生物反应器技术应用于植物组织培养的研究进展

生物反应器技术是植物组织大规模培养的重要组成部分,本文对植物组织培养生物反应器技术的应用研究进展进行了较详细的论述,涉及植物悬浮细胞,固定化植物细胞和植物器官培养等,并对今后的发展方向提出了参考意见。     

生物氧化浸矿反应器的研究进展

生物氧化浸出技术工业应用和发展将过程工程的研究和高效生物浸矿反应器的研制推上一个重要位置。综合分析了搅拌槽式和气升式这两种工业常用生物浸出反应器,指出其不完全适用于生物氧化浸矿,评述了近十年来生物氧化浸矿反应器的现状和发展趋势,总结了反应器设计的一般指导原则,介绍了几种最具开发潜力的反应器。     

生物氧化反应器的设计与应用

生物氧化是难处理金矿石预处理工艺技术之一。介绍了国内外生物氧化技术现状及特点,详述了CGACB型生物氧化反应器的配置、壳体、搅拌系统、鼓风供气系统及换热系统、消泡系统等基本结构与设计。应用实践表明：CGACB型生物氧化反应器结构简单,安装方便,不仅搅拌均匀、温度扩散和气体弥散效果好,而且能耗小。     

紫球藻的光生物反应器培养

利用光生物反应器就碳源及其供给形式、光强和反应器的操作条件等影响紫球藻生长的因素进行了研究。结果表明,反应器良好的液体循环速率有助于培养液中每个细胞对光能的吸收利用使紫球灌细胞可以获得较大的生长速度,利用ＣＯ２为碳儿得比利用ＮａＨＣＯ３更大的生长速度,有效地提高了紫球藻的生物量产量,在本实验条件下,细胞的生长速度和生物量产率分别达到了０．９５２ｄ、４２．３１ｇ／（ｍ＾２．ｄ）。     

一种新型生物氧化反应器的研制

根据生物氧化的工艺特点和目前工业应用的生物氧化反应器存在的问题,并结合实验室试验数据,提出了外置充气系统的创新结构,研制了一台30m3新型生物氧化反应器。工业试验结果表明,在给矿性质完全相同、精矿指标基本一样的条件下,新型生物氧化反应器的生产效率提高了约30%。     

升流式生物反应器处理含锰废水的中试研究

研究目的在于提供一种处理含锰废水的新方法。采用生物反应器的技术处理锰矿企业排放的含锰废水。在优化的环境及技术条件下,对原水锰浓度在3000mg／L左右的废水的平均去除效率可达87％以上。利用微生物处理含锰废水成本低,具有良好的经济效益,是传统方法以外的处理含锰废水的新思路。     

生物氧化反应器搅拌轴断轴原因探析

生物氧化反应器立式机械搅拌器实现气液固三相间的均匀混合,加速传热和传质过程。介绍了搅拌轴的结构及作业工况,分析了断轴受力和焊接对材质的影响以及多种腐蚀、设计缺陷、工作磨损、误操作对断轴的影响。通过对断轴原因分析与掌握,减少了工程应用中断轴现象,从而提高设备的使用寿命。     

难处理硫化矿生物湿法冶金研究进展Ⅱ氧化机制、强化细菌浸出与生物反应器设计

着重评述了难处理硫化矿的矿物结构、性质及表面特征与各种电化学因素、细菌氧化机制与难处理硫化矿细菌强化浸出、浸矿基因工程菌以及生物反应器等方面的研究进展。指出缩短生物氧化周期长是细菌强化氧化研究的核心；将细菌繁殖和矿物氧化两个过程分开进行的“分离器-发生器”设备设计，是一值得推广的高效生物反应器。     

生物制剂强化膜生物反应器处理生活污水

生物制剂对污水具有很强的适应性和广泛性,在污水处理方面有独特的效果.生物制剂与中空纤维膜生物反应器相结合,在一定运行条件下,反应器内COD,氨氮和总磷的去除率分别达到90%,99%和92%,其效果明显优于普通膜生物反应器.     

