【作者】 王新华；

【导师】 杨凤林；

【作者基本信息】 大连理工大学 ， 环境工程， 2008， 博士

【摘要】 好氧颗粒污泥是一种用于废水处理的新型微生物聚集体,是微生物在各种选择压的作用下自发凝聚而形成的结构致密、沉降性能良好、生物协作性强的生物颗粒。好氧颗粒污泥具有能够同时去除废水中的COD、N和P的特殊性能,是一项很有应用潜力的废水生物处理技术。本论文采用逐步提高选择压的培养策略,成功的培养了硝化菌大量富集、稳定性良好、能同时除碳脱氮的好氧硝化颗粒污泥,系统考察了好氧硝化颗粒污泥的培养形成过程、储存过程和解体过程,研究了储存和解体后恢复颗粒污泥性能的自修复行为,并验证了好氧硝化颗粒污泥处理高氨氮催化剂废水的可行性。主要研究内容如下:（1）研究逐步提高底物NH₄⁺-N浓度选择压的培养策略的优势和形成的好氧硝化颗粒污泥的性能。结果表明,在底物NH₄⁺-N浓度为200 mg/L的条件下无法完成好氧颗粒化过程;而底物NH₄⁺-N浓度为50 mg/L条件下培养的好氧颗粒污泥以异养菌为主,结构松散,丝状菌大量繁殖,稳定性差,反应器运行131天颗粒污泥就开始解体。将底物NH₄⁺-N浓度从50mg/L逐步提高到200 mg/L的培养策略使颗粒污泥内的硝化菌逐渐富集,最终形成了能同时去除COD和NH₄⁺-N并具有一定反硝化能力的好氧硝化颗粒污泥。逐步提高选择压的培养策略使好氧硝化颗粒污泥的性能得到逐步改善,反应器内污泥浓度（MLSS）和颗粒粒径逐步提高,颗粒沉降性能和硝化反硝化活性逐步得到强化。同时,硝化菌的大量富集抑制了丝状菌的生长,形成的好氧硝化颗粒污泥以杆菌为主,颗粒结构紧凑、稳定性能良好,反应器运行283天未出现明显颗粒解体现象。在进水COD和NH₄⁺-N浓度分别为500和200 mg/L时,COD、NH₄⁺-N和总氮（TN）平均去除率分别达到82%、98%和50%。（2）考察短期储存2个月对好氧硝化颗粒污泥的影响,并研究储存后的自修复阶段的操作条件对硝化菌活性恢复的影响。结果表明,储存2个月对好氧硝化颗粒污泥的物理性能和结构稳定性都没有明显影响。采用储存前的操作条件进行活性恢复,即较低的剪切力（0.9cm/s）和循环时间（4h）条件下,异养菌活性恢复最快,5天后COD去除率基本恢复并稳定在80%以上;而亚硝酸菌和硝酸菌的比耗氧速率（SOUR）只能分别恢复至储存前的88%和82%,NH₄⁺-N去除率仅在80%～90%之间:第41天剪切力提高至1.8cm/s后,亚硝酸菌活性完全恢复,NH₄⁺-N去除率达到98%以上,但硝酸菌的SOUR仍只有储存前的92%;第65天将循环时间延长至6h,硝酸菌活性完全恢复。（3）研究好氧硝化颗粒污泥长期储存7个月过程中的性能、结构和菌群衰减变化以及储存后的自修复行为。结果表明,长期储存使好氧硝化颗粒污泥的VSS/SS值下降,沉降性能恶化,颗粒表面出现较多孔穴和褶皱,但颗粒污泥并未发生明显解体现象,仍保持其形态结构的稳定性。好氧硝化颗粒污泥储存后,硝化菌和异养菌的活性都有明显的衰减,但硝化菌的衰减速度较慢。在储存阶段,微生物首先利用胞外聚合物（EPS）和混合液中残留的溶解氧（DO）进行代谢生长,随后分泌越来越多的EPS（尤其是多糖）。好氧硝化颗粒污泥内硝化菌的衰减速度慢以及EPS的大量分泌是其在长期储存阶段能保持形态结构稳定性的重要原因。在自修复阶段,好氧硝化颗粒污泥的物理性能和微生物活性都迅速恢复,经过1个月的时间,其结构、VSS含量、沉降性能等都完全恢复甚至优于储存前的水平。在剪切力为1.8cm/s,循环时间为6 h的条件下,好氧硝化颗粒污泥内的硝化菌和异养菌活性分别经11天和16天即可完全恢复。（4）对好氧硝化颗粒污泥的解体机制进行系统研究。结果表明,随着好氧硝化颗粒污泥粒径的增长,颗粒污泥内部底物和DO的传质限制是导致颗粒解体的根本原因。解体过程主要包括以下三个阶段:①颗粒污泥内部底物和DO的传质通道被堵塞,中心空穴区域逐渐扩大,最终颗粒污泥形成明显的中空结构;②反硝化以及有机物厌氧分解产生的气体在颗粒内部难以排出,颗粒内部产生较大气压,从而导致颗粒外层出现裂痕;③颗粒碎片沿颗粒裂痕处脱落,颗粒污泥完全解体。（5）考察加入新的活性污泥促进解体好氧硝化颗粒污泥完成自修复的可行性。结果表明,解体颗粒污泥的空穴能逐渐吸附新加入的活性污泥,并与之形成一个有机的整体。大约3周时间,解体颗粒污泥完全修复,被修复后的颗粒污泥结构规则,微生物相致密,颗粒污泥的沉降性能和强度都得到了极大的改善。剩余活性污泥在各种选择压的作用下形成新的颗粒污泥。由修复的和新形成的颗粒污泥组成的系统对COD和NH₄⁺-N都具有高效稳定的去除效果,在进水COD和NH₄⁺-N浓度分别为500和150mg/L时,COD、NH₄⁺-N和TN去除率分别稳定在90%、99%和50%左右。（6）研究好氧硝化颗粒污泥处理高氨氮催化剂废水的可行性。结果表明,好氧硝化颗粒污泥适合处理高氨氮催化剂废水,而且具有很好的抗冲击负荷能力。在循环时间为4h,NH₄⁺-N浓度为600 mg/L时,NH₄⁺-N容积负荷达到1.8kg/m³·d,NH₄⁺-N去除率达到98%以上。在模拟废水盐度为15g/L,COD和NH₄⁺-N浓度分别在100～400 mg/L和300～600 mg/L之间波动时,COD去除率在75%～90%之间,NH₄⁺-N去除率在97%以上,出水都能达到《污水综合排放标准（GB 8978-1996）》一级标准的要求。更多还原

【Abstract】 Aerobic granules,as self-aggregated bio-particles by microorganisms under certain selection pressures,have compact structure and good settling ability.It is believed that aerobic granulation would be a novel and promised biotechnology for simultaneous removal of COD,N and P in wastewater treatment.In this study,aerobic nitrifying granules were successfully cultivated under stepwise increased selection pressure.Aerobic nitrifying granules,which were enriched with nitrifying bacteria,had excellent stability and were able to simultaneous organic oxidation,nitrification,and partial denitrification.This study detailed investigated the cultivation,storage,and disintegration process of aerobic nitrifying granules, the self-remediation behaviors after granule storage and disintegration,and the