【作者】 王广智；

【导师】 李伟光；

【作者基本信息】 哈尔滨工业大学 ， 市政工程， 2008， 博士

【摘要】 随着饮用水水源污染日益严重,以生物活性炭为核心的饮用水深度处理技术受到人们广泛关注。采用人工培养优势菌群强化生物降解作用的固定化生物活性炭（IBAC）技术具有显著的优势,活性炭吸附作用和优势菌群生物降解作用大大提高了除污染效率。但由于是一个开放式的系统,IBAC在实际应用过程中易受到水质、水量冲击以及环境因素等影响,产生优势菌群生物稳定性受到破坏的问题,从而限制了其在供水行业推广应用。本研究针对北方某市原水水质状况,从影响IBAC工艺中优势菌群稳定性的各个关键环节入手,重点研究了优势菌群优化固定工艺条件、在活性炭表面的生长特性、活性炭性质和工艺条件对优势菌群稳定性的影响作用与优化控制、优势菌群的安全性控制等内容,为IBAC技术的实际工程应用提供技术支持。采用不同浓度梯度营养基质对优势菌群的生物活性进行了反复强化,提出了以生物活性达到300μg/mL作为优势菌群生物活性强化的指示终点。通过采用超声波预处理方法评价优势菌群在活性炭表面固定化性能,研究了优势菌群的优化固定条件,结果表明优势菌群最优固定化条件为:停留时间30min,循环4h、间歇2h的间歇式固定化方式,循环3次。将优势菌群固定于活性炭表面,通过采用PCR-DGGE和扫描电镜等技术,对优势菌群生长特性进行了深入研究,结果表明在启动初期优势菌群生物量与生物活性需经过约一周快速降低的过程,而后逐渐保持稳定,菌群生物活性保持在200μg/mL以上,生物量保持在10⁶CFU/（g炭）量级,初期优势菌群在活性炭表面是以单个菌体的方式,附着在活性炭表面孔隙较多的粗糙部分;经过长期运行后,IBAC表面微生物的种类从初期8种,一年后增加到16种,且菌量均有不同程度的增加,但人工固定的优势菌仍然占据主导地位,优势菌群在活性炭表面形成大量生物膜,以团状絮状形式存在,且大部分呈单层分布。由于土著杂菌的低量持续侵入系统,出现土著菌群和优势菌群对营养基质的争夺竞争、分摊竞争以及劣势菌群的细胞自融过程,从而使优势菌群活性受到了一定的抑制,上层活性炭床耗氧速率从初始11×10^-3 mgO₂ /（cm³·h）,18个月后下降到8×10^-3mgO₂ /（cm³·h）,下层活性炭床耗氧速率也从初始7.5×10^-3mgO₂/（cm³·h）,18个月后下降到6×10^-3mgO₂/（cm³·h）。将优势菌群在五种不同种的活性炭表面固定,采用动态试验对其净水效能、微生物生长状况进行系统的研究,并应用统计分析方法解析了活性炭性质对优势菌群生物稳定性影响。结果表明,对优势菌群生物稳定性影响较大的活性炭性能指标主要为糖蜜值、碘值、丁烷值、pH值、平均粒径、有效粒径、均匀系数、摩擦系数和强度,其中糖蜜值为首要控制指标,在选择活性炭时需控制在150mg/g以上。针对臭氧投加量、炭池停留时间与反冲洗等主要工艺条件,利用中试系统,研究了其对优势菌群生物稳定性的影响作用与优化控制条件。试验结果表明,IBAC系统的优化工艺条件为:臭氧投加量2.34mg/L左右,炭池停留时间20min,气-水反冲,气冲强度采用10L/m²·s,夏季气冲时间5min,冬季气冲时间采用3min,水冲强度采用12¹5L/m²·s,时间为8¹0min。对优势菌群强化活性炭除污染性能进行了长期监测,结果表明与普通生物活性炭相比,IBAC去除UV₂₅₄、COD_Mn和TOC分别提高了15%以上,对THMFP的去除率平均提高11.23%,水中的有毒有害物质的种类和含量显著降低。针对优势菌群在应用过程中的生物安全性,从菌体自身的毒理学试验、石英砂垫层控制各种生物泄露、工艺出水的毒理学试验等多个角度进行了试验研究,结果表明优势菌群具有较高的生物安全性。应用活性炭碘值和静态试验方法,对优势菌群的生物再生作用进行评价,结果表明优势菌群可以有效的延长活性炭使用寿命,在达到活性炭吸附饱和之前IBAC至少可延长1年以上使用时间,而IBAC中的活性炭达到真性失效时,则要在3年以上。因此本研究建立的IBAC工艺具有处理效率稳定、操作管理简单、运行成本低的特点,它的推广必将带来显著的经济、社会和环境效益。更多还原

