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Aerobic granular sludge formation based on substrate availability: Effects of flow pattern and fermentation

Quan Yuan, Hui Gong, Hao Xi, Kaijun Wang

《环境科学与工程前沿(英文)》 2020年 第14卷 第3期 doi: 10.1007/s11783-020-1226-0

摘要: Penetration depth and substrate characters affect AGS formation and performance. The relationship between substrate gradient and particle size affects AGS stability. The fermentation process is proposed as a pretreatment to improve AGS stability. The influences of flow patterns (mixed-flow and plug-flow) and fermentation pretreatment on aerobic granular sludge (AGS) formation with various substrate availability levels were investigated by running four identical laboratory-scale sequencing batch reactors (R1–R4), comparing two anaerobic feeding strategies and three kinds of substrates. R1 achieved faster granulation with a fast influent fill step followed by a modified anaerobic mixed-flow phase, but the AGS showed poorer stability with a cracked structure and a high suspended solids concentration in the effluent. The anaerobic plug-flow feeding mode (with influent fed slowly from the bottom) in R2 provided deeper penetration depth for the substance to reach the core of AGS and accordingly strengthen AGS stability. An acidogenic up-flow sludge bed reactor was introduced as a pretreatment to improve the AGS performance by enhancing glucose pre-fermentation (R4). AGS fed with mixed volatile fatty acids (VFA) after glucose fermentation showed similar performance compared with the reactor fed with acetate in the aspects of stability, structure, size distribution and nitrogen removal efficiency, and 74% similarity in the microbial community. For actual wastewater with low VFA concentrations, fermentation treatment was suggested as a promising pretreatment for stable AGS granulation and operation.

关键词: Anaerobic plug-flow feeding mode     Anaerobic mixed-flow mode     Fermentation pretreatment     Substrate gradient     Penetration depth    

Organic and inorganic phosphorus uptake by bacteria in a plug-flow microcosm

Jinbo ZHAO, Xuehua LIU

《环境科学与工程前沿(英文)》 2013年 第7卷 第2期   页码 173-184 doi: 10.1007/s11783-013-0494-3

摘要: Phosphorus (P) is a vital nutrient for sustaining natural water productivity. Both particulate and dissolved forms of organic and inorganic P are potentially important sources of bioavailable P for primary and secondary producers. A microcosm system to imitate the bacterial community in Plym river sediment and pore water is described and bacterial uptake rates for inorganic and organic phosphorus are presented in this paper. The aim of this study was to investigate the uptake of two organic phosphorus compounds (phytic acid and D-glucose-6-phosphate) by freshwater bacteria. The bioreactors comprise glass columns packed with two types of small glass beads on which bacterial biofilm can develop. The glass beads with different porosity were introduced to simulate River SPM. The selected P compounds spiked into the inflow of the microcosm, and measured the step change of P concentration in the outflow to investigate the behavior of bacterial uptake of nutrients. The results showed that organic phosphorus was converted into inorganic phosphorus but the conversion rate depended on the type of phosphorus species. One experiment suggested that phytic acid (refractory) could displace phosphate from the biofilm surface; the other experiment showed that D-glucose-6-phosphate (labile) could be hydrolysed and utilized easily by the bacteria. The results also suggested that bacteria might break down the C-P bonds to utilize the carbon. Further experiments should investigate the effect of varying the C:N:P ratio in the microcosm system to determine which nutrient limits bacteria uptake.

关键词: organic phosphorus     bacteria     uptake    

Feasibility assessment of up-flow anaerobic sludge blanket treatment of sulfamethoxazole pharmaceutical

Yi Chen, Shilong He, Mengmeng Zhou, Tingting Pan, Yujia Xu, Yingxin Gao, Hengkang Wang

《环境科学与工程前沿(英文)》 2018年 第12卷 第5期 doi: 10.1007/s11783-018-1069-0

摘要:

The UASB system successfully treated sulfamethoxazole pharmaceutical wastewater.

High concentration sulfate of this wastewater was the main refractory factor.

UASB recovery performance after a few days of inflow arrest was studied.

