二沉池数值模拟研究的综述与评论
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摘要
二沉池作为重要的污水处理构筑物,其运行性能决定着出水水质。二沉池两相流动的动力学行为对污泥沉降过程产生重要影响,其数值模型化及模拟对二沉池运行条件及结构设计优化具有重要意义。首先对应用于二沉池模拟的混合模型、组分输运模型、VOF-组分输运耦合模型的原理、模型精度、优缺点进行了探讨;其次,对影响二沉池内两相流动精确模拟的污泥沉降速度、混合液流变性质、外界风场、二沉池结构等因素进行阐述与分析,并梳理了目前的研究进展及不足;最后指出了今后二沉池数值模型及模拟的研究方向,以期为采用数值模拟手段对二沉池的研究提供借鉴和参考。
As an vital sewage treatment structure,the operation performance of secondary settling tank determines the effluent quality of the treated sewage. The dynamic behaviour of the two-phase flow in the secondary settling tank had an great influence on the sludge settling process,and its numerical modelling and simulation techniques were of great importance to the optimization of the operating conditions and structural design of the secondary settling tank. In this paper,firstly,three different models, including mixture model, component transport model and VOF-component transport coupling model,commonly adopted in the secondary settling tank simulation were discussed,in terms of model principle,model accuracy,advantages and disadvantages. Secondly,the sludge settlement velocity,the rheological properties of mixed liquid,the external wind field and the secondary settling tank structure and other factors affecting the accurate simulation of the two-phase flow dynamics in the secondary settling tank,were discussed and analysed,and the current research progress and shortcomings were also pointed out. Finally,the research orientation of numerical modelling and simulation for the secondary sedimentation tank in the future were pointed out. This paper can provide references for the researches on secondary settling tanks by means of numerical simulation.
As an vital sewage treatment structure,the operation performance of secondary settling tank determines the effluent quality of the treated sewage. The dynamic behaviour of the two-phase flow in the secondary settling tank had an great influence on the sludge settling process,and its numerical modelling and simulation techniques were of great importance to the optimization of the operating conditions and structural design of the secondary settling tank. In this paper,firstly,three different models, including mixture model, component transport model and VOF-component transport coupling model,commonly adopted in the secondary settling tank simulation were discussed,in terms of model principle,model accuracy,advantages and disadvantages. Secondly,the sludge settlement velocity,the rheological properties of mixed liquid,the external wind field and the secondary settling tank structure and other factors affecting the accurate simulation of the two-phase flow dynamics in the secondary settling tank,were discussed and analysed,and the current research progress and shortcomings were also pointed out. Finally,the research orientation of numerical modelling and simulation for the secondary sedimentation tank in the future were pointed out. This paper can provide references for the researches on secondary settling tanks by means of numerical simulation.
引文
[1] Ratkovich N,Horn W,Helmus F P,et al. Activated sludge rheology:a critical review on data collection and modelling[J].Water Research,2013,47(2):463-482.
[2] Wágner D S,Ramin E,Szabo P,et al. Microthrix parvicella abundance associates with activated sludge settling velocity and rheology-Quantifying and modelling filamentous bulking[J]. Water Research,2015,78:121-132.
[3] Goula A M,Kostoglou M,Karapantsios T D,et al. The effect of influent temperature variations in a sedimentation tank for potable water treatment-a computational fluid dynamics study[J]. Water Research,2008,42(13):3405-3414.
[4]魏文礼,张泽伟,白朝伟,等.辐流式沉淀池进口挡板影响的液固两相流数值模拟[J].应用力学学报,2016,33(1):93-98.
[5]魏文礼,李盼盼,洪云飞,等.挡板长度对辐流式沉淀池流场与污泥浓度场影响的数值模拟[J].西北农林科技大学学报(自然科学版),2016,44(7):228-234.
[6]陈斌,汪源,张华,等.周进周出矩形沉淀池配水孔分布的数值模拟[J].给水排水,2016,42(4):54-57.
[7] Ramin E,Wágner D S,Yde L,et al. A new settling velocity model to describe secondary sedimentation[J]. Water Research,2014,66:447-458.
[8] Patziger M. Computational fluid dynamics investigation of shallow circular secondary settling tanks:inlet geometry and performance indicators[J]. Chemical Engineering Research&Design,2016,112:122-131.
[9] Daniel Brennan. The numerical simulation of two phase flows in settling tanks[D]. London:Imperial College London,2001.
[10] Lakehal D,Krebs P,Krijgsman J,et al. Computing shear flow and sludge blanket in secondary clarifiers[J]. Journal of Hydraulic Engineering,1999,125(3):253-262.
[11] J.U Brackbill,D. B Kothe,C Zemach. A continuum method for modeling surface tension[J]. Journal of Computational Physics,1992,100(2):335-354.
