化学反应时间、极板材料、絮凝反应、pH等工艺条件对处理效果的影响。得到2最佳工艺条件为进水pH5.5左右、絮凝pH6.5~7.0、电化学反应时间6 min,铁铝极板比例为1:2,电流密度10.9 m A/cm。处理出水中的砷、氟能稳定达到《地表水环境质量标准》(GB3838—2002)Ⅲ类水体水质标准要求。     

Estimating emissions from crop residue open burning in China based on statistics and MODIS fire products

With the objective of reducing the large uncertainties in the estimations of emissions from crop residue open burning, an improved method for establishing emission inventories of crop residue open burning at a high spatial resolution of 0.25°× 0.25° and a temporal resolution of1 month was established based on the moderate resolution imaging spectroradiometer(MODIS) Thermal Anomalies/Fire Daily Level3 Global Product(MOD/MYD14A1). Agriculture mechanization ratios and regional crop-specific grain-to-straw ratios were introduced to improve the accuracy of related activity data. Locally observed emission factors were used to calculate the primary pollutant emissions. MODIS satellite data were modified by combining them with county-level agricultural statistical data, which reduced the influence of missing fire counts caused by their small size and cloud cover. The annual emissions of CO_2, CO, CH_4,nonmethane volatile organic compounds(NMVOCs), N_2O, NO_x, NH_3, SO_2, fine particles(PM2.5),organic carbon(OC), and black carbon(BC) were 150.40, 6.70, 0.51, 0.88, 0.01, 0.13, 0.07, 0.43,1.09, 0.34, and 0.06 Tg, respectively, in 2012. Crop residue open burning emissions displayed typical seasonal and spatial variation. The highest emission regions were the Yellow-Huai River and Yangtse-Huai River areas, and the monthly emissions were highest in June(37%).Uncertainties in the emission estimates, measured as 95% confidence intervals, range from a low of within ±126% for N_2O to a high of within ± 169% for NH_3.