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1.
Effect of carbon sources on phosphorus forms’ transformation of phosphate reduction system in domestic sewage 
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下载免费PDF全文 The influence of glucose, methanol, sodium acetate and starch on phosphorus removal performance and conversion of phosphorus transformation is studied. The results show that 42.05 mg per day of external phosphorus is removed in the systems using glucose as carbon source and it is significantly better than the other three carbon sources. When glucose is used as carbon source, NaOH-P and BD-P which are main ingredients of Inorg-P in system sludge transform 1.67 mg per gram dry sludge, and conversion capacity of NaOH85-P is relatively higher. The whole phosphorus transformation process goes toward reactive phosphorus which can be used by phosphorus reducing bacteria. When starch is used as carbon source, conversion capacity of Org-P in sludge is lowest for 2.86 mg per gram dry sludge, which is the restrictive process of entire phosphorus transformation. When starch is used as methanol, sodium acetate, conversion capacity of NaOH85-P in sludge is relatively low and BD-P is difficult to transform, which is the restrictive step of entire phosphorus transformation. 相似文献
2.
PCR DGGE and real time PCR technologies were applied to analyze the relationship between operation efficiency and microbial community structure of the Sequence Batch Biofilm Reactor(SBBR) autotrophic nitrogen removal process.The reactor was possessed of a high nitrogen removal efficiency.And the similarity of microbial community structure between active sludge and biofilm samples was 58.3%. The features of DO distributing on active sludge and biofilm made an appropriate condition for different bacteria.Ammonium oxidation bacteria and anammox were the preponderant bacterium in reactor.And their co metabolisms made TN removal rate reach to 90% and 80%,respectively.The reactor worked under a low efficiency with low concentration of biofilm.It is found that there is no much difference between biofilm and active sludge samples on the microbial community structure.The similarity reached to 100% and the variety of dominant bacteria was poor.Nitrite oxidation bacteria (NOB) were not “washed out” during the set up time that NO3- was accumulated in this reactor.TN removal rate was only about 20% to 30%. 相似文献
3.
The influences of dissolved oxygen (DO) on the removal process of nitrogen and phosphorous in a sludge reduction system had been studied by controlling aeration amounts. It was found that under the conditions of low doses of 2,4,5trichlorophenol (TCP), endogenous sour values of activated sludge increased with the extension of low DO state duration in SBR system and the decrease of cyclic average DO, which led to a low DO environment favored the formation of simultaneous nitrification and denitrification(SND).TCP concentration was recommended as 2mg / L and cyclic average DO value in SBR system was kept at 2mg / L based on the impacts of TCP concentration on sludge reduction, removal of nitrogen and phosphorous and sludge performance. Compared with the control system, aeration amounts increased by 23% and the discharge of excess sludge decreased by 34.6%. The water quality in effluents was equivalent in the aeration sludge reduction system with 2mg/LTCP, which met the discharge standards. Therefore, it was indicated that the removal of nitrogen and phosphorous and sludge reduction can obtain excellent performance in TCP system under low DO state with removing Phosphrous rich sewage. 相似文献
4.
SBR method is the short for intermittent sequencing batch freatment that is an ideal techmology to order a certain amount of intermittent operation of the activated sludge treatment process. SBR which is currently an in-depth study of the biological wastewater treatment technology is a simple process, the effect of stability, small footprint, and strong resistance to shock load and has good advantages of nitrogen and phosphorus removal capacity. This study first analyzes and discusses substrate degradation process of SBR method , compares among several different SBR methods, and then derives microbial growth and substrate degradation kinetics relationship with a view to promoting the progress of the work in this area. 相似文献
5.
