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Start-up of PN-anammox system under low inoculation quantity and its restoration after low-loading rate

Guoliang Zhang, Liang Zhang, Xiaoyu Han, Shujun Zhang, Yongzhen Peng

《环境科学与工程前沿（英文）》 2021年第15卷第2期 doi: 10.1007/s11783-020-1324-z

摘要： Abstract • PN-A was start-up under low inoculation amount and a higher NRR was achieved. • PN-anammox system was successfully restored by aggressive sludge discharge. • Increase in granular sludge was the important factor to rapid recovery. • Enrichment of AOB and AnAOB in granular sludge favors the stable operation. Partial nitritation (PN)-anaerobic ammonium oxidation (anammox) is a promising pathway for the biological treatment of wastewater. However, the destruction of the system caused by excessive accumulation of nitrate in long-term operation remains a challenge. In this study, PN-anammox was initialized with low inoculation quantity in an air-lift reactor. The nitrogen removal rate of 0.71 kgN/(m3·d) was obtained, which was far higher than the seed sludge (0.3 kgN/(m3·d)). Thereafter, excess nitrate build-up was observed under low-loading conditions, and recovery strategies for the PN-anammox system were investigated. Experimental results suggest that increasing the nitrogen loading rate as well as the concentration of free ammonium failed to effectively suppress the nitrite oxidation bacteria (NOB) after the PN-anammox system was disrupted. Afterwards, effluent back-flow was added into the reactor to control the up-flow velocity. As a result, an aggressive discharge of sludge that promoted the synergetic growth of functional bacteria was achieved, leading to the successful restoration of the PN-anammox system. The partial nitritation and anammox activity were in balance, and an increase in nitrogen removal rate up to 1.07 kgN/(m3·d) was obtained with a nitrogen removal efficiency of 82.4% after recovery. Besides, the proportion of granular sludge (over 200 mm) increased from 33.67% to 82.82%. Ammonium oxidation bacteria (AOB) along with anammox bacteria were enriched in the granular sludge during the recovery period, which was crucial for the recovery and stable operation of the PN-anammox system.

关键词： PN-anammox Granular sludge Excess nitrate build-up Recovery strategy for partial nitrification Aggressive discharge of sludge

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构建工程管理专业队伍是我国工程管理当务之急

张寿荣

《中国工程科学》 2008年第10卷第12期页码 36-38

摘要：

对我国工程管理现状做了简要回顾，认为构建工程管理专业队伍是提升我国工程管理水平的当务之急，并提出培养专业队伍的具体建议。

关键词：工程管理构建专业队伍提升水平

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自主开发——强国之道

金履忠

《中国工程科学》 2005年第7卷第7期页码 1-6

摘要：

论证了自主开发在政治、军事、经济、安全、科技等方面的重大意义。建议用10～15年的时间，使我国的绝大多数产业具备自主开发和国际竞争能力；分析了实现这个目标是完全可能的。最后提出了应在思想观念、精神状态、法律法规、政策、体制、宣传舆论等方面创造有利于自主开发的环境。

关键词：自主开发的重要性实现的目标可能性营造自主开发的环境

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建设现代农业推进农业科技创新与体制改革

卢良恕

《中国工程科学》 2008年第10卷第2期页码 4-6

摘要：

农业科技在现代农业建设的过程中发挥着重要作用。文章介绍了新时期现代农业的内涵、主要特点，指出农业科技创新是现代农业发展的强大支撑，农业科技体制改革是现代农业发展和服务“三农”的需要。

关键词：现代农业科技创新体制改革

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Recent advances and challenges of nitrogen/nitrate electro catalytic reduction to ammonia synthesis

《能源前沿（英文）》 doi: 10.1007/s11708-023-0908-2

摘要： The Haber-Bosch process is the most widely used synthetic ammonia technology at present. Since its invention, it has provided an important guarantee for global food security. However, the traditional Haber-Bosch ammonia synthesis process consumes a lot of energy and causes serious environmental pollution. Under the serious pressure of energy and environment, a green, clean, and sustainable ammonia synthesis route is urgently needed. Electrochemical synthesis of ammonia is a green and mild new method for preparing ammonia, which can directly convert nitrogen or nitrate into ammonia using electricity driven by solar, wind, or water energy, without greenhouse gas and toxic gas emissions. Herein, the basic mechanism of the nitrogen reduction reaction (NRR) to ammonia and nitrate reduction reaction (

NO 3 −

RR) to ammonia were discussed. The representative approaches and major technologies, such as lithium mediated electrolysis and solid oxide electrolysis cell (SOEC) electrolysis for NRR, high activity catalyst and advanced electrochemical device fabrication for

NO 3 −

RR and electrochemical ammonia synthesis were summarized. Based on the above discussion and analysis, the main challenges and development directions for electrochemical ammonia synthesis were further proposed.

