一种新型反应器——生物气射流循环厌氧流化床的启动与运行特性

A novel anaerobic reactor, jet biogas inter-loop anaerobic fluidized bed (JBILAFB), was designed and constructed. The start-up and performance of the reactor was investigated in the process of artificial glucose waste-water treatment. With the wastewater recycle ratio of 2.5:1, the recycled wastewater with biogas could mix sludge and wastewater in the JBILAFB reactor completely. The start-up of the JBILAFB reactor could be completed in less than 70 d through maintenance of hydraulic retention time (HRT) and stepwise increase of feed total organic carbon (TOC) concentration. After the start-up, with the volumetric TOC loadings of 14.3 kg·m-3·d-1 the TOC removal ra-tio, the effluent pH, and the volatile fatty acids (VFA)/alkalinity of the JBILAFB reactor were more than 80%, close to 7.0 and less than 0.4, respectively. Moreover, CH4 was produced at more than 70% of the theoretical value. The reactor exhibited high stability under the condition of high volumetric TOC loading. Sludge granules in the JBI-LAFB reactor were developed during the start-up and their sizes were enlarged with the stepwise increase of volu-metric TOC loadings from 0.8 kg·m-3·d-1 to 14.3 kg·m-3·d-1. Granules, an offwhite color and a similar spherical shape, were mainly comprised of global-like bacteria. These had good methanogenic activity and settleability,which were formed probably through adhesion of the bacteria. Some inorganic metal compounds such as Fe, Ca,Mg, Al, etc. were advantageous to the formation of the granules.     

厌氧-好氧生物处理工艺用于去除水中杀虫剂(英文)

The biodegradability of wastewater containing priority pollutant pesticideVydine or triadimenol(C14H18CLN3O2) in different bio-reactor configurations was investigated.Two laboratory scale biological reactors were employed:one reactor under aerobic condition and the other under anaerobic condition.The aerobic reactor was operated at an ambient temperature(22±2) °C,while the anaerobic reactor was run in the lower mesophilic range(30±2) °C.The effect of pesticide concentration,hydraulic retention time(HRT) ,and co-substrate on the treatment process was explored,using glucose as a supplemental carbon substrate.More than 96%pesticide was removed after an acclimation period of approximately 172 d(aerobic) and 230 d(anaerobic) .The aerobic reactor achieved complete Vydine utilization at feed concentrations up to 25 mg·L-1 .On the other hand,the anaerobic reactor was able to degrade 25 mg·L-1 of Vydine.Moreover,glucose was consumed first throughout the experiment in a sequential utilization pattern.The combination of anaerobic and aerobic biological processes yielded higher biomass concentration and lower retention time than individual units.The biomass in the combined reactors was first acclimated with the corresponding pesticide.Then,the target pesticide,at a concentration of 25 mg·L-1,was sequentially treated in a semi batch mode in the reactors.HRT studies showed that 24 h HRT of aerobic and 12 h HRT of anaerobic were the optimum combination for the treatment of simulated wastewater containing Vydine,which produced Vydine effluent at concentration below 0.1 mg·L-1 .The optimum ratio of substrate(Vydine) to co-substrate(glucose) was 1︰100.     

去除牛粪厌氧生物转化过程中的H2S

The main aim of this research was the experimental study at lab scale to check the absorption technology for the in situ removal of H2S from biogas during anaerobic digestion process. The reagent FeCl3 was used to check the removal efficiency of H2S produced from dairy manure during anaerobic bioconversion process. The experiments were conducted under mesophilic conditions. The composition of biogas was analyzed by gas chromatography analyzer equipped with flame photometer and thermal conductivity detectors. Experimental results under the same conditions demonstrate that high concentration of H2S in the form of FeS can be removed totally from the biogas using FeCl3 dosing with in anaerobic batch digester.     

