波形生物膜泡的数值法研究

磷脂双亲分子在水溶液中会形成各种各样形状的膜泡,实验显示,存在有一维的周期性柱面膜泡.扩展的Delaunay曲面是由Ou-Yang等首次给出的Helfrich变分问题的解析特解,与Delaunay曲面不同的是它所代表的曲面为非常数平均曲率曲面,其中之一为波形周期曲面.本文用数值计算的方法探讨了波形曲面形状,并与已知的解析解进行了比较.与球形拓扑不同的是,做数值计算时所采用的欧拉-拉格朗日方程中参数不取为零,加入周期性边界条件数值求解该方程,得到了与扩展的Delaunay曲面一致的波形曲面.目前我们还没有得到扩展的Delaunay曲面之外的周期波形形状.扩展的Delaunay曲面是否给出了非常数平均曲率的波形曲面的通解,仍然是需要进一步探讨的问题.然后根据形状方程和轴对称的微分方程绘出了自发曲率取不同数值时的二维波形图,并且得出结论:随着自发曲率的增加,参数的值逐渐减小,与解析法得到的结果一致.     

生活污水分散处理技术的进展

为了确保我国水体清洁,生活污水除了集中处理之外,分散式的净化槽系统也是不可缺少的。对生活污水分散处理的特点、难点及发展状况进行了论述,探讨了生活污水分散处理技术在应用中存在的问题及解决方法,指出厌氧和好氧生物膜联合处理的小型一体化生活污水净化槽的发展方向。     

湿地法处理生活污水对仙桃湿地地表水微生物群落结构的影响

【背景】随着中小城市经济的高速发展和人们生活水平的提高,生活污水排放量也日益增大,致使水源水质污染呈恶化趋势。【目的】了解湿地法处理生活污水对湿地地表水微生物群落多样性变化的影响。【方法】对人工湿地(仙桃)参照点(-2 000)、200、400、600、3 000、5 000 m水平方向6点地表水进行理化检测,再通过高通量测序对微生物群落结构进行解析,并探讨微生物群落结构变化与生活污水的污染效应。【结果】当湿地法处理的生活污水到达5 000 m时,化学需氧量、氨态氮、总氮和总磷均达《城镇污水处理厂污染物排放标准》一级标准,且理化指标之间均呈极显著正相关。样品在门水平上的优势物种分别为变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)、放线菌门(Actinobacteria)、蓝藻门(Cyanobacteria)、疣微菌门(Verrucomicrobia)、厚壁菌门(Firmicutes)、酸杆菌门(Acidobacteria)和绿弯菌门(Chloroflexi)。变形菌门(Proteobacteria)可用来作为排放生活污水污染物的指示性微生物,放线菌门(Actinobacteria)、蓝藻门(Cyanobacteria)、疣微菌门(Verrucomicrobia)和绿弯菌门(Chloroflexi)可用来作为排放生活污水净化的指示性微生物。【结论】首次比较分析了湿地法处理仙桃生活污水地表水环境中微生物群落多样性变化的情况,可使人们从微生物层面更加明确地了解人工湿地运作机理及地表水环境的污染情况。     

生物-化学一体化装置处理生活污水的研究

经济的不断发展,城市化的进程不断加快,人们排放的生活污水也越来越多。如何处理大量的生活污水,成为了人们城市化建设中尤为关心的一个问题。在文中,对生物-化学一体化装置处理生活污水的操作工艺、技术要点、操作流程以及实际的应用效果进行了详细的阐述。通过试验研究结果可以发现,使用生物-化学一体化装置处理污水比使用一般的生化工艺操作在成本上能够降低大约30%,占地面积上大约减少70%,而且有良好的处理操作效果,处理后的污水符合国家相关的排放标准。在文中就是对这项装置在推广使用工作中的可行性进行了简单的分析和探讨。     

生物膜法和SBR法相结合处理难降解制药废水的研究

采用生物膜法和SBR法相结合的废水处理工艺处理含抗生素类等难降解的制药废水 ,对生物膜的耐冲击负荷能力、生物膜对进水可生化性的影响、生物膜对好氧SBR活性污泥性能的影响、pH对系统去除效果的影响等工艺条件进行研究 ,并通过与传统SBR处理工艺的对比试验 ,进一步揭示了生物膜法和SBR法相结合的处理工艺强的耐冲击负荷能力。     

细菌生物膜研究技术

细菌生物膜是细菌生长过程中为适应生存环境而在固体表面上生长的一种与游走态细胞相对应的存在形式。只要条件允许,绝大多数细菌都可以形成生物膜。一旦形成了生物膜细菌就具有极强的耐药性,在医疗、食品、工业、军事等诸多领域给人类社会带来了严重的危害,造成巨大的经济损失。因此,细菌生物膜已成为全球关注的重大难题,也是目前科学界研究的前沿和热点。本文结合细菌生物膜研究技术的最新进展,重点介绍了几种常用生物膜发生装置及检测量化技术,并对其原理及优缺点进行了讨论。     

