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Search Results: 1 - 10 of 51567 matches for " PENG Yong-zhen "
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Denitrification potential enhancement by addition of external carbon sources in a pre-denitrification process
PENG Yong-zhen,MA Yong,WANG Shu-ying,
PENG Yong-zhen
,MA Yong,WANG Shu-ying

环境科学学报(英文版) , 2007,
Abstract: The aim of this study is to investigate the denitrification potential enhancement by addition of external carbon sources and to estimate the denitrification potential for the predenitrification system using nitrate utilization rate(NUR)batch tests.It is shown that the denitrification potential Can be substantially increased with the addition of three external carbon sources,i.e.methanol,ethanol,and acetate.and the denitrification rates of ethanol,acetate,and methanol reached up to 9.6,12,and 3.2 mgN/(gVSS·h),respectively,while mat of starch wastewater was only 0.74 mgN/(gVSS·h).By comparison,ethanol was found to be the best extemal carbon source.NUR batch tests with starch wastewater and waste ethanol were carried out.The denitrification potential increased from 5.6 to 16.5 mg NO.-N/L owing to waste ethanol addition.By means of NUR tests,the wastewater characteristics and kinetic parameters can be estimated.which are used to determine the denitrification potential of wastewater,to calculate the denitrification potential of the plant and to predict the nitrate effluent quality,as well as provide information for developing carbon dosage conlxol strategy.
Sterilization of Escherichia coli cells by the application of pulsed magnetic field
LI Mei,QU Jiu-hui,PENG Yong-zhen,
LI Mei
,QU Jiu-hui,PENG Yong-zhen

环境科学学报(英文版) , 2004,
Abstract: The inactivation of microorganisms by pulsed magnetic field was studied. It was improved that the application of electromagnetic pulses evidently causes a lethal effect on E. coli cells suspended in phosphate buffer solution Na 2HPO 4/NaH 2PO 4(0 334/0 867 mmol/L). Experimental results indicated that the survivability(N/N 0; where N 0 and N are the number of cells survived per mill il iter before and after electromagnetic pulses application, respectively) of E. coli decreased with magnetic field intensity B and treatment time t. It was also found that the medium temperatures, the frequencies of pulse f, and the initial bacterial cell concentrations have determinate influences in destruction of E. coli cells by the application of magnetic pulses. The application of an magnetic intensity B=160 mT at pulses frequency f=62 kHz and treatment time t=16 h result in a considerable destruction levels of E. coli cells (N/N 0=10 -4 ). Possible mechanisms involved in sterilization of the magnetic field treatment were discussed. In order to shorten the treatment time, many groups of parallel inductive coil were used. The practicability test showed that the treatment time was shortened to 4 h with the application of three groups of parallel coil when the survivability of E.coli cells was less than 0 01%; and the power consumption was about 0 2 kWh /m 3.
Effects of seawater salinity on nitrite accumulation in short-range nitrification to nitrite as end product
YU De-shuang,PENG Yong-zhen,ZHANG Kui,
YU De-shuang
,PENG Yong-zhen,ZHANG Kui

环境科学学报(英文版) , 2004,
Abstract: The effect of seawater salinity on nitrite accumulation in short-range nitrification to nitrite as the end product was studied by using a SBR. Experimental results indicated that the growth of nitrobacteria was inhibited and very high levels of nitrite accumulation at different salinities were achieved under the conditions of 25-28 degrees C, pH 7.5-8.0, and the influent ammonia nitrogen of 40-70 mg/L when seawater flow used to flush toilet was less than 35% (salinity 12393 mg/L, Cl- 6778 mg/L) of total domestic wastewater flow, which is mainly ascribed to much high chlorine concentration of seawater. Results showed that high seawater salinity is available for short-range nitrification to nitrite as the end product. When the seawater flow used to flush toilet accounting for above 70% of the total domestic wastewater flow, the removal efficiency of ammonia was still above 80% despite the removal of organics declined obviously (less than 60%). It was found that the effect of seawater salinity on the removal of organics was negative rather than positive one as shown for ammonia removal.
Study of control strategy and simulation in anoxic-oxic nitrogen removal process
PENG Yong-zhen,WANG Zhi-hui,WANG Shu-ying,
PENG Yong-zhen
,WANG Zhi-hui,WANG Shu-ying