The optimal UASB operating conditions for practical application were determined.

关键词: Up-flow anaerobic sludge blanket (UASB)     Methane production     Sulfate reduction     Sulfamethoxazole pharmaceutical wastewater     Electron flow     Recovery    

Anaerobic treatment of wastewater containing methanol in up-flow anaerobic sludge bed (UASB) reactor

LIN Yishan, HE Yanling, MENG Zhuo, YANG Shucheng

《环境科学与工程前沿(英文)》 2008年 第2卷 第2期   页码 241-246 doi: 10.1007/s11783-008-0040-x

摘要: The direct conversion of methanol into methane is the main process in anaerobic treatment of methanol containing wastewater. However, acetic acid can also be produced from methanol theoretically, which may probably result in an abrupt pH drop and deteriorate the anaerobic process. Therefore, it is interesting to know what would really happen in an anaerobic reactor treating methanol wastewater. In this study, an up-flow anaerobic sludge bed (UASB) reactor treating methanol wastewater was operated. The chemical oxygen demand (COD), acetic acid and pH of the effluent were monitored at different loadings and influent alkalinity. The results showed that the anaerobic reactor could be operated steadily at as low as 119 mg/L of influent alkalinity and high organic loading rate with no obvious pH drops. Volatile fatty acids accumulation was not observed even at strong shock loadings. The microorganisms in the sludge at the end of the test became homogeneous in morphology, which were mainly spherical or spheroidal in shape.

关键词: homogeneous     spherical     influent alkalinity     process     anaerobic treatment    

Deciphering the effect of sodium dodecylbenzene sulfonate on up-flow anaerobic sludge blanket treatment

《环境科学与工程前沿(英文)》 2021年 第15卷 第5期 doi: 10.1007/s11783-020-1385-z

摘要:

• UASB reactor can work efficiently with high COD/SO42- ratios when SDBS exists.

关键词: Up-flow anaerobic sludge blanket     Organic sulfur     Sodium dodecylbenzene sulfonate     COD/SO42 ratio     Microbial community    

Cumulant-based correlated probabilistic load flow considering photovoltaic generation and electric vehicle

Nitesh Ganesh BHAT, B. Rajanarayan PRUSTY, Debashisha JENA

《能源前沿(英文)》 2017年 第11卷 第2期   页码 184-196 doi: 10.1007/s11708-017-0465-7

摘要: This paper applies a cumulant-based analytical method for probabilistic load flow (PLF) assessment in transmission and distribution systems. The uncertainties pertaining to photovoltaic generations and aggregate bus load powers are probabilistically modeled in the case of transmission systems. In the case of distribution systems, the uncertainties pertaining to plug-in hybrid electric vehicle and battery electric vehicle charging demands in residential community as well as charging stations are probabilistically modeled. The probability distributions of the result variables (bus voltages and branch power flows) pertaining to these inputs are accurately established. The multiple input correlation cases are incorporated. Simultaneously, the performance of the proposed method is demonstrated on a modified Ward-Hale 6-bus system and an IEEE 14-bus transmission system as well as on a modified IEEE 69-bus radial and an IEEE 33-bus mesh distribution system. The results of the proposed method are compared with that of Monte-Carlo simulation.

关键词: battery electric vehicle     extended cumulant method     photovoltaic generation     plug-in hybrid electric vehicle     probabilistic load flow    

