【作者】 李宁；

【导师】 刘永军；

【作者基本信息】 西安建筑科技大学 ， 建筑与土木工程， 2019， 硕士

【摘要】 针对实际生活污水COD普遍偏低的特点以及以生活污水培养好氧颗粒污泥的研究较少的现状,本研究在SBR反应器中利用低有机负荷(0.63 kg COD m^-3·d^-1)的模拟生活污水完成对好氧颗粒污泥的培养。在好氧污泥颗粒化进程中,定期监测污泥的物化特性并提取污泥胞外聚合物（Extracellular Polymeric Substances,EPS）,研究低有机负荷条件下污泥EPS的分泌特性及其变化规律,并解析其对于好氧污泥颗粒化的影响机制。主要研究结果如下:（1）在低有机负荷条件下,污泥的颗粒化进程缓慢,在第38 d好氧颗粒污泥开始形成,直至第93 d才实现完全颗粒化。驯化期污泥为黄褐色絮体,平均粒径为72.37μm;形成期出现黄白色颗粒状污泥,且颗粒逐渐增大;成熟期,颗粒污泥的结构密实紧凑,平均粒径达到1254.7μm;驯化期,污泥沉降性能较差,对有机污染物COD的去除率由初始的80%⁹0%降至79.2%,氨氮去除率由初始的99.48%降至45.21%;形成期,污泥沉降性能逐渐变好,对COD、氨氮的去除率逐渐升高;成熟期,颗粒污泥SVI值为75.00±3 mL·g^-1,对COD去除率为95%左右,氨氮去除率稳定在97.45%以上,具有良好的沉降性能和污染物去除效能。（2）污泥颗粒化过程中,EPS含量呈先增长后下降的变化规律。初始污泥EPS含量为76.13 mg·g^-1 MLSS。颗粒形成期,EPS含量迅速增长,增至223.03 mg·g^-1MLSS,对颗粒污泥形成起到促进作用。颗粒成熟期EPS含量逐渐减小,但仍比驯化期EPS含量高,以维持颗粒污泥的紧密结构不失稳。蛋白（Proteins,PN）在EPS中含量最高,且其含量变化规律与EPS总量变化规律一致。颗粒成熟期PN含量约是初始污泥PN含量的两倍,对污泥颗粒化及维持颗粒稳定性起重要作用。EPS中多糖（Polysaccharide,PS）含量变化不明显。（3）荧光特性检测显示,EPS的主要荧光特性组分是芳香族类蛋白质和溶解性微生物代谢产物。在颗粒化过程中,各组分类型没有改变,但含量有显著变化。其中芳香族蛋白质类荧光峰的荧光强度始终高于其它峰,是促进污泥颗粒化的重要物质;红外谱图显示,颗粒化过程中EPS的主要官能团类型没有发生较大变化;XPS能谱分析,成熟颗粒污泥EPS中含量最高的元素依次为O,C,N,其中C-O,C=O,-NH₂等是EPS的主要化学基团;污泥颗粒化过程各时期EPS分子量分布在3.33¹13.20 kD范围内,颗粒化进程中EPS主要有机物质的分子量逐渐减小,驯化期时42.79 kD,形成期时34.97 kD,成熟期时29.20 kD;经树脂分级分析,EPS各分级组分中疏水酸性物质HOA与疏水中性物质HON之和占EPS总量的60%⁸0%。颗粒形成期,HOA与HON含量均逐渐增多,成熟期各组分含量关系HOB<HI<HON<HOA,说明HOA与HON在颗粒污泥形成过程中起到重要作用。（4）经统计学分析,EPS各组分含量与污泥粒径、SVI存在明显的相关性,而与MLSS的相关性不显著。其中PN、PS与污泥平均粒径呈显著性正相关,Pearson相关系数分别为0.531（P=0.028）和0.638（P=0.006）。PN、PS与污泥SVI呈显著性负相关,随EPS中PN、PS含量的增加污泥沉降性能趋好。EPS各组分与SV₃₀/SV₅之间均呈现显著正相关,说明EPS各组分在污泥颗粒化进程中起到明显的促进作用。（5）低有机负荷条件下,在进水基质中添加淀粉,模拟颗粒性碳源对好氧污泥颗粒化的影响。发现适当比例（25%）的颗粒性碳源能够刺激污泥EPS更快分泌,加快好氧污泥颗粒化,第56 d,污泥即完全颗粒化,平均粒径为619.6μm,EPS含量最高增长至170.23 mg·g^-1 MLSS。相比溶解性碳源条件,污泥颗粒化周期缩短,但成熟颗粒污泥粒径较小。提升基质中淀粉比例,颗粒污泥稳定性变差,EPS的含量减少,颗粒污泥沉降性能、对污染物的去除效能均变差。说明颗粒性碳源在基质中比例过高（>50%）不利于颗粒污泥的稳定运行。更多还原