feasibility in synthetic high ammonia-nitrogen catalytic wastewater treatment.The main experimental results were listed as follows:（1） This study evaluated the utility of a cultivation strategy of stepwise increased selection pressure for aerobic granulation and investigated the performance of aerobic nitrifying granules.Results showed that aerobic granules failed to be developed under substrate NH₄⁺-N of 200 mg/L.Heterotrophs dominated aerobic granules formed under substrate NH₄⁺-N of 50 mg/L were fluffy structured and unstable due to the outgrowth of filamentous bacteria and they were quickly disintegrated from day 131.Nitrifying bacteria were gradually selected and enriched in aerobic granules by adopted a cultivation strategy of stepwise increased substrate NH₄⁺-N from 50 to 200 mg/L.Finally,aerobic nitrifying granules capable of simultaneous organic oxidation,nitrification,and partial denitrification, were successfully formed.This cultivation strategy stepwise improved the performance of aerobic nitrifying granules,such as MLSS,granules size,settleability,and nitrifying and denitrifying activities.Enrichment of nitrifying bacteria also suppressed filamentous growth and further improved the stability of aerobic nitrifying granules.During 283 days’ operation, no evidence of granule disintegration could be found.The respective COD,NH₄⁺-N,and total nitrogen（TN） removal efficiency reached 82%,98%,and 50%when the substrate COD and NH₄⁺-N concentration were 500 and 200 mg/L,respectively.（2） A short-term storage of 2 months on the performance of aerobic nitrifying granules and the effect of operational conditions on the reactivation of nitrifying bacteria were investigated.The physical characteristics and structure stability of aerobic nitrifying granules had not significantly changed after short-term storage.At shear force of 0.9 cm/s and cycle time of 4 h,heterotrophs reactivated quickly and the COD removal efficiency recovered and stabilized above 80%after 5 days.While the respective specific oxygen utilization rate （SOUR） of AOB and NOB recovered 88%and 82%as that of before storage and the NH₄⁺-N removal efficiency was only between 80%～90%.When the shear force was increased to 1.8 cm/s on day 41,AOB was fully recovered and NH₄⁺-N removal efficiency reached above 98%,while the activity of NOB recovered only 92%during this period.Until day 65 when the cycle time was prolonged to 6 h,NOB was fully reactivated.（3） The evolution of physical characteristics,structure,and population decay of aerobic nitrifying granules during a long-term storage of 7 months and the self-bioremediation behavior after storage were investigated.Some cavities and pleats appeared on the surface of granules after storage.Meanwhile,the ratio of VSS/SS decreased and the settleability was also deteriorated.However,the structure stability of aerobic nitrifying granules was remained. During storage,though both heterotrophs and nitrifying bacteria significantly decayed, nitrifying bacteria decayed slower.Microorganisms firstly used extracellular polymeric substances（EPS） as substrate and residual