Technical measures to achieve a cleaner production mode for recycled paper mills

Chao HE, Zhaolin GU, Shucheng YANG, Jidong LIANG, Weina DAI, Yanling HE

《环境科学与工程前沿(英文)》 2010年 第4卷 第4期   页码 466-474 doi: 10.1007/s11783-010-0242-x

摘要: China’s paper production reached 79.8 ×10 t in 2008 and ranked number one in the world. Because of its high consumption of water, energy and materials and its serious pollution, the present processes are not likely to be sustainable. An alternative, the closed Water Loop-Papermaking Integration (WLPI) method, is put forward in this paper. The WLPI method can be realized in a recycled paper mill by adding technologies and using recycled water. Many industrial case studies have shown that a large quantity of water, energy and materials can be saved, and the quantity of waste sludge and wastewater discharge was minimized by using the WLPI method. The design of the water reuse system, control of calcium hardness, water recycling and minimal waste sludge are discussed. Anaerobic technology plays an important role in the WLPI method to lower cost, energy use and waste. In the brown paper and coated white board production, zero-effluent discharge can be realized. Fresh water consumption is only 1–2 m ·t . For the paper mills with deinking and bleaching processes, about 10 m ·t of fresh water and a similar amount of effluent discharge are needed. Power saving using anaerobic technology is 70% when recycled water is used in comparison with the conventional activated sludge process. Waste sludge can be decreased to about 5% of the initial process due to reuse of the waste sludge and the lower bio-sludge production of the anaerobic process.

关键词: water reuse     zero discharge     anaerobic treatment     recycled paper     cleaner production    

Full lifetime cost analysis of battery, plug-in hybrid and FCEVs in China in the near future

Zhihua CAI, Xunmin OU, Qian ZHANG, Xiliang ZHANG

《能源前沿(英文)》 2012年 第6卷 第2期   页码 107-111 doi: 10.1007/s11708-012-0182-1

摘要: This paper analyzes the full lifetime cost of battery electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs), and fuel cell electric vehicles (FCEVs) in China in the near future. The full lifetime cost comprises the initial and periodic cost of owning and operating the vehicle. Compared with the conventional gasoline vehicles, the full lifetime cost of the BEVs, PHEVs and FCEVs are approximately 1.5, 0.5 and 2.3 times more in the short term, respectively, due to the higher initial costs and higher non-energy-related costs though the fuel costs are lower. The results also suggest that with reasonably anticipatable technological progress in the long term, the lifetime cost of advanced electric vehicles (EVs) can be close to that of gasoline vehicles. It is found that two aspects of action are most important to make BEVs cost-effective: to support technology improvement to decrease the high cost of BEV and to formulate high energy cost of operating the conventional gasoline car. Moreover, it is important to decrease the non-energy operating costs including registration fee, tax rate and etc., of BEVs at the same time.

关键词: electric vehicle (EV)     life time cost     China    

Influence of glucose feeding on the ligninolytic enzyme production of the white-rot fungus Phanerochaete

ZHOU Xiaoyan, WEN Xianghua, FENG Yan

《环境科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 89-94 doi: 10.1007/s11783-007-0017-1

摘要: The present work studied the influence of glucose feeding on the ligninolytic enzyme production of in a nitrogen-limited (C/N ratio is 56/8.8 mmol/L) medium. Several sets of shaking flask experiments were conducted. The results showed that 2 g/L glucose feeding on the first day of the culture (24 h after the inoculation) stimulated both fungal biomass growth and enzyme production. The manganese peroxidase (MnP) activity was 2.5 times greater than that produced in cultures without glucose feeding. Furthermore, the glucose feeding mode in fed-batch culture was also investigated. Compared to cultures with glucose feeding every 48 h, cultures with glucose feeding of 1.5 g/L (final concentration) every 24 h produced more enzymes. The peak and total yield of MnP activity were 2.7 and 3 times greater compared to the contrast culture, respectively, and the enzyme was kept stable for 4 days with an activity of over 200 U/L.

关键词: enzyme production     fed-batch culture     nitrogen-limited     inoculation     mmol/L    

通过一个等价雷诺数揭示层流到湍流的转捩区域 Article

陈晓东

《工程(英文)》 2019年 第5卷 第3期   页码 576-579 doi: 10.1016/j.eng.2018.09.013

摘要:

