污泥不同脱水方法的实验分析及脱水机理探讨
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摘要
为进一步认识污泥脱水的机理,寻找更为有效的污泥脱水方法,提出了一种新的污泥中水分存在形式的划分方法,同时进行了自重、离心、盐溶液渗析脱水3种实验,并利用光学显微镜和扫描电镜等手段,对原状污泥与3种脱水后污泥的微观结构进行形态学及定量分析。自重、离心、盐溶液渗析脱水后污泥的最终含水率分别为89.4%、78.0%、28.4%,且不同脱水方式会影响污泥的微观结构,进而影响脱水效率;污泥中微生物、絮团、褶皱、裂隙及物质成分等方面是污泥中水分难以脱除的重要原因。污泥在不同的脱水阶段,水分的存在形式不同,脱水的难易程度也不同;脱水程度越高的脱水手段,其脱水后污泥的结构越紧密,孔隙率及等效孔径明显降低,可通过减小污泥内部孔隙的方式进一步提高脱水效率。
The objective of this paper was to explore the mechanism of sludge dewatering and find a more effective method for it. The distribution of water in sludge was re-classified. Then an experimental study was performed to better understand different mechanisms of dewatering methods including self-weight dehydration, centrifugal dewatering and salt solution dialysis. The microstructure of the raw sludge was first characterized by optical microscope and scanning electron microscope. The structure of the sludge dehydrated by different dewatering methods was quantitatively analyzed and compared. The results showed that the final moisture content of the sludge after dewatering by self-weight, centrifugation,and salt solution was 89.4%, 78.0%, and 28.4%. And different dewatering methods affected the microstructure of the sludge, which affected dewatering efficiency. The microorganism, floc, folds, cracks and material composition were the important factors that affect the dewatering effect. The forms of water in sludge is different in different dewatering stages,which lead to the different degree of dehydration. By applying the dewatering method that has a higher efficiency, the sludge exhibit a denser structure and smaller porosity and equivalent pore-diameter. The dewatering efficiency can be increased by reducing internal pores of the sludge.
The objective of this paper was to explore the mechanism of sludge dewatering and find a more effective method for it. The distribution of water in sludge was re-classified. Then an experimental study was performed to better understand different mechanisms of dewatering methods including self-weight dehydration, centrifugal dewatering and salt solution dialysis. The microstructure of the raw sludge was first characterized by optical microscope and scanning electron microscope. The structure of the sludge dehydrated by different dewatering methods was quantitatively analyzed and compared. The results showed that the final moisture content of the sludge after dewatering by self-weight, centrifugation,and salt solution was 89.4%, 78.0%, and 28.4%. And different dewatering methods affected the microstructure of the sludge, which affected dewatering efficiency. The microorganism, floc, folds, cracks and material composition were the important factors that affect the dewatering effect. The forms of water in sludge is different in different dewatering stages,which lead to the different degree of dehydration. By applying the dewatering method that has a higher efficiency, the sludge exhibit a denser structure and smaller porosity and equivalent pore-diameter. The dewatering efficiency can be increased by reducing internal pores of the sludge.
引文
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[15]邢奕,王志强,洪晨,等.不同p H值下胞外聚合物对污泥脱水性能及束缚水含量的影响[J].北京科技大学学报,2015,37(10):1387-1395.DOI:10.13374/j.issn2095-9389.2015.10.020.
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[17]XIE H H,HONG-LEI M A,YONG C,et al.Bound water measurement methods and moisture distribution within sewage sludge[J].Journal of Zhejiang University,2012,46(3):503-508.DOI:10.3785/j.issn.1008-973X.2012.03.019.
[18]裴海燕,胡文容,李晶,等.活性污泥与消化污泥的脱水特性及粒径分布[J].环境科学,2007,28(10):2236-2242.
[19]FENG J,WANG Y L,JI X Y.Dynamic changes in the characteristics and components of activated sludge and filtrate during the pressurized electro-osmotic dewatering process[J].Separation and Purification Technology,2014,134:1-11.DOI:10.1016/j.seppur.2014.07.019.
[20]XU H,HE P,LI M S.Characteristics of organic matters during anaerobic digestion of ultrasonically pretreated sludge and the effects on sludge dewaterability[J].Journal of Residuals Science and Technology,2009,6(3):119-124.DOI:10.1016/S1001-0742(09)60132-7.
