Internal circulating fluidized bed incineration system and design algorithm

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Determination of 4-tert-octylphenol in surface water samples of Jinan in China by solid phase extraction coupled with GC-MS

Octylphenols, considered as xenoestrogens, mainly exist as 4-tert-octylphenol (OP) in aquatic environments. The high stability and accumulation of OP in aquatic systems have caused endocrine disruption. The OP in surface water in Jinan, China was analyzed by gas chromatography-mass spectrometry (GC-MS) coupled with solid phase extraction (SPE). Water samples were extracted by SPE on a cartridge system containing C-18 as sorbent. To increase sensitivity and selectivity, OP was derivatized to 4-tert-octyl-phenoxy silane. With the use of phenanthrene-d10 as internal standard, the detection limit based on signal-to-noise ratio (S/N = 3) was 0.06 ng/mL. The average recovery was from 84.67% to 109.7%. The precision of the method given as the relative standard deviations (RSD) was within the range 6.24%-12.96%. In the target water samples, the concentrations of OP were as follows: 15.88-71.24 ng/L for Jinxiuchuan Reservoir, 3.850-26.68 ng/L for the city moat, 6.930-41.56 ng/L for Daming Lake, 66.03-474.2 ng/L for Xiaoqing River, 14.66-17.72 ng/L for the Yellow River, and 10.60-26.43 ng/L for Queshan Reservoir. The Xiaoqing River was seriously polluted due to the discharge of wastewater from Jinan. Jinxiuchuan Reservoir had a higher concentration of OP compared with the Yellow River and Queshan Reservoir, which is ascribed to the surrounding human activities. These data are reported for the first time, providing strong support for the control of OP pollution in Jinan.     

FACE试验对土壤有机质库组分及其激发效应的影响

以意大利的FACE(Free atmospheric CO2 enrichment)长期定位试验区和大气环境控制装置为研究对象,用化学分步酸提法将土壤有机质分离为活性库、慢库和惰性库,并培养测定土壤有机氮的矿化率,研究人工模拟大气CO2富集、施氮肥及植株类型对土壤有机质库及激发效应的影响.第一茬(POP FACE)试验产生了激发效应.但第二茬(Euro FACE)试验CO2处理区的总碳增加最显著高于对照处理区.即激发效应终止.主成分分析显示,有效氮的矿化水平已成为有机质降解的制约因素.据此推断,试验区巾活性碳和有效氮控制的激发效应阶段转变为氮利用受限所引起的碳积累阶段.CO2富集对N矿化率、慢库和惰性库均无显著性影响.研究结果表明,土壤的激发效应不仅受有机碳的活性库制约,氮的矿化率也是影响其发生的关键因子之一.     

土地利用规划环境影响评价若干问题探讨

土地利用规划环境影响评价的作用是为了实现土地的规划和环境相互适应、相互协调,为规划决策者提供一定的技术支撑。文章阐述了土地规划环境影响评价重要意义、内容及相关程序,同时也对此提出了针对性的建议,积极推进及完善土地利用规划环境影响评价在现阶段十分必要。     

天然色素生产废水的生物处理研究

天然色素生产废水是一种色度大、难处理的高浓度有机废水,为了寻找该废水的有效处理方法,本文作者采用由升流式厌氧污泥床(UASB)、生物接触氧化、混凝吸附组成的废水处理工艺,对该废水进行了处理试验,结果表明,对稀释4倍的原水,当进水COD为14900mg/L左右时,UASB经过36h的水力停留时间,COD的去除率为58.2%～60.2%、出水色度为180～270倍,SS为119～126mg/L,pH值为6.5～6.8;UASB出水经过24h好氧生物接触氧化反应,COD的去除率超过90%,SS<70mg/L;最终经过Ca(ClO)2氧化和煤渣吸附深度处理,脱色可至无色,出水COD为200mg/L以下。UASB生物接触氧化氧化吸附组合处理工艺处理该类天然色素生产废水是可行的。     

Research on polyhydroxyalkanoates and glycogen transformations: Key aspects to biologic nitrogen and phosphorus removal in low dissolved oxygen systems