环境科学学报(英文版) , 2005,
Abstract: The control strategy and simulation of external carbon addition were specially studied in an anoxic-oxic(A/O) process with low carbon: nitrogen(C/N) domestic wastewater. The control strategy aimed to adjust the flow rate of external carbon dosage to the anoxic zone, thus the concentration of nitrate plus nitrite(NOx--N) in the anoxic zone was kept closed to the set point. The relationship was studied between the NOx--N concentration in the anoxic zone(S_ NO) and the dosage of external carbon, and the results showed that the removal efficiency of the total nitrogen(TN) could not be largely improved by double dosage of carbon source when S_ NO reached about 2 mg/L. Through keeping S_ NO at the level of about 2 mg/L, the demand of effluent quality could be met and the carbon dosage could be optimized. Based on the Activated Sludge Model No.1(ASM No.1), a simplified mathematical model of external carbon dosage was developed. Simulation results showed that PI controller and feed-forward PI controller both had good dynamic response and steady precision. And feed-forward PI controller had better control effects due to its consideration of influent disturbances.
Constitute Analysis of the Dissolved Organic Carbon from Sewage Effluent of SBR: the Impact of pH Value

GUO Jin,PENG Yong-zhen,

环境科学 , 2008,
Abstract: To discuss the characteristics of effluent organic matter (EfOM) from biologically treated sewage effluent, the impact of pH value on SBR was originally evaluated with an artificial wastewater. The results revealed that dissolved organic matter (DOM) from SBR was greatly influenced by pH value. When pH value of the SBR with original pH of 6.5 was decreased to 6.0, DOC of its effluent gradually increased from its original 4.0 mg·L-1. Further increasing pH can alleviate this increase. For the SBR with original pH of 8.0, DOC of effluent decreased rapidly from its original 4.0 mg·L-1 to 2 mg·L-1, while further decreasing pH to 6.5 did not affected this. Tannin and soluble microbial products (SMPs) including protein, carbohydrate and DNA consist to the main part of DOM in the sewage effluent. The pH value had a long-term impact on the formation of SMPs. Decreasing pH will result in its gradual increase. The impact of pH value on anaerobic process dominated the DOM degradation during the operation period. Higher pH value was helpful for the degradation of DOM.
Nitrogen removal influence factors in A/O process and decision trees for nitrification/denitrification system
MA Yong,PENG Yong-zhen,WANG Shu-ying,WANG Xiao-Lian,
MA Yong
,PENG Yong-zhen,WANG Shu-ying,WANG Xiao-lian

环境科学学报(英文版) , 2004,
Abstract: In order to improve nitrogen removal in anoxic/oxic(A/O) process effectively for treating domestic wastewaters, the influence factors, DO(dissolved oxygen), nitrate recirculation, sludge recycle, SRT(solids residence time), influent COD/TN and HRT(hydraulic retention time) were studied. Results indicated that it was possible to increase nitrogen removal by using corresponding control strategies, such as, adjusting the DO set point according to effluent ammonia concentration; manipulating nitrate recirculation flow according to nitrate concentration at the end of anoxic zone. Based on the experiments results, a knowledge-based approach for supervision of the nitrogen removal problems was considered, and decision trees for diagnosing nitrification and denitrification problems were built and successfully applied to A/O process.
Analysis of On-line Control Strategies of Aeration Flow Rate for Aerobic-anoxic Biological Nitrogen Removal Process

