It is particularly important to comprehensively assess the biotoxicity variation of industrial wastewater along the treatment process for ensuring the water environment security.However,intensive studies on the biotox...It is particularly important to comprehensively assess the biotoxicity variation of industrial wastewater along the treatment process for ensuring the water environment security.However,intensive studies on the biotoxicity reduction of industrial wastewater are still limited.In this study,the toxic organics removal and biotoxicity reduction of coal chemical wastewater(CCW)along a novel full-scale treatment process based on the pretreatment process-anaerobic process-biological enhanced(BE)process-anoxic/oxic(A/O)process-advanced treatment process was evaluated.This process performed great removal efficiency of COD,total phenol,NH_(4)^(+)-N and total nitrogen.And the biotoxicity variation along the treatment units was analyzed from the perspective of acute biotoxicity,genotixicity and oxidative damage.The results indicated that the effluent of pretreatment process presented relatively high acute biotoxicity to Tetrahymena thermophila.But the acute biotoxicity was significantly reduced in BE-A/O process.And the genotoxicity and oxidative damage to Tetrahymena thermophila were significantly decreased after advanced treatment.The polar organics in CCW were identified as the main biotoxicity contributors.Phenols were positively correlated with acute biotoxicity,while the nitrogenous heterocyclic compounds and polycyclic aromatic hydrocarbons were positively correlated with genotoxicity.Although the biotoxicity was effectively reduced in the novel full-scale treatment process,the effluent still performed potential biotoxicity,which need to be further explored in order to reduce environmental risk.展开更多
Thermal Barrier Coatings(TBCs)technology is key to improving the service temperature and the productivity of aircraft engines.The performance and failure life of TBCs are strongly influenced by surface integrity and m...Thermal Barrier Coatings(TBCs)technology is key to improving the service temperature and the productivity of aircraft engines.The performance and failure life of TBCs are strongly influenced by surface integrity and microstructure.Therefore,recognizing failure mechanisms and developing effective surface treatment processes are crucial for further improving the reliability and durability of TBCs.This paper explains the primary reasons for TBC failure,emphasizing on how integrity of surface and interface influences interfacial oxidation,high-temperature erosion,and Calcium-Magnesium-Alumina-Silicate(CMAS)corrosion.Furthermore,this paper completely and rigorously evaluates the research status of TBCs surface treatment processes,including the characteristics and effects of various processes,and describes the requirements and goals of pretreatment and post-treatment.In addition,a potential direction for the development and application of TBCs surface treatment is suggested.展开更多
In wastewater treatment systems,extracting meaningful features from process data is essential for effective monitoring and control.However,the multi-time scale data generated by different sampling frequencies pose a c...In wastewater treatment systems,extracting meaningful features from process data is essential for effective monitoring and control.However,the multi-time scale data generated by different sampling frequencies pose a challenge to accurately extract features.To solve this issue,a multi-timescale feature extraction method based on adaptive entropy is proposed.Firstly,the expert knowledge graph is constructed by analyzing the characteristics of wastewater components and water quality data,which can illustrate various water quality parameters and the network of relationships among them.Secondly,multiscale entropy analysis is used to investigate the inherent multi-timescale patterns of water quality data in depth,which enables us to minimize information loss while uniformly optimizing the timescale.Thirdly,we harness partial least squares for feature extraction,resulting in an enhanced representation of sample data and the iterative enhancement of our expert knowledge graph.The experimental results show that the multi-timescale feature extraction algorithm can enhance the representation of water quality data and improve monitoring capabilities.展开更多
Dry sliding wear tests of a Cr-Mo-V cast hot-forging die steel was carried out within a load range of 50--300 N at 400℃ by a pin-on-disc high temperature wear machine. The effect of heat treatment process on wear res...Dry sliding wear tests of a Cr-Mo-V cast hot-forging die steel was carried out within a load range of 50--300 N at 400℃ by a pin-on-disc high temperature wear machine. The effect of heat treatment process on wear resistance was systematically studied in order to select heat treatment processes of the steel with high wear resistance. The morphology, structure and composition were analyzed using scanning electron microscopy （SEM）, X-ray diffraction （XRD） and energy dispersive spectroscopy （EDS） ; wear mechanism was also discussed. Tribo-oxide layer was found to form on worn surfaces to reduce wear under low loads, but appear inside the matrix to increase wear under high loads. The tribo-oxides were mainly consisted of Fe3O4 and Fe2O3, FeO only appeared under a high load. Oxidative mild wear, transition of mild-severe wear in oxidative wear and extrusive wear took turns to operate with increasing the load. The wear resistance strongly depended on the selection of heat treatment processes or microstructures. It was found that bainite presented a better wear resistance than martensite plus bainite duplex structure, martensite structure was of the poorest wear resistance. The wear resistance increased with increasing austenizing temperature in the range of 920 to 1 120 ℃, then decreased at up to 1 220 ℃. As for tempering temperature and microstructure, the wear resistance increased in following order： 700℃ （tempered sorbite）, 200 ℃ （tempered martensite）, 440 to 650 ℃ （tempered troostite）. An appropriate combination of hardness, toughness, microstructural thermal stability was re- quired for a good wear resistance in high-temperature wear. The optimized heat treatment process was suggested for the cast hot-forging steel to be austenized at 1020 to 1 120 ℃, quenched in oil, then tempered at 440 to 650℃ for 2 h.展开更多