常规和新型生物反应器氧化渣氰化浸出试验

新型生物反应器采用外置充气系统的创新结构,在给矿量比为1.2∶1的情况下,新型生物反应器中的硫化物氧化情况略优于常规生物反应器,给矿量比分别为1.1∶1和1.2∶1的情况下,新型生物反应器生物氧化渣的金氰化浸出率比常规生物反应器分别提高了0.5~1.3和0.2~0.5个百分点。     

Treatment of MTBE-Contaminated Water in Fluidized Bed Bioreactor

Methyl tertiary-butyl ether (MTBE) biodegradation was evaluated in a laboratory-scale granular activated carbon (GAC)-based fluidized bed bioreactor system. The reactor was operated in seven distinct phases during which the MTBE loading rate, hydraulic retention time, cocontaminant loading [butyl, toluene, ethylbenzene, and xylene (BTEX) and tertiary-butyl alcohol (TBA)] and temperature were varied. The reactor was able to treat MTBE to less than 20 ug/L at 25°C and total organic carbon (TOC) loading rates between 0.01 and 1.1 kg/m3 of expanded GAC bed per day (kg/m3?day). Net biomass yield in the reactor under high loading conditions was approximately 0.55 g of total suspended solids (TSS) per gram of TOC consumed. This high yield under the higher loading rates necessitated that biomass be removed from the reactor to control bed expansion. At a loading rate of 1.5 kg/m3?day, MTBE effluents exceeded 20 ug/L. Reactor performance decreased as the reactor temperature was reduced from 25 to 15°C, but even at the lower temperatures MTBE removal efficiency exceeded 99%. Methyl tertiary-butyl ether treatment efficiency was not affected by the addition of TBA or BTEX under the conditions evaluated. Results of this study demonstrate that fluid bed bioreactors inoculated with an appropriate microbial culture can efficiently treat MTBE-contaminated water.     

Strategy for Complete Nitrogen Removal in Bioreactor Landfills

Waste acclimation and batch microcosm studies containing digested municipal solid waste were conducted at different temperatures (22, 35, and 45°C) and gas-phase oxygen concentrations (0.7–100%, by volume) to provide guidance for field-scale implementation of in situ nitrogen removal processes. Results demonstrate that in situ ammonia–nitrogen is feasible in decomposed aerated solid waste environments at the gas-phase oxygen concentrations and temperatures evaluated and the potential for simultaneous nitrification and denitrification in field-scale bioreactor landfills is significant due to the presence of both aerobic and anoxic areas. Small amounts of oxygen were found sufficient for nitrification/ammonia removal to proceed, although removal rates increase with oxygen concentration. Laboratory results suggest field-scale implementation of in situ nitrogen removal occur in small dedicated treatment zones containing previously degraded waste (later in the life of a bioreactor landfill). Model simulations indicate removal of ammonia–nitrogen to low levels can occur with relatively short aeration depths (depth estimates ranged from 1.6 to 7.2?m below the point of leachate injection). Field-scale verification of these depth estimates is required prior to routine acceptance.     

Mammary ductal carcinoma in situ with microinvasion

BACKGROUND: The natural history of patients with intraductal carcinoma (DCIS) and microinvasion is poorly defined, and the clinical management of these patients, with particular reference to management of the axilla, has been controversial. Previous studies of this lesion have used varied and/or arbitrary criteria for the evaluation of microinvasion. METHODS: Thirty-eight DCIS lesions with microinvasion (n=29) or probable microinvasion (n=9), diagnosed during the period 1980-1996, were retrospectively analyzed after cases not treated with mastectomy and axillary lymph node dissection were excluded. Microinvasion was defined as a single focus of invasive carcinoma < or = 2 mm or up to 3 foci of invasion, each < or =1 mm in greatest dimension. RESULTS: The patients were all females with a mean age of 56.4 years. DCIS was of comedo (n=31) or papillary (n=7) subtype. Microinvasion was often associated with an altered, desmoplastic stroma (55%) or a lymphocytic infiltrate (39%). The foci of microinvasion ranged from 0.25 to 1.75 mm (mean, 0.6 mm), with an aggregate mean size of 1.1 mm (range, 0.25-2.25 mm). Foci of microinvasion, ranging from 1 to 3 (mean, 1.7), were adjacent to DCIS in 95.3% of cases. The extent of DCIS did not correlate with the number of foci of microinvasion. Axillary lymph node dissections yielded a mean of 19.3 lymph nodes (range, 7-38), and all lymph nodes were negative for metastasis. None of 33 patients, followed for a mean of 7.5 years (range, 1.0-14.4 years), developed local recurrence or metastasis. CONCLUSIONS: The cases of microinvasive carcinoma examined in this study, as defined above, were not associated with axillary lymph node metastases and appeared to be associated with an excellent prognosis. Further study is indicated to determine the appropriate management and long term prognosis of patients with this lesion.     

