Isotopic modelling of the significance of bacterial sulphate reduction for phenol attenuation in a contaminated aquifer

A Triassic sandstone aquifer polluted with a mixture of phenolic hydrocarbons has been investigated by means of high-resolution groundwater sampling. Samples taken at depth intervals of 1 m have revealed the presence of a diving pollutant plume with a sharply defined upper margin. Concentrations of pollutant phenols exceed 4 g/l in the plume core, rendering it sterile but towards the diluted upper margin evidence for bacterial sulphate reduction (BSR) has been obtained. Groundwaters have been analysed for both delta34S-SO4 and delta18O-SO4. Two reservoirs have been identified with distinct sulphate oxygen isotope ratios. Groundwater sulphate (delta18O-SO4 = 3-5/1000) outside the plume shows a simple linear mixing trend with an isotopically uniform pollutant sulphate reservoir (delta18O-SO4 = 10-12/1000) across the plume margin. The sulphur isotope ratios do not always obey a simple mixing relation, however, at one multilevel borehole, enrichment in 34SO4 at the plume margin is inversely correlated with sulphate concentration. This and the presence of 34S-depleted dissolved sulphide indicate that enrichment in 34SO4 is the result of bacterial sulphate reduction. Delta34S analysis of trace hydrogen sulphide within the plume yielded an isotope enrichment factor (epsilon) of -9.4/1000 for present-day bacterial sulphate reduction. This value agrees with a long-term estimate (-9.9/1000) obtained from a Rayleigh model of the sulphate reduction process. The model was also used to obtain an estimate of the pre-reduction sulphate concentration profile with depth. The difference between this and the present-day profiles then gave a mass balance for sulphate consumption. The organic carbon mineralisation that would account for this sulphate loss is shown to represent only 0.1/1000 of the phenol concentration in this region of the plume. Hence, the contribution of bacterial sulphate reduction to biodegradation has thus far been small. The highest total phenolic concentration (TPC) at which there is sulphur isotope evidence of bacterial sulphate reduction is 2000 mg/l. We suggest that above this concentration, the bactericidal properties of phenol render sulphate-reducing bacteria inactive. Dissolved sulphate trapped in the concentrated plume core will only be utilised by sulphate reducers when toxic phenols in the plume are diluted by dispersion during migration.     

SBR工艺处理晚期垃圾渗滤液的脱氮特性研究

采用有效容积为1 200 m3的SBR反应器处理晚期垃圾渗滤液,进行生物脱氮特性研究.结果表明,通过投加粪水调节进水C/N,能显著提高SBR反应器对晚期垃圾渗滤液中氮素污染物的去除效果,其中第112~136 d的TN平均去除率高达82.62%,出水TN≤190 mg.L-1,COD≤400 mg.L-1;能在反应器内达到各种生物脱氮反应的平衡状态,BOD5与TN去除量的比值稳定在1.43左右.在稳定平衡阶段,通过对反应器内氮素污染物和SO24-的含量变化进行周期跟踪监测,发现在搅拌回流阶段存在NH4+-N和SO24-的同时等比例去除现象,去除率分别为27.06%和76.17%,反应器内存在同步硝化反硝化和同步脱氮除硫(SO24-)过程;量化分析了反应器内各种生物脱氮反应,得到异养反硝化、同步硝化反硝化、同化作用、同步脱氮除硫(SO24-)和内源呼吸反硝化对TN去除量的贡献率分别为62.6%、33.8%、7.0%、26.1%和2.7%.     

厌氧氨氧化微生物在有机碳源条件下的代谢特性

通过多系列血清瓶实验并结合吉布斯自由能量分析探讨了厌氧氨氧化微生物在有机碳源条件下的代谢特性.实验结果表明：在葡萄糖作为有机碳源的条件下,低浓度的葡萄糖 (0.5 mmol·L-1) 能够促进厌氧氨氧化反应的速率,高浓度的葡萄糖 (≥1 mmol·L-1) 抑制了厌氧氨氧化活性;厌氧氨氧化微生物不仅具有厌氧氨氧化的代谢特性,还具有反硝化和硫酸盐还原的代谢能力.吉布斯自由能量分析表明： 在低浓度葡萄糖条件下,尽管最初厌氧氨氧化途径具有优势,但随后与反硝化途径展开竞争并处于劣势;在高浓度葡萄糖条件下,与厌氧氨氧化途径相比,反硝化途径完全占据优势;硫酸盐还原途径与厌氧氨氧化和反硝化途径相比不具有能量优势,只能发生在这两个途径之后.     

株洲市工业区大气中SO2转化速率的研究

在湖南省株洲市工业区的下风向布点,同时测定大气中ＳＯ２的浓度、ＴＳＰ和＜０．２５μｍ细粒子中ＳＯ２－４的浓度．结果表明,大气中ＳＯ２浓度随着离污染源距离的增加迅速下降,和ＳＯ２相比,颗粒物中ＳＯ２－４浓度随距离的增加而降低的程度要慢得多．同步测定的ＳＯ２浓度和细粒子ＳＯ２－４浓度有显著的相关关系．根据风向、风速和新产生的细粒子中的ＳＯ２－４浓度及大气中ＳＯ２的浓度计算了株洲教育学院处ＳＯ２的转化速率,春季湿度大,ＳＯ２转化速率也大,为４．８％／ｈ,秋季湿度小,ＳＯ２的转化速率变低,为１．５％／ｈ．春季中路铺ＳＯ２转化速率为３．１％／ｈ．     

