扬水曝气/生物接触氧化工艺的除藻效果研究

研究了扬水曝气与生物接触氧化组合工艺对藻类的去除效果，考察了生物填料悬挂于水体的深度、距扬水曝气器的距离以及生物接触氧化反应器的水力停留时间（HRT）等因素对除藻效果的影响。试验结果表明：扬水曝气／生物接触氧化组合工艺对藻类的平均去除率为41．7％．对蓝藻、绿藻、硅藻的平均去除率分别为39．3％、23．7％、31．3％，对滦河源水中优势藻种——铜绿微囊藻的平均去除率为25．6％；生物填料可以悬挂在扬水曝气器周围25m、深度为0～3m的水体内，HRT以3h左右为宜。     

Modelling algal behaviour in the river thames

Forecasting the movement and growth of algae in river systems as particularly important for operational managers responsible for the distribution and supply of potable water. Algae affect the taste and smell of water and pose considerable filtration problems at water treatment plants. In a collaborative study with the Thames Water Authority, algal models have been developed for the River Thames. The non-linear processes controlling algal growth are examined using a generalized sensitivity analysis technique and the dominant parameters controlling system behaviour are identified. The extended Kalman filter (EKF) is then used to estimate these important parameters. The technique of using generalized sensitivity analysis prior to EKF estimation is suggested as a pragmatic approach to the problem of identifying the subset of physically, chemically or biologically meaningful parameters controlling system behaviour in mechanistic models.     

处理水AGP值对受纳河流水质的影响

结合藻类增殖潜能试验(AGP试验)探讨了进行污水深度处理的必要性。试验结果表明,污水厂排水的AGP值在94～400mg/L,会导致受纳水体产生富营养化,因此需对污水进行深度处理以去除氮和磷,并加强对流域的水质管理。     

Removal of nitrogen from industrial wastewaters with the use of algal rotating disks and denitrification packed bed reactor

An attempt was made to use an algal rotating disk system in a two-step biological purification of nitrogen fertilizer industry wastewaters. The proposed method involved the removal of ammonium by Stichococcus bacillaris growing on the rotating disk and of oxidized forms of nitrogen by denitrifying bacteria. The use of a rotating algal disk followed by denitrification bed as the second step of biological treatment removed about 90% of nitrogen from the wastewater. A change of purification sequence resulted in the appearance of NO ⁻₃ and NO⁻₂ in the purified wastewater caused by the activity of nitrifying bacteria accompanying algae in the biological film on the disk. It was found that methanol used as a carbon source for denitrifying bacteria could be replaced by organic matter of algal origin.     

GC-MS测定藻油中角鲨烯含量

基于GB/T 22110—2008,建立一种利用GC-MS简单、快速测定藻油中角鲨烯含量的方法。考察了甲酯化试剂用量对甲酯化程度的影响与不同色谱柱对角鲨烯分离程度的影响。0.2 g藻油经1 m L 0.5 mol/L氢氧化钾-甲醇溶液进行甲酯化,正己烷提取后经HP-5MS色谱柱分离,用GC-MS选择离子监测模式对角鲨烯进行定量测定。方法在10~500 mg/L范围内线性关系良好,相关系数r=0.999 8,检出限为0.10 mg/L,加标回收率为92.14%~96.47%,此法也适用于其他植物油中角鲨烯含量的测定。通过比较"复合型"藻油和"非复合型"藻油样品成分及含量上的差异,得出两种类型的藻油除了脂肪酸含量存在差异外,"非复合型"藻油比"复合型"藻油角鲨烯含量高10倍多。     

Oxidative Stability of Whey Protein-stabilized Oil-in-water Emulsions at pH 3: Potential ω-3 Fatty Acid Delivery Systems (Part B)

ABSTRACT: Consumption of omega-3 (ω-3) fatty acids is beneficial for human health. Incorporation of ω-3 fatty acids into functional foods is limited by their high susceptibility to oxidative degradation. Oil-in-water emulsions may be a more effective method to deliver ω-3 fatty acids into functional foods. Protein-stabilized oil-in-water emulsions at pH values below the isoelectric point of the protein produce cationic emulsion droplets that decrease the oxidation of lipids by decreasing iron-lipid interactions. This research showed that whey protein isolate (WPI)-stabilized algal oil emulsions at pH 3.0 had good physical and oxidative stability after pasteurization. Addition of ethylenediaminetetraacetic acid     

微藻对混凝除藻效率的影响及改善措施

考察了富营养化水体中微型藻对混凝除藻效率的影响,以及控制“混凝-过滤”工艺出水中微藻的措施。微型藻含量增加会降低混凝除藻效率,因此微型藻的存在决定了混凝除藻效率的限度。微型藻大量存在时,预氧化可以改善混凝除藻的效率。增加过滤深度可以显著提高微型藻的去除效率,活性炭深度处理也可以有效地去除水中的微型藻。因此,决定富营养化源水除藻难易程度的主要因素是源水中藻类生物的种群结构,而不是叶绿素值。源水中藻类生物的种群结构决定了水厂除藻工艺的选择。加强水源水保护,生态调控优化源水中藻类生物种群结构是解决水厂除藻问题的根本途径。     

Optimal dosing time of acid algaecide for restraining algal growth

Restraining algal growth by algaecide has been studied by many researchers, but the dosing time has not yet been studied. In this study, we examined the appropriate dosing time of algaecide through a series of experiments. In the experiments, the pH value of water is significantly affected by Microcystis aeruginosa, and the variation of the pH value is in favor of the growth of the alga. Therefore, using acid algaecide in the period with maximum pH values, i.e., the stable phase, would change the acidity-alkalinity of the water significantly, and would negatively affect algal growth. Acid algaecide does not eliminate the alga effectively if the acid algaecide is dosed in the logarithmic growth phase. Using acid algaecide in the decline phase after algal bloom not only is unfavorable for eliminating the alga, but also prolongs the decline phase, and even brings about next larger algal bloom.     

注流方式对大方坯连铸结晶器内钢水流动与温度状态影响

依据改变水口侧孔射流方向来控制结晶器内钢流流动状态的思想,设计了一种大方坯连铸结晶器新型四分切向水口.对不同类型水口(直通式、四分径向以及四分切向水口)浇注条件下大方坯连铸结晶器内钢水流动形态和温度分布状况进行了流体动力学比较研究.结果表明,新型四分切向水口不仅可以使结晶器内钢水形成上、下两个回流,并能够产生较强的水平旋流.该水平旋流能降低钢水的冲击深度,抑制钢液面波动,促进夹杂物上浮,还具有促进钢水过热耗散的效果.与四分径向水口相比,新型四分切向水口能减弱射流对初生坯壳的冲击,均匀横截面坯壳厚度.此外,该旋流状态使热中心上移,自由液面附近钢水的温度可提高2～6℃,改善化渣条件.     

大方坯连铸过程凝固规律

通过建立425mm×320mm连铸大方坯二维凝固传热数学模型,模拟了凝固坯壳的长大过程,并通过窄面射钉实验对数学模型进行了验证,精确得到了任意位置处大方坯凝固坯壳的厚度分布情况及最终凝固终点的位置,发现经典的凝固平方根定律对于连铸大方坯的凝壳长大进程不再适用.回归宽面中心坯壳厚度与凝固时间平方根的关系式发现,结晶器弯月面至二冷区出口,近似为线性关系,符合平方根定律,二冷区出口至凝固终点,二者为非线性关系,不再符合平方根定律.