基于优化理论的藻类生长模型及在水华预测中的应用

在对水华产生机理分析和研究的基础上,建立了用于藻类生长模型,研究了有约束条件的非线性极小值问题求取最优参数估计值的方法。结合实验数据对模型中涉及的参数,运用多参数同时估计法进行估计并验证。仿真与实验结果表明了该模型能够较好地描述水华从产生到爆发过程的变化规律,为水华的预警及治理提供参考依据。     

主成分分析法(PCA)在藻类生长影响分析中的应用

水华的发生、发展是一个相当复杂的过程,众多影响因素共同导致藻类生长、水华爆发。常用的分析工具难以分析、预测实际情况下藻类的生长。该文利用当今世界上最大型的统计与图表分析软件之一STATISTICA对2008年和2009年奥运森林公园主湖的监测数据进行主成分分析。结果表明STATISTICA软件中的主成分分析适用于藻类生长分析,并发现除了已知的藻类生长影响因素(营养盐、温度等)之外,景观湖中底泥的累积效应也应纳入分析之内。     

藻类水华防治技术研究

随着全球水体富营养化的加剧,有害藻类的暴发日趋频繁,给环境、生态和经济造成了巨大的损失。有效控制水华的爆发是环境科学领域的一个难题,笔者对国内外水华防治措施进行了综述,并提出了藻类水华防治方法的发展方向。溶藻细菌一般分离自暴发水华的水体,这种土著细菌在工程应用中具有安全、特异、高效等特点。作为一种新的生物控藻手段显示出了广泛的应用前景。     

陆生植物对藻类化感抑制作用的研究进展

如何有效抑制藻类的生长、防治水华发生是目前水环境领域研究的热点和前沿问题之一.利用植物的化感作用抑藻作为一种新型的生物除藻技术而备受关注.阐述了陆生植物对水华微藻生长的抑制作用研究成果,论述了其对藻类生长的抑制作用方式、抑藻化感物质及种类,以及抑藻化感作用机理,并对植物化感抑藻前景进行了展望.     

景观水体藻类水华影响因素研究进展

随着人民生活水平的日益提高,人们对周围环境的要求也越来越高,而目前由于藻类大量生长引发的水华现象越来越频繁,危害也越趋严重,甚至连一些景观城市河道水体也频有发生,给周围的人民群众的日常生活和身心健康带来了较大的困扰。水华究竟是怎么发生的,哪些因素对它影响比较大,又是如何影响的,是文章所要讲诉的内容。文章分别从物理因素(温度、光照、pH、水文)、化学因素(营养盐)和其它因素(微量元素、生物因素)3个方面系统的对水华的影响因素进行了总结,详细的阐述了每种因素的作用机理以及部分适合藻类生长的最佳条件,同时对一些未来要重点进一步研究的方向进行了探讨与展望。     

光照强度对颤藻、小球藻、铜绿微囊藻的生长影响

该文采用颤藻(Oscillatoria sp)、小球藻(Chlorella)和铜绿微囊藻(Microcystis aeruginosa)为研究对象,通过检测叶绿素浓度(Chl-a)关键指标,考察了两种光照条件下(500、1 000 lux)三种藻类生长的规律。同时,利用SLogistic模型对三种藻生长规律进行拟合分析,为预测水华时期不同特征藻类的生长速率、潜能和规律提供参考。     

水体化学元素N/P比对云中河藻类生长的影响

工农业生产富含氮磷营养盐废水的排放,使河流水体富营养化程度升高,流速较缓的河流发生水华现象,导致河流流域生态环境的恶化。为了研究水华暴发的机制,以忻州云中河为研究对象,于春季采取云中河水样,在实验室内设置了2︰1、4︰1、8︰1、16︰1、20︰1、35︰1共6个氮磷比梯度进行为期7天的培养。研究结果表明,绿藻门和蓝藻门在N/P为16︰1的实验组中生长最优,密度最大值分别为,硅藻门藻类密度最大为4727.27×10~4 cells/L;在氮磷比为35︰1的培养组中,藻类密度最低;N/P为16︰1是藻类生长的最适比值,但不同的藻类这个比值会有所变化。     