In wastewater treatment process(WWTP), the accurate and real-time monitoring values of key variables are crucial for the operational strategies. However, most of the existing methods have difficulty in obtaining the r...In wastewater treatment process(WWTP), the accurate and real-time monitoring values of key variables are crucial for the operational strategies. However, most of the existing methods have difficulty in obtaining the real-time values of some key variables in the process. In order to handle this issue, a data-driven intelligent monitoring system, using the soft sensor technique and data distribution service, is developed to monitor the concentrations of effluent total phosphorous(TP) and ammonia nitrogen(NH_4-N). In this intelligent monitoring system, a fuzzy neural network(FNN) is applied for designing the soft sensor model, and a principal component analysis(PCA) method is used to select the input variables of the soft sensor model. Moreover, data transfer software is exploited to insert the soft sensor technique to the supervisory control and data acquisition(SCADA) system. Finally, this proposed intelligent monitoring system is tested in several real plants to demonstrate the reliability and effectiveness of the monitoring performance.展开更多
Waste water treatment process(WWTP)control has been attracting more and more attention.However,various undesired factors,such as disturbance,uncertainties,and strong nonlinear couplings,propose big challenges to the c...Waste water treatment process(WWTP)control has been attracting more and more attention.However,various undesired factors,such as disturbance,uncertainties,and strong nonlinear couplings,propose big challenges to the control of a WWTP.In order to improve the control performance of the closed-loop system and guarantee the discharge requirements of the effluent quality,rather than take the model dependent control approaches,an active disturbance rejection control(ADRC)is utilized.Based on the control signal and system output,a phase optimized ADRC(POADRC)is designed to control the dissolved oxygen and nitrate concentration in a WWTP.The phase advantage of the phase optimized extended state observer(POESO),convergence of the POESO,and stability of the closed-loop system are analyzed from the theoretical point of view.Finally,a commonly accepted benchmark simulation model no.1.(BSM1)is utilized to test the POESO and POADRC.Linear active disturbance rejection control(LADRC)and the suggested proportion-integration(PI)control are taken to make a comparative research.Both system responses and performance index values confirm the advantage of the POADRC over the LADRC and the suggested PI control.Numerical results show that,as a result of the leading phase of the total disturbance estimation,the POESO based POADRC is an effective and promising way to control the dissolved oxygen and nitrate concentration so as to ensure the effluent quality of a WWTP.展开更多
In order to explore the biodegradation behavior of nonylphenolic compounds during wastewater treatment processing, two full-scale wastewater treatment plants were investigated and batch biodegradation experiments were...In order to explore the biodegradation behavior of nonylphenolic compounds during wastewater treatment processing, two full-scale wastewater treatment plants were investigated and batch biodegradation experiments were conducted. The biodegradation pathways under the various operational conditions were identified from batch experiments： shortening of ethoxy-chains dominated under the anaerobic condition, whereas oxidizing of the terminal alcoholic group prevailed over the other routes under the aerobic condition. Results showed that the anoxic condition could accelerate the biodegradation rates of nonylphenolic compounds, but had no influence on the biodegradation pathway. The biodegradation rates of nonylphenol （NP） and short-chain nonylphenol polyethoxylates （NPnEOs, n： number of ethoxy units） increased from the anaerobic condition, then the anoxic, finally to the aerobic condition, while those of long-chain NPnEOs and nonylphenoxy carboxylates （NPECs） seemed similar under the various conditions. Under every operational condition, long-chain NPnEOs showed the highest biodegradation activity, followed by NPECs and short-chain NPnEOs, whereas NP showed relatively recalcitrant characteristics especially under the anaerobic condition. In addition, introducing sulfate and nitrate to the anaerobic condition could enhance the biodegradation of NP and short-chain NPnEOs by supplying more positive redox potentials.展开更多
Purification of surface water is widely practiced with conventional water treatment processes like coagulation-flocculation, sedimentation, filtration,and disinfection. Some reports have specified that conventional wa...Purification of surface water is widely practiced with conventional water treatment processes like coagulation-flocculation, sedimentation, filtration,and disinfection. Some reports have specified that conventional wastewater purification processes do not effectively remove many chemical contaminants,展开更多
Water resource is one of the important resources in the process of people's life and production, and it is also the key to people’s survival and development. With China’s great attention to environmental protect...Water resource is one of the important resources in the process of people's life and production, and it is also the key to people’s survival and development. With China’s great attention to environmental protection, the treatment of industrial wastewater and domestic sewage has become more and more important. This paper mainly expounds the significance of zero discharge of industrial wastewater and domestic sewage, and discusses the treatment process of industrial wastewater and domestic sewage, so as to promote the sustainable development of water resources in China.展开更多
In recent years, due to the increasing development of science and technology and industrial development in China, peoples demand for waste gas odor treatment technology in petrochemical enterprises is increasing becau...In recent years, due to the increasing development of science and technology and industrial development in China, peoples demand for waste gas odor treatment technology in petrochemical enterprises is increasing because the waste gas odor produced in daily operation of petrochemical production will pollute and harm our health environment, and at the same time, it will endanger the healthy development of the surrounding ecological environment, which is not conducive to the construction and development of ecological civilization in China. Therefore, this paper will mainly talk about the harmfulness of waste gas and peculiar smell produced in the manufacturing process of chemical enterprises, and at the same time, it will put forward targeted treatment technologies for different types of waste gas and peculiar smell, so as to effectively treat and solve the waste gas and peculiar smell in the production process of chemical enterprises.展开更多
