In order to enhance the hydraulic loading rate （HLR） of a subsurface wastewater infiltration system （SWIS） used in treating domestic sewage, the intermittent operation mode was employed in the SWIS. The results sh...In order to enhance the hydraulic loading rate （HLR） of a subsurface wastewater infiltration system （SWIS） used in treating domestic sewage, the intermittent operation mode was employed in the SWIS. The results show that the intermittent operation mode contributes to the improvement of the HLR and the pollutant removal rate. When the wetting-drying ratio （RwD） was 1.0, the pollutant removal rate increased by （13.6 ± 0.3）% for NH3-N, （20.7 ± 1.1）% for TN, （18.6± 0.4）% for TP, （12.2 ± 0.5）% for BOD, （10.1 ± 0.3）% for COD, and （36.2 ± 1.2）% for SS, compared with pollutant removal rates under the continuous operation mode. The pollutant removal rate declined with the increase of the HLR. The effluent quality met The Reuse of Urban Recycling Water - Water Quality Standard for Scenic Environment Use （GB/T 18921-2002） even when the HLR was as high as 10 cm/d. Hydraulic conductivity, oxidation reduction potential （ORP）, the quantity of nitrifying bacteria, and the pollutant removal rate of NH3-N increased with the decrease of the RWD. For the pollutant removal rates of TP, BOD, and COD, there were no significant difference （p 〈 0.05） under different RwDS. The suggested RWD was 1.0. Relative contribution of the pretreatment and SWlS to the pollutant removal was examined, and more than 80% removal of NH3-N, TN, TP, COD, and BOD occurred in the SWIS.展开更多
The artificial ecological floating bed is a commonly adopted in situ treatment technique for repairing and purifying polluted water. The plant root system of the floating bed is the primary region to absorb and degrad...The artificial ecological floating bed is a commonly adopted in situ treatment technique for repairing and purifying polluted water. The plant root system of the floating bed is the primary region to absorb and degrade the pollutant of water. Its inner flow field characteristics and the interactive water quantity with the surrounding water greatly impact the purification efficiency of the floating bed. In this paper, the particle image velocimetry （PIV） technology and the boundary velocity direct extraction method are used to study the velocity distribution of the root system region by numerical simulations and experiments in an experimental water channel. A pollution removal rate （PRR） evaluation model is built to calculate the PRR by coupling with the flow velocity field of the root system region. The variations of the total pollutant removal rate （TPRR） are discussed for different center distances （L =0.30 m, 0.45 m, 0.60 m）, flow velocities （v= 0.007 m/s, 0.015 m/s, 0.025 m/s, 0.040 m/s, 0.055 m/s, 0.070 m/s） and root system porosities （P = 54.73%, 68.33%, 79.17%）. The results indicate that the position arrangement of the floating beds influences the TPRR significantly, and the distance should be limited in a reasonable range for a high purification efficiency. Moreover, the root systems with higher porosity （P = 68.33%, 79.17%） have higher TPRR value than a lower porosity root system （P = 54.73%） within a certain flow velocity range, and the higher porosity root system has less fluctuation of the TPRR value than a lower porosity situation within a wide flow velocity range. Furthermore, under the same center distance condition, the lower flow velocity condition brings about a significantly higher TPRR value than the higher flow velocity situation.展开更多
In this study, a series of ecological porous spur-dikes are arranged in an experiment channel to simulate a real field drainage ditch. The inside and outside flow fields of spur-dikes are determined by numerical simul...In this study, a series of ecological porous spur-dikes are arranged in an experiment channel to simulate a real field drainage ditch. The inside and outside flow fields of spur-dikes are determined by numerical simulations and experimental methods. An Ammonia-Nitrogen（NH3-N） degradation evaluation model is built to calculate the pollution removal rate by coupling with the inner flow field of the porous spur-dikes. The variations of the total pollutant removal rate in the channel are discussed in terms of different porosities and gap distances between spur-dikes and inlet flow velocities. It is indicated that a reasonable parameter matching of the porosity and the gap distance with the flow velocity of the ditch can bring about a satisfactory purification efficiency with a small delivery quantity of ecological porous materials.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51108275)the Program for Liaoning Excellent Talents in Universities(LNET)(Grant No.LJQ2012101)+2 种基金the Program for New Century Excellent Talents in Universities(Grant No.NCET-11-1012)the Science and Technology Program of Liaoning Province(Grants No.2011229002 and2013229012)the Basic Science Research Fund in Northeastern University(Grants No.N130501001 and N140105003)
