【作者】 李珊；

【导师】 陈猷鹏；

【作者基本信息】 重庆大学 ， 环境工程， 2012， 硕士

【摘要】 与传统硝化反硝化工艺相比，单级自养脱氮工艺具有曝气量和污泥产量低、无需有机碳源等优点，因此，单级自养脱氮被认为是一种经济、环境友好型脱氮工艺。但是由于厌氧氨氧化菌（AnAOB）世代周期长（11d），对生存环境要求苛刻，因此，单级自养脱氮系统具有启动时间较长，较难长期稳定运行的缺点。本论文探讨了载体表面特性、溶解氧（DO）、自由氨（FA）和无机碳源（IC）对单级自养脱氮系统启动及稳定运行的影响，并对单级自养脱氮系统中微生物EPS的组成特性进行了研究。为考察载体表面亲水性对序批式生物膜反应器（SBBR）中单级自养脱氮系统生物膜形成及单级自养脱氮效果的影响，采用未改性的活性碳纤维（ACFs）和经热处理亲水性改性的ACFs作为载体进行研究。在SBBR中，以普通活性污泥为泥源启动单级自养脱氮系统。系统的运行温度为32±2°C，DO控制在^-1.5mg L^-1，同时FA的浓度维持在3.98–15.93mg L^-1之间。傅里叶红外光谱（FT-IR）和Boehm中和滴定法的结果表明改性后的ACFs表面含氧基团的含量高于未改性的ACFs。扫描电镜和生物膜干重的测定表明较多的生物膜生长在改性载体表面，并且改性载体表面的生物活性高于未改性填料表面生物的活性。这个研究证实了亲水性改性的ACFs与未改性的ACFs相比具有更好的生物相容性。在单级自养脱氮系统启动的第80天，系统的最大脱氮速率为0.088kg Nm3day^-1，并且出水中硝酸盐的产量与氨的消耗量的摩尔比接近0.11，此数据表明单级自养脱氮系统成功启动。除载体的影响，曝气方式、DO和FA浓度的控制也是在较短时间内成功启动单级自养脱氮系统的关键。AOB和AnAOB是化能自养菌，以IC为主要碳源。以SBBR中的单级自养脱氮系统为研究对象，考察IC限制对AOB和AnAOB活性的影响，并确定进水中最适IC浓度。当进水氮负荷为200mg-N·L^-1·d^-1，进水IC浓度为50mg-C·L^-1时AOB和AnAOB的活性受到影响，进水IC浓度恢复试验表明IC限制对AOB和AnAOB活性的抑制是可逆的。从经济角度考虑，在单级自养脱氮系统中，当进水氮负荷为200mg-N·L^-1·d^-1时，最适进水IC浓度为250mg-C·L^-1。FA在单级自养脱氮系统的启动和长期稳定运行中起到重要作用，因此，对FA对单级自养脱氮系统的影响进行研究。当FA控制在5.0¹0.0mg·L^-1的范围内，硝化细菌（NOB）的活性受到抑制并实现部分亚硝化，即以普通活性污泥为泥源成功快速启动单级自养脱氮系统的重要一步。然而，系统成功启动后，NOB逐渐适应了这个不利的环境。当FA浓度从^-10.0mg·L^-1增加到-17mg·L^-1时，亚硝化细菌（AOB）和AnAOB的活性未受到影响，NOB的活性仅受到暂时性的抑制。在pH为8.5，FA浓度在30.0³2.5mg·L^-1范围时，单级自养脱氮系统受到破坏，然而，NOB的活性未受到影响。经相关性分析证实FA浓度高于20mg/L是导致系统崩溃的原因。单级自养脱氮系统中生物膜和活性污泥絮体EPS的成分及结构特性的试验结果表明：EPS不同层面含量不同，并且不同层面蛋白质、腐殖酸、多糖和DNA四种有机质的含量不同。单级自养脱氮系统中生物絮体EPS难提取部分（TB-EPS）所占比例较高，易于提取部分（SEPS和LB-EPS）含量较低，而普通活性污泥的易于提取部分所占比重较高，因此，脱氮系统中生物絮体的稳定性要强于普通活性污泥。在同一反应器中，两种填料上生物膜的EPS中各有机质总量不同，并且EPS总量也存在较大差异。组合填料上生物膜EPS的总量为181.7mg/gVSS，是活性炭纤维上EPS总量的1.51倍，在组份含量上差距最大的是蛋白质，组合填料上蛋白质的总量为96.5mg/gVSS，是活性碳纤维填料的1.6倍。论文研究结果为SBBR单级自养脱氮系统的快速启动及长期稳定运行提供了理论依据，并为单级自养脱氮系统的进一步研究奠定了基础。本研究得到国家自然科学基金（51108482）和教育部高等学校博士学科点科研基金（20100191120035）的资助。更多还原

