微波与CPAM联用对污泥结构及其脱水性能的影响

发布时间：2018-04-17 15:51

本文选题：污泥 + 脱水　；参考：《长沙理工大学》2015年硕士论文

【摘要】：城市污水处理厂产生的污泥数量巨大且含水量极高。因此,如何提高污泥的脱水性能,是一个重要的研究课题。目前应用最广泛的预处理方法是添加阳离子聚丙烯酰胺(CPAM),然而,CPAM的广泛使用将对周围的环境造成潜在的风险。本研究采用微波辐射,CPAM调质以及微波与CPAM联用这三种调质方法,从微观角度出发,基于分形理论对微波调质和微波与阳离子聚丙烯酰胺联合调质前后污泥的比阻(SRF)、滤饼含水率、污泥粒径(d_(0.5))、分形维数(Df)、絮体强度(FS)、絮凝能力(FA)、表面相对疏水性(RH)的变化规律进行分析,并研究各个参数的变化对污泥脱水性能的影响,以此探讨调质污泥的机理。试验结果如下：适宜的微波辐射能够明显改善污泥脱水性能和结构。在不同的微波功率下,随着微波辐射时间的延长,污泥比阻和含水率均呈现先减小后增大的趋势。不同功率的微波辐射均能够增大污泥的粒径,使其粗大化。随着微波辐射时间的延长,污泥分形维数D_3与D_2以及絮体强度均呈现先增大后减小的趋势,而污泥颗粒表面相对疏水性则是始终保持增长趋势。同时,适量的微波调质可以使FA增大。单独采用CPAM时,CPAM的最佳投加量为80mg/L,此时污泥比阻和滤饼含水率较原污泥分别下降了81.60%和9.34%,而RH和FA分别增大至86.86%和38.36%。随着CPAM投加量的不断增加,D_3逐渐减小,而D_2值不断增大,FS显著增大。采用微波絮凝联合调质污泥可以使其脱水性能进一步提高,而微波辐射和CPAM联合进行污泥调质时,后者主要起到脱水作用。经微波预处理再絮凝的污泥比单独添加CPAM的污泥絮体粒径小。与单独微波调质不同,在同一投加量下,随着辐射时间的延长,污泥絮体粒径逐渐减小,分形维数D_3与D_2逐渐增大。微波絮凝剂联合调质后的污泥RH、FS、FA相比单独微波辐射后的较大。在微波调质下,较大的d_(0.5)可以明显提高污泥的脱水性能,密实的絮体结构有助于污泥脱水,同时增大的絮体强度也有利于真空过滤：对污泥比阻影响较大的因素主要有粒度、分形维数和絮体强度。在微波与CPAM联用调质下,污泥比阻和滤饼含水率随d_(0.5)增大而出现先减小后增大的趋势。在相同作用时间下,随着絮凝剂的投加量的增大,孔隙率逐渐增大,而D_3和污泥比阻逐渐减小。絮体强度的增大有利于絮体过滤,但在最强絮状结构下并未达到最优脱水效率,而污泥比阻随絮体强度的增大而减小。在微波与CPAM联用调质下对污泥比阻影响较大的因素同样也主要有粒度、分形维数和絮体强度。本文基于SPSS statistics 17.0软件建立污泥比阻和污泥结构参数的脱水特性模型,得到两种调质方法下污泥比阻和各参数的多元线性模型,由模型可知,d_(0.5)是提高污泥脱水性能的关键因素。
[Abstract]:The amount of sludge produced by municipal wastewater treatment plant is huge and the water content is very high.Therefore, how to improve sludge dewatering performance is an important research topic.At present, the most widely used pretreatment method is to add cationic polyacrylamide (CPAM). However, the widespread use of CPAM will pose a potential risk to the environment.In this study, the specific resistance of sludge before and after microwave conditioning and combined conditioning with cationic polyacrylamide and the moisture content of filter cake were studied based on fractal theory from the microscopic point of view by using microwave radiation CPAM conditioning and microwave and CPAM combined conditioning and tempering methods, respectively, in this study, the specific resistance of sludge before and after microwave conditioning and combined treatment with cationic polyacrylamide (CPAM) was studied.The variation rules of sludge particle size, fractal dimension, flocculation strength, flocculation capacity and surface relative hydrophobicity are analyzed, and the influence of various parameters on sludge dewatering performance is studied, so as to explore the mechanism of sludge dewatering.The results are as follows: suitable microwave radiation can obviously improve sludge dewatering performance and structure.Under different microwave power, the specific resistance and moisture content of sludge decreased first and then increased with the prolongation of microwave radiation time.Microwave radiation of different power can increase the particle size of sludge and make it coarse.With the prolongation of microwave radiation time, the fractal dimension D _ 3 and D _ S _ 2 of sludge and the strength of flocs increased first and then decreased, while the relative hydrophobicity of sludge granule surface was always increasing.At the same time, appropriate amount of microwave conditioning can make FA increase.When CPAM was used alone, the optimum dosage was 80 mg / L, the sludge specific resistance and cake moisture content decreased by 81.60% and 9.34%, respectively, while RH and FA increased to 86.86% and 38.36%, respectively.With the increase of the amount of CPAM, the number of DSC3 decreases gradually, while the value of DSC2 increases and FS increases significantly.Microwave flocculation combined with modified sludge can further improve the dewatering performance of sludge, while microwave radiation and CPAM combined with sludge conditioning, the latter plays a major role in dewatering.The size of sludge flocculated by microwave pretreatment was smaller than that by adding CPAM alone.Under the same dosage, the particle size of sludge floc decreases gradually with the prolongation of radiation time, and the fractal dimension D _ (3) and D _ (2) increase gradually.The sludge treated by microwave flocculant combined with conditioning was larger than that after microwave irradiation alone.Under the condition of microwave conditioning and tempering, the sludge dewatering performance can be improved obviously by the larger D _ S _ (0.5)). The dense flocs structure is helpful to sludge dewatering, and the increased flocs strength is also beneficial to vacuum filtration. The main factors affecting sludge specific resistance are granularity.Fractal dimension and floc strength.Under the combination of microwave and CPAM, the sludge specific resistance and filter cake moisture content increased with the increase of ds0. 5) and then decreased first and then increased.At the same time, with the increase of the dosage of flocculant, the porosity increased gradually, while Dass _ 3 and sludge specific resistance decreased gradually.The increase of flocs strength is beneficial to flocs filtration, but the optimum dehydration efficiency is not reached under the strongest flocculation structure, and the sludge specific resistance decreases with the increase of flocs strength.The factors affecting sludge specific resistance under the combination of microwave and CPAM also include particle size fractal dimension and floc strength.In this paper, based on SPSS statistics 17.0 software, the sludge specific resistance and sludge structural parameters dewatering characteristic model is established, and the multivariate linear model of sludge specific resistance and each parameter under two kinds of conditioning and tempering methods is obtained. According to the model, the sludge specific resistance and sludge structure parameters are the key factors to improve sludge dewatering performance.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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