关键词： electrochemical ammonia synthesis nitrogen nitrate nitrogen reduction reaction (NRR) to ammonia nitrate reduction reaction (NO^–3 RR)

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Projections of heat-related excess mortality in China due to climate change, population and aging

《环境科学与工程前沿（英文）》 2023年第17卷第11期 doi: 10.1007/s11783-023-1732-y

摘要：

● Four scenarios were used to project heat-related excess mortality in China.

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INTERCROPPING: FEED MORE PEOPLE AND BUILD MORE SUSTAINABLE AGROECOSYSTEMS

《农业科学与工程前沿（英文）》 2021年第8卷第3期页码 373-386 doi: 10.15302/J-FASE -2021398

摘要：

Intercropping is a traditional farming system that increases crop diversity to strengthen agroecosystem functions while decreasing chemical inputs and minimizing negative environmental effects of crop production. Intercropping is currently considerable interest because of its importance in sustainable agriculture. Here, we synthesize the factors that make intercropping a sustainable means of food production by integrating biodiversity of natural ecosystems and crop diversity. In addition to well-known yield increases, intercropping can also increase yield stability over the long term and increase systemic resistance to plant diseases, pests and other unfavorable factors (e.g. nutrient deficiencies). The efficient use of resources can save mineral fertilizer inputs, reduce environmental pollution risks and greenhouse gas emissions caused by agriculture, thus mitigating global climate change. Intercropping potentially increases above- and below-ground biodiversity of various taxa at field scale, consequently it enhances ecosystem services. Complementarity and selection effects allow a better understanding the mechanisms behind enhanced ecosystem functioning. The development of mechanization is essential for large-scale application of intercropping. Agroecosystem multifunctionality and soil health should be priority topics in future research on intercropping.

关键词： agroecosystems ， crop diversity ，intercropping，interspecific interactions，sustainable agriculture

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Utilizing big data to build personalized technology and system of diagnosis and treatment in traditional

null

《医学前沿（英文）》 2014年第8卷第3期页码 272-278 doi: 10.1007/s11684-014-0364-9

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架起科学与经济之间的桥梁

Hans-Jurgen Warnecke

《中国工程科学》 2000年第2卷第10期页码 16-17

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Numerical simulation of bituminous coal combustion in a full-scale tiny-oil ignition burner: influence of excess

Zhengqi LI, Chunlong LIU, Xiang ZHANG, Lingyan ZENG, Zhichao CHEN

《能源前沿（英文）》 2012年第6卷第3期页码 296-303 doi: 10.1007/s11708-012-0191-0

摘要： The progression of ignition was numerically simulated with the aim of realizing a full-scale tiny-oil ignition burner that is identical to the burner used in an 800 MWe utility boiler. The numerical simulations were conducted for four excess air ratios, 0.56, 0.75, 0.98 and 1.14 (corresponding to primary air velocities of 17, 23, 30 and 35 m/s, respectively), which were chosen because they had been used previously in practical experiments. The numerical simulations agreed well with the experimental results, which demonstrate the suitability of the model used in the calculations. The gas temperatures were high along the center line of the burner for the four excess air ratios. The flame spread to the burner wall and the high-temperature region was enlarged in the radial direction along the primary air flow direction. The O concentrations for the four excess air ratios were 0.5%, 1.1%, 0.9% and 3.0% at the exit of the second combustion chamber. The CO peak concentration was very high with values of 7.9%, 9.9%, 11.3% and 10.6% for the four excess air ratios at the exit of the second combustion chamber.

关键词： numerical simulation tiny-oil ignition burner pulverized coal temperature field

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Comparison between inhibitor and uncoupler for minimizing excess sludge production of an activated sludge

CHEN Guowei, XI Pengge, XU Deqian, YU Hanqing

《环境科学与工程前沿（英文）》 2007年第1卷第1期页码 63-66 doi: 10.1007/s11783-007-0012-6

摘要： In order to study the minimization of excess sludge production, the reduction in the excess sludge production in the presence of an inhibitor and uncoupler was studied in this work. The experimental results show that such an addition could effectively reduce the production of excess sludge. With the energy uncoupling model established in this work, energy uncoupling coefficient () was used to evaluate the reduction in excess sludge production. The energy uncoupling coefficients in the presence of dinitrophenol (dNP), Zn, and Cu was 0.75, 0.46, and 0.18, respectively. The analysis demonstrated that energy spilling occurred in the presence of dNP, and that dNP was an effective uncoupler for reducing the production of excess activated sludge without affecting the microbial respiration activity.

