Direction of glucose fermentation towards hydrogen or ethanol production through on-line pH control

The present study investigated the production of hydrogen (H₂) and ethanol from glucose in an Anaerobic Continuous Stirred Tank Reactor (ACSTR). Effects of hydraulic retention time (HRT) and pH on the preference of producing H₂ and/or ethanol and other soluble metabolic products in an open anaerobic enriched culture were studied. Production rates of H₂ and ethanol increased with the increase of biomass concentration. Open anaerobic fermentation was directed and managed through on-line pH control for the production of H₂ or ethanol. Hydrogen was produced by ethanol and acetate-butyrate type fermentations. pH has strong effect on the H₂ or ethanol production by changing fermentation pathways. ACSTR produced mainly ethanol at over pH 5.5 whereas highest H₂ production was obtained at pH 5.0. pH 4.9 favored the lactate production and accumulation of lactate inhibited the biomass concentration in the reactor and the production of H₂ and ethanol. The microbial community structure quickly responded to pH changes and the Clostridia dominated in ACSTR during the study. H₂ production was maintained mainly by Clostridium butyricum whereas in the presence of Bacillus coagulans glucose oxidation was directed to lactate production.     

生物沸石溶气滤罐处理低温微污染原水的中试

为考察以沸石为填料的溶气滤罐的性能，以低温微污染水为原水进行中试，分析其对氨氮、CODMn和浊度的去除效果，并以π定理推导的综合指标评价滤罐性能。结果表明：夏季运行20d后，对氨氮的去除率稳定在65％，出水NO2^-N浓度较低，生物膜成熟；低温时，HRT由1．5h减少至0.5h，对浊度、氨氮和CODM。的平均去除率分别降低30％、25％和10％。最短和最长HRT下的滤罐综合性能指标较小，综合考虑保证较低滤罐综合性能指标和较好出水水质，HRT可取1．5h，此时出水氨氮浓度〈2mg／L。     

一体式膜生物反应器过滤阻力影响因素的研究

采用一体式偏聚氟乙烯中空纤维膜生物反应器(IMBR)处理洗浴污水,通过测定运行过程中膜过滤压差的变化,对影响膜过滤阻力的几个主要因素：水力停留时间(HRT)、污泥浓度(MLSS)、曝气量进行分析探讨．以期为该工艺在实际应用中的稳定运行提供依据和经验参考。     

ZnO薄膜对于CdTe太阳电池的影响*

通过直流磁控溅射法在ITO薄膜上沉积的ZnO薄膜可以作为CdTe太阳电池的高阻层。通过XRD,可见-红外可见光谱仪和四探针法分析了制备薄膜的结构,光学和电学性质。通过紫外光电子能谱和X射线光电子能谱深度刻蚀法分析了ITO/ZnO和ZnO/CdS薄膜的界面性质。结果表明：ZnO 作为高阻层有良好的光学和电学性质。ZnO 薄膜降低了ITO和CdS之间的势垒。 制备出来电池有ZnO（没有ZnO）的能量转换效率和量子效率是12.77% (8.9%) 和 >90% (79%)。 进一步,通过AMPS-1D模拟分析了ZnO薄膜厚度对于CdTe太阳电池的影响。     

UASB处理污水现状及效果分析

说明UASB反应器的基本构造和工作原理,以及现阶段对其启动的主要研究方向问题,全面介绍UASB的应用现状．对其处理各种废水效果进行分析,并对其运行处理过程的一些问题提出自己的看法,总结UASB下一步的发展方向。     

人工湿地氧状态影响因素研究

试验研究了人工湿地中水力停留时间、植物、填料和水力流态对净化效率和氧状态的影响。结果表明,湿地溶氧和净化效果受水力停留时间影响较大,最佳停留时间时溶解氧出现最低值;植物种类的不同将影响湿地供氧;填料孔隙率和表面性质的不同将直接影响其复氧效果;垂直流人工湿地独特的结构设计和水力流态使其更有利于湿地内部的供氧。     

Impact of Acetate in Reduction of Perchlorate by Mixed Microbial Culture under the Influence of Nitrate and Sulfate

