木片土壤渗滤系统对养猪废水处理效能及功能菌群的分析

发布时间：2018-03-17 00:17

  本文选题：养猪废水　切入点：土壤渗滤　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：采用干清粪方式收集的养猪废水中仍然含有大量的有机物、氨氮、总磷、病虫卵等有害物质,若不经处理直接排放,不仅会造成环境污染还会危及人类健康。本研究对现有的土壤渗滤系统(SIT)进行工艺改进研究,通过向土壤填料中掺杂木片的方式构建了木片土壤渗滤系统(WSIT),并对该系统的启动方式和运行条件进行对比优化,同时采用荧光定量PCR技术对WSIT系统中的氮元素转化去除的微生物学原理进行分析。在WSIT的结构优化实验中,选取3个相同体积的反应器。1号反应器自下而上每间隔20 cm设置一组隔板,填料中木片与土壤的比例为1∶3;2号反应器渗滤柱中未设置隔板,填料中木片与土壤的比例为1∶3;3号反应器未设置隔板,填料中木片与土壤的比例为1∶4。研究表明,在表面水力负荷为0.2m3/m2?d,温度控制为25℃的条件下,3个WSIT均能在40天左右启动成功并稳定运行,然而其对废水中污染物的去除效果有所差异。1号WSIT对废水中COD、NH4+-N和TN的去除率分别为67.3%、87.7%和24.7%,2号WSIT对COD、NH4+-N和TN的去除率分别为61.0%、84.9%和35.2%,而3号WSIT对COD、NH4+-N和TN的去除率分别为68.5%、94.5%和45.0%。隔板的消除削弱了WSIT与外界交换氧气的能力,使其内部的氧浓度更低,产生更多的厌氧或缺氧区域,然而,这并没有降低WSIT对COD和NH4+-N的去除能力,反而强化了其对TN的去除作用。填料中土壤比例的增加,使得WSIT内部微生物量随之增加,进而使WSIT对NH4+-N和TN的去除能力有所增强。表面水力负荷对WSIT对COD的去除能力影响不大,但是,其对NH4+-N和TN的去除有显著影响。当水力负荷提升至0.3 m3/m2?d后,WSIT对NH4+-N和TN的去除能力明显下降,去除率为80.8%和37.9%左右。WSIT填料中的木片,不仅能够提高填料床的机械强度,使之能够承受较高的表面水力负荷,还可作为缓释碳源,为系统中的反硝化脱氮作用提供一定量的碳源。由于干清粪养猪废水中碳源严重不足,WSIT对TN的去除主要是通过短程硝化反硝化途径实现的,进水中的NH4+-N被氧化成NO2--N后,一部分被还原成气态氮排出系统,另一部分进一步被氧化成NO3--N并随出水流出系统。通过荧光定量PCR对系统中与氮代谢有关的微生物数量的分析表明,在WSIT中,表层的微生物含量较低,这可能是由营养物质分布不均匀和高浓度的氨氮抑制所导致的,在滤床纵深0.2 m处,细菌的拷贝数仅有3.55×107 copies/μL。微生物主要聚集在滤床高度为0.4-1.0 m的区域内,而这段区域也是废水中污染物降解的主要区域。亚硝酸盐还原菌和氨氧化细菌(AOB)变化规律一致,说明WSIT对氮元素的去除主要依靠短程反硝化过程,其最大拷贝数分别为2.67×107和4.70×107 copies/μL。在滤床纵深1.0-1.2 m的区域内,营养物质的匮乏成为微生物生长的限制因素,导致其含量迅速降低,系统内细菌的总拷贝数为1.03×108 copies/μL。
[Abstract]:The pig wastewater collected by dry defecation still contains a large amount of organic matter, ammonia nitrogen, total phosphorus, diseased eggs and other harmful substances, if it is discharged directly without treatment, Not only will it cause environmental pollution, but also endanger human health. In this study, the existing soil leachate system (SITs) was studied for technological improvement. The soil leachate system of wood chips was constructed by mixing wood chips into soil fillers, and the startup mode and operation conditions of the system were compared and optimized. At the same time, the principle of microbiology of nitrogen conversion and removal in WSIT system was analyzed by fluorescence quantitative PCR. In the structure optimization experiment of WSIT, Three reactors of the same volume were selected. A group of compartments were set up at 20 cm intervals from bottom to top in reactor 1. The ratio of wood slice to soil in packing was 1: 3; no partition was set in leachate column of reactor 2. The ratio of wood slice to soil in packing was 1: 3; in reactor 3, there was no partition, and the ratio of wood slice to soil in packing was 1: 4. The results showed that the hydraulic load on the surface was 0.2 m3 / m2? D, temperature is 25 鈩，

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