低氧活性污泥法除污及污泥减量研究.pdf.doc.doc

低氧活性污泥法除污及污泥减量研究重庆大学博士学位论文学生姓名：徐宇峰指导教师：郭劲松教授专业：市政工程学科门类：工学重庆大学城市建设与环境工程学院二 O一四年四月 The Investigation of Pollutant Removal and Sludge Reduction by Activated Sludge under Low Oxygen ConcentrationA Thesis Submitted to Chongqing Universityin Partial Fulfillment of the Requirement for theDoctors Degree of EngineeringByXu YufengSupervised by Prof. Guo JingsongSpecialty: Municipal EngineeringCollege of Urban Construction and Environmental Engineering of Chongqing University, Chongqing, China April 2014 中文摘要摘 要活性污泥工艺是目前应用最为广泛的污水处理技术，占城市污水处理工艺的90%以上和工业废水处理工艺的50%左右。但在运行过程中还有着种种的弊端：其一是污泥膨胀问题，这是活性污泥工艺中最常见、最主要也是最严重的问题；其二是能源消耗问题，活性污泥工艺处理城市污水过程中消耗的电费约占常规运行成本的三分之一以上；其三是剩余污泥问题，在处理污水的过程中，由于微生物的增殖，活性污泥会产生大量的剩余污泥，对这部分污泥的处理费用更是高达常规运行成本的50%以上。针对活性污泥工艺在运行过程中所表现出的三种弊端，众多学者开展了广泛的研究。基于低溶解氧（DO）污泥丝状菌微膨胀工艺，其核心是人为地控制活性污泥系统在低DO状态下运行，引发一定程度的污泥膨胀，其膨胀程度受控而不会导致严重的污泥流失；同时低溶解氧浓度，降低了曝气电耗。研究发现在低氧浓度条件下，污泥产率的下降，剩余污泥产量也将有所减少。为了更好地掌握和发挥低溶解氧污泥工艺的应用潜能，有必要对其进行深入的研究。本论文对低溶解氧活性污泥工艺的污染物去除、稳定性和减量效果及其作用机制、数学模拟进行了较系统的研究。主要从宏观分析了低氧活性污泥的污染物去除、参数影响和低氧污泥的减量效果及机制，从微观角度分析低氧活性污泥的种群及胞外酶的分布特征，并建立数学模型探讨了低氧活性污泥工艺的机理，获得了如下主要结论:1)与参照的传统活性污泥工艺相比，低溶解氧活性污泥工艺存在的最大弊端在于稳定性不强，易发膨胀。研究通过低氧适应性培养使反应器处于一种稳定的微膨胀状态，首次依据数学模型从理论上论证了这种状态存在的稳定性。实验观察证实低溶解氧活性污泥工艺曝气能耗降低 50%，且可稳定有效去除进水中的污染物质，并具备短程硝化特性。其 COD的去除率为 95%，氨氮去除率达到 95%以上，亚硝化率达到 80%以上，总氮去除率均达到 70%以上，PO43-P去除率达到 95以上，总体效果强于参照活性污泥工艺；研究发现低温条件会抑制活性污泥工艺的污染物去除，低溶解氧会进一步加剧低温对活性污泥工艺的不利影响； SRT在10d-20d范围内变化时，不会对低氧反应器污染物的去除效果造成明显影响。2)与参照的传统活性污泥工艺相比，低溶解氧活性污泥工艺的污泥产率下降了 13.3%。为对这一现象的本质进行研究，根据对污泥表观产率影响的差异，将引起污泥减量的因素分为两部分进行分析，其一为间接因素，其二为直接因素，间接因素如污泥活性、污泥粒径及 EPS等，可通过直接因素影响污泥的表观产率。I 重庆大学博士学位论文直接因素如污泥真实产率、污泥衰减率及水解性能等，可以直接对污泥的表观产率造成影响。通过以上两方面，对污泥的减量机理进行了分析，结果表明，长期在低氧条件下驯化活性污泥，导致其真实产率变低，污泥水解衰减率变低。结合Lawrence-Mccarty模型，可知低氧污泥减量效果为 13.3%，其中低污泥真实产率贡献占 16%，污泥衰减量贡献占 84%。3)在低溶解氧浓度下长期驯化，将诱导活性污泥微生物发生改变，并表现出一些显著的特点，这些特点是活性污泥微生物特殊性质所构成的功能表现。由 454高通量测序法检测发现，低溶解氧和参照系统污泥样品微生物群落中细菌均表现出较高的多样性，共检测到 18门、368属的细菌序列，低溶解氧反应器中菌门多为Acidobacteria、 BD1-5、 Bacteroidetes、 Candidate_division_SR1、Candidate_division_TM7、Chlorobi、Firmicutes等专性或兼性厌氧菌或氧亲和系数较低的菌门，而参照反应器中的菌门多为 Chloroflexi、Nitrospirae、Proteobacteria等好氧异氧型菌门，但优势菌门均为变形菌门，各占低溶解氧和参照系统污泥样品细菌总序列的 50.86%及 68.55%，其中低溶解氧污泥微生物群落优势菌属为发硫菌，即引起污泥膨胀的主要细菌；低溶解和参照系统污泥样品微生物群落中均含有多种脱氮功能细菌，但优势脱氮功能菌属有较大差异，优势 AOB菌属为uncultured Nitrosomonadaceae属及 Nitrosomonas属，在低溶解氧污泥样品中分别占0.14%及 0%，在参照污泥样品中分别占 0%及 0.16%；优势 NOB 菌属为Nitrospiraceae_Nitrospira属，在低溶解氧污泥样品中占 0.47%，在参照污泥样品中占 0.93%；优势反硝化细菌属为 Flexibacter、 Nitrosomonas、 unculturedComamonadeceae及 Thauera，在低溶解氧污泥样品中占 1.063%、0.06%、0.41%及1.85%、在参照污泥样品中占 2.02%，0.16%、0.35%及 2.55%；优势聚磷菌属菌属为 Acinetobacter及具有反硝化功能 Arcobacter，在低溶解氧污泥样品中占 0.19%及1.75%在参照污泥样品中占 0.1%及 0.89%。4)分析发现，低氧污泥水解菌属更多，与实验中低氧污泥水解率较低的结论相左，其可能受 No Rank序列或 EPS的影响，为进一步确定污泥中的胞外酶含量，采用 LCMS法测序活性污泥胞外蛋白质，在污泥胞外蛋白组中，发现低氧污泥及参照污泥胞外蛋白组中与水解类相关的蛋白个数分别为 8及 14个，属于生物合成的种类，分别为 12及 38个，属于能量产生和转换相关蛋白的种类分别为 15及 22个，这说明有很大一部分 EPS是来源于破碎的污泥细胞，同时可见低氧污泥胞外蛋白数目大大低于参照污泥，因此低氧污泥的自身水解性略差。5)在目前 ASM3模型构架的基础上，采用时间平衡、体积平衡及物料平衡方法，通过对低氧工艺下低氧污泥独特的生物动力学参数的分析研究，首次提出并建立了低氧/参照 SBR-ASM3-SMP模型。并且以污泥 SRT为变量，初步模拟和探讨了II 中文摘要SRT变动、污泥真实产率及污泥衰减率等对污泥增长、出水水质、污泥活性、污泥惰性颗粒积累等的影响，发现污泥衰减率、曝气时长、污泥龄、真实产率均会对污泥的出水及污泥性质带来较大影响，同等条件下，其会导致 15%的出水水质差异，12%的污泥表观产率差异，6%的污泥活性差异，低氧污泥的优势在于较低的 bH及较长的 TRO，使其可以在保持甚至提高污染物降解率的同时，降低污泥产率。