Flow transition from laminar to turbulent mode (and vice versa)—that is, the initiation of turbulence—is one of the most important research subjects in the history of engineering. Even for pipe flow, predicting the onset of turbulence requires sophisticated instrumentation and/or direct numerical simulation, based on observing the instantaneous flow structure formation and evolution. In this work, a local Reynolds number equivalence γ (ratio of local inertia effect to viscous effect) is seen to conform to the Universal Law of the Wall, where γ = 1 represents a quantitative balance between the abovementioned two effects. This coincides with the wall layer thickness (y+ = 1, where y+ is the dimensionless distance from the wall surface defined in the Universal Law of the Wall). It is found that the characteristic of how the local derivative of γ against the local velocity changes with increasing velocity determines the onset of turbulence. For pipe flow, γ  25, and for plate flow, γ 151.5. These findings suggest that a certain combination of γ and velocity (nonlinearity) can qualify the source of turbulence (i.e., generate turbulent energy). Similarly, a re-evaluation of the previous findings reveals that only the geometrically narrow domain can act locally as the source of turbulence, with the rest of the flow field largely being left for transporting and dissipating. This understanding will have an impact on the future large-scale modeling of turbulence.

关键词: 局部等价雷诺数     转捩     壁面律     管流     平板流动     建模    

Sustainable intensification of agriculture is key to feeding Africa in the 21st century

Shenggen FAN

《农业科学与工程前沿(英文)》 2020年 第7卷 第4期   页码 366-370 doi: 10.15302/J-FASE-2020342

摘要:

Africa in facing numerous challenges in the 21st century in feeding its rapidly increasing population. Land resources have become limited due to urbanization and industrialization. The existing agricultural land has been degraded and soil fertility has declined due to unsustainable farming practices. Despite of progress made in the past several decades, hunger and malnutrition in Africa still hinder health, human development and economic growth, which will become even worse in the future if proper measures are not taken. Sustainable intensification is the only solution to tackling both environmental sustainability including climate change and malnutrition, i.e., to produce more foods in terms of nutrients human body needs with less natural resources and carbon emissions. To achieve this vision, innovations in technologies, policies and institutions are essential. The Chinese experience in Agricultural Green Development (AGD) can be shared with Africans when the region is pursuing its sustainable intensification strategy.

关键词: Africa     sustainable intensification     Agricultural Green Development     climate change     malnutrition    

渠网恒定流及非恒定流数学模型的研究及应用

张明亮,沈永明

《中国工程科学》 2007年 第9卷 第8期   页码 92-96

摘要:

从求解一维圣维南方程组的Preissmann 4点隐式差分格式出发, 建立了一维河网及渠网数学模型,并对计算中所涉及的一些关键技术问题进行了较为详细的阐述。利用模型对树状渠网的恒定流及复杂的环状渠网和河网的非恒定流对模型进行验证。验证结果表明,水位和流量过程计算值与Islam的计算值吻合较好,各渠道的流量分配计算结果精度也较高,为河网及渠网的水量调度提供了一个较为简便实用的工具,为建立渠网及河网的综合水质生态数学模型打下基础。

关键词: Preissmann格式     渠网及河网     流量分配     水质模型    

Anefficient quadrature demodulator for medical ultrasound imaging

Hao ZHOU,Yin-fei ZHENG

《信息与电子工程前沿(英文)》 2015年 第16卷 第4期   页码 301-310 doi: 10.1631/FITEE.1400205

摘要: Quadrature demodulation is used in medical ultrasound imaging to derive the envelope and instantaneous phase of the received radio-frequency (RF) signal. In quadrature demodulation, RF signal is multiplied with the sine and cosine wave reference signal and then low-pass filtered to produce the base-band complex signal, which has high computational complexity. In this paper, we propose an efficient quadrature demodulation method for B-mode and color flow imaging, in which the RF signal is demodulated by a pair of finite impulse response filters without mixing with the reference signal, to reduce the computational complexity. The proposed method was evaluated with simulation and in vivo experiments. From the simulation results, the proposed quadrature demodulation method produced similar normalized residual sum of squares (NRSS) and velocity profile compared with the conventional quadrature demodulation method. In the in vivo color flow imaging experiments, the time of the demodulation process was 5.66 ms and 3.36 ms, for the conventional method and the proposed method, respectively. These results indicated that the proposed method can maintain the performance of quadrature demodulation while reducing computational complexity.

