生产性短程硝化-厌氧氨氧化装置处理制药废水的启动性能

为拓展新型生物脱氮技术的应用领域,研究了生产性短程硝化-厌氧氨氧化装置处理制药废水的启动性能。制药废水氨氮浓度为(430.40±55.43)mg/L时,氨氮去除率达(81.75±9.10)%,实现了短程硝化-厌氧氨氧化工艺对制药废水的生物脱氮。制药废水短程硝化系统的启动时间约为74 d,亚硝氮积累率达(52.11±9.13)%,证明了结合模拟废水和实际废水的"两步法"模式对短程硝化系统启动的适用性。制药废水厌氧氨氧化系统的启动时间约为145 d,最大容积氮去除速率达6.35 kg N/(m3·d),容积效能为传统硝化-反硝化工艺的数十倍,证明了结合菌种自繁和菌种流加的模式对厌氧氨氧化系统启动的适用性。     

红尾副鳅耗氧率和窒息点的初步研究

用封闭流水式装置测定了红尾副鳅的耗氧率变化及窒息点。结果表明,红尾副鳅耗氧率随着体重的增加而减小,红尾副鳅其耗氧率昼夜变化差异显著(P<0.05)。在水温14.0℃时,平均体重4.0 g的红尾副鳅的平均耗氧率为0.1659 mg/(g·h),日平均耗氧率为0.1389 mg/(g·h),夜间其平均耗氧率为0.1930 mg/(g·h);平均体重为7.9 g的红尾副鳅的平均耗氧率为0.1175 mg/(g·h),日平均耗氧率为0.1099 mg/(g·h),夜间其平均耗氧率为0.1251 mg/(g·h);平均体重9.5 g的红尾副鳅平均耗氧率为0.0534 mg/(g·h),日平均耗氧率为0.0509 mg/(g·h),夜间平均耗氧率为0.0559mg/(g·h),窒息点为1.137 mg/L。本研究表明红尾副鳅为耗氧率和窒息点较高的鱼类。     

西施舌的耗氧率与排氨率研究

采用室内实验生态学方法研究了不同栖息水温和不同溶解氧水平下处于标准代谢状态的西施舌耗氧率与排氨率,并测定了窒息点.结果表明,在25 ℃时,水中DO≥3.11±0.15 mg·L^-1时,西施舌的耗氧率和排氨率分别为0.7±0.05 mg·g^-1·h^-1和2.56±0.05 μmol·g^-1·h^-1,处于相对稳定状态;当DO低于此值则代谢出现异常,耗氧率随DO下降而下降,直到窒息为止,其窒息点为1.22±0.06 mg·L^-1,而排氨率也呈直线下降,但排氨停止滞后于耗氧停止.耗氧率与栖息水温呈二次线型关系:OCR=-0.0027T²+0.1367T-0.9557,R²=0.972;水温为25.3 ℃时,西施舌的耗氧率达到最大,为0.77 mg·g^-1·h^-1.处于适温状态(15 ℃和20 ℃)的O/N值要高于低温(10 ℃)和高温(25 ℃和30 ℃)时的O/N值,西施舌在适宜条件下更多地依赖于脂肪供能维持标准代谢,而在环境不适时则更多地调用机体的蛋白质来维持生理代谢需要.     

