胞外聚合物对活性污泥沉降性能影响机制研究
发布时间：2018-09-10 13:41
【摘要】：城镇污水处理厂作为重要的城市基础设施,在解决水污染与保护自然水体环境方面发挥着不可替代的作用。活性污泥法是城镇污水处理的主流技术,而现有城镇污水处理厂,冬季低温条件下普遍存在污泥膨胀问题,不仅会导致污泥沉降性能显著降低以及污水处理系统活性污泥的大量流失,而且直接导致污水处理厂处理能力与效率的降低,最终影响污水处理厂的正常运行。本课题以实际生产性活性污泥处理系统和现场序批式活性污泥小试系统为研究对象,探究不同温度条件下活性污泥中胞外聚合物及其组分含量的变化对污泥絮体结构和沉降性能的影响,分析了低温条件下胞外聚合物大量积累引起的污泥沉降恶化和污泥比重下降的原因。主要研究成果如下:(1)通过对一年四季不同温度条件下实际生产性活性污泥系统的研究,结果表明:随着反应温度的下降,活性污泥沉降性能逐渐变差,胞外聚合物不断积累,其中主要是LB-EPS(即疏松型的胞外聚合物)和Total-C(即胞外多糖)的大量累积。当反应温度从25.7℃降至11.1℃时,SVI值从232m L/g升至326m L/g,其增加量为94 m L/g,增加幅度达41%;LB-EPS从88mgCOD/gMLVSS增加至207mgCOD/gMLVSS,其增加量达到119mgCOD/gMLVSS,增幅高达135%,LB-EPS的增加量占Total-EPS增加量的73%;Total-C从34.51mg/gMLVSS增加至56.85mg/gMLVSS,其增加量达到22.34mg/gMLVSS,增幅为39%。此外,不同温度条件下,活性污泥SVI值与LB-EPS、Total-C存在较高的相关性。因此,在实际生产性活性污泥系统中,随着反应温度的下降活性污泥中LB-EPS和Total-C的不断积累是导致活性污泥沉降性能变差的直接原因。(2)通过外力作用人为改变污泥絮体结构,分析胞外聚合物对活性污泥基质传质影响的研究,结果表明:利用外力作用后的活性污泥进行现场序批式小试试验,作用强度为超声波(20W/gMLSS,20kHz)分别处理0min、1min、2min、5min,外力作用后活性污泥的代谢能力和污泥的沉降性能得到不同程度的提高,INT-ETS(即电子传递体系活性)分别为107、110、150、161 mg/(gVSS*h),SVI分别为213、207、147、109mL/g;而活性污泥的胞外聚合物含量发生明显变化,尤其是LB-EPS分别为276、242、192、175mgCOD/gMLVSS,TB-EPS分别为421、423、368、339 mgCOD/gMLVSS;作用强度不同的活性污泥系统之间SVI、INT-ETS值与LB-EPS、TB-EPS都存在很好的相关性。因此,当通过外力作用人为改变污泥絮体结构后提高了污泥的基质传质能力,进而增强了活性污泥的代谢能力,导致胞外聚合物含量的减少,最终改变了活性污泥的沉降性能。(3)通过对不同温度条件下现场活性污泥小试系统的研究,结果表明:①当反应温度从24℃降至8℃时,活性污泥系统沉降性能和污泥代谢能力逐渐变差,活性污泥系统的比重逐渐下降,胞外聚合物尤其是LB-EPS和Total-C的不断积累。SVI值从85m L/g升至328m L/g,其增加值高达243 m L/g,增加幅度更是高达286%;污泥比重值从1.0318g/m L降至1.0129g/m L;而LB-EPS则从167 mgCOD/gMLVSS增加至287 mgCOD/gMLVSS,其增加值为120 mgCOD/gMLVSS,增加幅度高达72%;Total-C从47.4 mg/gMLVSS增加至72.4 mg/gMLVSS,其增加值为25 mg/gMLVSS,增加幅度为53%。活性污泥的SVI值与LB-EPS、Total-C之间也存在很高的相关性;活性污泥的SVI值与污泥比重之间也存在很高的相关性。因此,对不同温度条件下现场活性污泥小试系统而言,随着反应温度的下降LB-EPS和Total-C的不断积累以及污泥比重的不断减小是导致活性污泥沉降性能变差的直接原因。②当反应温度从24℃降至8℃时,活性污泥的代谢能力逐渐下降。TTC-DHA(即脱氢酶活性)从16.74mg/(gVSS*h)降至4.39 mg/(gVSS*h),其值下降12.35 mg/(gVSS*h);INT-ETS(即电子传递体系活性)从170.86 mg/(gVSS*h)降至41.37 mg/(gVSS*h),其值下降129.49 mg/(gVSS*h)。活性污泥系统的反应温度与TTC-DHA与INT-ETS之间存在较高的相关性;TTC-DHA、INT-ETS与LB-EPS、Total-C、污泥比重之间存在很高的相关性。因此,对不同温度条件下现场序批式活性污泥小试系统而言,活性污泥代谢能力随反应温度下降而降低,进而导致胞外聚合物的不断积累和污泥比重下降,是导致活性污泥沉降性能变差的根本原因。
[Abstract]:As an important urban infrastructure, urban sewage treatment plants play an irreplaceable role in solving water pollution and protecting the natural water environment. Activated sludge process is the mainstream technology of urban sewage treatment. However, sludge bulking is a common problem in existing urban sewage treatment plants at low temperature in winter, which not only leads to sludge sedimentation. The performance of the sewage treatment system is significantly reduced and a large number of activated sludge is lost, which directly leads to the reduction of the treatment capacity and efficiency of the sewage treatment plant, and ultimately affects the normal operation of the sewage treatment plant. The effects of the content of extracellular polymers and their components on the structure and settling properties of activated sludge flocs at different temperatures were studied. The causes of sludge settling deterioration and sludge specific gravity decrease caused by the accumulation of extracellular polymers at low temperatures were analyzed. The results showed that with the decrease of reaction temperature, the sedimentation performance of activated sludge gradually deteriorated and the accumulation of extracellular polymers, mainly LB-EPS and Total-C, decreased from 25.7 to 11.1. The increase of M L/g to 326m L/g was 94 m L/g, with an increase of 41%; the