Oil fields in most areas of our country have stepped into the stage of three times of exploitation. After inspecting the sewage produced, the workers found that there are a series of substances such as polymer, surfac...Oil fields in most areas of our country have stepped into the stage of three times of exploitation. After inspecting the sewage produced, the workers found that there are a series of substances such as polymer, surfactant, oily suspended solids and so on in the oil fields. With the addition of surfactants, the petroleum acids in crude oil gradually react with them, and the interfacial tension between sewage and oil decreases, which results in the presence of pollutants in sewage becoming more stable. From this point of view, the oilfield sewage treatment technology at this stage can no longer meet the demand for decontamination. Based on this, this paper studies the oily wastewater treatment process and key technologies for reference.展开更多
Nowadays, energy problem, ecological environment problem has become two major problems that perplex countries all over the world. Therefore, the concept of environmental protection and energy conservation is gradually...Nowadays, energy problem, ecological environment problem has become two major problems that perplex countries all over the world. Therefore, the concept of environmental protection and energy conservation is gradually recognized by people. Urban sewage treatment has always had the disadvantages of large energy consumption and serious secondary pollution. Therefore, it is necessary to strengthen the implementation of the concept of environmental protection and energy conservation, based on each link of sewage treatment, to better highlight the characteristics of environmental protection and energy conservation, and to fundamentally improve the quality level of urban sewage treatment process. In this regard, the article focuses on the study and analysis of the practical measures of urban sewage treatment in environmental protection projects.展开更多
According to different mechanism of microbial degradation of organics, this article divided the treatment processes of garbage landfill into four kinds, analyzed each kind of the treatment leachate process and present...According to different mechanism of microbial degradation of organics, this article divided the treatment processes of garbage landfill into four kinds, analyzed each kind of the treatment leachate process and presented a better improved process. (Author abstract) 4 Refs.展开更多
The plan of heat-treatment process for 2014Al alloy is designed using orthogonal method, the heat-treatment experiments are made and the mechanical properties are tested according to the designed plan. The effect of s...The plan of heat-treatment process for 2014Al alloy is designed using orthogonal method, the heat-treatment experiments are made and the mechanical properties are tested according to the designed plan. The effect of solid solution temperature, ageing temperature, ageing time on microscopic mechanism of the mechanical properties of the 2014Al alloy is studied using microscope, transmission electron microscope. The best heat treatment process of the 2014Al alloy is developed. The experimental results indicate that the strength σ<sub>b</sub>, yield stress σ<sub>0.2</sub>, percentage elongation δ of the alloy reach separately 490～500 MPa, 450～490 MPa, 10～12％ adopting the new heat treatment process. Compared with GB, the strength increases 20～30％, the percentage elongation increases 30～40％. The mechanism of the new heat-treatment process is also discussed.展开更多
In the drinking water treatment processes, the optimization of the treatment is an issue of particular concern. In general, the process consists of many units as settling, coagulation, flocculation, sedimentation, fil...In the drinking water treatment processes, the optimization of the treatment is an issue of particular concern. In general, the process consists of many units as settling, coagulation, flocculation, sedimentation, filtration and disinfection. The optimization of the process consists of some measures to decrease the managing and monitoring expenses and improve the quality of the produced water. The objective of this study is to provide water treatment operators with methods and practices that enable to attain the most effective use of the facility and in consequence optimize the cubic meter price of the treated water. This paper proposes a review on optimization of drinking water treatment process by analyzing all of the water treatment units and gives some solutions in order to maximize the water treatment performances without compromising the water quality standards. Some practical solutions and methods are performed in the water treatment plant located in the middle of Morocco (Meknes).展开更多
In response to escalating environmental protection standards,enhancing effluent quality(EQ)and process efficiency within wastewater treatment processes(WWTP)has become paramount.Effluent scheduling is a crucial part o...In response to escalating environmental protection standards,enhancing effluent quality(EQ)and process efficiency within wastewater treatment processes(WWTP)has become paramount.Effluent scheduling is a crucial part of WWTPs as it regulates the effluent residence time by adjusting the flow rate,which significantly impacts the biochemical reaction process.However,the discrete regulation and time-varying nature of WWTPs present crucial challenges in achieving effective effluent scheduling.In this study,sampling-based particle swarm optimization is proposed to solve the dynamic effluent scheduling for WWTPs.First,priority-based encoding and decoding methods are proposed to map the relationship between the decision variables and schedules.Second,the Wasserstein distance is introduced to design an initialization strategy to track the new global optimum in the dynamic environment of WWTPs.Third,a velocity update method is designed to improve the search efficiency by sampling the elitist neighbor solution.Fourth,a dynamic constraint handling method is developed to ensure solution feasibility in WWTPs.Finally,the proposed algorithm is tested in Benchmark Simulation Model No.1 to demonstrate its solving ability for the dynamic effluent scheduling problem of WWTPs.Computational experiments with state-of-the-art methods show that the proposed algorithm can achieve superior performance in terms of EQ and process efficiency.展开更多