Optimization of Biological Nutrient Removal in a Membrane Bioreactor System

The main objective of the present study is to develop a modified membrane bioreactor (MBR) system for the treatment of municipal wastewater for the enhanced biological removal of nitrogen (N) and phosphorus (P) simultaneously with the ultimate goal of optimizing the two processes. The paper will address the implementation and optimization of the MBR process with respect to biological characteristics, operational performance, and effluent quality. The system utilizes anoxic P uptake and nitrification–denitrification in a MBR. Following optimization, the system achieved 99% chemical oxygen demand (COD), 98.4% NH3–N, 77.5% TN, and 96.3% P removal producing effluent biological oxygen demand, COD, NH3–N,NO3–N,NO2–N, and P of <3, 3, 0.4, 5.8, 0.050, and 0.18?mg/L, respectively.     

Cr(VI) Reduction in Continuous-Flow Coculture Bioreactor

A continuous-flow coculture bioreactor with a phenol-degrading organism, Pseudomonas putida DMP-1, and a Cr(VI)-reducing species, Escherichia coli ATCC 33456, was developed for simultaneous removal of phenol and Cr(VI). Phenol was the sole energy and carbon source added to the coculture along with a basal medium and hexavalent chromium. The coculture bioreactor was operated under three liquid detention times (0.20, 0.31, and 0.52 days) with phenol and Cr(VI) loadings ranging from 2,500 to 8,200 mg∕L∕day and 4.5–33.2 mg∕L∕day, respectively. After 279 days of continuous operation, eight quasi-steady-state operation conditions were obtained with near complete removal of phenol and Cr(VI). Elevated levels of Cr(VI) and phenol were observed in the effluent under a high influent Cr(VI) concentration (16 mg∕L) or a short liquid detention time (0.20 days). The system recovered from Cr(VI) toxicity after influent Cr(VI) level was reduced. Chromium mass balance analysis revealed that nearly all of the influent Cr(VI) was reduced to Cr(III) in the coculture bioreactor through biological activity. Spectra of UV-Vis and mass spectrometers suggested that phenol metabolites produced by P. putida were utilized by E. coli.     

新型微生物反应器氧化金精矿的工业试验

采用自主研发的700m3新型生物反应器开展金精矿预氧化平行对比工业试验,在给与金精矿一致、控制硫化物氧化程度基本一致的条件下,新型生物反应器比传统生物反应器气耗降低17.8%,效率提高20%。     

Simultaneous Removal of Phenol and Nitrate in an Anaerobic Bioreactor

Phenol and nitrate are two major pollutants simultaneously occurring in several industrial wastewaters. In this study, a 110-day gradual enrichment of an anaerobic culture has been carried out at 25°C in an anaerobic bioreactor for continuously treating a synthetic wastewater containing 600?mg/L phenol and 430?mg/L?NO3?–N. The results showed that the enriched culture can utilize phenol as a sole electron donor and nitrate as a sole electron acceptor. At the end of the enrichment (on Day 110), 93.3% of phenol and 98.0% of NO3?–N were simultaneously removed at a hydraulic retention time of 20.25?h in the anaerobic bioreactor. The removal of 1?g?NO3?–N required about 3.19?g chemical oxygen demand as the electron donor. Batch tests further revealed that cresol, nitrophenol, and monochlorinated phenol (MCP) could exert detrimental influences on the treatment abilities of the enriched culture. However, the inhibitory effects of cresol were impermanent, as compared to those of nitrophenol and MCP. In order to operate the anaerobic bioreactor steadily, high concentrations of cresol should be diluted before being fed while the existence of nitrophenol and MCP in the bioreactor should be avoided.     