The biological reduction of slow degradation contaminants such as perchlorate (ClO₄⁻) is considered to be a promising water treatment technology. The process is based on the ability of a specific mixed microbial culture to use perchlorate as an electron acceptor in the absence of oxygen. In this study, batch experiments were conducted to investigate the effect of nitrate on perchlorate reduction, the kinetic parameters of the Monod equation and the optimal ratio of acetate to perchlorate for the perchlorate reducing bacterial consortium. The results of this study suggest that acclimated microbial cultures can be applied to treat wastewater containing high concentrations of perchlorate. Reactor experiments were carried out with different hydraulic retention times (HRTs) to determine the optimal operating conditions. A fixed optimal HRT and the effect of nitrate on perchlorate reduction were investigated with various concentrations of the electron donor. The results showed that perchlorate reduction occurred after nitrate removal. Moreover, the presence of sulfate in wastewater had no effect on the perchlorate reduction. However, it had little effect on biomass concentration in the presence of nitrate during exposure to a mixed microbial culture, considering the nitrate as the inhibitor of perchlorate reduction by reducing the degradation rate. The batch scale experiment results illustrated that for efficient operation of perchlorate reduction, the optimal acetate to perchlorate ratio of 1.4:1.0 would be enough. Moreover, these experiments found the following results: the kinetic parameters equivalent to Y = 0.281 mg biomass/mg perchlorate, K_s = 37.619 mg/L and q_max = 0.042 mg perchlorate/mg biomass/h. In addition, anoxic–aerobic experimental reactor results verify the optimal HRT of 6 h for continuous application. Furthermore, it also illustrated that using 600 mg/L of acetate as a carbon source is responsible for 100% of nitrate reduction with less than 50% of the perchlorate reduction, whereas at 1000 mg/L acetate, approximately 100% reduction was recorded.     

回流比对短程硝化-厌氧氨氧化组合工艺处理晚期垃圾渗滤液自养脱氮的影响

厌氧氨氧化技术因其节省曝气能耗和有机碳源等突出优势,被认为是迄今为止最经济高效的污水脱氮工艺.然而该技术尚未实现主流城市污水处理的工程化应用,其瓶颈在于厌氧氨氧化所需基质亚硝酸盐（NO₂^-）难以稳定获取.目前普遍采用的短程硝化方法在主流条件下难以维持稳定的NO₂^-积累.短程反硝化是指将废水中的硝酸盐还原为亚硝酸盐（NO₃^-→NO₂^-）的过程.短程反硝化技术具有长期稳定的NO₂^-积累特性,反应速率快,节省有机碳源,是为厌氧氨氧化菌提供底物NO₂^-的新途径.基于此,本研究通过中试规模试验研究验证短程反硝化为厌氧氨氧化提供底物NO₂^-的可行性.结果表明,接种的城市污水处理厂剩余污泥具有一定的短程反硝化潜势,以城市污水及其硝化液为进水,通过对进水比例和水力停留时间（hydraulic retention time,HRT）等参数进行调控,成功启动了短程反硝化系统.长期试验结果表明,短程反硝化产生NO₂^-的性能逐渐提高,NO₃^-还原为NO₂^-的转化率（nitrate translation rate,NTR）高于75%,且在低温（13.7~16.2℃）条件下仍具有较高的产亚硝酸盐性能,低温阶段平均NTR可达62.3%.本研究为解决城市污水厌氧氨氧化脱氮过程底物NO₂^-难以稳定获取的问题提供了思路和方法,对短程反硝化耦合厌氧氨氧化技术在城市污水处理领域的推广应用具有重要意义和研究价值.

     

厌氧HRT对A/O除磷工艺的影响

为系统考察厌氧水力停留时间（AHRT）对生物除磷效果的影响,本文以实际生活污水作为进水,在实验室连续流厌氧／好氧（A／O）除磷系统稳定运行的基础上,统计了不同AHRT下系统除磷效果及胞内贮存物的变化。设计批式实验,考察了AHRT较长情况下生物增强除磷代谢过程,针对实验过程中出现的厌氧聚羟基链烷酸酯（PHAs）分解和厌氧糖原合成现象,提出聚磷不足情况下聚磷菌代谢的假想模式。最后根据实验结果指出A／O除磷工艺AHRT的确定应以PHAs的合成量最大作为控制目标。     

低碳高氮磷城市污水脱氮工艺研究

我国许多南方城市污水属于低碳高氮磷污水,COD一般在200mg／L左右。针对此类污水,研究了不同的充水比和反硝化时间对处理效果的影响。试验结果表明：充水比40％、每周期8h,其中缺氧4h（进水0．5h）、好氧1．5h、沉淀1h、排水0.5h、闲置1h时脱氮效率最高,总氮（TN）去除率可以达到60％以上,出水总氮满足城镇污水处理厂污染物排放标准（GB18918-2002）的一级A排放标准。