The abundance of microplastics(MPs)in wastewater from three wastewater treatment plants(WWTPs)were determined in Hangzhou,Zhejiang Province,China.The MPs abundance was 140-350 particles per litre in the influent and 1...The abundance of microplastics(MPs)in wastewater from three wastewater treatment plants(WWTPs)were determined in Hangzhou,Zhejiang Province,China.The MPs abundance was 140-350 particles per litre in the influent and 10-30 particles per litre in the effluent.Four shapes of MPs in the influent were observed,while mainly only debris was left in the effluent.The percentage of small(<100μm),medium(100-500μm),and large-sized(≥500μm)plastics in the raw leachate of the three WWTPs were 54.3%,8.6%,and 37.1%,28.6%,64.3%,and 7.1%,and 41.4%,24.1%,and 34.5%,respectively.Mainly only the size of≤100μm was left in the effluent of all.The removal efficiencies of MPs in a range of 78.6%to 96.6%were achieved.Polypropylene,polystyrene,polyethylene,polyethylene terephthalate and polyvinyl chloride were the main types and detected in all wastewater samples,accounting for over 75%of all types.The plastic components contained in different industrial wastewater were more complex.The distribution of MPs was significantly positively correlated with most conventional indicators such as chemical oxygen demead,ammonia nitrogen,and total phosphorus,but not with heavy metals.Similar wastewater,different treatment processes,or similar processes but different wastewater(industrial wastewater proportion varied)could all lead to differences in MPs removal.The MPs abundance measured in this experiment was similar to some previous studies,but relatively high.The three WWTPs can discharge up to 6.0×10^(-8)-1.8×10^(-9) plastics of MPs per day,which poses potential ecological risks.This study indicates that the source control of MPs and optimizing the process design of existing WWTPs are crucial for preventing and controlling MPs pollution.展开更多
Emerging pollutants,such as antibiotics and antibiotic-resistance genes,are becoming increasingly important sources of safety and health concerns.Drinking water safety,which is closely related to human health,should r...Emerging pollutants,such as antibiotics and antibiotic-resistance genes,are becoming increasingly important sources of safety and health concerns.Drinking water safety,which is closely related to human health,should receive more attention than natural water body safety.However,minimal research has been performed on the efficacy of existing treatment processes in water treatment plants for the removal of antibiotics and antibiotic resistance genes.To address this research gap,this study detected and analyzed six main antibiotics and nine antibiotic resistance genes in the treatment processes of two drinking water plants in Wuhan.Samples were collected over three months and then detected and analyzed using ultra-high-performance liquid chromatography-tandem mass spectrometry and fluorescence quantitation.The total concentrations of antibiotics and antibiotic resistance genes in the influent water of the two water plants were characterized as December>March>June.The precipitation and filtration processes of the Zou Maling Water Plant and Yu Shidun Water Plant successfully removed the antibiotics.The ozone-activated carbon process increased the removal rate of most antibiotics to 100%.However,a large amount of antibiotic resistance gene residues remained in the effluents of the two water plants.The experiments demonstrated that the existing ozone-activated carbon processes could not effectively remove antibiotic resistance genes.This study provides a reference for the optimization of drinking water treatment processes for antibiotics and antibiotic resistance gene removal.展开更多
In this study,the efects of diferent heat treatment process parameters on the microstructure and mechanical properties of Al-12Si-5Cu-1.1Mg-2.3Ni-0.3La alloy were explored.Research showed that eutectic Si underwent th...In this study,the efects of diferent heat treatment process parameters on the microstructure and mechanical properties of Al-12Si-5Cu-1.1Mg-2.3Ni-0.3La alloy were explored.Research showed that eutectic Si underwent three stages during solution treatment:difusing,spheroidization and coarsening.As the solution temperature and time increased,the size of eutectic Si showed a trend of frst decreasing and then increasing.Compared with the heat treatment time,the heat treatment temperature had a more signifcant efect on the mechanical properties.The coarsening of microstructure was the main reason for the deterioration of mechanical properties.The Al_(3)Ti and Al_(3)CuNiLa in the microstructure after aging can signifcantly improve the mechanical properties of the alloy.The Al_(11)La_(3) with secondary precipitation occurred in the La-rich phase.The addition of La inhibited the growth of coherent/semi-coherentθandβphases,which was very benefcial for the improvement of high-temperature strength.Under the optimal heat treatment process parameters of 500℃×4 h+190℃×4 h,the ultimate tensile strength(UTS)of the alloy reached 366.65 MPa.The high-temperature strength and elongation of the alloy reached 101.98 MPa and 13.77%at 350℃,respectively.展开更多
The pyrolysis properties of five different pyrolysis tars, which the tars from 1# to 5# are obtained by pyrolyzing the sewage sludges of anaerobic digestion and indigestion from the A2/O wastewater treatment process, ...The pyrolysis properties of five different pyrolysis tars, which the tars from 1# to 5# are obtained by pyrolyzing the sewage sludges of anaerobic digestion and indigestion from the A2/O wastewater treatment process, those from the activated sludge process and the indigested sludge from the continuous SBR process respectively, were studied by thermal gravimetric analysis at a heating rate of 10 ℃/min in the nitrogen atmosphere. The results show that the pyrolysis processes of the pyrolysis tars of 1#, 2#, 3# and 5# all can be divided into four stages: the stages of light organic compounds releasing, heavy polar organic compounds decomposition, heavy organic compounds decomposition and the residual organic compounds decomposition. However, the process of 4# pyrolysis tar is only divided into three stages: the stages of light organic compounds releasing, decomposition of heavy polar organic compounds and the residual heavy organic compounds respectively. Both the sludge anaerobic digestion and the "anaerobic" process in wastewater treatment processes make the content of light organic compounds in tars decrease, but make that of heavy organic compounds with complex structure increase. Besides, both make the pyrolysis properties of the tars become worse. The pyrolysis reaction mechanisms of the five pyrolysis tars have been studied with Coats-Redfern equation. It shows that there are the same mechanism functions in the first stage for the five tars and in the second and third stage for the tars of 1#, 2#, 3# and 5#, which is different with the function in the second stage for 4# tar. The five tars are easy to volatile.展开更多
