固定化微生物脱除工业酸性废气中H_2S的研究

以H 2软性填料作为氧化亚铁硫杆菌的固定化载体 ,构成了固定床生物反应器。在一定操作条件下 ,考察了固定床生物反应器对Fe2 +的氧化速率 ,最大可达 7.6 7g/ (L·h)。并对固定床生物反应器运行中在载体表面形成的络合物进行了研究 ,X射线衍射证明此络合物为黄钾铁矾 [KFe3(SO4 ) 2 (OH) 6]。     

Exit effect on hydrodynamics of the internal circulating fluidized bed riser

This is the first time an extensive investigation has been carried out regarding the effects of riser exit geometry on pressure drop and solid behaviour inside the Internal Circulating Fluidized Bed (ICFB) riser, using different riser exit geometries at several operating conditions.The Radioactive Particle-Tracking (RPT) technique was used for solid concentration measurements and solid residence time distribution at the exit zone. Experiments were conducted using Geldart B particles, in the gas superficial velocity range of 4 to 10 m/s. Axial solid hold-up, solid residence time distribution in the exit zone, and the reflux ratio factor k_m, (defined earlier by [E.H. Van der Meer, R.B. Thorpe, J.F. Davidson, Flow patterns in the square cross-section riser of a circulating fluidized bed and the effect of riser exit design, Chem. Eng. Sc. 55 (19) (2000) 4079-4099]), were the main criteria used to investigate the impact of gas-solid separator devices implemented at the ICFB riser exit.Solid residence time distribution results and axial solid hold-up profiles provided clear evidence that the separator device at the riser exit strongly influences the hydrodynamic structure of the ICFB riser. The V-shaped riser exit geometry was found to be the optimum of all the configurations studied.     

Simultaneous sulfide and acetate oxidation under denitrifying conditions using an inverse fluidized bed reactor

BACKGROUND: Simultaneous removal of sulfur, nitrogen and carbon compounds from wastewaters is a commercially important biological process. The objective was to evaluate the influence of the CH₃COO^?/NO₃^? molar ratio on the sulfide oxidation process using an inverse fluidized bed reactor (IFBR). RESULTS: Three molar ratios of CH₃COO^?/NO₃^? (0.85, 0.72 and 0.62) with a constant S^2?/NO₃^? molar ratio of 0.13 were evaluated. At a CH₃COO^?/NO₃^? molar ratio of 0.85, the nitrate, acetate and sulfide removal efficiencies were approximately 100%. The N₂ yield (g N₂ g^?1 NO₃^?‐N consumed) was 0.81. Acetate was mineralized, resulting in a yield of 0.65 g inorganic‐C g^?1 CH₃COO^?‐C consumed. Sulfide was partially oxidized to S⁰, and 71% of the S^2? consumed was recovered as elemental sulfur by a settler installed in the IFBR. At a CH₃COO^?/NO₃^? molar ratio of 0.72, the efficiencies of nitrate, acetate and sulfide consumption were of 100%, with N₂ and inorganic‐C yields of 0.84 and 0.69, respectively. The sulfide was recovered as sulfate instead of S⁰, with a yield of 0.92 g SO₄^2?‐S g^?1 S^2? consumed. CONCLUSIONS: The CH₃COO^?/NO₃^? molar ratio was shown to be an important parameter that can be used to control the fate of sulfide oxidation to either S⁰ or sulfate. In this study, the potential of denitrification for the simultaneous removal of organic matter, sulfide and nitrate from wastewaters was demonstrated, obtaining CO₂, S⁰ and N₂ as the major end products. Copyright © 2008 Society of Chemical Industry     

Effect of sampling density on the measurement of stream condition indicators in two lowland Australian streams

There is widespread application of indicators to the assessment of environmental condition of streams. These indicators are intended for use by managers in making various comparative and absolute assessments and often have a role in resource allocation and performance assessment. Therefore, the problem of formally defining confidence in the results is important but difficult because the sampling strategies used are commonly based on a compromise between the requirements of statistical rigour and the pragmatic issues of access and resources. It is rare to see this compromise explicitly considered and consequently there is seldom quantification of the uncertainty that could affect the confidence a manager has in an indicator. In this paper, we present a method for quantitatively assessing the tradeoffs between sampling density and uncertainty in meeting various monitoring objectives. Assessments using judgement‐based representative reaches are shown to be unreliable; instead a sampling approach is recommended based on the random selection of measuring sites. A detailed dataset was collected along two streams in Victoria, Australia, and the effect of sampling density was assessed by subsampling from this dataset with precision related to the number of sites assessed per reach length and the intensity of the sampling at each site. The sampling scheme to achieve a given precision is shown to depend on the monitoring objective. In particular, three objectives were considered: (1) making a baseline assessment of current condition; (2) change detection; and (3) detection of a critical threshold in condition. Change detection is shown to be more demanding than assessing baseline condition with additional sampling effort required to achieve the same precision. Sampling to detect a critical threshold depends on nominating acceptable values of Type I and II error and the size of the effect to be detected. Copyright © 2006 John Wiley & Sons, Ltd.     