[12] Sanin D F. Effect of solution physical chemistry on the rheological properties of activated sludge[J]. Water S A,2004,28(2):207-211.
[13] Battistoni P. Pretreatment,measurement execution procedure and waste characteristics in the rheology of sewage sludges and the digested organic fraction of municipal solids wastes[J]. Water Science and Technology,1997,36(11):33-41.
[14] Moeller G,Torres L G. Rheological characterization of primary and secondary sludges treated by both aerobic and anaerobic digestion[J]. Bioresource Technology,1997,61(3):207-211.
[15] Bougrier C,Albasi C,Delgenès J P,et al. Effect of ultrasonic,thermal and ozone pre-treatments on waste activated sludge solubilisation and anaerobic biodegradability[J]. Chemical Engineering&Processing Process Intensification,2006,45(8):711-718.
[16] Terashima M,Goel R,Komatsu K,et al. CFD simulation of mixing in anaerobic digesters[J]. Bioresource Technology,2009,100(7):2228-2233.
[17] Wu X H, Wang F, Sun D X, et al. Rheology and flow characteristic of urban untreated sewage for cooling and heating source[J]. Experimental Thermal&Fluid Science,2011,35(4):612-617.
[18] Guibaud G,Dollet P,Tixier N,et al. Characterisation of the evolution of activated sludges using rheological measurements[J].Process Biochemistry,2004,39(11):1803-1810.
[19] Mu Y,Yu H Q,Chen X H. Rheological and fractal characteristics of granular sludge in an upflow anaerobic reactor[J]. Water Research,2006,40(19):3596-3602.
[20] Saffarian M R,Hamedi Mohammad H. Numerical simulation of a secondary clarifier in a sewage treatment plant using modified Bingham model[J]. Canadian Journal of Civil Engineering,2011,38(1):11-22.
[21] Slatter P T. The rheological characterisation of sludges[J]. Water Science&Technology,1997,36(36):9-18.
[22] Baudez J C, Coussot P. Rheology of aging, concentrated,polymeric suspensions:application to pasty sewage sludges[J].Journal of Rheology,2001,45(5):1123-1139.
[23] Eshtiaghi N, Markis F, Yap S D, et al. Rheological characterisation of municipal sludge:a review[J]. Water Research,2013,47(15):5493-5510.
[24]涂朦朦.水温对二沉池运行影响的数值模拟[D].长沙:湖南大学,2014.
[25]刘百仓.沉淀池工况的数值模拟及流场测量[D].哈尔滨:哈尔滨工业大学,2009.
[26] Vesilind P A. Theoretical considerations:design of prototype thickeners from batch settling tests[J]. Water&Sewage Works,1968,115(7).
[27] Takács I,Patry G G,Nolasco D. A dynamic model of the clarification thickening process[J]. Water Research,1991,25(10):1263-1271.
[28] Bürger R. Phenomenological foundation and mathematical theory of sedimentation-consolidation processes[J]. Chemical Engineering Journal,2000,80(1/3):177-188.
[29] De C J,Nopens I,Defrancq J,et al. Extending and calibrating a mechanistic hindered and compression settling model for activated sludge using in-depth batch experiments[J]. Water Research,2008,42(3):781-791.
[30] Xanthos S,Ramalingam K,Lipke S,et al. Implementation of CFD modeling in the performance assessment and optimization of secondary clarifiers:the PVSC case study[J]. Water Science&Technology A Journal of the International Association on Water Pollution Research,2013,68(9):1901-1913.
[31] Xanthos S, Gong M, Ramalingam K, et al. Performance assessment of secondary settling tanks using CFD modeling[J].Water Resources Management,2011,25(4):1169-1182.
[32] Shahrokhi M,Rostami F,Said M A M,et al. Numerical modeling of baffle location effects on the flow pattern of primary sedimentation tanks[J]. Applied Mathematical Modelling,2013,37(6):4486-4496.
[33]刘百仓,马军,张素霞,等.带翼片侧向流斜板沉淀池内颗粒沉降过程的数值模拟[J].给水排水,2007,33(11):139-142.
[34] Tamayol A, Firoozabadi B, Ashjari M A. Hydrodynamics of secondary settling tanks and increasing their performance using baffles[J]. Journal of Environmental Engineering,2009,136(1):32-39.
[35] Lee B. Evaluation of double perforated baffles installed in rectangular secondary clarifiers[J]. Water,2017,9(6):407.
[36] Wells S A,La Liberte D. Winter temperature gradients in circular clarifiers[J]. Water Environment Research,1998,70(7):1274-1279.
[37] Lau Y L. Temperature effect on settling velocity and deposition of cohesive sediments[J]. Journal of Hydraulic Research,1994,32(1):41-51.