温度和游离氨对絮状和颗粒污泥硝化系统的短期影响(英文)

The short-term effects of temperature and free ammonia (FA) on ammonium oxidization were investigated in this study by operating several batch tests with two different partial nitrification aggregates, formed as either granules or flocs. The results showed that the rate of ammonium oxidation in both cultures increased significantly as temperature increased from 10 to 30 °C. The specific ammonium oxidation rate with the granules was 2-3 times higher than that with flocs at the same temperature. Nitrification at various FA concentrations and temperatures combination exhibited obvious inhibition in ammonium oxidation rate when FA was 90 mg·L 1 and tempera- ture dropped to 10 °C in the two systems. However, the increase in substrate oxidation rate of ammonia at 30 °C was observed. The results suggested that higher reaction temperature was helpful to reduce the toxicity of FA. Granules appeared to be more tolerant to FA attributed to the much fraction of ammonia oxidizing bacteria (AOB) and higher resistance to the transfer of ammonia into the bacterial aggregates, whereas in the floc system, the bacteria distributed throughout the entire aggregate. These results may contribute to the applicability of the nitrifying granules in wastewater treatment operated at high ammonium concentration.     

Advanced removal of organic and nitrogen from ammonium-rich landfill leachate using an anaerobic-aerobic system☆

A novel system coupling an up-flow anaerobic sludge blanket (UASB) and sequencing batch reactor (SBR) was introduced to achieve advanced removal of organic and nitrogen from ammonium-rich landfill leachate. UASB could remove 88.1%of the influent COD at a volumetric loading rate of 6.8 kg COD·m?3·d?1. Nitritation–denitritation was responsible for removing 99.8%of NH4+-N and 25%of total nitrogen in the SBR under alternating aerobic/anoxic modes. Simultaneous denitritation and methanogenesis in the UASB enhanced COD and TN removal, and replenished alkalinity consumed in nitritation. For the activated sludge of SBR, ammonia oxidizing bacteria were preponderant in nitrifying population, indicated by fluorescence in situ hybridization (FISH) anal-ysis. The Monod equation is appropriate to describe the kinetic behavior of heterotrophic denitrifying bacteria, with its kinetic parameters determined from batch experiments.     

Long-term nitritation performance of ammonium-rich landfill leachate☆

This study presents a biological system combined upflow anaerobic sludge bed (UASB) with sequencing batch reactor (SBR) to treat ammonium-rich landfill leachate. The start-up and operation of the nitritation at low temperatures were investigated. The synergetic interaction of free ammonia (FA) inhibition on nitrite-oxidizing bacteria (NOB) and process control was used to achieve nitritation in the SBR. It is demonstrated that nitritation was successful y started up in the SBR at low temperatures (14.0 °C–18.2 °C) by using FA inhibition coupled with process control, and then was maintained for 482 days at normal/low temperature. Although ammonia-oxidizing bacteria (AOB) and NOB co-existed within bacterial clusters in the SBR sludge, AOB were confirmed to be dominant nitrifying population species by scanning electron microscopic (SEM) observation and fluorescence in situ hybridization (FISH) analysis. This confirmation not only emphasized that cultivating the appropriate bacteria is essential for achieving stable nitritation performance, but it also revealed that NOB activity was strongly inhibited by FA rather than being eliminated altogether from the system.     