[21]汤连生,罗珍贵,张龙舰,等.污泥脱水研究现状与新认识[J].水处理技术,2016,42(6):12-17.DOI:10.16796/j.cnki.1000-3770.2016.06.003.
[22]HEUKELEKIAN H,WEISBERG E.Bound water and activated sludge bulking[J].Sewage and Industrial Wastes,1956,28(4):558-574.DOI:10.2307/25033052.
[23]TSANG K R,VESILIND P A.Moisture distribution in sludges[J].Water Science and Technology,1990,22(12):135-142.
[24]汤连生,张龙舰,罗珍贵.污泥中水分布形式划分及脱水性能研究[J].生态环境学报,2017,26(2):309-314.DOI:10.16258/j.cnki.1674-5906.2017.02.017.
[25]方彦彦,田野,王晓琳.正渗透的机理[J].膜科学与技术,2011,31(6):95-100.
[26]CATH T Y,CHILDRESS A E,ELIMELECH M.Forward osmosis:Principles,applications,and recent developments[J].Journal of Membrane Science,2006,281(1/2):70-87.DOI:10.1016/j.memsci.2006.05.048.
[27]TRIPATHY S,REES S W.Suction of some polyethylene glycols commonly used for unsaturated soil testing[J].Geotechnical Testing Journal,2013,36(5):768-780.DOI:10.1520/gtj20120041.
[28]任占强.超声波处理活性污泥细胞破壁脱水研究[J].环境科学与管理,2014,39(6):105-108.
[29]李玉瑛,何文龙,邓斌,等.超声波联合高分子絮凝剂对污泥的调理研究[J].工业水处理,2015,35(2):57-60.
[30]JIN L Y,ZHANG G M,ZHENG X.Effects of different sludge disintegration methods on sludge moisture distribution and dewatering performance[J].Journal of Environmental Sciences,2015,28(2):22-28.DOI:10.1016/j.jes.2014.06.040.
[31]DENG W Y,LI X D,YAN J H,et al.Moisture distribution in sludges based on different testing methods[J].Journal of Environmental Sciences,2011,23(5):875-880.DOI:10.1016/s1001-0742(10)60518-9.
[32]CHEN G H,YUE P L,MUJUMDAR A S.Sludge dewatering and drying[J].Drying Technology,2002,20(4/5):883-916.DOI:10.1081/DRT-120003768.
[33]VAXELAIR J,CEZAC P.Moisture distribution in activated sludges:A review[J].Water Research,2004,38(9):2215-2230.DOI:10.1016/j.watres.2004.02.021.
[34]SJINNER S J,STUDER L J,DIXON D R,et al.Quantification of wastewater sludge dewatering[J].Water Research,2015,82:2-13.DOI:10.1016/j.watres.2015.04.045.
[35]MAO H Z,CHI Y,WANG F,et al.Effect of ultrasonic pre-treatment on dewaterability and moisture distribution in sewage sludge[J].Waste and Biomass Valorization,2017,9(2):247-253.DOI:10.1007/s12649-016-9799-3.
[36]YUAN D Q,WANG Y L,QIAN X.Variations of internal structure and moisture distribution in activated sludge with stratified extracellular polymeric substances extraction[J].International Biodeterioration and Biodegradation,2017,116:1-9.DOI:10.1016/j.ibiod.2016.09.012.
[37]TURCHIULI C,FARGUES C.Influence of structural properties of alum and ferric flocs on sludge dewaterability[J].Chemical Engineering Journal,2016,103(1/2/3):123-131.
[38]KOPP J,DICHTL N.Prediction of full-scale dewatering results of sewage sludges by the physical water distribution[J].Water Science and Technology,2001,43(11):135-143.
[39]MOORE C A,DONALDSON C F.Quantifying soil microstructure using fractals[J].Geotechnique,1995,45(1):105-116.DOI:10.1680/geot.1995.45.1.105.
[40]谢学斌,潘长良.露天矿排土场散体岩石粒度分布的分形特征[J].湘潭矿业学院学报,2003,18(3):56-59.
[41]赵安平,王清,李杨,等.长春季冻区路基土微观孔隙特征的定量评价[J].工程地质学报,2008,16(2):233-238.
[2]白冰,李现瑾,徐长思,等.剩余污泥机械脱水技术研究进展[J].节能,2014,33(4):4-8.