新型异养硝化-好氧反硝化菌Paracoccus sp. QD-19的分离及脱氮特性研究

从沈阳市南部污水处理厂活性污泥中分离获得同时具备异养硝化和好氧反硝化能力的新型菌株,研究其脱氮特性,为改善污水厂的脱氮处理工艺奠定基础。对菌株进行形态学观察和16S rRNA基因鉴定;分别以NH₄Cl、NaNO₂、KNO₃为唯一氮源探究菌株的脱氮能力;以碳源、C/N比、pH值、温度、转速、接种量(V∶V)等因素对菌株脱氮效果的影响进行研究。获得一株新型异养硝化-好氧反硝化菌株,经16S rRNA基因序列比对为副球菌属(Paracoccus),命名为Paracoccus sp. QD-19。菌株对初始氨氮浓度在300 mg/L以下的低浓度氨氮去除率能够达到100%,去除速率为8.707 mg/(L·h)且在脱氮过程中几乎没有亚硝态氮和硝态氮的积累。以亚硝态氮和硝态氮作为唯一氮源时,对此两种氮源的去除率36 h内均能达到99%,去除速率分别为4.944和5.666mg/(L·h)。确定了去除氨氮的最佳脱氮条件：琥珀酸钠为碳源,C/N比为10,pH值为7,接种量(V:V)为1%,温度为30℃,转速为140 r/min。菌株Pa...     

短程硝化启动运行中功能菌群变化研究

【目的】短程硝化-厌氧氨氧化是可实现的最短生物脱氮工艺,短程硝化是实现该工艺的重要环节和必要条件。【方法】采用序批式反应器(SBR)来实现短程硝化过程的启动和稳定运行,并对该过程中的相关功能菌群变化进行检测分析。【结果】通过控制低DO浓度(<1 mg/L)和逐步提高氨氮进水负荷,可抑制氨氧化细菌(NOB)菌群增殖并促进亚硝酸氧化菌(AOB)菌群规模显著扩大,实现短程硝化过程的启动和稳定运行。在氨氮进水负荷为0.055 kg/(m3.d)时,平均氨氮去除容积负荷和污泥负荷可达到0.043kg/(m3.d)和0.16 kg/(kg.d),平均亚硝酸盐积累率可达到83.4%。在短程硝化启动和稳定运行过程中,NOB菌群密度从2.0×105CFU/mL降至1.5×104CFU/mL,相对丰度从5.51%降至2.14%;AOB菌群密度从4.5×104CFU/mL增加至1.5×107CFU/mL,相对丰度从0.18%增加至7.25%。【结论】AOB菌群规模的扩大是实现短程硝化和氨氮去除能力提高的主要原因,同时较高的进水氨氮浓度和负荷也会造成亚硝化活性的抑制。     

好氧反硝化菌Defluvibacter lusatiensis str.DN7的分离鉴定和异养硝化性能

从稳定运行处理竹子加工废水的生物接触氧化反应器中分离得到一株好氧反硝化菌DN7,其72 h NO3-降解率达99.4％.细胞显微镜观察显示,菌株为革兰氏阴性小杆菌,大小为0.5 μm×1.5 μm,菌落为乳白色.通过生理生化特性及16S rDNA同源性分析,初步推断该菌株为根瘤菌中的Defluvibacter lusatiensis str.碳源、C/N、硝酸盐初始浓度、溶解氧(DO)、pH对DN7反硝化性能影响的结果表明:菌株对柠檬酸钠、葡萄糖等小分子有机物的利用较好;C/N为9时,脱氮率达99.0％;硝酸盐浓度低于138.48 mg·L-1情况下,DN7脱氮率在96％以上,且亚硝酸盐浓度均在1.0mg·L-1以下;菌株DN7对DO不敏感,中性偏碱性环境有利于DN7反硝化反应的进行;DN7具有良好的异养硝化性能,72 h铵氮降解率达84.7％.     

高效反硝化菌aHD7的筛分、脱氮特性及厌氧氨氧化性

从活性污泥中筛选出一株高效反硝化菌aHD7,30℃静置培养3d,脱氮率可达91.7％,且反应过程中亚硝酸盐积累量较低,3d后亚硝酸盐氮浓度基本稳定在1.8mg.L-1.显微镜观察显示,菌株为革兰氏阴性杆菌,大小为0.5 μm×(1.5～2.5) μm.通过生理生化特性及16S rDNA同源性分析,初步推断该菌株为门多萨假单胞菌(Pseudomonas mendocina).考察了碳源、C/N、氮初始浓度、pH等因素对菌株反硝化性能的影响.结果表明:对中低浓度硝酸盐(硝酸盐氮浓度≤276.95 mg.L-1),脱氮率接近100％,硝酸盐氮浓度高达553.59 mg·L-1时,脱氮率可达66.8％,且亚硝酸盐积累量甚微;最适碳源为乙醇;C/N为6～8和偏中性条件有利于反硝化反应.aHD7具有较强的厌氧氨氧化性,平均氨利用率达4.56 mg·L-1·d-1.     