FISH技术监测硫酸盐还原反应器中碱度降低对功能微生物群落的影响

Alkalinity is one of the most important parameters that influence microbial metabolism and activity during sulfate-laden wastewater biological treatment. To comprehensively understand the structure and dynamics of functional microbial community under alkalinity changes in sulfate-reducing continuous stirred tank reactor （CSTR）, fluorescent in situ hybridization （FISH） technique was selected for qualitative and semi-quantitative analysis of functional microbial compositions in activated sludge. During 93d of bioreactor operation, the influent alkalinity was adjusted by adding sodium bicarbonate from 4000mg·L^-1 down to 3000mg·L^-1, then to 1500mg·L^-1, whereas other parameters, such as the loading rates of chenucal oxygen demand （COD） and sulfate （SO4^2-）, hydraulic retention time （HRT）, and pH value, were continuously maintained at 24g·L^-1·d^-1 and 4.8g·L^-1·d^-1, 10h,and about 6.7, respectively. Sludge samples were collected during diflerent alkalinity levels, and total Bacteria, tlae sulfate-reducing bacteria （SRB）, and four SRB genera were demonstrated with 16S ribosomal .RNA-targeted oligonucleotide probes. The results indicated that bioreactor started-up successfully in 30d. The two instances ot drop in alkalinity resulted in the fluctuation of sulfate removal rate. The diversity of SRB community showed significant shift, and the alteration of microbial community directly resulted in the corresponding statuses of bioreactor. The dominant genera during the bioreactor start-up and alkalinity drops were Desulfovibrio, Desulfobacter, Desulfovibrio, Desulfobacter, and Desulfovibrio, respectively. In addition, the acetotrophic SRB sutterecl more trom me reduction of alkalinity than the non-acetotrophic SRB. This strategy can present the functional microbial community structure during start-up and alkalinity drop stages, and provides a powerful theoretical guideline for optimization and adjustment of bioreactor, as well.     

新型惰性膜反应器中丁烷氧化脱氢制丁二烯和丁烯

The oxidative dehydrogenation of butane to butadiene and butene was studied using a conventional fixed-bed ractor (FBR), inert membrane reactor (IMR) and mixed inert membrane reactor (MIMR). When IMR and MIMR were employed, a ceramic membrane modified by partially coating with glaze was used to distribute oxygen to a fixed-bed of 24-V-Mg-O catalyst. The oxygen partial pressure in the catalyst bed could be decreased. The effect of feeding modes and operation conditions were investigated. The selectivity of C4 dehydrogenation products (bntene and bntadiene) was found to be higher in IMR than in FBR. The feeding mode with 20% of air mixing with butane in MIMR was found to be more efficient than the feeding mode with all air permeating through ceramic membrane. The MIMR gave the most smooth temperature profile along the bed.     

利用无膜微生物燃料电池废水处理并回收电能

An upflow mode membrane-less microbial fuel cell （ML-MFC） was designed for wastewater treatment. Granular graphite electrodes, which are flexible in size, were adopted in the ML-MFC. Microbes present in anaerobic activated sludge were used as the biocatalyst and artificial wastewater was tested as substrate. During the electrochemically active microbe enrichment stage, a stable power output of 536 mW.m-3 with reference to the anode volume was generated by the ML-MFC running in batch mode. The voltage output decreased from 203 mV to about 190 mV after the ML-MFC was changed from batch mode to normally continuous mode, indicating that planktonic electrochemically active bacterial strains in the ML-MFC may be carried away along with the effluent. Cyclic voltammograms showed that the attached microbes possessed higher bioelectrochemical activity than the planktonic microbes. Forced aeration to the cathode benefited the electricity generation obviously. Higher feeding rate and longer electrode distance both increased the electricity generation. The coulombic yield was not more than 20% throughout the study, which is lower than that of MFCs with membrane. It is proposed that dissolved oxygen diffused from the cathode to the anode may consume part of the substrate.     

Effect of endogenous hydrogen utilization on improved methane production in an integrated microbial electrolysis cell and anaerobic digestion: Employing catalyzed stainless steel mesh cathode

Improving the production of methane,while maintaining a significant level of process stability,is the main challenge in the anaerobic digestion process.Recently,microbial electrolysis cell (MEC) has become a promising method for CO2 reduction produced during anaerobic digestion (AD) and leads to minimize the cost of biogas upgrading technology.In this study,the MEC-AD coupled reactor was used to generate and utilize the endogenous hydrogen by employing biocompatible electrodeposited cobalt-phosphate as catalysts to improve the performance of stainless steel mesh and carbon cloth electrodes.In addition,the modified version of ADM1 model (ADM1da) was used to simulate the process.The result indicated that the MEC-AD coupled reactor can improve the CH4 yield and production rate significantly.The CH4 yield was enhanced with an average of 48％ higher than the control.The CH4 production rate was also increased 1.65 times due to the utilization of endogenous hydrogen.The specific yield,flow rate,content of CH4,and pH value were the variables that the model was best at predicting (with indexes of agreement:0.960/0.941,0.682/0.696,0.881/0.865,and 0.764/0.743) of the process with SS-meshes 80/SS-meshes 200,respectively.Employing the catalyzed SS mesh cathode,in the MEC-AD coupled reactor,could be an effective approach to generate and facilitate the utilization of endogenous hydrogen in anaerobic digestion of CH4 production technology,which is a promising and feasible method to scale up to the industrial level.     