oxygen as electron acceptor after storage began, and then produced more and more EPS during the rest storage,in particular polysaccharides （PS）.The slower decay rate of nitrifying bacteria and the production of EPS would be two important reasons for maintaining structural stability of aerobic nitrifying granules during long-term storage.During self-remediation period,the physical characteristics and microbial activities of aerobic nitrifying granules were quickly recovered.After one month,their structure,VSS content,and settleability were both reactivated and even became better.Under shear force of 1.8 cm/s and cycle time of 6 h,heterotrophs and nitrifying bacteria can by fully recovered within 16 and 11 days,respectively.（4） This study described the detailed disintegration mechanism of aerobic nitrifying granules.Along with the increase of granule size,the ultimate reason for disintegration of aerobic nitrifying granules was mass transfer limitation of substrates and dissolved oxygen （DO）.The detailed disintegration process can be concluded as follows.Firstly,granules exhibited distinct void structure because the channels presented within granules were eventually plugged and cavity structure in the center of granules was enlarged.Secondly,gas produced by denitrification and anaerobic fermentation came into being pressures within granules and further led to appearance of fissures on the granular shells.Finally,fragments broken off and granules were completely disintegrated.（5） The feasibility of adding fresh activated sludge for stimulating self-remediation of disintegrated granules was evaluated in this study.Results showed that fresh activated sludge was gradually adsorbed into disintegrated and cavity granules and then combined together with granules.Disintegrated aerobic granules were fully remedied after about 3 weeks. Remedied granules exhibited regular and compact structure.Granule settleability and strength were both improved profoundly during self-remediation.Besides those activated sludge used for bioremediation,the rest formed fresh aerobic granules finally.Reactor system which was composed of bioremedied and fresh granules exhibited excellent performance.The respective removal efficiency of COD,NH₄⁺-N and TN were stabilized at about 90%,99%and 50% when the substrate COD and NH₄⁺-N concentration were 500 mg/L and 150 mg/L, respectively.（6） This study also investigated and confirmed the feasibility of aerobic nitrifying granules in synthetic high ammonia-nitrogen catalytic wastewater treatment.At cycle time of 4 h and NH₄⁺-N concentration of 600 mg/L,the wolumetric load of NH₄⁺-N achieved 1.8 kg/m³·d and the NH₄⁺-N removal efficiency exceeded 98%.The system had a high capacity in resistance to shock loading.The removal efficiency of COD was about 75%to 90%when the COD concentration was fluctuated between 100 mg/L and 400 mg/L.When the NH₄⁺-N concentration was fluctuated between 300 mg/L and 600 mg/L,NH₄⁺-N removal efficiency was basically above 97%.The effluent reached the first class integrated wastewater discharge standard（GB 8978-1996）.更多还原