产油微藻的分离、筛选及自养培养氮源、碳源的优化

从云南滇池的水样中分离筛选得到一株自养产油小球藻(Chlorella vulgaris,C.vulgaris),其油脂产率可达28.6mg/(L·d),进一步考察了不同氮源、氮源浓度和添加无机碳源对其自养生长和油脂积累的影响。结果表明,硝酸钠为优化氮源,氮元素的优化浓度为123mg/L,油脂含量随氮元素浓度升高而降低;添加NaHCO3显著提高了C.vulgaris生物量产率和油脂产率,其优化浓度为800mg/L。在氮源和碳源的优化浓度下,C.vulgaris的最大生物量产率和油脂产率可达332.8mg/(L·d)和100.2mg/(L·d),分别是对照组的3.6和3.4倍。     

中试厌氧氨氧化反应器的启动与调控

研究了中试厌氧氨氧化(Anaerobic ammonium oxidation,Anammox)反应器的启动性能。结果表明,以硝化反硝化污泥、短程硝化污泥、厌氧絮体污泥和厌氧颗粒污泥混合接种,经过255d的运行,可在常温下(5oC～27oC)成功启动中试Anammox反应器,反应器的基质氮去除速率可达1.30kg/(m3·d)。厌氧氨氧化是致碱反应,厌氧氨氧化成为反应器内的主导反应后,进水pH宜控制在厌氧氨氧化适宜范围的偏低水平(6.8左右)。亚硝酸盐既是Anammox菌的基质,也是抑制剂,控制进水亚硝酸盐浓度(13～36mg/L)有助于厌氧氨氧化反应。菌种是生物反应器的功能之源,向中试装置投加少量厌氧氨氧化污泥(投加比2%),可大大加速中试Anammox反应器的启动进程。     

4种理化因子对菌株XH1硝化效果的影响

【背景】基于硝化菌群的富集培养技术可高效稳定地去除养殖水体中的有害氮素,而当前在水产养殖领域有关硝化菌群定向培育及硝化功能菌株的研究较少。【目的】研究不同盐度、pH、温度、通气量条件下硝化菌群分离菌株XH1的生长及其对氨氮和亚硝氮的去除效果。【方法】设置不同梯度的盐度、pH、温度、通气量条件,通过计数菌量、测定氨氮及亚硝氮的浓度变化,比较不同条件下菌株XH1的生长及其对氨氮和亚硝氮的影响。【结果】菌株XH1可在盐度5‰-35‰、pH 6.0-9.0、温度15-45°C和通气量0.5-1 V/(V·min)的条件下生长良好,菌量最高可达2.34×109cells/mL;在盐度5‰-35‰、pH 6.0-9.0、温度15-30°C、通气量0.5 V/(V·min)的条件下,对氨氮的去除效果显著(P0.05),在第1-3天对培养液中氨氮的最高去除率可达86%-97%,但培养液中的氨氮浓度先降后升;对亚硝氮的最高去除率达68%。【结论】菌株XH1对盐度、pH、温度等主要环境因子具有良好的适应性,其对水体氨氮的去除效果良好,可作为中低盐度养殖池塘水体氨氮防控菌剂产品研发的备选菌株。     

Continuous, real-time monitoring of the oxygen uptake rate (OUR) in animal cell bioreactors