关键词：低氧浓度，污染物去除，污泥减量，EPS，微生物，ASM3III 重庆大学博士学位论文IV 英文摘要ABSTRACT The activated sludge process is currently the most widely used and the mostpromising wastewater treatment technology, which treats more than 90% of municipalsewage and about 50% industrial wastewater of the world. However, during wastewatertreatment,there are a few disadvantages: the first problem is the sludge bulking, which isthe most common problem of the activated sludge process; the second problem is aboutenergy consumption, the electric bill accounts for about 1/3 of the total operating costsduring the municipal wastewater treatment plant; the third problem is the remainingsludge due to the proliferation of microorganisms, a large amount of sludge is generatedduring the treatment process,and the disposal of the excess sludge costs higher than50% of total operating costs For the three disadvantages occurred during the activatedsludge process, many scientists have carried out extensive research，that is filamentoussludge bulking in low dissolved oxygen(DO)condition. The core of the process is tocontrol artificially the activated sludge wastewater treatment system run in low DOcondition, and the level of the sludge bulking do not result in the serious sludge loss；Meanwhile the low DO level means low power consumption for aeration; many expertshave found that sludge production was reduced under low DO condition;and so theremaining sludge is reduced too. In order to better understand the potential of the lowDO sludge process, it is necessary tomake the further research.This paper studied the theremoval efficiency for contaminants, sludge reductioneffect, ts stability,the mechanisms and the mathematical modeling of the low DOactivated sludge process. The research has focused on the removal efficiency forcontaminants and the influential factors,the effect of sludge reduction and themechanismin in low DO situation. Besides, we analyzed the presence ofmicroorganisms and profiles of extracellular enzyme from a microscopic point of viewin low DO situation，and built a mathematical model to understand the mechanism ofactivated sludge process in low DO condition from a macro perspective. The mainresults are as follows:Compared with the conventional activated sludge process, the greatestdisadvantage present in the low dissolved oxygen activated sludge process is that itsstability is not strong and is prone to bulking. According to the research, sludge reactorwas in a steady bulking state by low DO adaptation training, it was the first time forV 重庆大学博士学位论文analyzing the existence of a stable state from a mathematical point of view，and itshowed that the low dissolved oxygen activated sludge process reduced the energyconsumption, and could effectively remove contaminants in influent, and had short-cutnitrification characteristics. the removal efficiencies of NH4+-N, PO43- - P and CODwere all more than 95%, and removal rate of total nitrogen exceeded 70%, andnitrosation rate was over 80%, Altogether， the removal efficiencies for thesecontaminants in low dissolved oxygen activated sludge process were greater than thosein the control, namely, the activated sludge process. Moreover, the obtained results haveshowed that the activated sludge process for the removal of pollutants would beinhibited in low temperatures, and low dissolved oxygen would further aggravate theadverse effects, and SRT varied within a certain range would not reduce the removal ofpollutants.Compared with the conventional activated sludge process, sludge yield wasreduced 13.3% in low dissolved oxygen activated sludge process, in order to study thenature of this phenomenon, we divided sludge reduction into three parts, according tothe difference of activated sludge and hydrolysis kinetic parameters, EPS, etc., the firstdifference is