复配药剂控制水华试验研究

城市化不断发展给景观水体造成了沉重的负担,以及景观水体自身承载能力有限,造成我国城市景观水体富营养化现象严重,藻类疯长,水华爆发严重,严重影响生态环境。为了控制水华爆发带来的危害,采用生物制剂H+络合铜复配作为杀藻剂对小球藻和铜绿微囊藻进行抑藻试验,得知蓝藻型水华生物制剂H+络合铜的最佳投药浓度为5 mg/L∶0.8 mg/L,绿藻型水华生物制剂H+络合铜最佳投药浓度为5 mg/L∶3 mg/L。     

藻类混凝过程的影响因素探讨

应对"水华"突发事件,最经济有效的方法之一是混凝沉淀除藻法,详细讨论了影响藻类混凝效果的因素,如混凝剂的种类、藻类生长周期、特性有机物(EOM、NOM)、预氧化作用等,通过对这些影响因素的研究,为提高藻类去除率和降低混凝剂的用量提供了参考,并且为藻类混凝去除方法的选择及开发提供一定的指导意义。     

有机碳源对产EPA微藻(Nannochloropsis sp.)生长及光合作用的影响

研究了几种有机碳源对Nannochloropsis sp．生长及光合作用的影响．结果表明，Nannochloropsis sp．具有混合营养生长的能力，葡萄糖对其生长有明显的促进作用，乙醇对藻细胞的生长有一定的促进作用，乙酸钠不能促进其生长，而乙酸、草酸、甘氨酸则抑制其生长．在含30mmol/L葡萄糖的培养基中培养8d后，该藻细胞生长的最大生物量干重可达550mg/L是光自养培养条件下(最大生物量干重为392mg/L)的1．4倍．通过测定该藻细胞的光合放氧速率发现，该藻细胞在自养和混养条件下，最大净光合放氧速率几乎不变，混养条件下的暗呼吸速率、光补偿点高于自养条件，而光饱和点低于自养条件．     

Use Of Ozone And Flotation For The Treatment Of A Reservoir Water: The Dinan Case History

The plant of Dinan supplies water to the urban district of Dinan (Brittany-France). The raw water is a dam water, soft, containing iron and manganese, highly colored with a high content of organic carbon. The area providing water to the dam is rural country, so water also contains residues of agricultural practices such as pesticides and nitrates.

During summer, algae blooms may occur. The old plant (including prechlorination, coagulation, flocculation, settling and sand filtration) has been replaced with a treatment line including: remineralization, preozonation, flotation, ozonation and granular activated carbon. Nitrate removal will be considered in the future. The paper presents the results obtained in the plant, the optimization of the preozonation dose as well as comparison with laboratory tests. A special reference concerns algae removal.     

A novel on‐line optical method for algae measurement

In recent years, algal blooms have occurred worldwide, and algae‐rich water often has adverse effects on water production. The technique of algae measurement is a critical issue for adjusting water treatment processes according to the numbers of algae cells. The algae particles in the water are generally 2–200 µm in size with only a few smaller than 2 µm. The traditional algae measuring method is by visual observation with an optical microscope. However, traditional visual observation often needs 48 h fixing time, which makes the measurement results lag behind the needs of water production. To solve the problem, this study employed on‐line optical devices to improve the efficiency and accuracy of algae measurement. A photometric dispersion analyzer (PDA) and particle counting analyzer (PCA) were jointly utilized to monitor on‐line the algae concentration in natural water. Algae cells can be classified by different sizes. It was found that there was good correlation between R²_PDA and total algae counts in water. The PCA could quantitatively characterize the algae counts and species distribution of dominant algae species in real water. PDA and PCA could be used jointly to define on‐line the characteristics of real water containing mixed algae. Copyright © 2010 Society of Chemical Industry     

天然有机物对混凝除藻的影响

试验研究了天然有机物(腐植酸、富里酸)对混凝除藻的影响,以及在含有天然有机物水体中混凝除藻的机理.结果表明,天然有机物会与藻细胞争夺絮凝剂,由于天然有机物与PAC亲和力强,PAC优先与天然有机物结合,再与藻细胞结合,当水体中天然有机物含量较多时,混凝除藻效果降低.当腐植酸质量浓度为20.2 mg/L时,藻去除率仅为2....     