The thickened surplus sludge from municipal wastewater treatment plants is generally mechanically dewatered after regulated with flocculants and the type and dosage of flocculants will influence the dewatering effect directly.And the cost of flocculants is the main part of operating cost of sewage sludge treatment.With the processing practice on yields,thickening and dewatering pattern of Zhenjiang Wastewater Treatment Plant,the analysis and selection of flocculants are carried out with respect to the type and dosage of flocculants for sewage sludge regulation.the principles for flocculants selection and simple calculation method for chemicals cost for sludge treatment are proposed.It is suggested that the dosage of flocculants for sludge regulation should be adjusted in different seasons in real operation of the municipal wastewater treatment plants. 相似文献
6.
Aiming at the hydraulic system of CVT (Continuously Variable Transmission), the transfer function of hydraulic system of CVT and the dynamic simulation model of this system based on AMESIM are built, and the characteristics of speed ratio response is simulated and calculated. The influences of spring constant, damping coefficient and mass of moving part on rising time, setting time and overshoot are analyzed. The result shows that the dynamic simulation model of this system is reasonable and will provide a basis and method for the optimization of CVT hydraulic system’s dynamic characteristics in the future. 相似文献
7.
As the key components of the wind turbine transmission, wind turbine drivetrain is always working under the complex and time-varing conditions, like flexible tower supporting, variable wind and changing load. Thus drivetrain is no wonder the weakest part for the wind turbine and its vibration characteristics determine the reliability and operating life of the wind turbine. This paper proposes a remote on-line test method for drivetrain vibration based on an intellectual monitoring unit named WindCon. The vibration characteristics of the commonly used multi-megawatt wind turbine are summoned through analyzing the collected data in different working conditions. The wind field results show that the vibration of drivetrain is relatively complex, and it’s mainly manifested as a combination vibration of torsion, bending, and waving. Main frequencies of vibration of mainshaft, gearbox, and other parts in drivetrain are gear meshing frequencies and shaft rotating frequencies of each transmission stage especially high speed stage, and are accompanied by rotating frequencies modulation. 相似文献
8.
The settling property, COD removal rate, Ca 2+ retention rate, variations of biofacies and the effect of sludge reduction of the high hardness wastewater of the activated sludge process by adding green and safe scale inhibitor PESA (Polyepoxysuccinic Acid) during the experiment have been studied for the COD was 100～300 mg/L, calcium concentration was 110～280 mg/L of the high hardness of wastewater. The results show that MLSS was less than the ordinary activated sludge reactor, the content of the inorganic substrate in activated sludge was significantly reduced and resulted in the decrease of calcium activated sludge putout, the reduction reached to 41.33%, The purpose of calcium wastewater treatment sludge reduction was achieved.The COD removal rate of PESA activated sludge reactor reached above 90%, the Ca 2+ retention rate reached above 80%. PESA inhibits the sedimentation of a part of calcium salt in activated sludge surface, bioactivity was kept well, and in this concentration range, indicative microbial were able to grow and reproduce. The ability to resist impact load has been enhanced in high hardness water, sludge age extension. 相似文献
9.
Aiming at the drawbacks of the current detecting methods, a nondestructive examination system design for bridge cables based on high speed digital signal processors chip DM642 is presented, and the hardware platform of the system is built. This examination system mainly consists of four parts: the image defaults acquisition part, DM642 hardware platform, creeping part and defaults locating equipment. The designed system is tested on the hardware platform based on digital image processing algorithm. The experimental results show that the detecting system has the advantages of high stability and reliability, real time, mass storage, and nondestructive examination, etc. This system uses high technology and has significant meaning on detecting the current bridge cables health, furthermore, this method can be used in other examination fields. 相似文献
10.
The crack tip region in an elastic composite can be divided into three different zones. The constitutive equations corresponding to these zones and the extent of the saturated damage zones are derived. The damage isotropy in the largest saturated damage zone is expressed by utilizing the Monte Carlo technique to create uniform distribution microcracks. The interaction between the main crack and microcracks can be evaluated by an alternating iteration scheme. In the assumption of a dilute concentration of microcracks, the interaction among microcracks is neglected, and the stress intensity factor produced by interaction between the main crack and each microcrack can be superposed. Two sources of loading are analyzed: one is for the main crack microcrack interaction under an applied remote load, and the other is for the main crack microcrack interaction accompanied by the relief of residual stresses on the microcrack surfaces. The results show that two sources of loading can shield the main crack tip, and microcracks behind the main crack tip can create the most shielding whereas the micro cracks ahead of the main crack tip play no role in shielding. 相似文献
11.