MA Yong,PENG Yong-zhen,WANG Shu-ying,

环境科学 , 2008,
Abstract: Aeration control is the important control variable for the biological nitrogen removal process, which determines the system removal performance and operational cost. Some typical control strategies of aeration for aerobic-anoxic biological nitrogen removal process were studied using Benchmark-BSM1 platform model. It was demonstrated that the best control strategy of aeration was feedforward-feedback control, following by feedback control, constant DO control and constant aeration flow rate control. Compared with constant DO control, the effluent ammonia concentration, the maximum effluent ammonia concentration and aeration cost were reduced by 24%, 18%, and 9%, respectively, with the feedforward-feedback control. The aeration control ideas and control strategies at different conditions were determined. In order to achieve nitrification optimal control, the aeration flow and aeration volume should be both controlled.
Optimization of Nitrate Recirculation Flow and External Carbon Dosage Integrated Control for A/O Biological Nitrogen Removal Process

MA Yong,PENG Yong-zhen,SUN Hong-wei,

环境科学 , 2008,
Abstract: In order to improve A/O process denitrification efficiency, five integrated control strategies of nitrate recirculation flow and external carbon dosage for denitrification were proposed and evaluated using the COST/IWA simulation Benchmark. Results show that control strategy No.1 is the best integrated control strategies from both external carbon consumption, effluent quality, and the stability of controller. It comprises two feedback control loops: one is to determine the flow rate of external carbon source, keeping the nitrate concentration at the end of anoxic zone at a pre-specified level 2 mg/L, and the other is to adjust the flow rates of the nitrate recirculation to keep the nitrate concentration at the end of the aerobic zone at a pre-specified level based on the effluent quality (usually 8-12 mg/L). This strategy can guarantee highly effective use of anoxic denitrification capacity in the low-load condition, and meet effluent discharge standards through carbon dosage in the high-load condition.
Effect of carbon source and nitrate concentration on denitrifying phosphorus removal by DPB sludge
WANG Ya-yi,PENG Yong-zhen,Wang Shu-ying,PAN Mian-li,
WANG Ya-yi
,PENG Yong-zhen,Wang Shu-ying,PAN Mian-li

环境科学学报(英文版) , 2004,
Abstract: Effect of added carbon source and nitrate concentration on the denitrifying phosphorus removal by DPB sludge was systematically studied using batch experiments, at the same time the variation of ORP was investigated. Results showed that the denitrifying and phosphorus uptake rate in anoxic phase increased with the high initial anaerobic carbon source addition. However once the initial COD concentration reached a certain level, which was in excess to the PHB saturation of poly-P bacteria, residual COD carried over to anoxic phase inhibited the subsequent denitrifying phosphorus uptake. Simultaneously, phosphate uptake continued until all nitrate was removed, following a slow endogenous release of phosphate. High nitrate concentration in anoxic phase increased the initial denitrifying phosphorus rate. Once the nitrate was exhausted, phosphate uptake changed to release. Moreover, the time of this turning point occurred later with the higher nitrate addition. On the other hand, through on-line monitoring the variation of the ORP with different initial COD concentration, it was found ORP could be used as a control parameter for phosphorus release, but it is impossible to utilize ORP for controlling the denitrificaion and anoxic phosphorus uptake operations.
Automatic control strategy for step feed anoxic/aerobic biological nitrogen removal process
ZHU Gui-bing,PENG Yong-zhen,WU Shu-yun,WANG Shu-ying,
ZHU Gui-bing
,PENG Yong-zhen,WU Shu-yun,WANG Shu-ying

环境科学学报(英文版) , 2005,
Abstract: Control of sludge age and mixed liquid suspended solids concentration in the activated sludge process is critical for ensuring effective wastewater treatment. A nonlinear dynamic model for a step-feed activated sludge process was developed in this study. The system is based on the control of the sludge age and mixed liquor suspended solids in the aerator of last stage by adjusting the sludge recycle and wastage flow rates respectively. The simulation results showed that the sludge age remained nearly constant at a value of 16 d in the variation of the influent characteristics. The mixed liquor suspended solids in the aerator of last stage were also maintained to a desired value of 2500 g/m3 by adjusting wastage flow rates.
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