关键词： uncoupling coefficient Cu minimization presence uncoupling

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Structure controlling and process scale-up in the fabrication of nanomaterials

Chunzhong LI,

《化学科学与工程前沿（英文）》 2010年第4卷第1期页码 18-25 doi: 10.1007/s11705-009-0305-3

摘要： Nanotechnology is already having a significant commercial impact, and will very certainly have a much greater impact in the future. The research on process engineering and scale-up will be very important for the commercial production and application of nanomaterials, because the properties and structure of nanomaterials are not only determined by the nucleation and growth process, but also strongly affected by the engineering properties, such as the mixing, the heat and mass transfer, and also the distribution of temperature, concentration, etc. This paper will present some research work in our laboratory on the fabrication of nanomaterials. Based on the chemical engineering principle and methods, many kinds of novel nanomaterials can be synthesized and their structure can be easily controlled through adjusting the parameters of the fluid mixing, and the distribution of temperature, residence time and concentration, etc. By using the micro-mixing, heat and mass transfer and reaction control methods, the host-guest nanocomposites have been assembled and assumed as the novel electroanalytical sensing nanobiocomposite materials. Based on the principles of chemical engineering, the manufacturing technologies for magnetic powders, calcium carbonate, and titanium dioxide have been developed for commercial-scale production, and the largest production scale has reached 15 kt/year.

关键词： scale-up significant commercial electroanalytical engineering laboratory

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Mechanism on minimization of excess sludge in oxic-settling-anaerobic (OSA) process

WANG Jianfang, ZHAO Qingliang, JIN Wenbiao, LIN Jikan

《环境科学与工程前沿（英文）》 2008年第2卷第1期页码 36-43 doi: 10.1007/s11783-008-0001-4

摘要： The oxic-settling-anaerobic (OSA) process is a promising wastewater treatment technique for efficiently reducing sludge production and improving the stability of process operation. In this paper, the possible factors of sludge reduction such as sludge decay, uncoupled metabolism, and anaerobic oxidation with low sludge production were discussed in the OSA process. It has been confirmed that sludge decay is the decisive cause in the OSA process, accounting for 66.7% of sludge production reduction. Sludge decay includes hydrolysis and acidogenesis of dead microorganisms and particle organic carbon adsorbed in sludge floc and endogenous metabolism. By batch experiments, it has been proven that there is energetic uncoupling in the OSA system since microorganisms were exposed to alternative anaerobic and aerobic environment. It accounts for about 7.5% of sludge production reduction. Soluble chemical oxygen demand (SCOD) released from the anaerobic sludge tank in the OSA process was used as the substrate for cryptic growth. The substrate was used for anoxic denitrifying, anaerobic phosphorus release, sulfate reduction, and methane production. These anaerobic reactions in the sludge anaerobic tank have lower sludge production than in the aerobic oxidation when equivalent SCOD is consumed, which may lead to approximately 23% of sludge reduction in the OSA process. It has been concluded that multiple causes resulted in the minimization of excess sludge in the OSA system. The microbial community structure and diversity of sludge samples from the CAS (conventional activated sludge) and OSA systems were investigated by 16 SrDNA PCR-DG-DGGE (polymerase chain reaction-double gradient-denaturing gradient gel electrophoresis). DGGE profile and cluster analysis showed more abundant species in the OSA system contrasting to microbial communities in the CAS system.

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硝酸铵膨化理论研究

吕春绪

《中国工程科学》 2001年第3卷第9期页码 58-63

摘要：

描述了硝酸铵膨化过程，计算与测定了其物理化学参数，研究了膨化过程的影响因素，并给出了膨化过程可能的机理。

关键词：膨化硝酸铵膨化理论物理化学参数影响因素

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BUEES: a bottom-up event extraction system

Xiao DING,Bing QIN,Ting LIU

《信息与电子工程前沿（英文）》 2015年第16卷第7期页码 541-552 doi: 10.1631/FITEE.1400405

摘要： Traditional event extraction systems focus mainly on event type identification and event participant extraction based on pre-specified event type paradigms and manually annotated corpora. However, different domains have different event type paradigms. When transferring to a new domain, we have to build a new event type paradigm and annotate a new corpus from scratch. This kind of conventional event extraction system requires massive human effort, and hence prevents event extraction from being widely applicable. In this paper, we present BUEES, a bottom-up event extraction system, which extracts events from the web in a completely unsupervised way. The system automatically builds an event type paradigm in the input corpus, and then proceeds to extract a large number of instance patterns of these events. Subsequently, the system extracts event arguments according to these patterns. By conducting a series of experiments, we demonstrate the good performance of BUEES and compare it to a state-of-the-art Chinese event extraction system, i.e., a supervised event extraction system. Experimental results show that BUEES performs comparably (5% higher -measure in event type identification and 3% higher -measure in event argument extraction), but without any human effort.

关键词： Event extraction Unsupervised learning Bottom-up