increase of LB-EPS from 88 mgCOD/gMLVSS to 207 mgCOD/gMLVSS reached 119 mgCOD/gMLVSS, an increase of 135%; the increase of LB-EPS accounted for 73% of the increase of Total-EPS; the increase of Total-C from 34.51 m g/gMLVSS to 56.85 m g/gMLVSS, with an increase of 22.34 M g/gMLVSS, an increase of 36.85 m g/gMLVSS. In addition, the SVI value of activated sludge was highly correlated with LB-EPS and Total-C at different temperatures. Therefore, the accumulation of LB-EPS and Total-C in activated sludge with the decrease of reaction temperature was the direct reason for the deterioration of activated sludge sedimentation performance. The effect of extracellular polymer on the mass transfer of activated sludge substrate was studied by changing the structure of sludge flocs. The results showed that the field sequencing batch test was carried out on the activated sludge after external force. The strength of action was ultrasonic wave (20W/gMLSS, 20kHz) treatment for 0 min, 1 min, 2 min, 5 min, respectively. The INT-ETS (i.e. electron transfer system activity) was 107,110,150,161 mg / (gVSS * h) and the SVI was 213,207,147,109 mL / g, respectively, while the extracellular polymer content of activated sludge changed significantly, especially the LB-EPS was 276,242,192,175 mg COD / gMLVSS, and the TB-EPS was 421,423,368,339 mg COD / gMLVSS, respectively. The SVI and INT-ETS values of activated sludge systems with different strengths are well correlated with LB-EPS and TB-EPS. Therefore, when the structure of sludge flocs is artificially changed by external forces, the substrate transfer capacity of activated sludge is enhanced, and the metabolic capacity of activated sludge is enhanced, resulting in the decrease of extracellular polymer content, and ultimately the activity is changed. The results show that: (1) when the reaction temperature drops from 24 to 8, the sedimentation performance and sludge metabolic capacity of the activated sludge system become worse, the proportion of the activated sludge system gradually decreases, and the extracellular polymers especially LB-EPS and Total-C are not. SVI increased from 85m L/g to 328m L/g, with an increase of 243 m L/g and 286%; sludge specific gravity decreased from 1.0318 g/ml to 1.0129 g/ml; and LB-EPS increased from 167 mgCOD/gMLVSS to 287 mgCOD/gMLVSS, with an increase of 72%; Total-C increased from 47.4 m g/gMLVSS to 72.4 m g/gMLVSS. LVSS increased by 53% with an increase of 25 mg/g MLVSS. There was also a high correlation between SVI of activated sludge and LB-EPS, Total-C. There was also a high correlation between SVI of activated sludge and sludge specific gravity. The accumulation of otal-C and the decrease of sludge specific gravity are the direct reasons for the deterioration of the sedimentation performance of activated sludge. The activity of electron transfer system decreased from 170.86 mg / (gVSS * h) to 41.37 mg / (gVSS * h) and decreased by 129.49 mg / (gVSS * h). There was a high correlation between the reaction temperature of activated sludge system and TTC-DHA and INT-ETS, and between TTC-DHA, INT-ETS, LB-EPS, Total-C and sludge specific gravity. In the sequencing batch reactor, the metabolic capacity of activated sludge decreases with the decrease of reaction temperature, which leads to the accumulation of extracellular polymers and the decrease of sludge specific gravity, which is the fundamental reason for the deterioration of activated sludge settling performance.