基金supported by the Natural Science Foundation of Shandong Province,China(No.ZR2021QE227)the Natural Science Foundation of Shandong Province,China(No.ZR2021QE272)+1 种基金the Open Project of State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(No.ES202120)the Taishan Scholars Program of Shandong Province,China(No.tsqn201812091)。
文摘It is particularly important to comprehensively assess the biotoxicity variation of industrial wastewater along the treatment process for ensuring the water environment security.However,intensive studies on the biotoxicity reduction of industrial wastewater are still limited.In this study,the toxic organics removal and biotoxicity reduction of coal chemical wastewater(CCW)along a novel full-scale treatment process based on the pretreatment process-anaerobic process-biological enhanced(BE)process-anoxic/oxic(A/O)process-advanced treatment process was evaluated.This process performed great removal efficiency of COD,total phenol,NH_(4)^(+)-N and total nitrogen.And the biotoxicity variation along the treatment units was analyzed from the perspective of acute biotoxicity,genotixicity and oxidative damage.The results indicated that the effluent of pretreatment process presented relatively high acute biotoxicity to Tetrahymena thermophila.But the acute biotoxicity was significantly reduced in BE-A/O process.And the genotoxicity and oxidative damage to Tetrahymena thermophila were significantly decreased after advanced treatment.The polar organics in CCW were identified as the main biotoxicity contributors.Phenols were positively correlated with acute biotoxicity,while the nitrogenous heterocyclic compounds and polycyclic aromatic hydrocarbons were positively correlated with genotoxicity.Although the biotoxicity was effectively reduced in the novel full-scale treatment process,the effluent still performed potential biotoxicity,which need to be further explored in order to reduce environmental risk.
基金the National Natural Science Foundation of China (Nos.52075362 and 51975399)the Central Government Guides Local Foundation for Science and Technology Development,China (Nos.YDZJSX2022A020 and YDZJSX2022B004).
文摘Thermal Barrier Coatings(TBCs)technology is key to improving the service temperature and the productivity of aircraft engines.The performance and failure life of TBCs are strongly influenced by surface integrity and microstructure.Therefore,recognizing failure mechanisms and developing effective surface treatment processes are crucial for further improving the reliability and durability of TBCs.This paper explains the primary reasons for TBC failure,emphasizing on how integrity of surface and interface influences interfacial oxidation,high-temperature erosion,and Calcium-Magnesium-Alumina-Silicate(CMAS)corrosion.Furthermore,this paper completely and rigorously evaluates the research status of TBCs surface treatment processes,including the characteristics and effects of various processes,and describes the requirements and goals of pretreatment and post-treatment.In addition,a potential direction for the development and application of TBCs surface treatment is suggested.
基金the National Key Research and Development Program of China(2022YFB3305800-5)the National Natural Science Foundation of China(62125301,62021003)+2 种基金the Beijing Outstanding Young Scientist Program(BJJWZYJH01201910005020)the Natural Science Foundation of Beijing Municipality(KZ202110005009)Youth Beijing Scholar(037).
文摘In wastewater treatment systems,extracting meaningful features from process data is essential for effective monitoring and control.However,the multi-time scale data generated by different sampling frequencies pose a challenge to accurately extract features.To solve this issue,a multi-timescale feature extraction method based on adaptive entropy is proposed.Firstly,the expert knowledge graph is constructed by analyzing the characteristics of wastewater components and water quality data,which can illustrate various water quality parameters and the network of relationships among them.Secondly,multiscale entropy analysis is used to investigate the inherent multi-timescale patterns of water quality data in depth,which enables us to minimize information loss while uniformly optimizing the timescale.Thirdly,we harness partial least squares for feature extraction,resulting in an enhanced representation of sample data and the iterative enhancement of our expert knowledge graph.The experimental results show that the multi-timescale feature extraction algorithm can enhance the representation of water quality data and improve monitoring capabilities.
基金Item Sponsored by National Nature Science Foundation of China(51071078)
文摘Dry sliding wear tests of a Cr-Mo-V cast hot-forging die steel was carried out within a load range of 50--300 N at 400℃ by a pin-on-disc high temperature wear machine. The effect of heat treatment process on wear resistance was systematically studied in order to select heat treatment processes of the steel with high wear resistance. The morphology, structure and composition were analyzed using scanning electron microscopy （SEM）, X-ray diffraction （XRD） and energy dispersive spectroscopy （EDS） ; wear mechanism was also discussed. Tribo-oxide layer was found to form on worn surfaces to reduce wear under low loads, but appear inside the matrix to increase wear under high loads. The tribo-oxides were mainly consisted of Fe3O4 and Fe2O3, FeO only appeared under a high load. Oxidative mild wear, transition of mild-severe wear in oxidative wear and extrusive wear took turns to operate with increasing the load. The wear resistance strongly depended on the selection of heat treatment processes or microstructures. It was found that bainite presented a better wear resistance than martensite plus bainite duplex structure, martensite structure was of the poorest wear resistance. The wear resistance increased with increasing austenizing temperature in the range of 920 to 1 120 ℃, then decreased at up to 1 220 ℃. As for tempering temperature and microstructure, the wear resistance increased in following order： 700℃ （tempered sorbite）, 200 ℃ （tempered martensite）, 440 to 650 ℃ （tempered troostite）. An appropriate combination of hardness, toughness, microstructural thermal stability was re- quired for a good wear resistance in high-temperature wear. The optimized heat treatment process was suggested for the cast hot-forging steel to be austenized at 1020 to 1 120 ℃, quenched in oil, then tempered at 440 to 650℃ for 2 h.