[38] Ekama G A,Barnard J L,Günthert F W. Secondary settling tanks:theory, modelling, design and operation[M]. International Association on Water Quality,1997.
[39]施周,涂朦朦,王涛,等.水温对平流式二沉池运行影响的数值模拟[J].安全与环境学报,2015,15(4):222-226.
[40]谭立新,李博,李尔康.平流二次沉淀池中温差对异重流影响的数值模拟[J].西安理工大学学报,2013,29(2):182-187.
[41]刘百仓,罗麟,马军,等.圆形沉淀池内温差异重流与浮力流的数值模拟[J].四川大学学报(工程科学版),2009,41(1):34-40.
[42]白玉华,李琳,柳藤,等.基于LDV测速考察风速风向对平流式沉淀池水流运动的影响[J].西南给排水,2014,36(4):14-20.
[43] Asgharzadeh H, Firoozabadi B, Afshin H. Experimental and bumerical simulation of the effect of particles on flow structures in secondary sedimentation tanks[J]. Journal of Applied Fluid Mechanics,2012,5(2):15-23.
[44] Khezri S M,Biati A,Erfani Z. Determination of the effect of wind velocity and direction changes on turbidity removal in rectangular sedimentation tanks[J]. Water Science&Technology,2012,66(12):2814-2820.
[45] Gkesouli A,Nitsa M,Stamou A I,et al. Modeling the effect of wind in rectangular settling tanks for water supply[J]. Desalination&Water Treatment,2016:1-10.
[2] Wágner D S,Ramin E,Szabo P,et al. Microthrix parvicella abundance associates with activated sludge settling velocity and rheology-Quantifying and modelling filamentous bulking[J]. Water Research,2015,78:121-132.
[3] Goula A M,Kostoglou M,Karapantsios T D,et al. The effect of influent temperature variations in a sedimentation tank for potable water treatment-a computational fluid dynamics study[J]. Water Research,2008,42(13):3405-3414.
[4]魏文礼,张泽伟,白朝伟,等.辐流式沉淀池进口挡板影响的液固两相流数值模拟[J].应用力学学报,2016,33(1):93-98.
[5]魏文礼,李盼盼,洪云飞,等.挡板长度对辐流式沉淀池流场与污泥浓度场影响的数值模拟[J].西北农林科技大学学报(自然科学版),2016,44(7):228-234.
[6]陈斌,汪源,张华,等.周进周出矩形沉淀池配水孔分布的数值模拟[J].给水排水,2016,42(4):54-57.
[7] Ramin E,Wágner D S,Yde L,et al. A new settling velocity model to describe secondary sedimentation[J]. Water Research,2014,66:447-458.
[8] Patziger M. Computational fluid dynamics investigation of shallow circular secondary settling tanks:inlet geometry and performance indicators[J]. Chemical Engineering Research&Design,2016,112:122-131.
[9] Daniel Brennan. The numerical simulation of two phase flows in settling tanks[D]. London:Imperial College London,2001.
[10] Lakehal D,Krebs P,Krijgsman J,et al. Computing shear flow and sludge blanket in secondary clarifiers[J]. Journal of Hydraulic Engineering,1999,125(3):253-262.
[11] J.U Brackbill,D. B Kothe,C Zemach. A continuum method for modeling surface tension[J]. Journal of Computational Physics,1992,100(2):335-354.
[12] Sanin D F. Effect of solution physical chemistry on the rheological properties of activated sludge[J]. Water S A,2004,28(2):207-211.
[13] Battistoni P. Pretreatment,measurement execution procedure and waste characteristics in the rheology of sewage sludges and the digested organic fraction of municipal solids wastes[J]. Water Science and Technology,1997,36(11):33-41.
[14] Moeller G,Torres L G. Rheological characterization of primary and secondary sludges treated by both aerobic and anaerobic digestion[J]. Bioresource Technology,1997,61(3):207-211.
[15] Bougrier C,Albasi C,Delgenès J P,et al. Effect of ultrasonic,thermal and ozone pre-treatments on waste activated sludge solubilisation and anaerobic biodegradability[J]. Chemical Engineering&Processing Process Intensification,2006,45(8):711-718.
[16] Terashima M,Goel R,Komatsu K,et al. CFD simulation of mixing in anaerobic digesters[J]. Bioresource Technology,2009,100(7):2228-2233.
[17] Wu X H, Wang F, Sun D X, et al. Rheology and flow characteristic of urban untreated sewage for cooling and heating source[J]. Experimental Thermal&Fluid Science,2011,35(4):612-617.
[18] Guibaud G,Dollet P,Tixier N,et al. Characterisation of the evolution of activated sludges using rheological measurements[J].Process Biochemistry,2004,39(11):1803-1810.