企业水环境监测及污水氧化法处理的研究

我国长期以来的先污染后治理的模式以及企业水环境污染的外部性特征,导致企业水环境的监管责任就更为重大。本文分析了企业水环境监管的重要意义,并根据实践经验探讨了监管水环境的技术要求以及可采用的技术措施,最后根据水污染的情况探讨了氧化法处理水源污染的方式。     

湿地处理污水的研究

作为一项新兴的污水处理技术,近几年来,湿地在全世界范围内被广泛地研究和利用。国外大量的研究表明,各种类型的湿地都具有潜在的处理和净化污水的能力。利用湿地降低污水所载营养物被普遍认为是经济而有效的途径,最近更有报道建议开发人工湿地以减少自然水体中的氮素     

论生物膜法A/O~2工艺处理城市小区污水并回用的研究

随着全球性水资源短缺、人口的快速增长和经济的快速发展,水资源危机已经成为威胁全球生存与发展的最大危机之一。目前各国纷纷出台相关政策,用以保护水资源,提高水资源利用率。其中,废水处理回用受到各个国家的认可和重视,在经过了十多年的研究与发展,新型的膜生物反应器污水处理工艺已趋于成熟,其以处理能力高、出水水质稳定、工艺简单、污泥产出率低、占地面积小、投资运行费用低、安装灵活方便且易于实现自动化控制等传统污水处理系统所不具有的优点,在水污染防治方面受到广泛的重视和采用。本文所讨论的A/O2工艺以膜生物反应器为基础,设计以A段的厌氧池以及O段含氧池设计工艺来对城市小区生活污水进行处理回用。通过模拟实验,在室温(15～25℃)环境下进行仿真实验,在系统稳定运行后进行相关数据测试,并进行分析,最终得出生物膜法A/O2工艺能够很好的处理小区生活污水,且出水水质完全达标国家杂用水水质标准,可用于小区绿化以及道路清洗降尘等。     

生物膜细管形成过程的研究*

我们都知道磷脂双亲分子在水或者油溶液中会形成各种不同的形状。现在我们探讨的是一种细的管状生物膜泡。它通常是指在磷脂双亲分子形成膜泡后,我们对它在显微镜下进行的一系列使用光镊施加拉力操作而形成的细的管状结构。实验显示,膜泡形成的管状结构在生物学中是普遍存在的。本文主要研究怎样应用数值计算的方法进行模拟细的管状膜泡,从而得到一些长短,粗细不同的管状生物膜泡。我们从极小曲面悬链面的角度出发,研究管状膜泡的形成结构特点。最后我们认为管状膜泡的形成不同形状是与对膜泡施加拉力、细管的半径、以及管子的长度等因素有着密切的联系。     

Composting domestic sewage sludge with natural zeolites in a rotary drum reactor

This work aimed the influence of zeolites addition on a sludge-straw composting process using a pilot-scale rotary drum reactor. The type and concentration of three commercial natural zeolites were considered: a mordenite and two clinoptilolites (Klinolith and Zeocat). Mordenite caused the greatest carbon removal (58%), while the clinoptilolites halved losses of ammonium. All zeolites removed 100% of Ni, Cr, Pb, and significant amounts (more than 60%) of Cu, Zn and Hg. Zeocat displayed the greatest retention of ammonium and metals, and retention efficiencies increased as Zeocat concentration increased. The addition of 10% Zeocat produced compost compliant with Spanish regulations. Zeolites were separated from the final compost, and leaching studies suggested that zeolites leachates contained very low metals concentrations (<1 mg/kg). Thus, the final compost could be applied directly to soil, or metal-polluted zeolites could be separated from the compost prior to application. The different options have been discussed.     

Anaerobic treatment of raw domestic sewage at ambient temperatures using a granular bed UASB reactor

Results obtained in a 120 liter 2 m high UASB-reactor with raw domestic sewage and using a granular sugar beet waste cultivated seed sludge, reveal the feasibility of this type of anaerobic treatment for domestic sewage. Under dry weather conditions 65-85% COD reduction can be achieved at temperatures in the range of 8-20 degrees C and at hydraulic loads as high as 2 m(3) . m(-3) . day(-1). In the case of heavy rainfall the COD-reduction drops to 50-70% and occasionally, viz.at very low influent COD, even below 50%. The net methane production amounts to 7.1-7.3 m(3) . PE(-1) . year(-1), and the excess sludge production ranges form 5.0-8.6 kg TS . PE(-1) . year(-1). Regarding the results obtained anaerobic treatment of raw sewage not only looks an attractive proposition for tropic areas but also for moderate climatic areas.     

Studies with an anaerobic expanded bed reactor comparing the performances achieved with synthetic waste and domestic sewage

The performance of an anaerobic expanded bed reactor has been examined during the treatment of a synthetic low strength waste whose consistency and composition were constant. The organic loading rates used were in the range 0.2–5 kg total organic carbon m^?3 day^?1 and the removal efficiencies varied from 89 to 52%. Comparing these results with those obtained previously for the treatment of domestic sewage, whose strength and composition was very variable, showed that not only can higher removal efficiencies be achieved with the synthetic waste but also that a significantly better (R² > 0.85, as opposed to <0.5) correlation between data could be obtained. This indicates the potential danger of using synthetic feedstocks for the prediction of reactor performance under real conditions.     