生物气射流内循环厌氧流化床中复杂化工有机废水的催化还原过程

针对集约化化工园区排放的高浓度、高色度、高时变性及难降解性复杂化工废水，自行研制了处理能力为24 m³·d^-1、内置Fe⁰作为生物催化剂的生物气射流内循环厌氧流化床，研究了新型反应器及其工艺对该废水预处理的催化还原过程及运行参数。结果表明：以射流的方式使生物气和废水在反应器内主动循环，使催化剂、活性炭、污泥与废水之间保持良好的接触传质，通过产氢、絮凝和提供营养等方式强化厌氧反应过程。在回流比为2、环境温度为23～34℃及水力停留时间（HRT）为12～24 h的条件下，当进水容积负荷为0. 874～2. 996 kg COD·m^-3·d^-1和色度为250～2000倍时，其COD和色度的平均去除率分别达到26. 2%和70. 8%;出水pH稳定在6～8之间，原废水BOD/COD值由0. 26±0. 04提高到0. 43±0. 03。该新型反应器及工艺在实现部分有机负荷去除的同时明显改善了废水的可生化性，可作为复杂化工有机废水的高效预处理技术。     

Continuous operation of membrane bioreactor treating toluene vapors by Burkholderia vietnamiensis G4

A laboratory-scale biofilm membrane bioreactor inoculated with Burkholderia vietnamiensis G4 was examined to treat toluene vapors in a waste gas stream. The gas feed side and nutrient solution were separated by a composite membrane consisting of a porous polyacrylonitrile (PAN) support layer coated with a very thin (0.3 μm) dense polydimethylsiloxane (PDMS) top layer. After inoculation, a biofilm developed on the dense layer. The biofilm membrane bioreactor was operated continuously at different residence times (28–2 s) and loading rates (1.2–26.7 kg m⁻³ d⁻¹), with inlet toluene concentrations ranging from 0.21 to 4.1 g m⁻³. The overall performance of the membrane bioreactor was evaluated over a period of 165 days. Removal efficiencies ranging from 78% to 99% and elimination capacities from 4.2 to 14.4 kg m⁻³ d⁻¹ were observed after start-up period depending on the mode of operation. A maximum elimination capacity of 14.4 kg m⁻³ d⁻¹ was observed at a loading rate of 17.4 kg m⁻³ d⁻¹. Overall, the results illustrate that biofilm membrane reactors can potentially be more effective than conventional biofilters and biotrickling filters for the treatment of air pollutants such as toluene.     

钠盐浓度对厌氧产氢颗粒污泥从蔗糖中产氢的影响

This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L-1(Na ), on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the optimum sodium ion concentration [1000-2000mg·L-1(Na )] for hydrogen production at 37℃, the maximum sucrose degradation rate, the specific hydrogen production yield and the specific hydrogen production rate were 393.6-413.1mg·L-1·h-1, 28.04-28.97ml·g-1, 7.52-7.83ml·g-1·h-1, respectively. The specific production yields of propionate, butyrate and valerate decreased, with increasing sodium ion concentration, whereas the specific acetate production yield increased, meanwhile the specific production yields of ethanol and caproate were less than 55.3 and 12.6mg·g-1, respectively. The hybrid fermentation composition gradually developed from acetate, propionate and butyrate to acetate with the increase in sodium ion concentration.     

