共查询到20条相似文献,搜索用时 62 毫秒
1.
2.
采用长污泥龄、低氧或微氧工艺控制亚硝化反应,成功地开发出了一种全新的亚硝化工艺,连续运转245d。试验结果表明,新型亚硝化工艺氨氮转化率平均为68.1%,亚硝酸盐氮生成率为63.7%,硝酸盐氮生成率平均为1.2%,氨氮几乎全部转化为亚硝酸盐氮,未发生硝酸盐积累。出水中氨氮负荷为0.238kgN/(m3·d),亚硝酸盐氮负荷为0.526kgN/(m3·d),污泥龄为198d,污泥比增长率为0.0051d-1,污泥产率为0.0375gVSS/gNH3-N。长污泥龄、低溶解氧、游离氨、亚硝酸抑制等的共同作用,是实现稳定亚硝化的关键。 相似文献
3.
亚硝酸型硝化-厌氧氨氧化联合工艺处理"中老龄"垃圾渗滤液 总被引:8,自引:0,他引:8
亚硝酸型硝化和厌氧氨氧化有机结合构成的新型全程自养生物脱氮技术为处理高氨氮和低C/N的"中老龄"渗滤液提供了新的思路.主要针对系统内部能否实现稳定的亚硝酸氮自给和厌氧氨氧化反应器的启动这两个关键条件进行研究.结果表明,在氨氮负荷率(ALR)为0.069~0.284 3 gNH3-N/(gVSS·d)条件下,前置亚硝酸型硝化反应器(SBR)能实现稳定的亚硝酸氮积累,出水NO-2-N/NH3-N在1.45左右,NO-2-N/NO-x-N大于90%.而且,接种前置SBR中具有硝化活性的污泥用作厌氧氨氧化反应器(UASB)的接种污泥,可以加快反应器的成功启动.在进水氨氮和亚硝酸氮浓度不超过250 mg/L的条件下,厌氧氨氧化反应器稳定运行时NH3-N和NO-2-N的去除率分别可达到80%和90%左右. 相似文献
4.
5.
采用常温亚硝化—厌氧氨氧化工艺对淀粉废水生物处理出水进行生物脱氮处理,在SBR亚硝化反应器和气提式亚硝化反应器中均实现了稳定的半亚硝化反应。亚硝化—厌氧氨氧化工艺正常运行时,全流程总氮去除率基本维持在80%左右,最高达85.5%。一级亚硝化反应进水容积负荷为0.20kg/(m3·d),平均HRT为1.11d。厌氧氨氧化平均总氮进水容积负荷为1.11kg/(m3·d),最高达1.61kg/(m3·d);平均总氮去除负荷为0.83kg/(m3·d),最高去除负荷达1.29kg/(m3·d);平均HRT为0.20d。淀粉工业废水生物处理后出水中的有机物对亚硝化和厌氧氨氧化反应均未产生显著影响,所含过多的悬浮物和胶体物对亚硝化—厌氧氨氧化反应器存在潜在影响。 相似文献
6.
7.
本文采用两种不同来源的活性污泥 ,利用CSTR反应器对亚硝化工艺处理高浓度氨氮自配废水进行了试验研究。试验结果表明 :(1)以处理饮料废水的活性污泥接种的CSTR反应器 ,从第 2 6天开始成功地实现了亚硝化 ,并从第 73天开始 ,反应器出水中检测不到NO3 -;反应器在进水氨氮容积负荷达到 1 4kg/(m3 ·d)时 ,氨氮去除率仍保持在 95 %以上 ;(2 )以处理生活污水的活性污泥为接种污泥的CSTR反应器 ,以高浓度氨氮废水在较高负荷下直接启动 ,从第 1天开始就成功地实现了亚硝化 ,至第 2 3天之后出水中检测不到NO3 -;亚硝化反应器的… 相似文献
8.
亚硝酸型硝化试验研究 总被引:35,自引:0,他引:35
利用煤气废水水质,从影响因素及游离氨毒性作用两方面对亚硝酸型硝化的可行性及稳定性进行了试验研究。研究结果表明,亚硝酸型硝化具有一定可行性,可以从影响因素及游离氨(FA)的毒性作用两方面进行控制。亚硝酸型硝化要求pH>7.4,碱度>350mg/L,出水氨氮浓度>20mg/L,游离氨浓度>0.4mg/L,此时亚硝酸盐氮占硝态氮比例大于90%。 相似文献
9.
以某污水处理厂低浓度、含氨氮混合污水为研究对象 ,进行SBR池的生产性试验、小试试验。试验结果表明 :(1)对该污水 ,投加有机物 ,增加有机负荷 ,可使氨氮通过生物合成去除。(2 )对该污水 ,当SBR池处理的容积负荷低于 0 0 5 4kgCOD/ (m3 ·d)时 ,基本不去除氨氮 ;当容积负荷在 0 0 5 4~0 14kgCOD/ (m3 ·d)之间时 ,对氨氮有去除作用 ,但处理效果不稳定 ;当容积负荷大于 0 14kgCOD/ (m3 ·d) ,氨氮获得了稳定的去除 ,同时COD的去除效果也较好。(3)当反应器中MLVSS高于 12 0 0mg/L时 ,氨氮的去除效果良好 ;当反应器中MLVSS在 4 5 0mg/L时 ,氨氮基本不能去除。(4 )通过试验数据分析得出 :2 5℃时动力学参数K1=0 2 5h-1,S0 =10 2mg/L ,Sn=37mg/L ;2 9℃时动力学参数K1=0 33h-1,S0 =76mg/L ,Sn=33mg/L。(5 )出水氨氮处理效果不佳的直接原因是负荷不够。在低负荷下 ,系统活性污泥浓度过低 ,硝化菌群难以在低浓度的悬浮污泥系统中生长 相似文献
10.
采用间歇式反应器(Batch Reactor,BR)研究了晚期垃圾渗滤液短程硝化反硝化工艺(SND)工艺特性.试验发现:在进水氨氮负荷约为0.27 gNH3—N/(L·d),温度约为27℃,pH控制在7.5时,该工艺DO浓度控制在1 mg/L时硝化效果较好.DO浓度从0.75 mg/L增加到1 mg/L时,氨氧化速率明显增加;继续再增加溶解氧浓度,氨氧化速率增加不明显.在整个过程中,亚硝酸盐积累率变化不大,维持在91%以上.当温度控制在25℃以上时,反应器处理效果较好.随着温度的下降,亚硝酸菌和反硝化菌活性降低,当温度低于25℃时,氨氧化速率和亚硝酸盐降解速率下降较快,曝气时间和出水亚硝酸盐氮浓度明显增加. 相似文献
11.
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。 相似文献
12.
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. 相似文献
13.
14.
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. 相似文献
15.
16.
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. 相似文献
17.
18.
19.
V. K. Konovalov O. V. Yashkin V. V. Ermakov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2008,42(2):105-109
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). 相似文献
20.
Peter B. Bayley 《河流研究与利用》1991,6(2):75-86
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. 相似文献