垃圾焚烧厂垃圾沥滤液生物处理中抑制因子的解析与系统调控策略

In respect to several inhibitors (ammonium, aquatic humic substance (AHS), salinity and their combinations) during the treatment of fresh leachate from municipal waste solid incineration plant by using "Anaerobic EGSB + aerobic MBBR" combined processes, which severely affect the treatment efficiency, the concentration threshold of the inhibitors in the bio-treatment of fresh leachate is analyzed and the inhibition kinetics equation is established. By molecular biological technologies, the population dynamics in the bio-system with various concentrations of inhibitors was studied. By combining with the variation in functional microorganism activity (methanogenic activity of anaerobic sludge, specific oxygen utilization rate and specific nitrification rate of aerobic biofilm) under the same conditions, the mechanisms of inhibition caused by the inhibitors over the biotreatment system is evaluated. The salinity of the selective medium is gradually elevated to strengthen and cultivate the functional bacteria in order to obtain highly effective functional strains for the biological treatment of fresh leachates from solid wastes. Based on the physiological and biochemical characteristics of the functional strains, the biological activity of the anti-salinity AHS degrading bacteria and anti-salinity nitrification bacteria is analyzed as well as the interaction between those bacterial and the natural microorganism in the systems, which is used to optimize the operational parameters of the reactors for a high-efficiency bio-system. The result of this research can provide scientific support for effective improvements during the treatment of fresh leachates.

针对采用"厌氧EGSB+好氧MBBR"主体组合工艺处理垃圾焚烧厂沥滤液中存在的几种抑制因子（包括：氨氮、溶解性腐殖质、盐度及其复合抑制因子）显著影响处理效率的问题，实验分析垃圾沥滤液生物处理系统中抑制因子的阈值，建立各抑制因子的抑制动力学方程；借助分子生物学手段，研究各抑制因子不同浓度条件下微生物群落结构的动态变化特征，结合相应条件下功能微生物活性的变化（厌氧系统中污泥的产甲烷活性、好氧系统中生物膜的比耗氧速率或比硝化速率），探讨各抑制因子对处理系统的微观抑制机制；通过梯度增加各种选择性培养基的盐度，强化培养功能菌，获得适于垃圾沥滤液生物处理系统的高效功能菌；根据筛选出的功能菌生理生化特性，研究耐盐腐殖质降解菌和耐盐硝化菌的的活性及其与系统内原有菌群相互作用的机制，并通过调控反应系统工艺参数，构建高效处理系统。研究结果可为提高沥滤液的处理效率提供科学依据。

垃圾焚烧沥滤液在厌氧生物处理过程中会受到氨氮、盐度和溶解性腐殖质（AHS）等抑制因子的抑制作用，进而降低处理效能。本课题研究了垃圾焚烧沥滤液在厌氧生物处理过程中各抑制因子的抑制浓度阈值以及抑制机制。通过筛选与培养系统中的功能菌，强化处理效果。.氨氮对垃圾焚烧沥滤液处理效能的研究表明，在维持进水COD稳定的情况下，梯度提升进水氨氮浓度由500mg/L至1000mg/L，COD去除率由97%下降至45%，CH4产率由0.270LSTP/h下降至0.110LSTP/h，VFAs浓度达到70mmol/L，达到抑制浓度阈值（1000mg/L）。随着氨氮浓度提高，COD去除率和CH4产率等的降低是由于高浓度的氨氮对微生物活性产生了抑制。AHS对垃圾焚烧沥滤液处理效能的研究表明，进水中AHS浓度从1500mg/L提升到8000mg/L时，COD去除率从96%逐渐降低至81%，生物气中甲烷的含量从72%逐渐降低至60%。AHS通过与反应器内的产甲烷菌竞争电子来影响EGSB反应器的处理效果。同时，研究发现AHS进水浓度为4000mg/L起，反应器的COD去除率下降明显且在长期运行后无法恢复。盐度对垃圾焚烧沥滤液处理效果的研究表明，当钙浓度高于6000mg/L时，COD去除率随运行时间明显下降，厌氧污泥的产甲烷活性受到明显抑制。随着反应器钙负荷的提升，厌氧颗粒污泥中有多种细菌和古菌的生长受到抑制，维持生长的微生物主要集中在梭菌科的细菌和产甲烷髦毛菌。.采用静态实验的方法，研究复合抑制因子对垃圾沥滤液厌氧生物处理的影响。研究结果表明：抑制阈值为：盐度6,000mg/L，氨氮400mg/L，AHS 4,000mg/L，其中，盐度的影响最大。高浓度复合抑制因子主要抑制了丙酸和丁酸的降解。较低的COD去除率和产甲烷活性，可能是由于细菌的活性基因受到复合抑制因子的影响。古菌群落结构中Methanosaeta明显受到高浓度的复合抑制因子影响。.采用改良的Gibbons培养基从EGSB反应器中筛选3株具有耐盐性的COD降解菌。利用16S rDNA技术确定降解菌分别为Bacillus,Clostridium和Enterobacter种属；同时确定在COD为20,000mg/L，总接种量为10%，Strain1和Strain2接种比例为1:2时，COD去除率达到54.3%，为最优接种组合。