Continuous methanogenesis of black liquor of pulp and paper mills in an anaerobic baffled reactor using an immobilized cell system

An anaerobic baffled reactor together with an immobilized cell system has been proposed for methanogenesis of the black liquor from pulp and paper mills in a continuous system. A maximum chemical oxygen demand reduction of 50%, and biogas generation of 10 L d^?1, having methane content of 66% (v/v) at an organic loading rate (OLR) of 7 kg m^?3 d^?1 with hydraulic retention time of 2 days, were recorded. OLR values higher than 7 kg m^?3 d^?1 were toxic to methanogenesis and destabilized the reactor system. Copyright © 2006 Society of Chemical Industry     

葡萄糖及磷酸盐对刺糖多孢菌多杀菌素发酵的影响

The effects of glucose and inorganic phosphate on mycelium growth and spinosad production with Saccharopolyspora spinosa were studied. The results showed that the increase of glucose concentration from 18.6g·L-1 to 58.8g·L-1 could promote the mycelium growth and spinosad production. And when the glucose concentration increased from 58.8g·L-1 to 79.6g·L-1, no obvious change was detected but a slight drop in spinosad production was observed, whereas, when the glucose concentration increased from 79.6g·L-1 to l15.3g·L-1, substantial decrease in both mycelium growth and spinosad production occurred. The increase of phosphate conccntration from 3.68mmol· L-1 to 29.41mmol·L-1 rendered corresponding increase in mycelium growth and spinosad production. When phosphate concentration increased from 29.41mmol· L-1 to 44.12mmol·L-1, mycelium growth slightly increased and spinosad production dropped, while when phosphate concentration increased from44.12mmol·L-1 to 57.62mmol·L-1, both mycelium growth and spinosad production decreased sharply. Conclusively,the optimal initial concentration of glucose and phosphate is 58.8g·L-1 and 29.41mmol·L-1, respectively. The spinosad fermentation in the production medium containing 58.8g·L-1 glucose and 29.41mmol·L-1 phosphate was scaled up in 5-L fermentation and the spinosad production reached 507mg·L-1, which was 28% higher than that in the flask fermentation.     

钙钛矿型混合导体透氧膜SrFe0.6Cu0.3Ti0.1O3－δ的制备与表征

Dense membrane with the composition of SrFe0.6Cu0.3Ti0.1O3-δ （SFCTO） was prepared by solid state reaction method. Oxygen permeation flux through this membrane was investigated at operating temperature ranging from 750℃ to 950℃ and different oxygen partial pressure. XRD measurements indicated that the compound was able to form single-phased perovskite structure in which part of Fe was replaced by Cu and Ti. The oxygen desorption and the reducibility of SFCTO powder were characterized by thermogravimetric analysis and temperature programmed reduction analysis, respectively. It was found that SFCTO had good structure stability under low oxygen pressure at high temperature. The addition of Ti increased the reduction temperature of Cu and Fe. Performance tests showed that the oxygen permeation flux through a 1.5 mm thick SFCTO membrane was 0.35-0.96 ml·min ^-1·cm^-2 under air/helium oxygen partial pressure gradient with activation energy of 53.2 kJ·mol^-1. The methane conversion of 85%, CO selectivity of 90% and comparatively higher oxygen permeation flux of 5 ml·min^-1·cm^- 2 were achieved at 850℃, when a SFCTO membrane reactor loaded with Ni-Ce/Al2O3 catalyst was applied for the partial oxidation of methane to syngas.     