【学位授予单位】：青岛理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703
[Abstract]:As an important urban infrastructure, urban sewage treatment plants play an irreplaceable role in solving water pollution and protecting the natural water environment. Activated sludge process is the mainstream technology of urban sewage treatment. However, sludge bulking is a common problem in existing urban sewage treatment plants at low temperature in winter, which not only leads to sludge sedimentation. The performance of the sewage treatment system is significantly reduced and a large number of activated sludge is lost, which directly leads to the reduction of the treatment capacity and efficiency of the sewage treatment plant, and ultimately affects the normal operation of the sewage treatment plant. The effects of the content of extracellular polymers and their components on the structure and settling properties of activated sludge flocs at different temperatures were studied. The causes of sludge settling deterioration and sludge specific gravity decrease caused by the accumulation of extracellular polymers at low temperatures were analyzed. The results showed that with the decrease of reaction temperature, the sedimentation performance of activated sludge gradually deteriorated and the accumulation of extracellular polymers, mainly LB-EPS and Total-C, decreased from 25.7 to 11.1. The increase of M L/g to 326m L/g was 94 m L/g, with an increase of 41%; the increase of LB-EPS from 88 mgCOD/gMLVSS to 207 mgCOD/gMLVSS reached 119 mgCOD/gMLVSS, an increase of 135%; the increase of LB-EPS accounted for 73% of the increase of Total-EPS; the increase of Total-C from 34.51 m g/gMLVSS to 56.85 m g/gMLVSS, with an increase of 22.34 M g/gMLVSS, an increase of 36.85 m g/gMLVSS. In addition, the SVI value of activated sludge was highly correlated with LB-EPS and Total-C at different temperatures. Therefore, the accumulation of LB-EPS and Total-C in activated sludge with the decrease of reaction temperature was the direct reason for the deterioration of activated sludge sedimentation performance. The effect of extracellular polymer on the mass transfer of activated sludge substrate was studied by changing the structure of sludge flocs. The results showed that the field sequencing batch test was carried out on the activated sludge after external force. The strength of action was ultrasonic wave (20W/gMLSS, 20kHz) treatment for 0 min, 1 min, 2 min, 5 min, respectively. The INT-ETS (i.e. electron transfer system activity) was 107,110,150,161 mg / (gVSS * h) and the SVI was 213,207,147,109 mL / g, respectively, while the extracellular polymer content of activated sludge changed significantly, especially the LB-EPS was 276,242,192,175 mg COD / gMLVSS, and the TB-EPS was 421,423,368,339 mg COD / gMLVSS, respectively. The SVI and INT-ETS values of activated sludge systems with different strengths are well correlated with LB-EPS and TB-EPS. Therefore, when the structure of sludge flocs is artificially changed by external forces, the substrate transfer capacity of activated sludge is enhanced, and the metabolic capacity of activated sludge is enhanced, resulting in the decrease of extracellular polymer content, and ultimately the activity is changed. The results show that: (1) when the reaction temperature drops from 24 to 8, the sedimentation performance and sludge metabolic capacity of the activated sludge system become worse, the proportion of the activated sludge system gradually decreases, and the extracellular polymers especially LB-EPS and Total-C are not. SVI increased from 85m L/g to 328m L/g, with an increase of 243 m L/g and 286%; sludge specific gravity decreased from 1.0318 g/ml to 1.0129 g/ml; and LB-EPS increased from 167 mgCOD/gMLVSS to 287 mgCOD/gMLVSS, with an increase of 72%; Total-C increased from 47.4 m g/gMLVSS to 72.4 m g/gMLVSS. LVSS increased by 53% with an increase of 25 mg/g MLVSS. There was also a high correlation between SVI of activated sludge and LB-EPS, Total-C. There was also a high correlation between SVI of activated sludge and sludge specific gravity. The accumulation of otal-C and the decrease of sludge specific gravity are the direct reasons for the deterioration of the sedimentation performance of activated sludge. The activity of electron transfer system decreased from 170.86 mg / (gVSS * h) to 41.37 mg / (gVSS * h) and decreased by 129.49 mg / (gVSS * h). There was a high correlation between the reaction temperature of activated sludge system and TTC-DHA and INT-ETS, and between TTC-DHA, INT-ETS, LB-EPS, Total-C and sludge specific gravity. In the sequencing batch reactor, the metabolic capacity of activated sludge decreases with the decrease of reaction temperature, which leads to the accumulation of extracellular polymers and the decrease of sludge specific gravity, which is the fundamental reason for the deterioration of activated sludge settling performance.
【学位授予单位】：青岛理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703
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