The main object of this paper is to research the liquidity risk management of the open-end securities investment fund in line with the real position of China's securities market and investment regulation of the open-end securities investment fund.So the paper concentrates on discussing the redemption forecasting methods,stock liquidity assessment system,portfolio selection in line with the redemption forecast,and financing from the other institution,which are the main parts of liquidity risk management of the open-end securities investment fund. 相似文献
12.
With the development of industrial automation technology, the monitoring system becomes more and more important in the control system. The paper discusses the monitoring system design based on the pump station for high press water. At first, the paper introduced the base process and the control system of the pump station for high press water. The control system includes two parts: upper part and lower part. The control network consisted of some PLC controls the device in the system. Then the method of the OOP technology application to the monitoring system design are emphatically introduced and discussed. Finally, the paper briefly introduced the main function models and the key technologies. 相似文献
13.
The authors analyze major factor influencing the vehicle starting and shifting character of electronic-control AMT. By taking the mini-vehicle of Chan'an Star as carrier, electronic-control hydraulic AMT is developed, comprehensive shift-control strategy and clutch joint-control strategy are constitued, and related factors affecting clutch joint disciplinarian are complemented. The authors also put forward control aim of engine speed in the process of vehicle start and shifting, and automatic control to engine speed is realized by adopting electronic throttle. A last tests on prototype vehicle start &shift are made under different working conditions. The result shows newly-developed automatic transmission system is of more satisfactory control effect. 相似文献
14.
XIANG Li-jun WANG Bo-chu DUAN Chuan-ren LIU Liu WANG Qing-hongnistry of Education College of Bioengineering Chongqing University Chongqing Chin 《保鲜与加工》2004,(10):71-74
The paper researches on the degradation of LAS (Linear Alkyl benzene Sulphonate) by combining AS1.860 immobilized with low intensity ultrasonic irradiation. The paper also discusses the influence of pH, rotary velocity, LAS concentration and the condition of low intensity ultrasonic irradiation on the degradation of LAS, the degradation rate of LAS is the main index of our experiment, the results of orthogonal test shows that low ultrasonic irradiation can increase the metabolizing of microorganism cells and facilitate the biodegradation of immobilized cells to LAS, here we research the degradation condition of 50mg/L LAS simulation wastewater with low ultrasonic irradiation, and the results show that the influence is obvious, the optimization degradation rate is about 83%, nine point five percent higher than that of the immobilized cells without ultrasonic irradiation. 相似文献
15.
Under the salt frost environment, the flexural behavior of reinforced concrete was studied. The bearing capacity and deformation performance of the beams were analyzed by comparing with the reference beam(undamaged) and beams subjected to 25,50,75 and 100 salt freeze-thaw cycles respectively. The results showed the plane section hypothesis still was satisfied for the concrete strains of frost beam section, and the mechanical characteristics of frost beam was similar to reference; The main reason to affect the beam bearing capacity under salt freeze-thaw environment was the concrete cover scaling in the compressive zone. Secondly, it was the reduction in concrete strength, while the degradation of bond properties between rebar and concrete was not a dominated factor; the deformations of concrete beam increased mainly due to the reduction in concrete strength, the damage of concrete cover and the degradation of bond properties. In addition to the number of freeze-thaw cycles, the positions of freeze-thaw damage and the load level affected the degree of reduction in beam stiffness. 相似文献
16.
Based on GRI Mech 3.0 mechanism, using kinetic model, the auto ignition characteristics of nature gas hydrogen air mixture are studied in different initial conditions under constant pressure. This study focuses on the changes of temperature and component concentrations,ignition delay time and flame propagation speed. The results show that under different initial conditions, with the increase of hydrogen fraction in the mixture, the ignition delay time decreases significantly and flame propagation speed increases significantly. On the other hand, Hydrogen fraction has been found of little influence on flame temperature. 相似文献
17.