基金Supported by the National Natural Science Foundation of China(61622301,61533002)Beijing Natural Science Foundation(4172005)Major National Science and Technology Project(2017ZX07104)
文摘In wastewater treatment process(WWTP), the accurate and real-time monitoring values of key variables are crucial for the operational strategies. However, most of the existing methods have difficulty in obtaining the real-time values of some key variables in the process. In order to handle this issue, a data-driven intelligent monitoring system, using the soft sensor technique and data distribution service, is developed to monitor the concentrations of effluent total phosphorous(TP) and ammonia nitrogen(NH_4-N). In this intelligent monitoring system, a fuzzy neural network(FNN) is applied for designing the soft sensor model, and a principal component analysis(PCA) method is used to select the input variables of the soft sensor model. Moreover, data transfer software is exploited to insert the soft sensor technique to the supervisory control and data acquisition(SCADA) system. Finally, this proposed intelligent monitoring system is tested in several real plants to demonstrate the reliability and effectiveness of the monitoring performance.
基金supported by the Key program of Beijing Municipal Education Commission(KZ201810011012)National Natural Science Foundation of China(61873005)Support Project of High-level Teachers in Beijing Municipal Universities in the Period of 13th Fiveyear Plan(CIT&TCD201704044)。
文摘Waste water treatment process(WWTP)control has been attracting more and more attention.However,various undesired factors,such as disturbance,uncertainties,and strong nonlinear couplings,propose big challenges to the control of a WWTP.In order to improve the control performance of the closed-loop system and guarantee the discharge requirements of the effluent quality,rather than take the model dependent control approaches,an active disturbance rejection control(ADRC)is utilized.Based on the control signal and system output,a phase optimized ADRC(POADRC)is designed to control the dissolved oxygen and nitrate concentration in a WWTP.The phase advantage of the phase optimized extended state observer(POESO),convergence of the POESO,and stability of the closed-loop system are analyzed from the theoretical point of view.Finally,a commonly accepted benchmark simulation model no.1.(BSM1)is utilized to test the POESO and POADRC.Linear active disturbance rejection control(LADRC)and the suggested proportion-integration(PI)control are taken to make a comparative research.Both system responses and performance index values confirm the advantage of the POADRC over the LADRC and the suggested PI control.Numerical results show that,as a result of the leading phase of the total disturbance estimation,the POESO based POADRC is an effective and promising way to control the dissolved oxygen and nitrate concentration so as to ensure the effluent quality of a WWTP.
基金supported by the National Natural Science Foundation of China (No. 51138009)
文摘In order to explore the biodegradation behavior of nonylphenolic compounds during wastewater treatment processing, two full-scale wastewater treatment plants were investigated and batch biodegradation experiments were conducted. The biodegradation pathways under the various operational conditions were identified from batch experiments： shortening of ethoxy-chains dominated under the anaerobic condition, whereas oxidizing of the terminal alcoholic group prevailed over the other routes under the aerobic condition. Results showed that the anoxic condition could accelerate the biodegradation rates of nonylphenolic compounds, but had no influence on the biodegradation pathway. The biodegradation rates of nonylphenol （NP） and short-chain nonylphenol polyethoxylates （NPnEOs, n： number of ethoxy units） increased from the anaerobic condition, then the anoxic, finally to the aerobic condition, while those of long-chain NPnEOs and nonylphenoxy carboxylates （NPECs） seemed similar under the various conditions. Under every operational condition, long-chain NPnEOs showed the highest biodegradation activity, followed by NPECs and short-chain NPnEOs, whereas NP showed relatively recalcitrant characteristics especially under the anaerobic condition. In addition, introducing sulfate and nitrate to the anaerobic condition could enhance the biodegradation of NP and short-chain NPnEOs by supplying more positive redox potentials.
基金supported by grants from Science and Technology Planning Project of Shenzhen [No.200703079]
文摘Purification of surface water is widely practiced with conventional water treatment processes like coagulation-flocculation, sedimentation, filtration,and disinfection. Some reports have specified that conventional wastewater purification processes do not effectively remove many chemical contaminants,
文摘Water resource is one of the important resources in the process of people's life and production, and it is also the key to people’s survival and development. With China’s great attention to environmental protection, the treatment of industrial wastewater and domestic sewage has become more and more important. This paper mainly expounds the significance of zero discharge of industrial wastewater and domestic sewage, and discusses the treatment process of industrial wastewater and domestic sewage, so as to promote the sustainable development of water resources in China.
