【作者】 陈尚智；

【导师】 胡勇有；

【作者基本信息】 华南理工大学 ， 环境工程， 2011， 硕士

【摘要】 我国湖泊和水库普遍受到总氮、总磷的污染,富营养化严重,有机物污染面广,许多己达不到Ⅲ类水质标准。极大地降低了水体的生态功能,严重地威胁到人民的身体健康和工业生产,湖泊和水库的治理与修复己经到了不可不为的程度。微生物净水剂以其高效率的特点成为野外水处理的主流方法。微生物固定化可提高生化分解的降解速率,提高污染物的去除效率,而且具有费用较低、挂膜时间短、能耐受冲击、生物不容易脱落、对环境影响较小等优点。国内外专家学者对固定化技术的研究很多,但大多只用于工业生产,用于野外水体环境治理的微生物固定化技术的研究还不够成熟,成功应用的例子极少。本文研发出了一种固定化枯草芽孢杆菌技术,通过游离枯草芽孢杆菌剂与固定化枯草芽孢杆菌在封闭微污染水净化性能的比较,考察了固定枯草芽孢杆菌在微污染水修复处理中,适宜的环境与条件及对模拟水物化性质的影响。确定了主要的应用条件及控制参数,为固定化枯草芽孢杆菌技术在于湖泊、水库水体修复的应用提供理论和技术依据。研究表明辫式飘带上负载的枯草芽孢杆菌的最大负载量为2.1×10¹²cfu/m²,对应的负载条件为pH=6,溶解氧为4mg/L,负载菌液浓度为3.2×10⁸ cfu/ml,负载时间为5周。最大负载量下的固定化枯草芽孢杆菌净化处理系统,适宜的环境条件比游离枯草芽孢杆菌宽,适宜的pH由5⁷扩展为5⁸,溶解氧由4⁶ mg/L扩展为3⁶ mg/L。运行7d后,COD_Mn、NH₄⁺ -N、NO₂^--N及NO₃^--N去除率分别达到97.4%、96.8%、89.4%、40.8%,达到同样甚至更高的处理效果比游离枯草芽孢杆菌处理需要的时间少2天,微污染水经处理后,达到地表Ⅱ类水水质标准。净化系统对pH低于4或高于9的冲击不可恢复,较低的溶解氧将对系统的除污能力有一定的抑制,但随溶解氧的升高系统容易恢复净化能力。受到环境条件变化冲击时,固定化枯草芽孢杆菌处理系统中COD_Mn、NH₄⁺ -N、NO₂^--N及NO₃^--N的去除率下降幅度较游离枯草芽孢杆菌处理系统少。不重新添加固定化枯草芽孢杆菌的情况下的批式运行,系统能5次将COD_Mn降低到4mg/L以下,净化时间分别为7d、10d、12d、15d、19d。重新添加固定化枯草芽孢杆菌后,水的pH值波动不大,但溶解氧总体下降到3.3mg/L,需要启动曝气设备以提高溶解氧。更多还原

【Abstract】 Pollution of total nitrogen and total phosphorus is common in lakes and reservoirs in our country, which leads to severe eutrophication and wide organic contamination. Many lakes and reservoirs can not reach the water-quality standard of grade III. Since ecological function of water is extremely declined and health and industrial production are seriously threatened, treatment and remediation of lakes and reservoirs have been in urgent necessity. Microbial purifying agent has become one of the main methods in field water treatment because of its efficiency. Immobilization of microorganisms can improve the degrading rate of biochemical decomposition and removal efficiency of contaminants. And it also has advantages such as low expense, short biofilm formation time, resistance of impaction, uneasy to flake off and so on. To date, there are various researches on immobilization all over the world, but most of them have been applied in industry. Studies on microbial immobilization applying to field water treatment are not so mature, and successful application examples are rare.An immobilization technology of Bacillus subtilis was studied. By comparison of purifying performance between free and immobilized Bacillus subtilis in sealed micro-contaminated water, environmental conditions and effect on physical and chemical properties of simulated water were investigated. Main applicable conditions and controlling parameters were identified, providing theoretical and technical foundation to application of immobilized Bacillus subtilis to water remediation in lakes and reservoirs.Research showed that the maximum Bacillus subtilis loading amount carried by braided ribbon was 2.1×10¹² cfu/m², with corresponding conditions that pH of 6, dissolved oxygen of 4 mg/L, Bacterial concentration of 3.2×10⁸ cfu/ml, and loading time of 5 weeks. For purification system of immobilized Bacillus subtilis under the maximum loading amount, appropriate environmental conditions were broader than free Bacillus subtilis system.For instances, pH range extended from 5-7 to 5-8, dissolved oxygen value expanded from 4-6 mg/L to 3-6 mg/L. After operation of 7d, the removal rates of COD_Mn, NH₄⁺ -N, NO₂^--N and NO₃^--N reached 97.4%, 96.8%, 89.4%, 40.8%, respectively. There was 2d less needed in treatment using immobilization system to achieve the same or better performance of free system. After disposal of micro-contaminated water by immobilization system, water could reach the water-quality standard of Grade II. It was beyond retrieve when the pH was blew 4 or above 9 for purification system. Lower dissolved oxygen would inhibit the decontamination capacity to some extent, but with growth of dissolved oxygen, it is easy to recover. When environmental conditions changed, less decrease of removal rate of COD_Mn, NH₄⁺ -N, NO₂^--N and NO₃^--N could be observed in immobilized system. Batch operation without re-addition of immobilized Bacillus subtilis, COD_Mn decreased to below 4 mg/L 5 times, as the purifying time was 7 d, 10 d, 12 d, 15 d, 19 d. After re-addition of immobilized Bacillus subtilis, there was not significant fluctuation of pH, but the dissolved oxygen reduced to 3.3 mg/L, which result in start of aeration equipment.更多还原