Performance of Anaerobic Reactors during Pseudo-Steady-State Operation

Four anaerobic reactors were studied for the purposes of this work: two anaerobic fluidized bed reactors (AFBR) using diatomaceous earth and granular activated carbon as immobilization media (R1 and R2, respectively), a packed-bed reactor (R3), and a suspended growth reactor (R4). A nutrient-supplemented wastestream with glucose as the main carbon source was treated. Successful reactor start-up was achieved for all four anaerobic reactors. These reactors were able to handle organic loading rates of more than 12000, 7500, 6000 and 650 mg dm⁻³ day⁻¹ for R1–R4, respectively. Anaerobic fluidized bed reactors were less affected by interruptions and adverse operating conditions than were packed-bed and suspended growth reactors. Immobilized cell reactors and, specifically, AFBRs were clearly superior to conventional high-rate digesters. This enhanced performance is primarily due to the very high cell retention ability of such reactors. High total organic carbon (TOC) removal efficiencies were achievable under pseudo-steady state operation. Removal efficiencies above 98% were observed for all reactors. Specific biogas production rates of 1·5–1·7, 1·4–1·7, 1·1–1·5 and 0·9–1·3 dm³ of methane per gram of TOC removed for R1–R4, respectively, were attained. A consistent biogas methane content of 52·5–55·9% was observed. Biomass concentrations of 84, 91, 21 and 1·9 g VS dm⁻³ were measured for R1–R4, respectively. Extremely high biomass concentrations in AFBRs were possible due to the high available specific surface area. © 1997 SCI.     

Magnetic properties of CNX whiskers

Carbon–nitrogen whiskers have been prepared by pyrolysis of 1,2-diaminopropane at 950 °C or of allylamine at 900 °C followed by quenching. They are scrolls of carbon film typically 250 nm thick and up to 1 mm long with about five layers in a structure like a “cigare russe” or “brandy snap”, about 50 μm in diameter. Approximately 8 wt% of nitrogen is incorporated into the carbon films, which are practically amorphous, exhibiting a broad diffraction peak at d = 0.34 nm. The whiskers are on the border of metallic conductivity with a resistivity of about 10⁻⁶ Ωm, and they may show either a positive or a negative temperature coefficient of resistance. The pyrolysis produces either whiskers, soot or both. Magnetization measurements of the whiskers made from 1,2-diaminopropane reveal a large diamagnetic susceptibility of χ = −170 × 10⁻⁹ m³  kg⁻¹ and a small ferromagnetic component of unknown origin with σ_S of up to 0.2 A m² kg⁻¹, whereas the soot shows a purely diamagnetic signal, with χ ≈ −40 × 10⁻⁹ m³ kg⁻¹.     

Gasification of charcoal using supercritical CO2 at high pressures

A novel one-shell high temperature and high pressure semi-continuous reactor has been developed for the study of the Boudouard reaction at temperatures up to 820 °C and pressures up to 32.5 MPa. Semicontinuous gasification of charcoal using supercritical CO₂ has been achieved at conversions up to 90.8% (w/w) at LSHV between 20 and 30 h⁻¹ after 5–9 h. A gasification model is proposed and validated. Effective rates of gasification (1.32 ± 0.12) × 10⁻⁶ to (6.10 ± 2.03) × 10⁻⁵ s⁻¹ were obtained. The results indicated that this method is technically feasible for the on-line production of high pressures streams of CO/CO₂ in the lab for carrying out further chemistries, avoiding the use of CO high pressure bottles.     

Electrodeposition of silver from the system AgNO3—ethyleneglycol—water. Effect of temperature ( −30°C) on the smoothness of silver deposits

The electrodeposition of silver from a nitrate bath can be improved by lowering the temperature and by the addition of ethyleneglycol as anti-freeze. When the bath temperature is lowered below 0°C, the dendritic silver deposition is suppressed and a smooth surface is obtained; at −30°C a very finegrained deposit results. The dendritic growth is supposedly prohibited partly by the lowering of temperature and to a less extent by the adsorption of ethyleneglycol at the surface both of which might enhance the activation overvoltage of silver deposition. From the polarisation measurement in, 0·25 M AgNO₃ electrolytes, the exchange current density of Ag deposition was evaluated as 1·70 × 10⁻² A/cm²(25°C) and with 50 vol. per cent ethyleneglycol, 9·72 × 10⁻⁴ A/cm² (25°C) and 1·22 × 10⁻⁵ A/cm² (−32°C). Adsorption of ethyleneglycol on Ag cathode was discussed by differential capacitance change.