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611.
曝气生物滤池与类似传统工艺的比较 总被引:1,自引:1,他引:1
就生物滤池、生物接触氧化、曝气生物滤池三种同为生物膜法的工艺技术在原理、特点、适用范围、经济性能等方面作了比较,为水处理的工艺选择提供了依据。 相似文献
612.
中小型造纸厂造纸废水处理 总被引:6,自引:0,他引:6
针对中小型造纸厂造纸废水处理的特点,分析讨论了采用混凝与生化处理相结合的工艺,处理中小型纸厂造纸废水的可行性,并在实验室条件下研究了生化处理过程中曝气强度、pH值等因素对CODCr去除率的影响 相似文献
613.
间歇曝气A2/C氧化沟工艺处理城市污水中试研究 总被引:1,自引:0,他引:1
为降低氧化沟工艺的运行成本,研究了连续进水间歇曝气缺氧(Anoxic)-厌氧(Anaerobic)-Carrousel氧化沟(A2/C)工艺.采用A2/C氧化沟模型运用连续进水间歇曝气模式对城市污水处理进行了研究.结果表明,增强外源反硝化是提高脱氮效率的关键.在一定范围内加大回流比,能够提高间歇频率,减小各污染指标在反应系统中的积累.在曝气1 h,停止曝气3 h,回流污泥比200%的模式下(模式Ⅱ),出水CODcr,NH4 -N和TN分别为40~50 mg·L-1、3.0~5.7 mg·L-1和10.2~12.5 mg·L-1.3个模式在1个周期内平均曝气量分别为连续曝气过程的66%、50%、44%.模式Ⅱ中在线监测仪表数据分析显示,曝气过程中出现NH4 -N氧化的终点--在pH曲线上表现为出现"氨谷",若利用在线监测仪表在曝气阶段采用自动控制,则可避免过量曝气.采用实际城市污水,应用中试试验模型,能够为实际生产提供重要技术参数,为原有氧化沟工艺技术改造提供支持. 相似文献
614.
通过对深圳七家游泳池水中三氯甲烷的监测,三氯甲烷超标严重(52%超标,最高超标4倍)对对卤代烃的形成及其影响因素进行探讨,提醒人们不要忽视来自游泳池中的有机污染。 相似文献
615.
The concentration of dissolved oxygen is an important indicator of water quality because aquatic life lives on the dissolved
oxygen in the water. Aeration can increase dissolved oxygen when levels become deficient. Hydraulic structures can significantly
improve dissolved oxygen levels by creating turbulent conditions where small air bubbles are carried into the bulk of the
flow. Recent researches have focused on developing measurement and predictive techniques for oxygen transfer at hydraulic
structures to maintain and enhance water quality. However, reviewing existing studies on aeration performance of hydraulic
structures, it seems that there are not too many studies on venturi aeration. The present paper shows applications of venturi
principle to water aeration systems. The aeration characteristics of venturi nozzle, venturi conduit and venturi weir are
analyzed. The results indicate that venturi aeration might contribute significantly to air entrainment and aeration efficiency.
Therefore, venturi device can be used as highly effective aerator in aeration processes. 相似文献
616.
不同气油比的油气混输管道泄漏后果危害形式和风险差异的准确判断对于管道泄漏应急处置至关重要。以中国西部某油田集输管道为研究对象,针对不同气油比管道泄漏的火灾危害进行了对比分析,构建了FLACS CFD模型,并研究了油气混输管道原油泄漏形成池火的火灾特征和影响范围,以及天然气泄漏形成喷射火的高温分布和影响规律。研究结果表明:应急处置应考虑不同气油比下池火与喷射火危害的差异。在油气混输管线泄漏10 min形成稳定火焰的场景中,气油比低于100 m3/t时,原油池火为火灾危险的主要影响因素;气油比高于200 m3/t时,天然气喷射火为主要影响因素;气油比超过250 m3/t,高温覆盖距离不再明显增加;40 m为此场景下混输油气泄漏喷射火致死距离上限,120 m为温度影响上限。 相似文献
617.
Barry C. Moore Ping-Hung Chen William H. Funk David Yonge 《Journal of the American Water Resources Association》1996,32(4):723-731
ABSTRACT: Hypolimnetic aeration is a widely used technique for lake restoration and fisheries enhancement. However, system design still depends on application of “safety factors” to observed oxygen demand rates, in large part because actual oxygen demand may be greater after aeration than before. Laboratory incubations of sediment show that sediment oxygen demand (SOD) rates follow mixed order kinetics, with an initial period of zero order reaction, followed by first order kinetics. The transition from zero to first order kinetics may correspond to the transition from laminar to turbulent flow. This suggests that SOD reaction kinetics are governed by thickness of the diffusive sublayer adjacent to the sediments. Therefore, zero and first order reaction regions correspond with oxygen diffusion limitation and substrate limitation, respectively. Such a mechanism would account for the induced oxygen demand observed following hypolimnetic aeration and would reconcile differences in SOD reaction orders noted in the literature. This paper describes development of equations based on laboratory SOD incubations for predicting induced oxygen demand following hypolimnetic aeration. 相似文献
618.
Bessel D. van't Woudt 《Journal of the American Water Resources Association》1981,17(4):571-577
The geometry and formation of and the energy dissipation in flow accelerations in short steep reaches have been assessed, the latter as to its contribution to the energy expenditure in a long channel reach. An analysis of river gradients, aerial photos and additional field surveys has shown that flow accelerations can (1) originate naturally and sequentially from bars across a channel and nonsequentially from channel abandonment and channelside deposits and (2) be induced by a bankside groyne. 相似文献
619.
620.
Richard A. Osgood Jonathan E. Stiegler 《Journal of the American Water Resources Association》1990,26(2):209-217
ABSTRACT: Crystal Lake, a small urban lake in Robbinsdale, MN, had been artificially circulated for 12 years before a detailed water quality evaluation was undertaken. In 1986, the circulation system was shut off for a two-year assessment. Although the lake remained hypereutrophic, the use of the lake, which included shoreline fishing and feeding ducks and geese, did not appear to be seriously impaired by the absence of artificial circulation. The circulation system was returned to service in October 1987 (there are 16 diffusers in this 0.31 km?2 lake). Continuous limnological data from October 1987 through October 1988, plus several sampling dates in 1989, compares to the two non-circulation years (1986 and 1987) as follows: there was a two- to three-fold increase in the lake's concentration of total phosphorus, total Kjeldahl nitrogen, and chlorophyll and a similar decrease in Secchi disk transparency. The surface oxygen concentration was reduced and the deep waters were nearly anoxic. In fact, following a wind storm in 1988, the entire lake became anoxic due to the mixing of high BOD throughout the water column, and a summertime fish-kill resulted. All of these occurrences are related to the artificial circulation of the lake. 相似文献