Main particulate matter components in Saxony (Germany)

Aerosol filter samples have been collected nearby the industrialised basin of Leipzig in Saxony (Germany) at the research station Melpitz of the Institut für Troposphärenforschung e.V. (IfT). Time series (1992–1998) and a three year comparison (1995–1997) of two different aerosol filter sampling systems, the Sierra-Andersen-PM 10 high volume sampler (daily sample, PM 10 inlet) and the Rupprecht and Patashnik Co. Inc. Model Partisol 2000 (weekly sample, PM 10 and PM 2.5 inlet) are presented and discussed. The comparison of the different sampling systems and strategies yields small differences between the daily and weekly samples for mass and different ions, which may be influenced by sampling duration and flow rates. A general trend of change in aerosol composition was observed: Soot and Sulphate concentrations decreased whereas Nitrate and Ammonium concentrations increased. During summers the mass of coarse particles is higher than in other seasons. One reason could be found in the occurence of longer periods of dry ground surfaces enabling reemission of crustal and biological material. The time series have been integrated in a longer historical aerosol mass trend for Saxony and do show a good agreement. Since 1990 a significant downward trend in gravimetric mass concentration was found.     

用钢管酸洗废水生产聚合硫酸铁技术的研究和应用

为了解决钢管酸洗废水污染环境和浪费资源难题,可用其生产聚合硫酸铁,从而实现循环经济。采用蒸发浓缩和催化聚合反应实现聚合硫酸铁的生成。其产品质量达《净水剂聚合硫酸铁》标准,可作为絮凝剂使用。研究和实践证明,用钢管酸洗废水制备聚合硫酸铁是可行的,具有明显的经济效益和环境效益,值得推广。     

硫酸锰废渣浸出液对斑马鱼的毒性及抗氧化酶活性的影响

已有研究表明,堆积在湘西花垣河河岸的硫酸锰废渣含有多种重金属,可能是导致花垣河河水和沉积物重金属污染的主要原因.为了评价硫酸锰废渣的潜在生态风险和对水生动物的毒性,本研究分析了硫酸锰废渣浸出液中的主要重金属成分,用漫出液对斑马鱼进行了急性毒性实验,观察在急性胁迫下斑马鱼的体征变化,测定了斑马鱼在亚致死浓度下的生化指标的...     

Valorization of agro-industrial fruit peel waste to fluorescent nanocarbon sensor: Ultrasensitive detection of potentially hazardous tropane alkaloid

• Transformation of agro-industrial waste to value-added material via green chemistry. • Orange peel is valorized into fluorescent nanodiamond-like carbon (fNDC) sensor. • fNDC detects potentially hazardous drug atropine sulfate (AS). • fNDC recognizes AS in biological fluids and pharmaceuticals. • fNDC assures applications in clinical and forensic toxicology. Millions of tonnes of agro-industrial waste are generated each year globally, with the vast majority of it going untreated, underutilized, and disposed of by burning or landfilling, causing severe environmental distress and economic downturn. A practical solution to this global issue is to use green chemistry to convert this waste into value-added products. Accordingly, in the present study, agro-industrial orange peel waste was valorized into fluorescent nanodiamond-like carbon sensor via a green route involving hydrothermal treatment of microwave carbonized orange peel waste. The developed sensor, used for the fluorescence detection of potentially hazardous drug atropine sulfate, exhibits unique dual linearity over concentration ranges of 300 nM to 1 M and from 1 M to 10 M, as well as ultra-low sensitivity of 34.42 nM and 356.46 nM, respectively. Additionally, the sensor demonstrates excellent reproducibility, high stability, and satisfactory recovery when used to identify and quantify atropine sulfate in biological samples and commercially available pharmaceuticals, indicating promising multidisciplinary applications.     

聚合硫酸铁制备方法研究及其发展

聚合硫酸铁是一种优质高效无机高分子絮凝剂,在水处理领域中有良好的应用前景.本文探讨和综述了聚合硫酸铁制备方法的研究现状和发展趋势,并比较了各种方法的优缺点.内容包括:直接氧化法、催化氧化法、一步法、两步法、微生物氧化法以及其它一些新颖的制备方法.     

A red water occurrence in drinking water distribution systems caused by changes in water source in Beijing,China: mechanism analysis and control measures

A red water phenomenon occurred in several communities few days after the change of water source in Beijing, China in 2008. In this study, the origin of this problem, the mechanism of iron release and various control measures were investigated. The results indicated that a significant increase in sulphate concentration as a result of the new water source was the cause of the red water phenomenon. The mechanism of iron release was found that the high-concentration sulphate in the new water source disrupted the stable shell of scale on the inner pipe and led to the release of iron compounds. Experiments showed that the iron release rate in the new source water within pipe section was over 11-fold higher than that occurring within the local source water. The recovery of tap water quality lasted several months despite ameliora- tive measures being implemented, including adding phosphate, reducing the overall proportion of the new water source, elevating the pH and alkalinity, and utilizing free chlorine as a disinfectant instead of chloramine. Adding phosphate was more effective and more practical than the other measures. The iron release rate was decreased after the addition of 1.5 mg. L-1 orthophosphate- P, tripolyphosphate-P and hexametaphosphate-P by 68%, 83% and 87%, respectively. Elevating the pH and alkalinity also reduced the iron release rate by 50%. However, the iron release rate did not decreased after replacing chloramine by 0.5-0.8 mg. L-1 of free chlorine as disinfectant.