In this paper, a study was conducted on the effect of polyhydroxyalkanoates (PHA) and glycogen transformations on biologic nitrogen and phosphorus removal in low dissolved oxygen (DO) systems. Two laboratory-scale sequencing batch reactors (SBR1 and SBR2) were operating with anaerobic/aerobic (low DO, 0.15–0.45 mg·L^-1) configurations, which cultured a propionic to acetic acid ratio (molar carbon ratio) of 1.0 and 2.0, respectively. Fewer poly-3-hydroxybutyrate (PHB), total PHA, and glycogen transformations were observed with the increase of propionic/acetic acid, along with more poly-3-hydroxyvalerate (PHV) and poly-3-hydroxy-2-methyvalerate (PH2MV) shifts. The total nitrogen (TN) removal efficiency was 68% and 82% in SBR1 and SBR2, respectively. In the two SBRs, the soluble ortho-phosphate (SOP) removal efficiency was 94% and 99%, and the average sludge polyphosphate (poly-P) content (g·g-MLVSS^-1) was 8.3% and 10.2%, respectively. Thus, the propionic to acetic acid ratio of the influent greatly influenced the PHA form and quantity, glycogen transformation, and poly-P contained in activated sludge and further determined TN and SOP removal efficiency. Moreover, significant correlations between the SOP removal rate and the (PHV+ PH2MV)/PHA ratio were observed (R²>0.99). Accordingly, PHA and glycogen transformations should be taken into account as key components for optimizing anaerobic/aerobic (low DO) biologic nitrogen and phosphorus removal systems.     

钛改性锰矿的除砷效果及机理研究

天然锰矿是一种廉价、易得的除砷矿物材料,为了进一步提高天然锰矿的除砷效果和吸附容量,采用TiCl4对广西桂林天然锰矿进行改性,并对其改性的条件进行优化。实验结果表明最佳的改性条件为:TiCl4浓度为10 mg/L,浸泡时间为18 h,pH=3.05,振荡吸附时间为1 h。与天然锰矿的去除效率(82.95%和77.93%)相比,改性锰矿对As(Ⅲ)和As(Ⅴ)去除率分别可达94.87%和99.31%,相应的饱和吸附量分别为3.48 mg/g和3.27 mg/g,较天然锰矿各自提高了1.25 mg/g和1.21 mg/g。改性锰矿对As(Ⅲ)的吸附符合Freundlich等温吸附模型,对As(Ⅴ)的吸附更符合Langmuir等温吸附模型。     

Mechanisms behind the accelerated extracellular electron transfer in <Emphasis Type="Italic">Geobacter sulfurreducens</Emphasis> DL-1 by modifying gold electrode with self-assembled monolayers

Modification of electrode surface with carboxylic acid terminated alkanethiol self-assembled monolayers (SAMs) has been found to be an effective approach to improve the extracellular electron transfer (EET) of electrochemically active bacteria (EAB) on electrode surface, but the underlying mechanism behind such enhanced EET remains unclear. In this work, the gold electrodes modified by mercapto-acetic acid and mercaptoethylamine (Au-COOH, Au-NH₂) were used as anodes in microbial electrolysis cells (MECs) inoculated with Geobacter sulfurreducens DL-1, and their electrochemical performance and the bacteria-electrode interactions were investigated. Results showed that the Fe(CN) ₆ ^3–/4– redox reaction occurred on the Au-NH₂ with a higher rate and a lower resistance than that on the Au or the Au-COOH. Both the MECs with the Au-COOH and Au-NH₂ anodes exhibited a higher current density than that with a bare Au anode. The biofilm formed on the Au-COOH was denser than that on bare Au, while the biofilm on the Au-NH₂ had a greater thickness, suggesting a critical role of direct EET in this system. This work suggests that functional groups such as–COOH and-NH₂ could promote electrode performance by accelerating the direct EET of EAB on electrode surface.     

Seasonal variation in the occurrence of ischemic stroke: A meta-analysis

Stroke was demonstrated to correlate with seasonal variation. However, the relevant studies were incongruous. To better understand the rules of seasonal impact on ischemic stroke (IS) patients, we performed this meta-analysis. We systematically searched relevant observational studies in Pubmed, Web of science and Embase from January 1, 1980, to November 1, 2017, in English. Patients included in this study were adults who suffered from IS. Stata version 12.0 software was used to pool useful data and calculate incidence rate ratios (IRRs) and their 95% confidence intervals (CIs). We also performed heterogeneity and sensitivity analyses and evaluated publication bias. Thirty-three observational studies involving 234,196 participants were incorporated into the meta-analysis. Summer and December were regarded as reference, respectively. The IRRs were calculated showing: IRR_Winter 1.05 (95% CI 1.04–1.07), IRR_Autumn 1.03 (95% CI 1.02–1.04), IRR_Spring 1.02 (95% CI 1.01–1.03). No obvious difference existed among 12 months. Stratified analyses on Köppen classification were also conducted. Between-study heterogeneity was discovered; however, predefined stratified analyses and meta-regression could not reduce this heterogeneity. Our meta-analysis has revealed very little seasonal variation in the overall study. Both cold and hot months may be high risky for IS after stratified by Köppen Climate Classification. Thus, a rationale to environmental setting of risky patient management could be provided. More studies with specific assessments are warranted for further comprehensive investigation.