A new method for real-time monitoring of the oxygen uptake rate (OUR) in bioreactors, based on dissolved oxygen (DO) measurement at two points, has been developed and tested extensively. The method has several distinct advantages over known techniques.It enables the continuous and undisturbed monitoring of OUR, which is conventionally impossible without gas analyzers. The technique does not require knowledge of k(L)a. It provides smooth, robust, and reliable signal. The monitoring scheme is applicable to both microbial and mammalian cell bioprocesses of laboratory or industrial scale. The method was successfully used in the cultivation of NSO-derived murine myeloma cell line producing monoclonal antibody. It was found that while the OUR increased with the cell density, the specific OUR decreased to approximately one-half at cell concentrations of 16 x 10(6) cells/mL, indicating gradual reduction of cell respiration activity. Apart from the laboratory scale cultivation, the method was applied to industrial scale perfusion culture, as well as to processes using other cell lines. (c) 1994 John Wiley & Sons, Inc.     

Determination of oxygen profiles in agar-based gelled in vitro plant tissue culture media

Keeping account of the limited knowledge concerning the relevance of the oxygen status of the medium during in vitro culture, a technique was elaborated to systematically study the oxygen concentration in gelled media. In a first series of experiments, the Oxygen Diffusion Rate (ODR) technique was used to investigate the dissolved oxygen concentration as a function of time at different depths. The results obtained demonstrated that the oxygen concentration in agar media was reduced by 80% during the heating steps included in the preparation procedure. It took about one week to reach an oxygen concentration equal to 90% of the equilibrium value at a depth of 1 cm, irrespective of the brand of agar used. As the recovery of the oxygen concentration at various depths could be nicely modelled by Fick's law, it follows that this process is diffusion limited. In this respect, fluorescence recovery after photobleaching (FRAP) measurements revealed that the diffusion coefficient of oxygen in gelled media was only affected to a very small extent by the presence of up to 2% (w/v) agar. In a final experiment, explants of Ficus benjamina were cultured on a rooting medium. As the oxygen concentration in the gelled medium was not significantly affected by the presence of the biological material, it was concluded that the oxygen uptake by explants from gelled media is negligibly small and hence cannot be considered as being a growth-limiting factor during in vitro micropropagation. This revised version was published online in June 2006 with corrections to the Cover Date.     

始红蝽呼吸代谢的季节变化及对温度的适应性

为阐明始红蝽呼吸代谢的季节变化规律,探讨其对温度适应的呼吸代谢策略,运用多通道昆虫呼吸仪逐月测定始红蝽自然种群的O_2吸收率、CO_2释放率、代谢率和呼吸商。基于预实验获得始红蝽完成一次完整的呼吸代谢活动的时间为90 s,故每90 s记录1次数据。结果表明,始红蝽的呼吸代谢存在明显的季节变化。冬季种群(12—2月)呼吸代谢水平最弱,O_2吸收率、CO_2释放率和代谢率的平均值依次为(3.16±1.02)×10~(-5)mL/min、(2.09±0.78)×10~(-5)m L/min、(0.11±0.08)×10-3mLg~(-1)min~(-1);春季种群(3—5月)呼吸代谢水平迅速增加,夏季种群(6—8月)呼吸代谢水平最高,O_2吸收率、CO_2释放率和代谢率的平均值分别为(33.68±2.68)×10~(-5)mL/min、(36.00±3.07)×10~(-5)m L/min、(18.16±0.83)×10-3m Lg~(-1)min~(-1);秋季种群的呼吸代谢水平开始减弱并持续到冬季。始红蝽O_2吸收率、CO_2释放率和代谢率的值与栖息地的地表温度成正相关(r_1=0.914,r_2=0.909,r_3=0.836);春、夏、秋3个季节始红蝽以糖类物质作为呼吸代谢消耗的底物,冬季则消耗脂类物质。研究得出,随季节温度变化,始红蝽不仅能够调节呼吸代谢水平的强弱以提高自身对温度的适应能力,还可通过调整呼吸代谢消耗的底物类型以最大程度降低消耗,这对维持始红蝽种群数量和扩大其地理分布具有重要的生态学意义。     