[19] Mu Y,Yu H Q,Chen X H. Rheological and fractal characteristics of granular sludge in an upflow anaerobic reactor[J]. Water Research,2006,40(19):3596-3602.
[20] Saffarian M R,Hamedi Mohammad H. Numerical simulation of a secondary clarifier in a sewage treatment plant using modified Bingham model[J]. Canadian Journal of Civil Engineering,2011,38(1):11-22.
[21] Slatter P T. The rheological characterisation of sludges[J]. Water Science&Technology,1997,36(36):9-18.
[22] Baudez J C, Coussot P. Rheology of aging, concentrated,polymeric suspensions:application to pasty sewage sludges[J].Journal of Rheology,2001,45(5):1123-1139.
[23] Eshtiaghi N, Markis F, Yap S D, et al. Rheological characterisation of municipal sludge:a review[J]. Water Research,2013,47(15):5493-5510.
[24]涂朦朦.水温对二沉池运行影响的数值模拟[D].长沙:湖南大学,2014.
[25]刘百仓.沉淀池工况的数值模拟及流场测量[D].哈尔滨:哈尔滨工业大学,2009.
[26] Vesilind P A. Theoretical considerations:design of prototype thickeners from batch settling tests[J]. Water&Sewage Works,1968,115(7).
[27] Takács I,Patry G G,Nolasco D. A dynamic model of the clarification thickening process[J]. Water Research,1991,25(10):1263-1271.
[28] Bürger R. Phenomenological foundation and mathematical theory of sedimentation-consolidation processes[J]. Chemical Engineering Journal,2000,80(1/3):177-188.
[29] De C J,Nopens I,Defrancq J,et al. Extending and calibrating a mechanistic hindered and compression settling model for activated sludge using in-depth batch experiments[J]. Water Research,2008,42(3):781-791.
[30] Xanthos S,Ramalingam K,Lipke S,et al. Implementation of CFD modeling in the performance assessment and optimization of secondary clarifiers:the PVSC case study[J]. Water Science&Technology A Journal of the International Association on Water Pollution Research,2013,68(9):1901-1913.
[31] Xanthos S, Gong M, Ramalingam K, et al. Performance assessment of secondary settling tanks using CFD modeling[J].Water Resources Management,2011,25(4):1169-1182.
[32] Shahrokhi M,Rostami F,Said M A M,et al. Numerical modeling of baffle location effects on the flow pattern of primary sedimentation tanks[J]. Applied Mathematical Modelling,2013,37(6):4486-4496.
[33]刘百仓,马军,张素霞,等.带翼片侧向流斜板沉淀池内颗粒沉降过程的数值模拟[J].给水排水,2007,33(11):139-142.
[34] Tamayol A, Firoozabadi B, Ashjari M A. Hydrodynamics of secondary settling tanks and increasing their performance using baffles[J]. Journal of Environmental Engineering,2009,136(1):32-39.
[35] Lee B. Evaluation of double perforated baffles installed in rectangular secondary clarifiers[J]. Water,2017,9(6):407.
[36] Wells S A,La Liberte D. Winter temperature gradients in circular clarifiers[J]. Water Environment Research,1998,70(7):1274-1279.
[37] Lau Y L. Temperature effect on settling velocity and deposition of cohesive sediments[J]. Journal of Hydraulic Research,1994,32(1):41-51.
[38] Ekama G A,Barnard J L,Günthert F W. Secondary settling tanks:theory, modelling, design and operation[M]. International Association on Water Quality,1997.
[39]施周,涂朦朦,王涛,等.水温对平流式二沉池运行影响的数值模拟[J].安全与环境学报,2015,15(4):222-226.
[40]谭立新,李博,李尔康.平流二次沉淀池中温差对异重流影响的数值模拟[J].西安理工大学学报,2013,29(2):182-187.
[41]刘百仓,罗麟,马军,等.圆形沉淀池内温差异重流与浮力流的数值模拟[J].四川大学学报(工程科学版),2009,41(1):34-40.
[42]白玉华,李琳,柳藤,等.基于LDV测速考察风速风向对平流式沉淀池水流运动的影响[J].西南给排水,2014,36(4):14-20.
[43] Asgharzadeh H, Firoozabadi B, Afshin H. Experimental and bumerical simulation of the effect of particles on flow structures in secondary sedimentation tanks[J]. Journal of Applied Fluid Mechanics,2012,5(2):15-23.
[44] Khezri S M,Biati A,Erfani Z. Determination of the effect of wind velocity and direction changes on turbidity removal in rectangular sedimentation tanks[J]. Water Science&Technology,2012,66(12):2814-2820.
[45] Gkesouli A,Nitsa M,Stamou A I,et al. Modeling the effect of wind in rectangular settling tanks for water supply[J]. Desalination&Water Treatment,2016:1-10.