关键词: B-mode ultrasound imaging     Color flow imaging     Quadrature demodulation     Finite impulse response filter    

主支式排烟道中主烟道横截面尺寸的确定

黄锐,杨立中,范维澄

《中国工程科学》 2001年 第3卷 第11期   页码 45-48

摘要:

高层住宅主支式排烟道的主烟道中烟气流动可看作是一维定常垂直摩擦管流。通过计算管流流动相与颗粒相的物理参数沿管程分布情况,确定了颗粒相流动情况,进而判断烟气排放情况。这受到排烟系统高度、烟道管径,及材料组成等因素的影响,通过预设排烟系统高度并保证良好排放情况,求得主烟道管径应满足的条件。这使得布设排烟道时可以找到一个较好的横截面尺寸,既满足烟气排放条件,又节约修建材料。

关键词: 多相流     主支式厨房排烟道     计算模型    

Dissolved methane in anaerobic effluent: Emission or recovery?

《环境科学与工程前沿(英文)》 2022年 第16卷 第4期 doi: 10.1007/s11783-022-1537-4

摘要: Various anaerobic processes have been explored for the energy-efficient treatment of municipal wastewater. However, dissolved methane in anaerobic effluent appears to be a barrier towards the energy and carbon neutrality of wastewater treatment. Although several dissolved methane recovery methods have been developed, their engineering feasibility and economic viability have not yet been assessed in a holistic manner. In this perspective, we thus intend to offer additional insights into the cost-benefit of dissolved methane recovery against its emission.

关键词: Anaerobic treatment     Municipal wastewater     Dissolved methane     Methane recovery     Carbon emission    

标题 作者 时间 类型 操作

Aerobic granular sludge formation based on substrate availability: Effects of flow pattern and fermentation

Quan Yuan, Hui Gong, Hao Xi, Kaijun Wang

期刊论文

Organic and inorganic phosphorus uptake by bacteria in a plug-flow microcosm

Jinbo ZHAO, Xuehua LIU

期刊论文

Feasibility assessment of up-flow anaerobic sludge blanket treatment of sulfamethoxazole pharmaceutical

Yi Chen, Shilong He, Mengmeng Zhou, Tingting Pan, Yujia Xu, Yingxin Gao, Hengkang Wang

期刊论文

Anaerobic treatment of wastewater containing methanol in up-flow anaerobic sludge bed (UASB) reactor

LIN Yishan, HE Yanling, MENG Zhuo, YANG Shucheng

期刊论文

Deciphering the effect of sodium dodecylbenzene sulfonate on up-flow anaerobic sludge blanket treatment

期刊论文

Cumulant-based correlated probabilistic load flow considering photovoltaic generation and electric vehicle

Nitesh Ganesh BHAT, B. Rajanarayan PRUSTY, Debashisha JENA

期刊论文

Technical measures to achieve a cleaner production mode for recycled paper mills

Chao HE, Zhaolin GU, Shucheng YANG, Jidong LIANG, Weina DAI, Yanling HE

期刊论文

Full lifetime cost analysis of battery, plug-in hybrid and FCEVs in China in the near future

Zhihua CAI, Xunmin OU, Qian ZHANG, Xiliang ZHANG

期刊论文

Influence of glucose feeding on the ligninolytic enzyme production of the white-rot fungus Phanerochaete

ZHOU Xiaoyan, WEN Xianghua, FENG Yan

期刊论文

通过一个等价雷诺数揭示层流到湍流的转捩区域

陈晓东

期刊论文

Sustainable intensification of agriculture is key to feeding Africa in the 21st century

Shenggen FAN

期刊论文

渠网恒定流及非恒定流数学模型的研究及应用

张明亮,沈永明

期刊论文

Anefficient quadrature demodulator for medical ultrasound imaging

Hao ZHOU,Yin-fei ZHENG

期刊论文

主支式排烟道中主烟道横截面尺寸的确定

黄锐,杨立中,范维澄

期刊论文

Dissolved methane in anaerobic effluent: Emission or recovery?

期刊论文