Characterization of dynamic behavior of a spout-fluid bed with Shannon entropy analysis

Differential pressure fluctuation time series were obtained at different locations in a two-dimensional spout-fluid bed with a cross section of 300 × 30 mm and height 2000 mm. Shannon entropy analysis of differential pressure fluctuations was developed to characterize the dynamic behavior. Effects of two important operating parameters (spouting gas velocity and fluidizing gas flow rate) on the Shannon entropy were examined. It was demonstrated that a spout-fluid bed at a high spouting gas velocity or fluidizing gas flow rate was a deterministic chaos system since the Shannon entropies at all bed locations increased sharply and asymmetric unstable flows occurred. Shannon entropies were found to be significantly different at various bed locations. Shannon entropies of different flow regimes were distinct, so they were used to identify the flow regimes. The results show that the Shannon entropy helps to grasp the complex characteristics of dynamic behavior in spout-fluid beds.     

河流工程中的图形绘制与处理

在河流工程领域,不管是实体模型还是数学模型,对多样化的数据和丰富多彩的图形的需要越来越强烈,旧的表现形式已经被层出不穷的新的、信息量大而且地位高的2D、3D图形所取代,因此在工程中合理地选择绘图方式和开发软件就变得十分重要。以实际操作经验为基础,从基本操作类到二次开发类再到高端图形图像开发类,详细地讨论了在河流工程中各种图形的绘制和处理方法选择,具有一定参照价值。     

2,4,6‐Trichlorophenol and phenol removal in methanogenic and partially‐aerated methanogenic conditions in a fluidized bed bioreactor

A fluidized bed bioreactor (FBBR) was operated for more than 575 days to remove 2,4,6‐trichlorophenol (TCP) and phenol (Phe) from a synthetic toxic wastewater containing 80 mg L^?1 of TCP and 20 mg L^?1 of Phe under two regimes: Methanogenic (M) and Partially‐Aerated Methanogenic (PAM). The mesophilic, laboratory‐scale FBBR consisted of a glass column (3 L capacity) loaded with 1 L of 1 mm diameter granular activated carbon colonized by an anaerobic consortium. Sucrose (1 g COD L^?1) was used as co‐substrate in the two conditions. The hydraulic residence time was kept constant at 1 day. Both conditions showed similar TCP and Phe removal (99.9 + %); nevertheless, in the Methanogenic regime, the accumulation of 4‐chlorophenol (4CP) up to 16 mg L^?1 and phenol up to 4 mg L^?1 was observed, whereas in PAM conditions 4CP and other intermediates were not detected. The specific methanogenic activity of biomass decreased from 1.01 ± 0.14 in M conditions to 0.19 ± 0.06 mmolCH₄ h^?1 gTKN^?1 in PAM conditions whereas the specific oxygen uptake rate increased from 0.039 ± 0.008 in M conditions to 0.054 ± 0.012 mmolO₂ h^?1 gTKN^?1, which suggested the co‐existence of both methanogenic archaea and aerobic bacteria in the undefined consortium. The advantage of the PAM condition over the M regime is that it provides for the thorough removal of less‐substituted chlorophenols produced by the reductive dehalogenation of TCP rather than the removal of the parent compound itself. Copyright © 2005 Society of Chemical Industry     

Ozonation of CI Reactive Black 5 using rotating packed bed and stirred tank reactor

This study investigates the ozonation of CI Reactive Black 5 (RB5) by using the rotating packed bed (RPB) and completely stirred tank reactor (CSTR) as ozone contactors. The RPB, which provides high gravitational force by adjusting the rotational speed, was employed as a novel ozone contactor. The same ozone dosage was separately introduced into either the RPB or the CSTR for the investigation, while the experimental solution was continuously circulated within the apparatus consisting of the RPB and CSTR. The decolorization and mineralization efficiencies of RB5 in the course of ozonation are compared for these two methods. Moreover, the dissolved and off‐gas ozone concentrations were simultaneously monitored for the further analysis. As a result, the ozone mass transfer rate per unit volume of the RPB was significantly higher because of its higher mass transfer coefficient and gas–liquid concentration driving force. Furthermore, ozonation kinetics was found to be independent of the gravitational magnitude of an ozone gas–liquid contactor. Therefore, the results suggest employing RPBs as ozone‐contacting devices with the advantage of volume reduction. The experimental results, which can be used for further modeling of the ozonation process in the RPB, also show the requirement of correct design for the RPB. Consequently, the present study is useful for the understanding of practical application of RPBs. Copyright © 2004 Society of Chemical Industry     

高温皂碱练与酶制剂练精干绵性能比较

通过测试比较，分析了酶制剂练、高温皂碱练由精练方法不同而造成纤维在微观、外观、机械、吸湿及电学等方面的异同点。提出酶制剂练对提高纤维梳折、提高成纱品质、提高劳动生产率、降低工人劳动强度等方面均优于高温皂碱练，是精练工程改造方向之一。     

河口水流、波浪、潮流、泥沙、河床变形二维数学模型

根据河口“波浪掀沙，潮流输沙”的泥沙运动机制，引入“波浪幅射应力”反应波浪对水体和泥沙的驱动力．考虑波浪对底部泥沙作用力、波浪对水流挟沙能力的影响及风场对水流和泥沙运动的影响．同时考虑泥沙粒径大小、水体含盐度、含沙量及水流紊动程度等因素对絮凝沉速的影响．用ＡＤＩ算法求解沿水深平均方程，破开算子法解悬移质不平衡输沙方程及河床变形方程，引入通度概念处理岸滩不规则边界，建立河口水流、波浪、潮流、泥沙、河床变形二维数学模型．通过实测资料及卫星摇感图像对所建数学模型进行检验，表明它可以较好地预测河口泥沙的运动