堆肥-生物滴滤塔耦合系统中N2O减排机制及机理模型研究

How to effectively reduce of nitrous oxide (N2O) emission and trickling liquid discharge from the Composting-Biotrickling Filter coupled system has become a critical issue in development of composting technology. As trickling liquid (TL) containing high concentration of inorganic nitrogen and nitrifying bacteria, this study aims to investigate the feasibility and the influence of applying TL discharged from a biotrickling filter on the humification progress and N2O generation behavior of the composting. The study will firstly investigate the performance of biotrickling filter for ammonia (NH3) containing gas purification. The influence of different biotrickling filter operating conditions on NH3 removal efficiency, N2O generation behavior and biochemical properties of TL will be illustrated; Secondly, the feasibilities of recycling TL as a moisture conditioning agent for composting will be demonstrated from the perspective of the influence of applying TL with different biochemical properties on the physic-chemical properties, N2O generation amount and change of microbial populations of the compost from different composting stage; Moreover, this study will improve the mechanism of organic matter degradation and microbial reaction mechanism, and construct a aerobic-anaerobic co-reaction based composting mechanistic modeling for illustrating and simulating the influence of TL recycling on the humification progress and N2O generation behavior of the composting with better practicability and strong generalization ability. The results of this study can provide a theoretical and technical support for process optimization, energy conservation promotion and ecological security ensuring of the composting system.

如何有效降低堆肥-生物滴滤塔耦合系统中N2O产生和含氮喷淋液排放量，是发展堆肥化技术所亟待解决的问题。鉴于生物滴滤塔喷淋液内含有较高浓度无机氮和硝化菌的特性，本课题主要研究其回用至堆肥化过程时，对堆肥腐殖化进程及N2O产生特性的影响。本课题首先以生物滴滤塔去除含氨臭气为研究对象，揭示不同操作条件对生物滴滤塔NH3去除效果、N2O产生及喷淋液中生化组成特性的影响；然后从不同生化组成喷淋液回用，对堆肥化不同时期物料的理化指标、N2O产生量和微生物种群数量变化等影响的角度，探究喷淋液回用的可行性，并基于好氧-厌氧共作反应机制理论，完善有机质降解机制和微生物反应机制，构建与实际更切合、泛化能力强的堆肥化系统反应机制及N2O产排机理模型，科学阐释喷淋液回用对堆肥腐殖化进程及N2O产排影响的作用机制，为科学指导堆肥化系统工艺优化、有效提升节能减排和确保生态安全提供理论基础和技术支持。

如何有效降低堆肥-生物滴滤塔耦合系统中N2O的产生和含氮喷淋液的排放量，是发展堆肥化技术所亟待解决的问题。鉴于生物滴滤塔喷淋液内含有较高浓度无机氮，本课题研究其回用至堆肥化过程时，对堆肥腐殖化进程及N2O产排特性的影响。课题首先研究不同聚乳酸和淀粉组成的缓释碳在不同试验条件下的释碳及其脱氮特性，遴选出较为理想的缓释碳作为生物滴滤塔填料；其次，考察了以选定缓释碳为填料的两套脱臭系统[即同步硝化反硝化生物滴滤塔系统（SNDBT）和异步硝化生物滴滤塔-反硝化生物滤池耦合系统（ANDBF）]，在不同运行参数下对NH3的去除效果、N2O排放特性以及喷淋液中化学组成变化规律；最后论证喷淋液回用至堆肥化过程的可行性。研究主要成果如下：.（1）缓释碳释碳特性实验结果表明，缓释碳中聚乳酸和淀粉的配比及溶液pH值对缓释碳系统释碳及其脱氮性能影响较大。与其他组成相比，缓释碳中聚乳酸/淀粉比例为5:5时，反硝化速率快。同时，响应面优化结果表明，该缓释碳体系内存在同步硝化反硝化现象。.（2）以该缓释碳为填料的生物滴滤塔除氨实验结果表明，SNDBT和ANDBF系统均在进水负荷为800 mg/L，通气量为100 L/h，喷淋率为200 mL/min，水力停留时间6 d的工况下达到最佳脱氮性能。在此工况下，两套系统的最高脱氮体积负荷分别为1375.8 kg/ (m3•d)和745.2 kg/ (m3•d)；生物滴滤塔的喷淋率及通气量是影响体系N2O产生量的关键因素。在最佳工况下，生物滴滤塔出气中N2O浓度在检测限以下。.（3）以含硝氮的废弃喷淋液作为堆肥化过程中水分补充源，不影响堆肥化进程的顺利进行。同时，喷淋液回用可减少堆肥化过程中的氮素损失、提高堆肥产品的农用价值、降低堆肥化体系温室气体及臭气的排放量。.综上所述，以聚乳酸和淀粉混合制备的缓释碳材料作为填料的生物滴滤塔系统，在有效净化含氨臭气的同时，降低喷淋液中代谢产物的积累，有效延长喷淋液的使用周期。此外，将含有硝氮的喷淋液作为堆肥化过程中的水分补充源是一个理想的生物滴滤塔废弃含氮喷淋液处置方法。