超声波-高锰酸钾耦合工艺对污泥破解效果的研究
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摘要
采用超声波、超声波-高锰酸钾耦合工艺预处理剩余污泥。通过对比破解前后污泥上清液中混合液挥发性悬浮固体浓度/混合液悬浮固体浓度(MLVSS/MLSS)、污泥体积指数(SVI)、污泥破解率(DD)、溶解性蛋白质质量浓度、溶解性多糖质量浓度、含固率等变化,考察超声波、超声波-高锰酸钾(KMnO_4)耦合工艺对污泥破解以及污泥特性的影响。结果表明,超声波单独处理最佳处理条件为:声能密度为2. 0 k W/L、反应时间为20 min。此时,污泥的DD、蛋白质质量浓度、多糖质量浓度分别可达18. 41%、180. 21 mg/L、185. 88 mg/L,同时污泥破解后含固率可达6. 2%,污泥的离心脱水性能得到改善。KMnO_4-超声耦合工艺可进一步促进剩余污泥破解。破解效果影响因素的主次顺序为声能密度>反应时间>KMnO4投加量。因此,确定的最佳声能密度为2. 4 kW/L、最佳反应时间为25 min、最佳KMnO_4投加量为2 200 mg/L。此时污泥上清液中蛋白质、多糖的质量浓度分别可达295. 56、361. 27 mg/L;粒径和电镜结果与此匹配。
Municipal excess sludge is treated respectively by ultrasonic method and the coupling process of ultrasonic and KMnO_4. The influences of ultrasonic method and the coupling process on the disintegration and characteristics of sludge are investigated by comparing the variations of mixture volatile suspension solid concentration/mixture suspension solid concentration( MLVSS/MLSS),sludge volume index( SVI),disintegration rate of sludge( DD),concentration of soluble protein,concentration of soluble polysaccharide and content of solids before and after disintegration.The optimal conditions for ultrasonic treatment alone are obtained as follows: the sound energy density is 2. 0 k W·L~(-1) and reaction time is 20 min. Under these conditions,DD,concentrations of protein and polysaccharide in sludge can reach 18. 41%,180. 21 mg·L~(-1) and 185. 88 mg·L~(-1) respectively,the content rate of solid in sludge after disintegration can reach 6. 2% and the centrifugal dehydration performance of sludge can be improved. The KMnO_4-ultrasonic coupling process can further promote the disintegration of excess sludge.The order of the factors affecting the disintegration effect is as follows: the sound energy density > reaction time > KMnO_4 dosage. Therefore,the best sound energy density determined in this experiment is 2. 4 k W·L~(-1),the best reaction time is 25 min and the best dosage of KMnO_4 is 2 200 mg·L~(-1). Under these conditions,the concentrations of protein and polysaccharide in sludge can reach295. 56 mg·L~(-1) and 361. 27 mg·L~(-1) respectively,which matches well with the analysis results of particle size and electron microscopy.
Municipal excess sludge is treated respectively by ultrasonic method and the coupling process of ultrasonic and KMnO_4. The influences of ultrasonic method and the coupling process on the disintegration and characteristics of sludge are investigated by comparing the variations of mixture volatile suspension solid concentration/mixture suspension solid concentration( MLVSS/MLSS),sludge volume index( SVI),disintegration rate of sludge( DD),concentration of soluble protein,concentration of soluble polysaccharide and content of solids before and after disintegration.The optimal conditions for ultrasonic treatment alone are obtained as follows: the sound energy density is 2. 0 k W·L~(-1) and reaction time is 20 min. Under these conditions,DD,concentrations of protein and polysaccharide in sludge can reach 18. 41%,180. 21 mg·L~(-1) and 185. 88 mg·L~(-1) respectively,the content rate of solid in sludge after disintegration can reach 6. 2% and the centrifugal dehydration performance of sludge can be improved. The KMnO_4-ultrasonic coupling process can further promote the disintegration of excess sludge.The order of the factors affecting the disintegration effect is as follows: the sound energy density > reaction time > KMnO_4 dosage. Therefore,the best sound energy density determined in this experiment is 2. 4 k W·L~(-1),the best reaction time is 25 min and the best dosage of KMnO_4 is 2 200 mg·L~(-1). Under these conditions,the concentrations of protein and polysaccharide in sludge can reach295. 56 mg·L~(-1) and 361. 27 mg·L~(-1) respectively,which matches well with the analysis results of particle size and electron microscopy.
引文
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[3]曾祥文,王海霞.我国污水处理厂污泥处置的回顾与展望[J].工业安全与环保,2007,33(7):20-22.
[4]Gayathri T,Kavitha S,Adish K S,et al.Effect of citric acid induced deflocculation on the ultrasonic pretreatment efficiency of dairy waste activated sludge[J].Ultrason Sonochem,2015,22:333-340.
[5]Wang F,Lu S,Ji M.Components of released liquid from ultrasonic waste activated sludge disintegration[J].UltrasonicsSonochemistry,2006,13(4):334-338.
[6]Tiehm A,Nickel K,Zellhorn M,et al.Ultrasonic waste activated sludge disintegration for improving anaerobic stabilization[J].Water Research,2001,35(8):2003-2009.
[7]Yan S T,Chu L B,Xing X H,et al.Analysis of the mechanism of sludge ozonation by a combination of biological and chemical approaches[J].Water Research,2009,43(1):195-203.
[8]王裕祥,黄祎晨,张鑫,等.微气泡臭氧强化污泥碳源的释放过程[J].环境工程学报,2017,11(4):2426-2432.
[9]Liu J,Wei Y,Li K,et al.Microwave-acid pretreatment:A potential process for enhancing sludge dewaterability[J].Water Research,2016,90:225-234.
[10]Bilgin O N,Akmehmet B I.Microwave-assisted chemical oxidation of biological waste sludge:Simultaneous micropollutant degradation and sludge solubilization[J].Bioresource Technology,2013,146(10):126.
[11]Guan S,Deng F,Huang S Q,et al.Optimization of magnetic fieldassisted ultrasonication for the disintegration of waste activated sludge using Box-Behnken design with response surface methodology[J].Ultrasonics Sonochemistry,2017,38:9-18.
[12]苏建文,郑浩,王彩冬,等.超声波或生石灰单独及联合作用对污泥脱水性能的影响[J].净水技术,2014,(3):48-51.
[13]蔺舒,白向玉,周磊,等.低声能密度超声波破解污泥的效果研究[J].环境污染与防治,2015,37(2):78-82.
[14]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.
[15]李云雁,胡传荣.试验设计与数据处理-第2版[M].北京:化学工业出版社,2008.