[3]刘吉宝,李亚明,吕鑑,等.污水处理厂不同工艺的污泥脱水效能分析及其影响因素研究[J].环境科学,2015,36(10):3794-3800.DOI:10.13227/j.hjkx.2015.10.031.
[4]MARTINEZ J,ROSAS J G,MORAN A,et al.Effect of ultrasound pretreatment on sludge digestion and dewatering characteristics:Application of particle size analysis[J].Water,2015,11(11):6483-6495.DOI:10.3390/w7116483.
[5]石秀娟,梁文俊,李依丽,等.超声波技术在城市污泥处理中的应用进展[J].四川环境,2017,36(1):157-162.DOI:10.14034/j.cnki.schj.2017.01.030.
[6]HANG S T,YANG Z J,LV X B,et al.Novel electro-dewatering system for activated sludge biosolids in bench-scale,pilot-scale and industrial-scale applications[J].Chemical Engineering Research and Design,2017,121:44-56.DOI:10.1016/j.cherd.2017.02.035.
[7]SUN B,XIN Y B,HAO J,et al.Influence of conductivity on the electro-dewatering of sewage sludge under constant voltage[J].Separation Science and Technology,2017,52(15):2429-2434.DOI:10.1080/01496395.20171368561.
[8]刘阳,程洁红.不同固含量城市污泥的电化学预处理工艺研究[J].水处理技术,2016,42(7):126-129.DOI:10.16796/j.cnki.1000-3770.2016.07.029.
[9]HUA L C,HUANG C,Su Y C,et al.Effects of electro-coagulation on fouling mitigation and sludge characteristics in a coagulation-assisted membrane bioreactor[J].Journal of Membrane Science,2015,495:29-36.DOI:10.1016/j.memsci.2015.07.062.
[10]李红欣,田博,杨雯晶,等.冷冻预处理剩余污泥脱水性能研究[J].黑龙江科技信息,2014,18(1):63.
[11]卢映专,王景芝,高淑涛,等.南方14种污泥中六溴环十二烷的浓度水平与组成特征[J].生态环境学,2016,25(1):118-123.DOI:10.16258/j.cnki.1674-5906.2016.01.017.
[12]王鸣,吴海珍,刘雷,等.厌氧条件下不同共基质对焦化污泥降解多环芳烃的影响[J].生态环境学报,2016,25(3):510-516.DOI:10.16258/j.cnki.1674-5906.2016.03.021.
[13]HIGGINS M J,NOVAK J T.The effect of cations on the settling and dewatering of activated sludges:Laboratory results[J].Water Environment Research,1997,69(2):215-224.DOI:10.2175/106143097x125371.
[14]WANG L F,QIAN C,JIANG J K,et al.Response of extracellular polymeric substances to thermal treatment in sludge dewatering process[J].Environmental Pollution,2017,231:1388-1392.DOI:10.1016/j.jhazmat.2003.11.014.
[15]邢奕,王志强,洪晨,等.不同p H值下胞外聚合物对污泥脱水性能及束缚水含量的影响[J].北京科技大学学报,2015,37(10):1387-1395.DOI:10.13374/j.issn2095-9389.2015.10.020.
[16]ZHAO P,GE S,YOSHIKAWA K.Effect of operating conditions on measurement of bound water in sludge by employing drying test[J].Fresenius Environmental Bulletin,2015,24(11B):3912-3920.
[17]XIE H H,HONG-LEI M A,YONG C,et al.Bound water measurement methods and moisture distribution within sewage sludge[J].Journal of Zhejiang University,2012,46(3):503-508.DOI:10.3785/j.issn.1008-973X.2012.03.019.
[18]裴海燕,胡文容,李晶,等.活性污泥与消化污泥的脱水特性及粒径分布[J].环境科学,2007,28(10):2236-2242.
[19]FENG J,WANG Y L,JI X Y.Dynamic changes in the characteristics and components of activated sludge and filtrate during the pressurized electro-osmotic dewatering process[J].Separation and Purification Technology,2014,134:1-11.DOI:10.1016/j.seppur.2014.07.019.
[20]XU H,HE P,LI M S.Characteristics of organic matters during anaerobic digestion of ultrasonically pretreated sludge and the effects on sludge dewaterability[J].Journal of Residuals Science and Technology,2009,6(3):119-124.DOI:10.1016/S1001-0742(09)60132-7.