【Abstract】 Drinking source water pollution is more and more serious, so it is widely concerned that drinking water advanced treatment to biological activated carbon as core. Immobilization biological activated carbon （IBAC） technology by immobilizating artificial cultivated dominant bacteria on activated carbon takes significant advantages and it improves the removal efficiency of organic contaminations depending on the adsorption of ctivated carbon cooperating with biological degradation of dominant bacteria. For open system, IBAC produces the problem of stabilization destruction due to vulnerable impact such as water quality, quantity and environmental factors in practical application, and it limites its broad application in the water industry.Aimming at the raw water quality conditions of the north city, the paper researchs effectively maintaining the biological stability of dominant bacteria from the various key of impacting biological stability of dominant bacteria, the major researches include that optimizing immobilization conditions of dominant bacteria, growth characteristics of dominant bacteria on activated carbon, influence and control of activated carbon property and process conditions to biological stabilization and security control of dominant bacteria and it provides technical support for project application of IBAC.Repeatedly enhancing biological activity of dominant bacteria by different concentration gradient nutrition substrate, it takes biological activity of 300μg/mL as the indicated end-point. By ultrasonic pretreatment to evaluate the immobilization characters of dominant bacteria, the optimizing immobilization conditions are researched. The results show that the optimizing immobilization conditions of dominant bacteria include the contact time 30 min, immobilization manner of cycling 4 h, intermittent 2 h and repeating three times.The growth characteristics of dominant bacteria on activated carbon are monitored at the long-term pilot-scale test by PCR-DGGE and SEM. The results show that at start-up period, there is a quickly reducing process in biomass and biological activity for about a week, then the biomass and biological activity gradually maintain stability for biological activity of 200μg/mL above and biomass quantity class of 10⁶CFU/（g carbon） and the dominant bacteria immobilize on activated carbon in the form of single bacterium and in the rough part of activated carbon surface with more porous; after a long-term operation, the bacteria kinds of IBAC surface increase from 8 at initial stages to 16 after one year with different leves of biomass, but the artificial immobilized dominant bacteria still hold the advantaged position in plentiful biofilm and mission-floc formed on the activated carbon surface, mostly single-layer distribution. The aboriginal bacteria in low volume invasive system lead biological activity decreases of dominant bacteria in long-term slow downward for nutritional competition, sharing competitive and losing of disadvantage bacteria. The biological activity of upper and lower activated carbon deceases from 11×10^-3mg O₂/（cm³·h） and 7.5×10^-3mgO₂/（cm³·h）at initial stages to 8×10^-3mgO₂/（cm³·h） and 6×10^-3mgO₂/（cm³·h） after 18 months respectively.The water purification effect and growth characteristics of dominant bacteria are systematically researched at the dynamic test by immobilization dominant bacteria on 5 different types of activated carbon and the effect of activated carbon properties to biological stability is analyzed with statistical analysis methods. The results showed that the performance indexes of activated carbon greatly impact on biological stability mainly include molasses, iodine,butane, pH, average particle size, effective particle size, uniformity coefficient, friction coefficient, intensity, and molasses is primary control index of greater than or equal 150mg/g at selecting activated carbon.The effect of process conditions to biological stability including ozone dosage, EBCT and backwashing condition is researched by pilot-scale tests. The results show that the optimizing IBAC process conditions include ozone dosage of about 2.34mg/L, EBCT of 20min, air-water backwash, air backwashing intensity of 10L/m²·s with backwashing time of 5min at summer and 3min at winter, water backwashing intensity of 12¹5L/m²·s with backwashing time of 8¹0min. The enhanced removal organic pollutions by dominant bacteria are monitored in long-term and the results show that compared with BAC, IBAC improves removal rates of 15% above in UV₂₅₄, COD_Mn and TOC respectively and 11.23% in THMFP. The IBAC effluence of toxic substances kinds and concentration has significantly decreases. Aimming at the bio-security of dominant bacteria in application the process, it has been researched from the bacterium toxicology tests, sand controlling various biological leak, effluence toxicology tests and other points and the results showed that the dominant bacteria has higher bio-security. Application of activated carbon iodine value and static test methods, the renewable role of dominant bacteria have been evaluated and the results show that the the life-time of activated carbon can be effectively extended by dominant bacteria. Before reaching adsorption saturation of activated carbon, IBAC may be extended at least 1 year and achieving true failure of activated carbon will need in more than 3 years.The IBAC process has distinct characteristics of stable treatment efficiency, simple operation and management, low-cost operation, so it will bring about significant promotion of the economic, social and environmental benefits.更多还原