污泥预处理对微生物絮凝剂制备及性能的影响
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摘要
试验研究了不同污泥预处理方法对微生物絮凝剂的制备及其絮凝性能的影响.结果表明,污泥经碱热预处理后释放的有机物质量最大,SCOD/TCOD可达到0.56.以碱热预处理污泥作为基质制备的微生物絮凝剂,其产量为2.3 g·L-1,高于热预处理的1.6 g·L-1,酸热预处理的0.6 g·L-1,以及未接种污泥絮凝剂的18 mg·L-1.采用响应面分析法对碱热预处理污泥制备的微生物絮凝剂与PAM复配改善污泥脱水的过程进行了优化,实验分别拟合了关于污泥比阻(SRF)和干污泥量(DS)的二次模型,决定系数(R2)分别为0.9057和0.9171,表明拟合情况良好.实验中最佳的污泥脱水条件为微生物絮凝剂投加量12.6 g·kg-1,PAM投加量1.0 g·kg-1,Ca Cl2投加量59.7 mg·L-1,p H值6.7,搅拌速度185r·min-1.在此条件下,DS和SRF分别为29.1%和2.2×1012m·kg-1,表明碱热预处理污泥制备的微生物絮凝剂与PAM的联合使用有助于改善污泥脱水性能.
Effects of sludge pre-treatments on the preparation and performances of bioflocculants from sludge were investigated. Results showed that the organic quality released from sludge was the highest after the alkali-heat-treatment( ALT),with SCOD / TCOD reaching 0. 56. Concentration of the bioflocculant from ALT sludge was 2. 3 g·L- 1,which was higher than that from the sterilized( ST),acid-heat-treatment( ACT),and the unvaccinated sludge( 1. 6 g·L- 1,0. 6 g·L- 1,and 18 mg·L- 1,respectively). Response surface methodology was employed to optimize the sludge dewatering processes by the composite of bioflocculant from ALT sludge and PAM,with correlation coefficients( R2) of 0. 9057 and 0. 9171,the quadratic models of SRF and DS could well fit to experimental data. The optimal conditions for sludge dewatering were at the dosage of bioflocculant 12. 6 g·kg- 1,PAM 1.0 g·kg- 1,Ca Cl259. 7 mg·L- 1,p H = 6. 7,with an agitation speed of 185 r·min- 1. Under the optimal conditions,DS and SRF of the sludge reached29. 1% and 2. 2 × 1012m·kg- 1,respectively,indicating that the sludge dewatering was greatly improved by the combination of the bioflocculant and PAM.
Effects of sludge pre-treatments on the preparation and performances of bioflocculants from sludge were investigated. Results showed that the organic quality released from sludge was the highest after the alkali-heat-treatment( ALT),with SCOD / TCOD reaching 0. 56. Concentration of the bioflocculant from ALT sludge was 2. 3 g·L- 1,which was higher than that from the sterilized( ST),acid-heat-treatment( ACT),and the unvaccinated sludge( 1. 6 g·L- 1,0. 6 g·L- 1,and 18 mg·L- 1,respectively). Response surface methodology was employed to optimize the sludge dewatering processes by the composite of bioflocculant from ALT sludge and PAM,with correlation coefficients( R2) of 0. 9057 and 0. 9171,the quadratic models of SRF and DS could well fit to experimental data. The optimal conditions for sludge dewatering were at the dosage of bioflocculant 12. 6 g·kg- 1,PAM 1.0 g·kg- 1,Ca Cl259. 7 mg·L- 1,p H = 6. 7,with an agitation speed of 185 r·min- 1. Under the optimal conditions,DS and SRF of the sludge reached29. 1% and 2. 2 × 1012m·kg- 1,respectively,indicating that the sludge dewatering was greatly improved by the combination of the bioflocculant and PAM.
引文
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Zhang Z Q,Xia S Q,Zhang J.2010.Enhanced dewatering of waste sludgewith microbial flocculant TJ-F1 as a novel conditioner[J].WaterResearch,44(10):3087-3092
Aravinthan V,Mino T,Takizawa S,et al.2001.Sludge hydrolysate as acarbon source for denitrification[J].Water Science&Technology,43(1):191-199
Drouin M,Lai C K,Tyagi R D,et al.2008.Bacillus licheniformisproteases as high value added products from fermentation ofwastewater sludge:pre-treatment of sludge to increase theperformance of the process[J].Water Science&Technology,57(3):423-429
郭俊元,杨春平,邱国良.2012.生物絮凝剂与改性沸石复配处理猪场废水厌氧消化液的响应面优化[J].中国环境科学,32(11):1999-2005
Guo J Y,Yang C P,Peng L Y.2014.Preparation and characteristics ofbacterial polymer using pre-treated sludge from swine wastewatertreatment plant[J].Bioresource Technology,152:490-498
Guo J Y,Yang C P,Zeng G M.2013.Treatment of swine wastewater usingchemically modified zeolite and bioflocculant from activated sludge[J].Bioresource Technology,143:289-297
黄兢,杨朝晖,孙珮石,等.2008.微生物絮凝剂与聚合氯化铝复配的响应面优化[J].中国环境科学,28(11):1014-1019
More T T,Yan S,Hoang N V,et al.2012.Bacterial polymer productionusing pre-treated sludge as raw material and its flocculation anddewatering potential[J].Bioresource Technology,121:425-431
Sun J,Zhang X H,Miao X J,et al.2012.Preparation and characteristicsof bioflocculants from excess biological sludge[J].BioresourceTechnology,126:362-366
Tchobanoglous G,Burton F L,Stensel H D.2003.WastewaterEngineering:Treatment and Reuse(4th ed)[M].New York:Matcalf&Eddy Inc
Tian Y.2008.Behaviour of bacterial extracellular polymeric substancesfrom activated sludge:a review[J].International Journal ofEnvironment and Pollution,32(1):78-89
Verma M,Brar S K,Riopel A R,et al.2007.Pre-treatment of wastewatersludge-biodegradability and rheology study[J].EnvironmentalTechnology,28(3):273-284
王春燕,周集体,金若菲.2007.利用脱水污泥制备微生物絮凝剂及其絮凝条件研究[J].中国给水排水,23(21):105-108
Yang Q,Luo K,Liao D X,et al.2012.A novel bioflocculant produced byKlebsiella sp.and its application to sludge dewatering[J].Water andEnvironment Journal,26(4):560-566
Yang Z H,Huang J,Zeng G M,et al.2009.Optimization of flocculationconditions for kaolin suspension using the composite flocculant ofMBFGA1 and PAC by response surface methodology[J].BioresourceTechnology,100(18):4233-4239
Yi T,Lee E-H,Ahn Y G,et al.2011.Novel biodegradation pathways ofcyclohexane by Rhodococcus sp.EC1[J].Journal of HazardousMaterials,191(1/3):393-396
Zhang Z Q,Xia S Q,Zhang J.2010.Enhanced dewatering of waste sludgewith microbial flocculant TJ-F1 as a novel conditioner[J].WaterResearch,44(10):3087-3092