Latency of oxygen toxicity of the central nervous system in rats as a function of carbon dioxide production and partial pressure of oxygen

Oxygen toxicity of the central nervous system (CNS) can occur as convulsions and loss of consciousness, with no warning symptoms. A quantitative study of the effect of metabolic rate on sensitivity to oxygen toxicity was made in the rat. A group of 19 rats were exposed (126 exposures) to 12 combinations of four pressures (456, 507, 608 and 709 kPa) and three ambient temperatures (15, 23 and 29°C) until the appearance of the first electrical discharge (FED) preceding clinical convulsions. Carbon dioxide production (V˙CO₂) was also measured. A thermoneutral zone (mean V˙CO₂ 0.87 ml · g⁻¹ · h⁻¹) existed between the temperatures of 24 and 29°C; at temperatures lower than this, the metabolic rate increased by 1.2 to 4 times the resting level. Latency of FED decreased linearly with the increase in V˙CO₂ at all four oxygen pressures. The slopes (absolute value) and intercepts decreased with the increase in oxygen pressure. This linear relationship made possible the derivation of an equation which described latency of the FED as a function of both oxygen pressure and metabolic rate. Various environmental and other physiological factors that have been said to influence sensitivity to CNS oxygen toxicity, enhancing the effect of the partial pressure of oxygen, can be explained by their effect on metabolic rate. It is suggested that in situations where there is a risk of oxygen toxicity of the CNS, that risk would be reduced by a lower metabolic rate. Accepted: 4 May 1998     

温度、盐度对强壮箭虫耗氧率和窒息点的影响

研究了不同温度、盐度下强壮箭虫的耗氧率和窒息点.结果表明:温度和盐度均对强壮箭虫的耗氧率和比耗氧率有显著影响.试验温度在5℃-25℃,强壮箭虫个体耗氧率(IO)和比耗氧率(SO)开始随温度的升高而升高,之后呈明显下降趋势.其回归方程分别为y=0.0058x3 -0.2956x2+4.415x-8.7816(R2=0.99,P＜0.05)和y=0.0011x3 -0.0546x2+0.8161x-1.6232(R2=0.99,P＜0.05),数值分别为6.30～11.71μg·ind-1·h-1和1.22 ～2.16μg· mg-1·h-1,窒息点为4.18～6.87 mg·L-1.盐度10 ～40条件下,IO和SO随盐度的升高逐渐下降,回归方程分别为y=-0.0068x2 -0.1412x+21.702(R2=0.89,P＜0.05)和y=-0.0013x2-0.0261x+4.0114( R2 =0.89,P＜0.05),数值分别为4.98～17.73μg ·ind-1·h-1和0.92～3.56 μg·mg-1 ·h-1,窒息点为4.02～6.24 mg·L-1.对强壮箭虫与其他水生动物的耗氧率和窒息点进行比较得出,强壮箭虫是一种狭氧性浮游动物.     

温度、盐度和体长对西藏拟溞耗氧率的影响

在实验室内研究了盐度(S=5、10、15、20和25)、温度(T=3、8、14、20和22℃)和体长(L=0.83、1.25、1.49、1.87和2.42mm)对西藏拟耗氧率的影响。结果表明,在试验盐度内该的个体耗氧率(IO)和比耗氧率(SO)均随盐度(S)升高而升高,其回归方程分别为IO=0.0014S 0.0126和SO=0.115S0.5612,数值范围为0.02～0.045μg/(indh)和0.31～0.67μg/(mg·h)。个体耗氧率和比耗氧率在温度试验中有同样的趋势,回归方程分别为IO=0.0049e0.1574T和SO=0.0678e0.1605T,数值分别为0.0076～0.13μg/(ind·h)和0.10～1.71μg/(mg·h)。体长试验中个体耗氧率随体长增大而增大,而比耗氧率则降低,回归方程分别为:IO=0.0545L2.5962和SO=-0.2059L 0.7908,数值范围为0.036～0.68μg/(ind·h)和0.38～0.63μg/(mg·h)。讨论了盐度、温度和体长对西藏拟耗氧率的影响。     