Based on the sewage treatment device of Two-phase Integrated Sludge Thickening and Digestion reactor (TISTD), microbial community structure in stable operation and its ecological variation when load changes are investigated. During a stable operation with 30% sludge dosage rate, 20 dominant bacterial strains are individually isolated from acid-phase and methane-phase of the reactor. Sequence analysis of 16S rDNA reveals that six of the achieved strains belong to Bacillus, Methanospirillum and Methanococcus respectively. Ten sludge samples are collected separately in 5 periods when the reactor operates with 10%, 20% and 30% sludge dosage rate and in the state of started-up and disordered, and followed by DNA extraction, purification, 16S rDNA PCR amplification and temperature gradient gel electrophoresis (TGGE). The good quality of DNA extraction and amplification demonstrates that there is an abundant biomass in the sludge under mid-temperature condition. The results show that TISTD reactor has a high biodiversity in microbial communities and is complex and stable in ecosystem structure, which effectively supports the good digestion in sludge thickening. 相似文献
18.
In order to investigate the local and stirring effect of converters, a converter water model whose prototype is a 55 t converter is built. The method of multi-electrode simultaneous detection is used under different blowing ways. Under pure bottom blowing conditions, the mixing time at the bottom center is relatively short. While, in the condition of top blowing, the weak stirring zone is at the bottom center. In the condition of top-bottom combined blowing, with the increase of lance height, the mixing time of the position of the 4 measuring points in BOF bath first decrease and then increase. And the bottom nozzles layout is obtained when the average mixing time is the shortest. When the lance height is 0.16 m, the mixing effect is better on the upper and lower part of the sidewall and at the center of circulation; when the lance height is 0.20 m, the mixing time at the bottom center is the shortest. The stirring and mixing effect of the symmetrical and the asymmetrical layout of bottom blowing nozzles is compared, and it’s found the asymmetrical and centralized arrangement is more conductive to improve the flow field of the converter and reduce weak stirring zones. 相似文献
19.
WANG Qing-hai~ 《保鲜与加工》2003,(12):133-137
The fractures distribution and fracture rock mass permeation research is the premise condition that to study groundwater movement and pollutant migration in fracture rock mass in bed rock area, which includes the dominance orientation of fracture that groundwater fluxes in it, the brisk zone distribution of fracture water and the permeability calculation of rock mass. This paper mainly analyzes the fracture distribution and the dominance orientation of fracture and the permeability of a low-medium radioactive waste disposal field based on its rich geologic record. The following results are found through Statistical analysis and comparison calculation.The active zone of fractural water in bed rock is an active channel of active nucleus migration. Tthe headrace fracture of disposition have a dominant orientation. The penetrating coefficient tensor in bed rock fracture is also calculated. 相似文献
20.
Aiming at domestic garbage aerobic compost and town sludge anaerobic treatment, on the basis of reactor TISTD (the integrated of sludge thickening and digestion)which is developed by the authors’ team, a TIDGTS (the integrated of domestic garbage and town sludge)reactor is designed.The reactor is made up of garbage and sludge chambers.Aerobic compost is adopted in the garbage chamber, while anaerobic fermentation is used in the sludge chamber, thus garbage and sludge can be treated in the same reactor.32~36 ℃ of sludge digestion can be ensured by the heat from sludge digestion, and 20 L sludge and 15 kg garbage can be treated per day.While inlet sludge moisture content is 97.2%~99.8% and VS/TS is 0.45~0.69, the discharged sludge moisture content is 92.7%~96.1% and VS/TS is 0.28~0.42.When the inlet garbage moisture content is 73.5% and VS/TS is 0.65~0.88, the discharged garbage moisture content is 48.6% and VS/TS is 0.32~0.44.The results show that the efficiency of concentration and digestion is near to TISTD which is heated by heating wire. 相似文献