小区生活污水处理模式的研究进展

分析了小区生活污水处理模式的现状,指出了集中式处理模式和分散式处理模式的不足.依据人工湿地、地下渗滤为主的土地生态处理技术的特点,提出小区污水处理采取土地生态处理模式的构想.通过分析污水土地生态处理技术的特征及其运行局限性,建议土地生态处理技术应重视强化预处理,采取低进水污染物浓度,高水力负荷的运行方式.     

不同植物构成的人工湿地对生活污水中氮的去除效应

测定由不同植物构成的人工湿地的氨态氮、硝态氮和亚硝态氮含量,对比不同植物对生活污水中氮的去除效率.结果表明,与不种植物的人工湿地相比,由风车草[Cyperus alternifolius L. ssp. flabelliformis (Rottb.) Kiikenth.]、香根草[Vertiveria zizanioides (Linn.) Nash]、芦苇(Phragmitas communis Trin.)和美人蕉(Canna indica Linn.)构成的人工湿地对氨态氮去除率分别提高6%、8%、11%和14%;对硝态氮去除率分别提高5%、6%、13%和9%;对亚硝态氮去除率分别提高5%、7%、10%和7%,说明种植芦苇和美人蕉的人工湿地对生活污水中的氮具有较好的去除效果.     

Anaerobic and complementary treatment of domestic sewage in regions with hot climates--a review

This study presents a literature review on the treatment of domestic sewage in controlled environments having the anaerobic process and specifically the upflow anaerobic sludge blanket (UASB) concept as the core, under natural hot conditions. The UASB process application is however beset by the preponderance of suspended solids, and the paper looks at its optimization via pre- and post-treatments to curb the prevailing problems, in the light of possible discharge and re-use/recycling/resource recovery, leading to efficient environmental protection. Pre-treatment clarification could be done with ferric chloride/polyelectrolyte, so that phosphate precipitates during the process. The pre-treated liquid phase can be submitted to a high rate anaerobic process, using the simple and robust UASB technology. In a subsequent post-treatment step, ammonium can be removed by ion exchange using a zeolite column through which the wastewater percolates after leaving the anaerobic digester. The various stages can also eliminate a large fraction of the pathogens present in the raw wastewater, mainly through the pre-treatment sedimentation and the ion exchange filtration. The sludge produced in the precipitation stage can be stabilized in a conventional anaerobic digester. Integration of the different treatment steps provides a sustainable technology to treat domestic sewage under hot climate conditions.     

Low temperature pre-treatment of domestic sewage in an anaerobic hybrid or an anaerobic filter reactor

The ability of pigs to use nitrogen and energy in Bermuda grass was evaluated in order to assess whether Bermuda grass harvested from spray fields could be fed to pigs as a means to recycle nitrogen. Digestibility of Bermuda grass incorporated into corn-soybean meal diets was evaluated in heavy finishing pigs and gestating sows. Results suggest that Bermuda grass digestibility is negative in animals not adapted to a high-fiber diet. Enzymes improve this digestibility, but even with enzymes, nitrogen digestibility was poor. Pigs fed a diet containing 10% Bermuda grass required a one week adaptation period for maximal digestion; following adaptation, pigs can digest approximately 40% of the energy in Bermuda grass but none of the nitrogen. Feeding Bermuda grass to pigs as a means of recycling nitrogen is thus not recommended.     

Treatment of strong domestic sewage in a 96 m3 UASB reactor operated at ambient temperatures: two-stage versus single-stage reactor

A 96 m3 UASB reactor was operated for 2.5 years under different conditions to assess the feasibility of treating strong sewage (COD(tot) = 1531 mg/l) at ambient temperatures with averages of 18 and 25 degrees C for winter and summer respectively. During the first year, the reactor was operated as a two-stage system at OLRs in the range of 3.6-5.0 kg COD/m3 d for the first stage and 2.9-4.6 kg COD/m3 d for the second stage. The results of the first stage showed average removals of 51% and 60% for COD(tot) and COD(ss) respectively without significant effect of temperature. The second stage reactor was unstable. The temperature affected sludge stabilization. During the second year, the first stage was operated as a single-stage UASB reactor at half of the previous loading rates. The results showed an average removal efficiency of 62% for COD(tot) during summer, while it dropped to 51% during wintertime. However, the effluent suspended solids were stabilized with VSS/TSS ratio around 0.50 all over the year. The sludge in the single-stage reactor was well-stabilized and exerted an excellent settlability. During the last three months of research, sludge was discharged regularly from the single-stage UASB reactor. The results showed no significant improvement in the performance in terms of COD(tot). Based on the results of the experiment, a single-stage UASB reactor operated at relatively long HRT is preferred above two-stage system at the Jordanian conditions.