A3菌产絮凝剂培养动力学及靛蓝废水脱色研究

从土壤中筛选出1株产微生物絮凝剂的菌株A3,利用均匀设计安排试验,用曲线拟合创建数学模型的方法研究了其产絮凝剂的培养基条件和利用A3菌产絮凝剂对靛蓝废水进行脱色处理,获得A3菌最佳絮凝剂生产条件和最佳靛蓝废水脱色工艺.结果表明,A3菌产絮凝剂的最佳培养条件为葡萄糖添加量2.2%、酵母膏添加量0.51%、pH 7.6、温...     

胞外生物高聚物絮凝剂的研究进展(上)

就微生物分泌的胞外生物高聚物絮凝剂 (EBF)的研究和应用做了一个全面的综述 ,对化学絮凝剂与生物絮凝剂的比较 ,胞外生物高聚物絮凝剂产生菌的分离、培养条件、EBF的分类、化学组成和结构、絮凝机理和在絮凝过程中物理化学因素的影响以及生物絮凝的遗传学研究等进行了详细的分析讨论。     

微絮凝直接过滤用于印染尾水回用的可行性研究

以某典型印染企业废水尾水为研究对象,针对尾水回用的实际需求,进行了印染废水深度处理回用工艺的适用性研究.同时对微絮凝直接过滤工艺中絮凝剂、G值、微絮凝时间、滤料等条件进行了优化.试验结果表明,铝系絮凝剂中的HPAC处理效果显著,当投药量为20 mg/L,絮凝时间为2min,G值控制在100 s-1时,处理效果较好;微絮...     

响应曲面法优化絮凝处理印染废水研究

采用响应曲面分析法和中心组合试验设计,对自制无机高分子复合絮凝剂聚硅酸铝铁硼镁(PSAFBM)絮凝处理印染废水进行考察,以废水的pH、絮凝剂投加量为考察因素,以COD(?)、脱色率为指标,分别建立考察因素和指标间的二次多项式响应曲面模型。模型优化结果显示,在投加量0.63g,废水pH为6.1条件下,COD(?),去除率和脱色率分别可达86.15%和96.54%。经过试验验证,其试验值与模型计算值相对误差小于5%,该方法对优化絮凝处理印染废水具有一定指导意义。     

微生物絮凝剂处理矿井水实验研究

实验以菌株L01作为絮凝剂产生菌,考察了其所产絮凝剂对矿井水的絮凝处理效果,确定了最佳的絮凝条件.结果表明,菌株L01对矿井水有较好的絮凝效果,其菌液离心上清液比菌悬液的絮凝性能更好;在酸性条件下絮凝剂的处理效果较好,且随着酸性的增强,效果递增,选择pH=4为矿井水处理的最佳pH值;温度对絮凝剂的处理效果没有明显的影响;Ca2 有很好的助絮凝效果,添加助凝剂CaCl2后,絮凝剂对矿井水中悬浮物的最终去除率可以达到93.54%,上清液吸光度仅为0.104.     

化学絮凝法处理海产品加工中高浓度含磷废水

针对海产品加工中高浓度含磷废水(1 000 mg/L)会恶化生物除磷的问题,通过化学絮凝法对高磷废水进行处理,分析了几种单一与混合絮凝剂的除磷效果。结果表明:聚合氯化铝与海泡石以质量比m_(聚合氯化铝)∶m_(海泡石)=10∶3制作的混合絮凝剂,在投加量为26 g/L,快速搅拌(160 r/min) 60 min,慢速搅拌(80 r/min) 30 min后,磷去除率最高,达到99. 68%。混合絮凝剂絮凝沉淀物的XRD分析表明,沉淀的主要成分为CaAl_3(PO_3OH)SiO_3,说明海泡石中含有的CaO和SiO_2成分对磷的去除有促进作用。     

微生物絮凝剂的絮凝特性及其絮凝形态表征研究

利用实验室分离、筛选和优化培养的微生物絮凝剂高产茵菌株G15,研究了微生物絮凝剂的絮凝特性和所形成絮体的微观形态结构,分析探讨了微生物絮凝剂的絮凝机理.研究结果表明:微生物絮凝剂的絮凝活性随茵株生长量的增加而提高;该絮凝剂在碱性条件下有较强的絮凝活性,当pH=10时最佳投加量为2.5 mL;絮凝剂具有较强的热稳定性;加入茵株G15的发酵液后,高岭土悬浊液的ζ电位从-36.27 mV显著上升至-12.97 mV;并且该微生物絮凝剂产生的絮体颗粒大且结构密实,形态上有明显的分形特征.     

裂化剂生产高悬浮物强酸性废水回用处理试验研究

在不改变废水pH的条件下,通过试验研究絮凝沉淀和离心分离去除悬浮物的特性。烧杯试验表明,在投加30mg/L PAM-I或90mg/L PAM-II,混合-絮凝反应-沉淀时间为1min-15min-30min,混合和絮凝反应G值875s-1和50s-1,絮凝反应GT4.5×104时,清液悬浮物含量可降到100mg/L以下,满足尾气洗涤系统内回用要求。离心分离试验表明,离心机转速5 000r/min(FCR 4 390g)、3 500r/min(FCR 2 191g)和2 500r/min(FCR 1 098g),分别离心5min、10min和15min时,清液悬浮物含量可降至100mg/L以下,满足尾气洗涤系统内回用要求;另外,絮凝预处理没能改善离心分离效果。综合考虑,现阶段推荐采用絮凝沉降法处理,同时建议絮凝剂采用PAM-I。     

微生物絮凝剂G5絮凝机理的初步研究

通过絮凝试验和高岭土表面Zeta电位测定,初步研究了微生物絮凝剂G5的絮凝机理,结果表明絮凝剂G5对高岭土的絮凝作用主要是吸附架桥;对絮凝剂G5进行热处理及紫外光谱扫描实验,得出其活性成分为多糖,絮凝剂G5具有很好的热稳定性。     

细菌BF-6的产絮促进因子及发酵条件优化研究

生物絮凝剂作为一种安全无毒、絮凝活性高、无二次污染的新型絮凝剂,对人类的健康与环境保护都有重要的现实意义。本研究即针对从发酵法生物制氢残液中筛选出来的高效产絮菌BF-6,探讨产絮促进因子对细菌BF-6产絮能力的影响,以及发酵工艺的优化。碳源浓度对BF-6产絮的影响试验表明,向BF-6的第二段发酵培养基中添加0.2 g/L葡萄糖时,其产絮能力很强。其发酵液絮凝率达到97%;控制碳氮比在10:1时     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

Serial discontinuities in a Rocky mountain river. I. Distribution and abundance of plecoptera

Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m^?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m^?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m^?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m^?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m^?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river.     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.