文摘In recent years, due to the increasing development of science and technology and industrial development in China, peoples demand for waste gas odor treatment technology in petrochemical enterprises is increasing because the waste gas odor produced in daily operation of petrochemical production will pollute and harm our health environment, and at the same time, it will endanger the healthy development of the surrounding ecological environment, which is not conducive to the construction and development of ecological civilization in China. Therefore, this paper will mainly talk about the harmfulness of waste gas and peculiar smell produced in the manufacturing process of chemical enterprises, and at the same time, it will put forward targeted treatment technologies for different types of waste gas and peculiar smell, so as to effectively treat and solve the waste gas and peculiar smell in the production process of chemical enterprises.
文摘Oil fields in most areas of our country have stepped into the stage of three times of exploitation. After inspecting the sewage produced, the workers found that there are a series of substances such as polymer, surfactant, oily suspended solids and so on in the oil fields. With the addition of surfactants, the petroleum acids in crude oil gradually react with them, and the interfacial tension between sewage and oil decreases, which results in the presence of pollutants in sewage becoming more stable. From this point of view, the oilfield sewage treatment technology at this stage can no longer meet the demand for decontamination. Based on this, this paper studies the oily wastewater treatment process and key technologies for reference.
文摘Nowadays, energy problem, ecological environment problem has become two major problems that perplex countries all over the world. Therefore, the concept of environmental protection and energy conservation is gradually recognized by people. Urban sewage treatment has always had the disadvantages of large energy consumption and serious secondary pollution. Therefore, it is necessary to strengthen the implementation of the concept of environmental protection and energy conservation, based on each link of sewage treatment, to better highlight the characteristics of environmental protection and energy conservation, and to fundamentally improve the quality level of urban sewage treatment process. In this regard, the article focuses on the study and analysis of the practical measures of urban sewage treatment in environmental protection projects.
文摘According to different mechanism of microbial degradation of organics, this article divided the treatment processes of garbage landfill into four kinds, analyzed each kind of the treatment leachate process and presented a better improved process. (Author abstract) 4 Refs.
文摘The plan of heat-treatment process for 2014Al alloy is designed using orthogonal method, the heat-treatment experiments are made and the mechanical properties are tested according to the designed plan. The effect of solid solution temperature, ageing temperature, ageing time on microscopic mechanism of the mechanical properties of the 2014Al alloy is studied using microscope, transmission electron microscope. The best heat treatment process of the 2014Al alloy is developed. The experimental results indicate that the strength σ<sub>b</sub>, yield stress σ<sub>0.2</sub>, percentage elongation δ of the alloy reach separately 490～500 MPa, 450～490 MPa, 10～12％ adopting the new heat treatment process. Compared with GB, the strength increases 20～30％, the percentage elongation increases 30～40％. The mechanism of the new heat-treatment process is also discussed.
文摘In the drinking water treatment processes, the optimization of the treatment is an issue of particular concern. In general, the process consists of many units as settling, coagulation, flocculation, sedimentation, filtration and disinfection. The optimization of the process consists of some measures to decrease the managing and monitoring expenses and improve the quality of the produced water. The objective of this study is to provide water treatment operators with methods and practices that enable to attain the most effective use of the facility and in consequence optimize the cubic meter price of the treated water. This paper proposes a review on optimization of drinking water treatment process by analyzing all of the water treatment units and gives some solutions in order to maximize the water treatment performances without compromising the water quality standards. Some practical solutions and methods are performed in the water treatment plant located in the middle of Morocco (Meknes).
基金supported by the National Key Research and Development Project(Grant No.2022YFB3305800-05)the National Natural Science Foundation of China(Grant Nos.92467205,62021003,62125301)+1 种基金the Beijing Nova Program(Grant No.K7058000202402)the Youth Beijing Scholar(Grant No.037)。
文摘In response to escalating environmental protection standards,enhancing effluent quality(EQ)and process efficiency within wastewater treatment processes(WWTP)has become paramount.Effluent scheduling is a crucial part of WWTPs as it regulates the effluent residence time by adjusting the flow rate,which significantly impacts the biochemical reaction process.However,the discrete regulation and time-varying nature of WWTPs present crucial challenges in achieving effective effluent scheduling.In this study,sampling-based particle swarm optimization is proposed to solve the dynamic effluent scheduling for WWTPs.First,priority-based encoding and decoding methods are proposed to map the relationship between the decision variables and schedules.Second,the Wasserstein distance is introduced to design an initialization strategy to track the new global optimum in the dynamic environment of WWTPs.Third,a velocity update method is designed to improve the search efficiency by sampling the elitist neighbor solution.Fourth,a dynamic constraint handling method is developed to ensure solution feasibility in WWTPs.Finally,the proposed algorithm is tested in Benchmark Simulation Model No.1 to demonstrate its solving ability for the dynamic effluent scheduling problem of WWTPs.Computational experiments with state-of-the-art methods show that the proposed algorithm can achieve superior performance in terms of EQ and process efficiency.