[21]汤连生,罗珍贵,张龙舰,等.污泥脱水研究现状与新认识[J].水处理技术,2016,42(6):12-17.DOI:10.16796/j.cnki.1000-3770.2016.06.003.
[22]HEUKELEKIAN H,WEISBERG E.Bound water and activated sludge bulking[J].Sewage and Industrial Wastes,1956,28(4):558-574.DOI:10.2307/25033052.
[23]TSANG K R,VESILIND P A.Moisture distribution in sludges[J].Water Science and Technology,1990,22(12):135-142.
[24]汤连生,张龙舰,罗珍贵.污泥中水分布形式划分及脱水性能研究[J].生态环境学报,2017,26(2):309-314.DOI:10.16258/j.cnki.1674-5906.2017.02.017.
[25]方彦彦,田野,王晓琳.正渗透的机理[J].膜科学与技术,2011,31(6):95-100.
[26]CATH T Y,CHILDRESS A E,ELIMELECH M.Forward osmosis:Principles,applications,and recent developments[J].Journal of Membrane Science,2006,281(1/2):70-87.DOI:10.1016/j.memsci.2006.05.048.
[27]TRIPATHY S,REES S W.Suction of some polyethylene glycols commonly used for unsaturated soil testing[J].Geotechnical Testing Journal,2013,36(5):768-780.DOI:10.1520/gtj20120041.
[28]任占强.超声波处理活性污泥细胞破壁脱水研究[J].环境科学与管理,2014,39(6):105-108.
[29]李玉瑛,何文龙,邓斌,等.超声波联合高分子絮凝剂对污泥的调理研究[J].工业水处理,2015,35(2):57-60.
[30]JIN L Y,ZHANG G M,ZHENG X.Effects of different sludge disintegration methods on sludge moisture distribution and dewatering performance[J].Journal of Environmental Sciences,2015,28(2):22-28.DOI:10.1016/j.jes.2014.06.040.
[31]DENG W Y,LI X D,YAN J H,et al.Moisture distribution in sludges based on different testing methods[J].Journal of Environmental Sciences,2011,23(5):875-880.DOI:10.1016/s1001-0742(10)60518-9.
[32]CHEN G H,YUE P L,MUJUMDAR A S.Sludge dewatering and drying[J].Drying Technology,2002,20(4/5):883-916.DOI:10.1081/DRT-120003768.
[33]VAXELAIR J,CEZAC P.Moisture distribution in activated sludges:A review[J].Water Research,2004,38(9):2215-2230.DOI:10.1016/j.watres.2004.02.021.
[34]SJINNER S J,STUDER L J,DIXON D R,et al.Quantification of wastewater sludge dewatering[J].Water Research,2015,82:2-13.DOI:10.1016/j.watres.2015.04.045.
[35]MAO H Z,CHI Y,WANG F,et al.Effect of ultrasonic pre-treatment on dewaterability and moisture distribution in sewage sludge[J].Waste and Biomass Valorization,2017,9(2):247-253.DOI:10.1007/s12649-016-9799-3.
[36]YUAN D Q,WANG Y L,QIAN X.Variations of internal structure and moisture distribution in activated sludge with stratified extracellular polymeric substances extraction[J].International Biodeterioration and Biodegradation,2017,116:1-9.DOI:10.1016/j.ibiod.2016.09.012.
[37]TURCHIULI C,FARGUES C.Influence of structural properties of alum and ferric flocs on sludge dewaterability[J].Chemical Engineering Journal,2016,103(1/2/3):123-131.
[38]KOPP J,DICHTL N.Prediction of full-scale dewatering results of sewage sludges by the physical water distribution[J].Water Science and Technology,2001,43(11):135-143.
[39]MOORE C A,DONALDSON C F.Quantifying soil microstructure using fractals[J].Geotechnique,1995,45(1):105-116.DOI:10.1680/geot.1995.45.1.105.
[40]谢学斌,潘长良.露天矿排土场散体岩石粒度分布的分形特征[J].湘潭矿业学院学报,2003,18(3):56-59.
[41]赵安平,王清,李杨,等.长春季冻区路基土微观孔隙特征的定量评价[J].工程地质学报,2008,16(2):233-238.