污水处理及其冲击过程中絮体结构的变化规律研究

发布时间：2018-02-20 23:44

本文关键词： 絮体结构冲击负荷 A~2/O工艺呼吸图谱胞外聚合物　出处：《西安建筑科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：活性污泥法作为生物处理过程中广泛应用的技术,首要面对的问题是脱氮除磷效率较低且能耗过高,系统的耐冲击负荷稳定性较差。而絮体结构作为絮凝工艺中最重要的基本参数之一,不仅在微生物生化反应过程中影响污水中有机底物的吸附作用和传质效果等,还在宏观上决定了污泥的压缩,沉降效果以及污泥的稳定性等,对水处理效率有重要影响。本文以絮体结构这一参数为视角,对一种新型改良A2/O工艺的运行特性和机理,及其后续不同絮体结构受冲击影响规律进行了研究,为污水处理过程效率的提高和系统稳定性的改进提供了新思路。研究的内容及结果包括:1、通过调整改良型A2/O工艺反应器的生物选择器,并对生物选择器内上升流速变化发生的40天内参数进行监测,发现:(1)通过加大改良型A2/O工艺中生物选择器的上升流速可以实现对密实絮体富集。加大上升流速的40天内,好氧池的絮体粒径峰值从280μm增长到410μm,增大了46%,SV5、SV30以及SVI等沉降性参数分别下降了44%,48%和78%,微生物絮体尺寸也相应增长。(2)因生物选择器而筛选的密实絮体更容易使自养菌依附生长,通过密实絮体的富集可以实现硝化细菌的富集,进而提高脱氮效率。在密实絮体开始富集的40天过程里,总氮去除率从42%升高到62%,提高了20%。(3)在本次实验生物选择器实现密实絮体富集的过程中,除磷效果的变化没有特别明显的规律,去除率基本都在40%~50%之间波动。可能是受温度和泥龄等因素影响,无法比较疏松与密实絮体的除磷效果,仍需进一步研究。2、为了进一步探究分析改良工艺所筛选的絮体对环境影响程度的敏感性,继续对不同絮体结构的代表污泥进行改变基质短期冲击试验进行分析,结果表明:(1)短期冲击发生后,疏松絮体污泥密度变小,沉淀性变差;而密实絮体密度则持续变大,沉淀性变好。通过基质的选择,可在短期内改变絮体的密度和沉降性能。而密实絮体在受冲击后,污泥的密实程度和沉降性能好转,对后续的沉降和脱水过程影响较小,不易发生污泥膨胀等问题。(2)疏松絮体异养菌活性持续下降,其所占的呼吸比例也明显下降,而密实絮体异养菌活性在出现短暂抑制后快速上升,最终异养菌所占的呼吸比例略有上升。在冲击过程中异养菌的活性对絮体结构变化起关键作用,密实絮体在受到短期冲击时总呼吸速率恢复更快,而这部分呼吸速率恢复中以异养菌为主。(3)荧光强度方面,腐殖酸类物质区的峰B在基质变化冲击后,变化趋势都是减小甚至消失,因此峰B与原水组分有关;色氨酸区的峰A在受到冲击后变化不大。总体来说,EPS的荧光峰虽然存在一定变化,但絮体结构的改变关联性不大。
[Abstract]:As a widely used technology in biological treatment, activated sludge process mainly faces the problems of low efficiency of nitrogen and phosphorus removal and high energy consumption. As one of the most important basic parameters in flocculation process, flocs not only affect the adsorption and mass transfer effect of organic substrates in wastewater during microbial biochemical reaction, but also affect the stability of the system. It also determines the compressing, settling effect and stability of sludge, which has an important effect on water treatment efficiency. This paper takes the parameter of floc structure as a visual angle to study the operation characteristics and mechanism of a new modified A _ 2 / O process. The impact law of different floc structures was studied. It provides a new way to improve the efficiency of wastewater treatment process and the stability of the system. The contents and results of the study include: 1, by adjusting the biological selectors of the modified A2 / O process reactor, The parameters of the rising velocity change in the biological selector were monitored within 40 days. It was found that the concentration of the dense flocs could be realized by increasing the rising velocity of the biological selector in the modified A2 / O process, and the rising velocity of the biological selector could be increased within 40 days. The peak particle size of flocs in aerobic tank increased from 280 渭 m to 410 渭 m, and the sedimentation parameters such as 46% SV5SV30 and SVI decreased by 44% and 78%, respectively, and the size of microbial flocs increased accordingly. The enrichment of nitrifying bacteria can be realized through the enrichment of dense flocs, and the denitrification efficiency can be improved. The removal rate of total nitrogen increased from 42% to 62%, which increased 20%.) in the process of realizing the enrichment of dense flocs in the biological selector in this experiment, the change of phosphorus removal efficiency was not particularly obvious. The removal rate fluctuates between 40% and 50%. It may be affected by temperature and mud age, so it is impossible to compare the phosphorus removal effect of loose and dense floc. In order to further explore the sensitivity of the flocs selected by the improved technology to the environmental impact, the short-term impact test of changing the substrate for the representative sludge of different floc structures was carried out. The results show that after short-term impact, the density of loose flocs becomes smaller and the sedimentation becomes worse, while the density of dense flocs continues to increase and the sedimentation becomes better. The density and settling performance of the flocs can be changed in a short period of time. However, the compactness and settling performance of the sludge improve after the impact, which has little effect on the subsequent sedimentation and dewatering process. Problems such as sludge bulking are not easy to occur. (2) the activity of heterotrophic bacteria in loose flocs decreases continuously, and the respiration ratio decreases obviously, while the activity of heterotrophic bacteria in dense flocs increases rapidly after a short period of inhibition. In the process of impact, the activity of heterotrophic bacteria plays a key role in the change of floc structure, and the total respiration rate of dense floc recovers faster when it is subjected to short-term shock. In this part of respiratory rate recovery, the fluorescence intensity of heterotrophic bacteria is dominant. The peak B of humic acid material region decreases or even disappears after the matrix changes, so peak B is related to the composition of raw water. The peak A of tryptophan region did not change much after shock. Generally speaking, the fluorescence peak of EPS changed to a certain extent, but the change of floc structure was not relevant.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

【相似文献】