Oxygen transfer kinetics of riboflavin fermentation by Ashbya gossypii in agitated fermentors

Effects of agitation and aeration rates on volumetric oxygen transfer coefficient and oxygen uptake rate of a riboflavin broth containing Ashbya gossypii were investigated in three batch, sparged, and agitated fermentors having the working volumes of 0.42, 0.85, and 2.5 l. The change of oxygen uptake rate with time at 250 rev min⁻¹ stirring and vvm aeration rates was shown. The volumetric oxygen transfer coefficients and maximum oxygen uptake rates obtained have been correlated to mechanical power inputs per unit volume of the fermentation broth and the superficial air velocities.     

Nitrifying bacterial growth inhibition in the presence of algae and cyanobacteria

Nitrifying bacteria, cyanobacteria, and algae are important microorganisms in open pond wastewater treatment systems. Nitrification involving the sequential oxidation of ammonia to nitrite and nitrate, mainly due to autotrophic nitrifying bacteria, is essential to biological nitrogen removal in wastewater and global nitrogen cycling. A continuous flow autotrophic bioreactor was initially designed for nitrifying bacterial growth only. In the presence of cyanobacteria and algae, we monitored both the microbial activity by measuring specific oxygen production rate (SOPR) for microalgae and cyanobacteria and specific oxygen uptake rate (SOUR) for nitrifying bacteria. The growth of cyanobacteria and algae inhibited the maximum nitrification rate by a factor of 4 although the ammonium nitrogen fed to the reactor was almost completely removed. Terminal restriction fragment length polymorphism (T‐RFLP) analysis indicated that the community structures of nitrifying bacteria remained unchanged, containing the dominant Nitrosospira, Nitrospira, and Nitrobacter species. PCR amplification coupled with cloning and sequencing analysis resulted in identifying Chlorella emersonii and an uncultured cyanobacterium as the dominant species in the autotrophic bioreactor. Notwithstanding their fast growth rate and their toxicity to nitrifiers, microalgae and cyanobacteria were more easily lost in effluent than nitrifying bacteria because of their poor settling characteristics. The microorganisms were able to grow together in the bioreactor with constant individual biomass fractions because of the uncoupled solids retention times for algae/cyanobacteria and nitrifiers. The results indicate that compared to conventional wastewater treatment systems, longer solids retention times (e.g., by a factor of 4) should be considered in phototrophic bioreactors for complete nitrification and nitrogen removal. Biotechnol. Bioeng. 2010;107: 1004–1011. © 2010 Wiley Periodicals, Inc.     

Oxygen uptake rates in cultured rat hepatocytes

One potential treatment of acute liver failure involves the use of an extracorporeal device composed of functional hepatocytes. A major issue in the design of such a large-scale device is providing the hepatocytes with a sufficient supply of oxygen and other nutrients. In this study, we have designed and characterized a simple perfusion system hepatocytes using this system. The OUR of hepatocytes was determined during the first day after seeding on a single collagen gel and during the long-term stable culture after the addition of a top layer of collagen. The OUR increased to 20.7 +/- 0.57 pmol/sec/mug DNA during the first 13 hours of culture on a single collagen gel, while during the next 11 hours, the OUR declined to 10.6 +/- 1.5 pmol/sec/mug DNA. In parallel with the increase in OUR during the first 10 hours, we observed significant cell spreading, suggesting that the oxygen supply to the cells may be critical for the spreading and adaptation of the anchorage-dependent hepatocytes following isolation. Addition of a top layer of collagen to hepatocyte cultures for 24 hours of culture on a single collagen layer resulted in a stable OUR for 15 days. These results indicate that OUR of hepatocytes in culture may vary depending on the phase of culture (i.e., early vs. late) and on the extracellular environment. (c) 1992 John Wiley & Sons, Inc.