基金funded by the National Natural Science Foundation of China(42477406,51878617)the horizontal scientific research project(KYY-HX-20220803)the Engineering Research Center of Ministry of Education for Renewable Energy Infrastructure Construction Technology。
文摘The abundance of microplastics(MPs)in wastewater from three wastewater treatment plants(WWTPs)were determined in Hangzhou,Zhejiang Province,China.The MPs abundance was 140-350 particles per litre in the influent and 10-30 particles per litre in the effluent.Four shapes of MPs in the influent were observed,while mainly only debris was left in the effluent.The percentage of small(<100μm),medium(100-500μm),and large-sized(≥500μm)plastics in the raw leachate of the three WWTPs were 54.3%,8.6%,and 37.1%,28.6%,64.3%,and 7.1%,and 41.4%,24.1%,and 34.5%,respectively.Mainly only the size of≤100μm was left in the effluent of all.The removal efficiencies of MPs in a range of 78.6%to 96.6%were achieved.Polypropylene,polystyrene,polyethylene,polyethylene terephthalate and polyvinyl chloride were the main types and detected in all wastewater samples,accounting for over 75%of all types.The plastic components contained in different industrial wastewater were more complex.The distribution of MPs was significantly positively correlated with most conventional indicators such as chemical oxygen demead,ammonia nitrogen,and total phosphorus,but not with heavy metals.Similar wastewater,different treatment processes,or similar processes but different wastewater(industrial wastewater proportion varied)could all lead to differences in MPs removal.The MPs abundance measured in this experiment was similar to some previous studies,but relatively high.The three WWTPs can discharge up to 6.0×10^(-8)-1.8×10^(-9) plastics of MPs per day,which poses potential ecological risks.This study indicates that the source control of MPs and optimizing the process design of existing WWTPs are crucial for preventing and controlling MPs pollution.
基金supported by the Wuhan Science and Technology Planning Project(No.2018060401011313).
文摘Emerging pollutants,such as antibiotics and antibiotic-resistance genes,are becoming increasingly important sources of safety and health concerns.Drinking water safety,which is closely related to human health,should receive more attention than natural water body safety.However,minimal research has been performed on the efficacy of existing treatment processes in water treatment plants for the removal of antibiotics and antibiotic resistance genes.To address this research gap,this study detected and analyzed six main antibiotics and nine antibiotic resistance genes in the treatment processes of two drinking water plants in Wuhan.Samples were collected over three months and then detected and analyzed using ultra-high-performance liquid chromatography-tandem mass spectrometry and fluorescence quantitation.The total concentrations of antibiotics and antibiotic resistance genes in the influent water of the two water plants were characterized as December>March>June.The precipitation and filtration processes of the Zou Maling Water Plant and Yu Shidun Water Plant successfully removed the antibiotics.The ozone-activated carbon process increased the removal rate of most antibiotics to 100%.However,a large amount of antibiotic resistance gene residues remained in the effluents of the two water plants.The experiments demonstrated that the existing ozone-activated carbon processes could not effectively remove antibiotic resistance genes.This study provides a reference for the optimization of drinking water treatment processes for antibiotics and antibiotic resistance gene removal.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.U2241232,U2341253 and 52375317)the National Key R&D Program of China(No.2022YFB3404204).
文摘In this study,the efects of diferent heat treatment process parameters on the microstructure and mechanical properties of Al-12Si-5Cu-1.1Mg-2.3Ni-0.3La alloy were explored.Research showed that eutectic Si underwent three stages during solution treatment:difusing,spheroidization and coarsening.As the solution temperature and time increased,the size of eutectic Si showed a trend of frst decreasing and then increasing.Compared with the heat treatment time,the heat treatment temperature had a more signifcant efect on the mechanical properties.The coarsening of microstructure was the main reason for the deterioration of mechanical properties.The Al_(3)Ti and Al_(3)CuNiLa in the microstructure after aging can signifcantly improve the mechanical properties of the alloy.The Al_(11)La_(3) with secondary precipitation occurred in the La-rich phase.The addition of La inhibited the growth of coherent/semi-coherentθandβphases,which was very benefcial for the improvement of high-temperature strength.Under the optimal heat treatment process parameters of 500℃×4 h+190℃×4 h,the ultimate tensile strength(UTS)of the alloy reached 366.65 MPa.The high-temperature strength and elongation of the alloy reached 101.98 MPa and 13.77%at 350℃,respectively.
基金supported by the project of Tianjin higher education under contract (20060522)the project of Tianjin Polytechnic University (2230004)
文摘The pyrolysis properties of five different pyrolysis tars, which the tars from 1# to 5# are obtained by pyrolyzing the sewage sludges of anaerobic digestion and indigestion from the A2/O wastewater treatment process, those from the activated sludge process and the indigested sludge from the continuous SBR process respectively, were studied by thermal gravimetric analysis at a heating rate of 10 ℃/min in the nitrogen atmosphere. The results show that the pyrolysis processes of the pyrolysis tars of 1#, 2#, 3# and 5# all can be divided into four stages: the stages of light organic compounds releasing, heavy polar organic compounds decomposition, heavy organic compounds decomposition and the residual organic compounds decomposition. However, the process of 4# pyrolysis tar is only divided into three stages: the stages of light organic compounds releasing, decomposition of heavy polar organic compounds and the residual heavy organic compounds respectively. Both the sludge anaerobic digestion and the "anaerobic" process in wastewater treatment processes make the content of light organic compounds in tars decrease, but make that of heavy organic compounds with complex structure increase. Besides, both make the pyrolysis properties of the tars become worse. The pyrolysis reaction mechanisms of the five pyrolysis tars have been studied with Coats-Redfern equation. It shows that there are the same mechanism functions in the first stage for the five tars and in the second and third stage for the tars of 1#, 2#, 3# and 5#, which is different with the function in the second stage for 4# tar. The five tars are easy to volatile.