the nature of the sludge, the second difference is the sludge dynamics, thethird aspect is the difference of hydrolysis. Though these differences , we analyzed themechanism of the reduction of sludge. It was concluded that the real sludge yields weredecreased under long-term low DO conditions and sludge endogenous oxygen uptakerate and the decay rate also become low, and under the combined action, the activatedsludge yield was reduced, sludge yield was reduced by 13.3%compared to control,and the contribution of low real sludge yield was 16%, and the sludge decay contributed84%.Long-termlowdissolvedoxygenlevelswouldleadtothechangesofmicroorganisminsludge and exhibits some remarkable characteristics, andthese characteristics are the core of the activated sludge - the special nature of themicroorganisms constituting the appearance, In low DO process, the removal of organicmatter, nitrogen and phosphorus and sludge reduction are the particularity ofmicroorganisms, Therefore, in order to clearly understand the difference between lowDO process and the control, we analyzed the influence on microbial reactor and sludgecharacteristics of extracellular enzymes in low DO conditions using454 pyrosequencingfrom the microscopic point of view,It was found that the microbial communities ofbacteria from low dissolved oxygen sludge samples and the reference system bothVI 英文摘要showed a higher diversity，totally 18, 368 bacterial sequences genus, the dominantbacteria weredetectedProteobacteria, with 50.86% of the total low dissolved oxygensludge sequence and 68.55% of the total reference bacterial system sludge samplesequence. The major of the Actinobacteria of the sludge sample in low dissolved oxygenwasAcidobacteria,BD1-5,Bacteroidetes,Candidate_division_SR1,Candidate_division_TM7、Chlorobi、Firmicutes et.al. The major of the Actinobacteriaofthe reference sludge sample was Chloroflexi、Nitrospirae、Proteobacteria et.al.Base on the current framework of the model ASM3，Using material balancetheory, and through analysis of kinetic parameters of unique biological process underlow DO sludge process, first proposed and established the low DO referenceSBR-ASM3-SMP model, besides， with sludge SRT was variable Preliminarilysimulated and discussed the impact of sludge real yield rate, sludge decay to waterquality, active sludge, sludge accumulation of inert particles, etc. during the changesSRT. It was also Found that pH, HRT, SRT, yH would all cause greater impact on thenature of the sludge and water of sludge, the advantages of low DO sludge lies in lowerpH and longer HRT, which can maintain and even improve pollutant degradation ratewhile reducing sludge yield.Key words: Low oxygen concentration, Pollutant removal, Sludge reduction, EPS,Microorganism, ASM3VII 重庆大学博士学位论文VIII 目录目 录中文摘要.I英文摘要. V1绪论. 11.1活性污泥法的特点及应用 . 11.2活性污泥法的主要不足 . 11.2.1活性污泥法污泥膨胀问题 . 11.2.2活性污泥法高能耗问题 . 21.2.3剩余污泥产量大的问题 . 31.3低溶解氧（DO）活性污泥工艺 . 31.3.1低溶解氧活性污泥工艺除污特性 . 41.3.2低溶解氧活性污泥工艺的稳定性 . 61.3.3低溶解氧活性污泥工艺的节能性 . 61.3.4低溶解氧环境条件下的生物特性 . 71.3.5低溶解氧环境条件下的污泥减量特性 . 71.3.6低溶解氧环境条件下污泥减量评价 . 141.4本研究的目的、意义和主要研究内容 . 161.4.1主要研究内容. 171.4.2技术路线图. 172低浓度溶解氧条件下反应器的除污效果及稳定性 . 192.1引言. 192.2实验材料与方法 . 192.2.1试验装置. 192.2.2试验用水. 212.2.3试验方案. 212.2.4检测方法. 212.3工艺参数的确定 . 222.3.1 SBR反应器曝气量的确定. 222.3.2 SBR反应器 HRT的确定. 232.3.3反应器 HRT的确定的依据. 242.3.4低溶解氧条件下活性污泥的驯化方案 . 252.3.5温度对反应器污染物去除影响的实验方案 . 25IX 重庆大学博士学位论文2.4低溶解氧条件下活性污泥工艺的稳定性和污染物去除 . 262.4.1低溶解氧条件下反应器对 COD去除影响. 262.4.2低溶解氧条件下反应器对氮去除影响. 272.4.3低溶解氧条件下反应器对氮转化影响. 282.4.4低溶解氧条件下反应器对总磷去除影响.