附着生物膜的泥沙颗粒对磷的吸附特性研究

附着在泥沙表面的生物膜具有很强的吸附特性,对水环境中营养盐等物质的迁移转化具有重要的作用.本文对去除生物膜的泥沙和表面附着生物膜的泥沙分别进行了吸附营养盐磷的实验研究,对比了去除生物膜与附着生物膜的泥沙颗粒对磷的吸附能力,研究了附着生物膜的泥沙颗粒吸附磷的动力学及热力学特征.研究结果表明,去除生物膜的泥沙对磷的吸附性微小,而附着生物膜的泥沙颗粒对磷的吸附能力很强,在相同条件下附着生物膜的泥沙颗粒的吸附量比纯净泥沙吸附量高出1个数量级;同时附着生物膜的泥沙颗粒吸附磷的动力学特性符合准二级动力学模型,等温吸附特性符合Langmuir等温式,吸附速率和平衡吸附量随泥沙粒径减小而增大.     

十七大以来农村改革发展理论与实践的深化

农村改革发展事关党和国家的工作大局,是全面建成小康社会的关键环节和重要领域。十七大以来,党对农村改革发展的历史和作用有了更加清晰的认识,强化了农村改革、加快发展对国民经济发展的战略性作用,明确了农业现代化的发展路径,制定了一系列农业现代化和加快推进农村改革发展的制度体系,提出了一系列重要的科学论断,进一步深化和完善了党的农村改革理论。     

水流含沙量和流速对水轮机磨蚀性能的影响

水流含沙量和流速是影响水轮机磨蚀性能的非常重要的两大因素,其影响规律对水轮机磨蚀的防治有很重要的理论意义和参考价值.采用黄河原型沙,通过试验研究不同泥沙含量和不同水流流速条件下水轮机材料的磨蚀外貌、磨蚀失重量和磨蚀失重率.通过对试验结果进行定性和定量分析,得到水轮机磨蚀与水流含沙量、磨蚀与水流流速之间的关系,并得到数学回归式,找出水轮机磨蚀的基本规律,为多泥沙河流水轮机的参数选择与磨蚀防治提供了依据.     

Survey on production quality of electrodialysis reversal and reverse osmosis on municipal wastewater desalination

Water shortage has become an emerging environmental issue. Reclamation of the effluent from municipal wastewater treatment plant (WWTP) is feasible for meeting the growth of water requirement from industries. In this study, the results of a pilot-plant setting in Futian wastewater treatment plant (Taichung, Taiwan) were presented. Two processes, sand filter - ultrafiltration - reverse osmosis (SF-UF-RO) and sand filter - electrodialysis reversal (SF-EDR), were operated in parallel to evaluate their stability and filtrate quality. It has been noticed that EDR could accept inflow with worse quality and thus required less pretreatment compared with RO. During the operation, EDR required more frequent chemical cleaning (every 3 weeks) than RO did (every 3 months). For the filtrate quality, the desalination efficiency of SF-EDR ranged from 75 to 80% in continuous operation mode, while the conductivity ranged from 100 to 120 μS/cm, with turbidity at 0.8 NTU and total organic carbon at 1.3 mg/L. SF-EDR was less efficient in desalinating the multivalent ions than SF-UF-RO was. However for the monovalent ions, the performances of the two processes were similar to each other. Noticeably, total trihalomethanes in SF-EDR filtrate was lower than that of SF-UF-RO, probably because the polarization effects formed on the concentrated side of the EDR membrane were not significant. At the end of this study, cost analysis was also conducted to compare the capital requirement of building a full-scale wastewater reclamation plant using the two processes. The results showed that using SF-EDR may cost less than using SF-UF-RO, if the users were to accept the filtrate quality of SF-EDR.     

海河隧道工程防洪影响分析

海河隧道线路全长2 3034 m,其中主河道沉管段长240 m,沉管断面宽度374 m,高98 m,共设置两节,每节120 m。河道沉管段采用水中沉管法施工。管段安装会对河道的防洪安全产生较大的影响,故须对河段的水沙条件有严格的要求。本文采用三维分层水流泥沙数学模型,通过错层处理,较好地解决了同层网格产生急剧变化,在突变点处隔层网格物理量的影响远大于层间网格的影响问题。对隧道管段悬浮状态、沉放过程中的过流能力、水流流态和河段水流泥沙运移规律进行了深入分析,提出管段对河段水沙的影响程度及解决措施。本研究拓展了三维分层水流泥沙数学模型的应用范围,为保证工程施工安全提供了理论基础。     

Gravity filtration performances of the bio-diatomite dynamic membrane reactor for slightly polluted surface water purification

A bio-diatomite dynamic membrane (BDDM) reactor for surface water treatment under a water head of 30, 40, 50, 60 and 70 cm, respectively, was investigated, which was very effective for pollutants removal. The water head exerted strong influences on filtration flux of BDDM during the precoating process, as well as on the formation of BDDM and turbidity variations. A high filtration flux (approximately 200-300 L/m2 h) could be achieved in the long filtration times of BDDM with a stable effluent turbidity of approximately 0.11-0.25 NTU. The BDDM could remove particles larger than 25 μm completely. The adopted sintered diatomite mainly consisted of macro pores, which were beneficial for improving the filtration flux of BDDM. During the backwash stage, the BDDM could be removed completely by the air backwash.     

水资源定价方法与实践研究Ⅱ:海河流域水价探析

以水资源价值内涵分析为基础,对水资源定价理论与实践进行了研究,提出水资源供给价格应包括水资源费、供给成本和水环境补偿税;水资源需求价格通过产业用水经济价值确定;供给价格和需求价格共同作用决定水资源市场价格;在非市场化体系中通过影子价格评价水资源价值;依据水价构成及平衡关系,确定了水资源费的定量评价方法;利用投入产出分析技术构建简化的CGE模型,结合多种评价方法对水资源影子价格、水经济价值、水资源费、供给成本和水环境补偿税分别进行了定量评价,为水价形成机制提供了理论基础,为水资源定价标准提供了方法和实践支撑。研究成果可对实行最严格的水资源管理制度、完善水价定价机制、促进利用价格杠杆调控水资源分配提供参考。     

地震形成堰塞湖潜在影响范围快速评估

以汶川地震诱发的唐家山堰塞湖为研究区域,以下游各水文站点的实测水文历史数据为基础,采用模拟退火智能算法训练计算了该河段的马斯京根演算方程系数,并在给定初始条件下,快速预报了下游各个重要地区的流量变化过程。结合断面的水位流量关系得到水位变化过程。最后,使用空间信息技术得到了下游潜在淹没范围。结果表明：在溃决水位为690 m的条件下,洪水将全部淹没下游北川县城。     

控制体变及干湿循环下膨胀土强度变化规律研究

在控制体变条件下,用三轴仪对经历干湿循环后的膨胀土抗剪强度进行测定,分析得到抗剪强度随干湿循环次数的变化规律。结果表明：膨胀土的凝聚力随干湿循环次数的增加而降低,最初3次衰减幅度最大,随后趋于稳定,其变化趋势可用指数衰减函数描述;膨胀土的内摩擦角受干湿循环影响不大。建议在设计膨胀土边坡时,选用干湿循环后稳定的强度参数值作为设计参数。     

吉安市“2010·6”暴雨洪水分析

2010年6月,吉安市发生了大范围的持续暴雨洪水过程,由于本次暴雨洪水的特殊性,曾引发了一系列的洪涝灾害甚至溃堤.本文分析了该次暴雨洪水特性及重现期,有利于掌握该地区暴雨洪水的特点,为防汛减灾提供依据.