Leachate Recirculation in Bioreactor Landfills Using Geocomposite Drainage Material

The key purpose of this study was to test the use of a permeable blanket made up of a geocomposite drainage layer (GDL) for leachate recirculation in municipal solid waste (MSW) landfills and to predict the observed leachate travel in the blanket using a numerical model. A 34?m long by 12?m wide permeable blanket made up of GDL was constructed at an active MSW landfill located in Michigan. Leachate was injected in the GDL using a perforated pipe placed centrally above the GDL along its length. Moisture content sensors, pressure transducers, thermistors, thermocouple sensors, and a vertical load sensor were embedded immediately below the GDL blanket to monitor the flow of injected leachate. After the blanket was covered with waste, leachate was injected into the blanket at rates ranging from 0.9 to 2.6?m3/h per meter length of the blanket. Data collected from the embedded sensors indicated that the injected leachate traveled at rates ranging from 5 to 18?m/h through the blanket depending upon the leachate injection rate. Only pressure transducers and thermistors were consistently able to detect migration of injected leachate once the blanket got saturated. Moisture content sensors could not register any change in readings once the blanket became saturated. Leachate injection pressure monitored over a period of about 12 months indicated no signs of clogging of the blanket. The leachate pressures measured immediately below the blanket were less than the net leachate injection pressure indicting that there was a head loss in the GDL blanket. Numerical modeling of liquid flow in the blanket indicated that predicted leachate travel in the blanket was consistent with the field data for assumed values of the waste hydraulic conductivity. In the absence of measured representative hydraulic properties of the waste, absolute verification of the field data was not possible.     

Membrane Bioreactor for Cometabolism of Trichloroethene Air Emissions

Biofilters have been of limited use for cometabolism of chlorinated organic compounds, such as trichloroethene (TCE), due to enzyme inhibition or toxicity effects. A hollow fiber membrane bioreactor was investigated that involves a bundle of polypropylene fibers through which volatile organic compound contaminated air passes. The fibers are immersed in a recirculating nutrient/cosubstrate solution. Batch culture experiments were performed with a mixed culture that could cometabolize TCE with toluene as a primary substrate. No inhibition or inquiry to the toluene degrading ability was observed at up to 15 mg L?1 toluene or up to 1.5 mg L?1 TCE. The culture was inoculated into the hollow-fiber membrane bioreactor. Initially toluene was supplied to the reactor to build a sufficient biomass density on the fibers. After steady-state toluene removal was achieved, TCE was added to the gas phase of the reactor. Toluene was added in three different configurations: (1) As a mixture with TCE in the gas phase; (2) by pulsing into the gas phase; or (3) to the liquid phase. This paper investigates which reactor configuration is most favorable for cometabolism of toluene and TCE.     

Use of Membrane Bioreactor for Biodegradation of MTBE in Contaminated Water

An ultrafiltation membrane bioreactor was evaluated for biodegradation of methyl tert-butyl ether (MTBE) in contaminated water. The system was fed 5 mg/L MTBE in granular activated carbon (GAC) treated Cincinnati tap water containing ample buffer and nutrients. Within 120 days the culture had adapted to membrane operational conditions and was consistently achieving greater than 99.95% biological removal of both MTBE and tert-butyl alcohol. This condition was steadily maintained for the next 200 days of study. Effluent dissolved organic carbon values remained at or below concentrations of the feed GAC treated tap water alone. An increase in biomass concentration as measured by volatile suspended solids was observed to correlate with an increase in MTBE removal efficiency. Some operational observations, including fouling, recovery from an accident, and overall performance, are described.