黄河高藻污染原水的强化混凝处理

采用聚合铁 聚合氯化铝FL45C除藻剂粉末活性炭组合强化混凝工艺,处理黄河高藻高有机污染源水,在保证了原有主体构筑物设施不变的基础上,通过强化混凝工艺的改进．达到了较好的除藻、除有机物的效果。最高曾处理过色度为45度、藻类高达1700万个／L的严重污染水体,实现了生产性试验的成功。     

改性滤料强化过滤处理微污染水

实验室制备涂氧化钛的改性滤料,对微污染水进行强化过滤处理,结果表明;其去除浊度、有机物、藻细胞等污染物的能力要比普通石英砂滤料强：与涂氧化铁的改性滤料相比,二者去除浊度的能力相近,但涂氧化钛的改性滤料去除有机物、藻细胞的能力要强。根据改性滤料的除污机理,滤料去除浊度的能力与其表面电位和其结合有机物的能力有关;而去除有机物、藻细胞的能力主要与其表面晶格金属阳离子价数有关,金属离子价数越高,其结合有机物阴离子基团的摩尔数就多,去除有机物、藻细胞的能力就强。这为新型高效滤料的研制提供了方向。     

The Use Of Ozoflotation For The Removal Of Algae And Pesticides From A Stored Lowland Water

Tophill Low, a water treatment plant supplying the city of Hull, in Yorkshire, England, suffers from water quality problems due to algae and small residuals of pesticides. This plant is due for upgrading, and investigations into new compact processes were carried out to determine a cost-effective (treatment process to meet the current standards. A pilot plant was constructed to determine the efficiency of the Ozoflot® process and results for the removal of algae and oxidation of pesticides are presented, together with data on the formation and reduction of biodegradable organic carbon.     

PAC与PAC/PAM对藻类的去除效果研究

采用静态试验研究了混凝工艺对水源水中的细胞内和溶解性(细胞外)微囊藻毒素的去除效果,并初步探讨了其去除机理。试验结果表明,当将原水的pH值调节到5.5~6.0混凝剂投加量定为30 mg/L时,对去除水中的细胞内微囊藻毒素效果明显,此方法的去除率可以达95.3%。PAC/PAM工艺对藻浓度、浊度的去除率都要高于PAC工艺,但对藻毒素的去除效果二者都不显著。但在混凝前投加活性炭,对源水进行预氧化处理,实验结果表明,PAC/PAM+C工艺可以显著地提高对溶解性微囊藻毒素的去除效果,去除率达到50%到60%,主要是因为混凝工艺的强化作用与活性炭结合能够明显地去除弱疏水性有机物。     

Micro-Bubble Flotation of Freshwater Algae: A Comparative Study of Differing Shapes and Sizes

This study investigates the effects of the morphology (shape and size) of differing algae species on the removal efficiency by the dissolved air flotation (DAF) process. Three selected shapes in this research are spherical (Microcystis sp.), oval (Chlamydomonas angulosa), and filamentous algae (Phormidium sp.), cultured in the laboratory under certain cultivated conditions. Physical properties of three differing algae were understood as morphology, size distribution, and zeta potential in various pHs. Under pH conditions of 4.5?7, all algae species showed negative charges: ?10 mV for filamentous shape, ? ?20 mV for oval shape, and ? ?40 mV for spherical shape. The size of these shapes ordered increasingly as spherical < oval < filamentous algae. In order to separate algae from water, positively charged bubbles were generated by adding a coagulant (as Al³⁺) and were applied at 10%, 20%, and 30% recycling ratio. Assessment of algae removal efficiency was shown by the number of the cells, total organic carbon (TOC), dissolved organic carbon (DOC), and the morphological changes (i.e., shape or size distribution). In terms of the number of cell, filamentous algae showed the greatest removal, i.e., 86% removal at 30% recycling ratio and 5 mg/L of Al³⁺ addition. For TOC and DOC removal perspectives, spherical algae showed the greatest removal above 80%. These results, therefore, confirm that the shapes and sizes of algae affect the removal process of bubble technology.