【Abstract】 Compared with conventional nitrification/denitrification processes, completelyautotrophic nitrogen removal over nitrite （CANON） has low aeration requirements andlow sludge yield, and does not require carbon; thus, this technology is consideredeconomical and environment friendly. However, because anaerobic ammoniumoxidizing bacteria （AnAOB） growth doubles slowly （11days）, and survives in verycomfortable environment, yet the CANON process entails a long start-up time andtreatment performance would be limited over a long period of time function. Theobjective of this paper was to explore the influence of support surface characteristics,dissolved oxygen （DO）, free ammonia （FA） and inorganic carbon （IC） on the CANONprocess, and the characteristics of extracellular polymerie substane （EPS） in CANONprocess were also studied.In order to assess the effects of the surface hydrophilicity of supports on thebiofilm formation and evaluate the performance of CANON process in a sequencingbatch biofilm reactor （SBBR）, unmodified activity carbon fibers （ACFs） and ACFshydrophilic modified by heat treatment were used as supports. CANON process wasinitiated in a SBBR from conventional activated sludge. An operation temperature of32±2°C, DO level at-1.5mg L^-1and FA concentration with3.98–15.93mg L^-1weremaintained in the SBBR. Fourier transform infrared （FT-IR） spectra and Boehm’sneutralizing titration exhibited that modified ACFs had more oxygen-containing groupsthan unmodified ACFs. Larger biofilm growth on the modified surfaces examined byscanning electron microscopy and biofilm’s total dry weight, and the biofilm on themodified surfaces were more active, compared with those on the unmodified surfaces.This study demonstrates the hydrophilic-modified ACFs have better biological affinitythan unmodified ACFs. Maximal total nitrogen removal rate of0.088kg Nm3day^-1wasachieved for the CANON process on day80, and the molar ratio of nitrate production toammonium consumption approached0.11, indicating the CANON process wassuccessfully started up. Apart from supports, the strategies of DO supplying andcontrolling FA concentration were also keys in starting up the CANON process within ashorter period.AOB and AnAOB are autotrophic microorganisms. IC is their main carbon source.The efects of IC limitation on AOB and AnAOB in the CANON process in a SBBR were examined. The optimal IC concentration in the influent was investigated. The AOBand AnAOB activities were limited by an IC concentration of50mg-C·L^-1in theinfluent, as the nitrogen loading rate （NLR） was200mg-N·L^-1·d^-1. The experiment onrecovering the influent IC showed that the activities of AOB and AnAOB wererecovered by increasing the IC concentration in the influent. From an economic point ofview, the optimal IC concentration in the influent was250mg-C·L^-1at200mg-N·L^-1·d^-1NLR in this CANON system.FA plays an important role in the stable, long-term CANON system operation. Theinfluence of FA on the CANON process in a sequencing batch biofilm reactor wasexplored. Under controlled FA concentrations of5.0mg·L^-1to-10.0mg·L^-1,nitrite-oxidizing bacteria （NOB） was inhibited and achieved partial nitrification, whichwas important for a successful quick start-up of the CANON process from activatedsludge. However, NOB was acclimated to the condition after the process start-up.Ammonia-oxidizing bacteria （AOB） and AnAOB activities were unaffected when FAconcentration was increased from-10mg·L^-1to-17mg·L^-1, but NOB was completelyinhibited only briefly. The AOB and AnAOB activities were inhibited and the CANONsystem was deteriorated when FA concentration reached30mg·L^-1to32.5mg·L^-1at pH8.5, whereas NOB activity was unaffected. Correlation analysis was performed todemonstrate that FA concentration higher than20mg L^-1resulted in the deterioration ofthe system.The composition and distribution of EPS that were extracted from biofilm andactivated sludge in CANON system were investigated. The conclusions were asfollows：EPS content, including carbohydrates, proteins, humic and DNA, with differentlayers changed great. The composition of EPS in CANON process was mainlycomposed of TB-EPS, rather than SEPS and LB-EPS, compared with the EPS ofconventional activated sludge. So, compared with conventional activated sludge, thesludge in the CANON process owned more stability. In the same reactor, differentcarrier own different EPS content including carbohydrates, proteins, humic and DNA.The amount of EPS biofilm on carrier SCP was-181.7mg/gVSS, which was-1.51timesof that on carrier ACFs. The difference of EPS of the two biofilms was almostly causedby the significant difference of protein composition. The protein content of biofilm oncarrier SCP was96.5mg/gVSS, which was-1.6times of that on carrier ACFs.The research results of this paper could provide theoretical basis for starting up theCANON process within a shorter period and long term stable operation, as well as lay dawn the foundation for further research on the CANON process.This research was supported by the Natural Science Foundation of China（51108482） and the Research Fund for the Doctoral Program of Higher Education ofChina （2010019120035）.更多还原