【Abstract】 In view of the general low COD of actual domestic sewage and the fact that there are few studies on the cultivation of aerobic granular sludge with domestic sewage,this study completed the cultivation of aerobic granular sludge with simulated domestic sewage with low organic load(0.63 kg COD m^-3·d^-1)in SBR reactor.In the process of aerobic granular sludge,the physical and chemical properties of sludge was regularly monitored and the sludge Extracellular polymers（EPS）was extracted,the secretion of organic load under the condition of low sludge EPS features and its change rule were studied,and its influence on aerobic granular sludge system was also analyzed.The main research results were as follows:（1）Under the condition of low organic load,the granulation process of sludge was slow,aerobic granular sludge began to form on the 38th day,and complete granulation was not realized until the 93rd day.The average particle size of the acclimated sludge was 72.37μm;Yellow and white granular sludge appeared in the forming stage,and the granules gradually increased;In the mature stage,granular sludge had compact structure and average particle size of 1254.7μm;During the acclimation period,the sludge sedimentation performance was poor,the removal rate of COD of organic pollutants decreased from the initial 80%⁹0%to 79.2%,and the removal rate of ammonia nitrogen decreased from the initial 99.48%to 45.21%;During the formation period,the sludge sedimentation performance gradually improved,and the removal rate of COD and ammonia nitrogen gradually increased.In the mature stage,the SVI value of granular sludge was 75.00±3 mL·g^-1,the removal rate of COD was about 95%,the removal rate of ammonia nitrogen was stable at more than 97.45%,with good sedimentation performance and pollutant removal efficiency.（2）In the process of sludge granulation,the content of EPS increased first and then decreased.The initial sludge EPS content was 76.13 mg·g^-1 MLSS.During the particle formation period,EPS content increased rapidly to 223.03 mg·g^-1 MLSS,which promoted the formation of granular sludge.The content of EPS in the mature stage decreased gradually,but the content was still higher than that in the domestication stage,so as to maintain the tight structure of granular sludge without losing stability.Proteins（Proteins,PN）in EPS content was the highest,and the content change rules consistented with EPS total change rule.The PN content in the mature stage was about twice of that in the initial stage,which played an important role in the granulation of sludge and the maintenance of particle stability.The content of Polysaccharide（PS）in EPS did not change significantly.（3）Fluorescence analysis showed that the main fluorescence components of EPS were aromatic proteins and soluble microbial metabolites.In the granulation process,the type of each component did not change,but the content changed significantly.The fluorescence intensity of aromatic protein was always higher than that of other peaks,which was an important material to promote sludge granulation;The infrared spectra showed that the main functional groups of EPS did not change significantly during the granulation process;According to XPS energy spectrum analysis,the elements with the highest content in mature granular sludge EPS were O,C,N in turn,among which C-O,C=O,-NH₂ and so on were the main chemical groups of EPS;The molecular weight of EPS in each period of sludge granulation ranged from 3.33 to 113.20 kD.During the granulation process,the molecular weight of EPS was gradually decreased,with 42.79kD at the domestication stage,34.97 kD at the formation stage,and 29.20 kD at the maturity stage;According to resin grading analysis,the sum of hydrophobic acid HOA and hydrophobic neutral material HON in each grading component of EPS accounted for 60%⁸0%of the total amount of EPS.The content of HOA and HON increased gradually during the granulation stage,and the relationship between HOB<HI<HON<HOA during the maturation stage indicated that HOA and HON were beneficial to the formation of granular sludge.（4）According to the statistical analysis,the contents of EPS components were significantly correlated with sludge particle size and SVI,but not with MLSS.Among them,PN and PS were significantly positively correlated with the mean particle size of sludge,and Pearson correlation coefficients were 0.531（P=0.028）and 0.638（P=0.006）,respectively.PN and PS were significantly negatively correlated with sludge SVI,and sludge settling performance tended to be better with the increase of PN and PS content in EPS.There was a significant positive correlation between EPS components and SV₃₀/SV₅,indicating that EPS components played an obvious promoting role in the process of sludge granulation.（5）The effect of granular carbon source on the granulation of aerobic sludge was simulated by adding starch into the intake matrix under low organic load.It was found that granular carbon source with appropriate proportion（25%）could stimulate the faster secretion of EPS and accelerate the granulation of aerobic sludge.On the 56th day,the sludge was completely granulated with an average particle size of 619.6μm and the maximum EPS increased to 170.23 mg·g^-1 MLSS.Compared with dissolved carbon source condition,the granulation period of sludge was shorter,but the particle size of mature granular sludge was smaller.The ratio of starch in the matrix was increased,the stability of granular sludge was decreased,the content of EPS was decreased,the sedimentation performance of granular sludge and the removal efficiency of pollutants were also decreased.It indicated that the proportion of granular carbon source in the matrix was too high（>50%）,which was not conducive to the stable operation of granular sludge.更多还原