文摘In order to enhance the hydraulic loading rate （HLR） of a subsurface wastewater infiltration system （SWIS） used in treating domestic sewage, the intermittent operation mode was employed in the SWIS. The results show that the intermittent operation mode contributes to the improvement of the HLR and the pollutant removal rate. When the wetting-drying ratio （RwD） was 1.0, the pollutant removal rate increased by （13.6 ± 0.3）% for NH3-N, （20.7 ± 1.1）% for TN, （18.6± 0.4）% for TP, （12.2 ± 0.5）% for BOD, （10.1 ± 0.3）% for COD, and （36.2 ± 1.2）% for SS, compared with pollutant removal rates under the continuous operation mode. The pollutant removal rate declined with the increase of the HLR. The effluent quality met The Reuse of Urban Recycling Water - Water Quality Standard for Scenic Environment Use （GB/T 18921-2002） even when the HLR was as high as 10 cm/d. Hydraulic conductivity, oxidation reduction potential （ORP）, the quantity of nitrifying bacteria, and the pollutant removal rate of NH3-N increased with the decrease of the RWD. For the pollutant removal rates of TP, BOD, and COD, there were no significant difference （p 〈 0.05） under different RwDS. The suggested RWD was 1.0. Relative contribution of the pretreatment and SWlS to the pollutant removal was examined, and more than 80% removal of NH3-N, TN, TP, COD, and BOD occurred in the SWIS.
基金Project supported by the National Science Funds for Creative Research Groups of China(Grant No.51421006)the Program for Changjiang Scholars and Innovative Research Team in University(Grant No.IRT13061)+4 种基金the National Science Fund For Distinguished Young Scholars(Grant No.51225901)the National Science Fund Key Projects(Grant No.41430751)the Qing Lan Project of Jiangsu Provincethe Fun-damental Research Funds for the Central Universities(Grant Nos.2014B03814,2015B25314)the PAPD
文摘The artificial ecological floating bed is a commonly adopted in situ treatment technique for repairing and purifying polluted water. The plant root system of the floating bed is the primary region to absorb and degrade the pollutant of water. Its inner flow field characteristics and the interactive water quantity with the surrounding water greatly impact the purification efficiency of the floating bed. In this paper, the particle image velocimetry （PIV） technology and the boundary velocity direct extraction method are used to study the velocity distribution of the root system region by numerical simulations and experiments in an experimental water channel. A pollution removal rate （PRR） evaluation model is built to calculate the PRR by coupling with the flow velocity field of the root system region. The variations of the total pollutant removal rate （TPRR） are discussed for different center distances （L =0.30 m, 0.45 m, 0.60 m）, flow velocities （v= 0.007 m/s, 0.015 m/s, 0.025 m/s, 0.040 m/s, 0.055 m/s, 0.070 m/s） and root system porosities （P = 54.73%, 68.33%, 79.17%）. The results indicate that the position arrangement of the floating beds influences the TPRR significantly, and the distance should be limited in a reasonable range for a high purification efficiency. Moreover, the root systems with higher porosity （P = 68.33%, 79.17%） have higher TPRR value than a lower porosity root system （P = 54.73%） within a certain flow velocity range, and the higher porosity root system has less fluctuation of the TPRR value than a lower porosity situation within a wide flow velocity range. Furthermore, under the same center distance condition, the lower flow velocity condition brings about a significantly higher TPRR value than the higher flow velocity situation.
基金Project supported by the National Science Funds for Creative Research Groups of China(Grant No.51421006)the National Major Projects of Water Pollution Control and Management Technology(No.2017ZX07204003)+2 种基金the National Key Plan for Research and Development of China(Grant 2016YFC0502203)the Key Program of National Natural Science Foundation of China(Grant No.91647206)the Qing Lan Project of Jiangsu Province
文摘In this study, a series of ecological porous spur-dikes are arranged in an experiment channel to simulate a real field drainage ditch. The inside and outside flow fields of spur-dikes are determined by numerical simulations and experimental methods. An Ammonia-Nitrogen（NH3-N） degradation evaluation model is built to calculate the pollution removal rate by coupling with the inner flow field of the porous spur-dikes. The variations of the total pollutant removal rate in the channel are discussed in terms of different porosities and gap distances between spur-dikes and inlet flow velocities. It is indicated that a reasonable parameter matching of the porosity and the gap distance with the flow velocity of the ditch can bring about a satisfactory purification efficiency with a small delivery quantity of ecological porous materials.
