改性聚乙烯悬浮载体挂膜及其脱氮性能研究

发布时间：2018-06-28 22:45

本文选题：改性PE载体 + 亲水性　；参考：《大连理工大学》2015年硕士论文

【摘要】：聚乙烯(Polyethylene,简称PE)载体亲水性和生物亲和性较差,存在挂膜速度较慢、生物膜量较低及生物膜活性不高等缺陷,影响其污水处理效果。为解决这一问题,本文通过共混改性分别生产了亲水型和营养缓释型改性PE载体,并应用改性载体加速移动床生物膜反应器(Moving bed biofilm reactor,简称MBBR)工艺的挂膜启动,应用改性载体增强序批式移动床生物膜反应器(Sequencing batch moving bed biofilm reactor,简称SBMBBR)工艺的脱氮效果。引入亲水性基团能够改善PE载体的表面亲水性。分别向HDPE基料中添加一定量的淀粉和辅助剂、添加一定量的硅藻土和辅助剂、同时添加一定量的淀粉、硅藻土及辅助剂使其表面接触角从94.3。分别降低至79°、77.8°、76.6°。并且,水环境中淀粉的缓慢溶出使改性载体具备了营养缓释性能。挂膜启动实验结果显示,相同条件下,实验前36天,同时添加淀粉和硅藻土的复合型载体生物膜内多糖和蛋白质含量的平均增长速率分别是PE载体的1.8倍和1.9倍。实验第60天时,复合型载体生物膜内多糖和蛋白质的含量分别是68.4 mg/L和69.5 mg/L,比PE载体高67.8%和47.9%。多糖和蛋白质的含量越高,表明生物膜的生物活性和细胞活性越高。生物膜成熟期,复合型载体上的生物膜量为2.3±0.3∥L,比PE载体高89.3%,表明复合型载体具有富集微生物的能力。SEM和FISH结果显示,复合型载体生物膜内不同类型的菌群组成互生或共生体系,硝化菌群数量较多。上述复合型载体在挂膜性能方面的优势,使其第20天出水COD和NH4+-N就达到了国家一级A标准,比PE载体早12天,缩短了MBBR工艺的启动时间。SBMBBR实验中,多组分改性剂的添加使改性载体的密度增加到0.972g/cm3,接触角降低至72.4。。实验期间,两组SBMBBRs工艺的NH4+-N去除效果明显优于传统SBR工艺,投加改性载体的SBMBBR2出水NH4+-N在第18天达到了国家一级A标准,分别比投加PE载体的SBMBBR1和无载体投加的SBR早2天和8天。实验后期,SBMBBR2总氮去除效果最优,SBMBBR1次之,SBR较差。稳定期SBMBBR2的总氮平均去除率比SBR高近20%。单个周期内,两组SBMBBRs工艺的NH4+-N去除速率更快。并且,生物膜的空间异质性为实现同步硝化反硝化(Simultaneous Nitrification and Denitrification,简称SND)创造了有利的环境条件,使SBMBBRs工艺的总氮去除效果更好。加之改性载体良好的挂膜性能,单个周期内好氧结束和二次缺氧结束时SBMBBR2的总氮去除率分别比SBR高20.2%和18.4%。
[Abstract]:Polyethylene (PE) carrier has some disadvantages such as poor hydrophilicity and biological affinity, low biofilm amount and low biofilm activity, which affects the wastewater treatment efficiency. In order to solve this problem, hydrophilic and nutrient slow-release modified PE carriers were produced by blending modification, and the modified carrier was used to accelerate the start-up of membrane suspension in moving bed biofilm reactor (MBBR) process. The modified carrier was used to enhance the denitrification effect of sequencing batch moving bed biofilm reactor (SBMBBR). The hydrophilic group can improve the surface hydrophilicity of PE carrier. A certain amount of starch and auxiliary agent, a certain amount of diatomite and auxiliary agent, and a certain amount of starch, diatomite and auxiliary agent were added to HDPE base material, respectively, and the surface contact angle of HDPE was 94.3%. It was reduced to 79 掳/ 77.8 掳/ 76.6 掳respectively. In addition, the slow dissolution of starch in water environment makes the modified carrier have nutrient sustained release properties. The results showed that the average growth rate of polysaccharide and protein content in biofilm of composite carrier with starch and diatomite was 1.8 and 1.9 times higher than that of PE respectively under the same conditions and 36 days before the experiment. On the 60th day, the contents of polysaccharides and proteins in biofilm were 68.4 mg / L and 69.5 mg / L respectively, which were 67.8% and 47.9% higher than that of PE carrier. The higher the content of polysaccharide and protein, the higher the biological activity and cell activity of biofilm. At the mature stage of biofilm, the amount of biofilm on composite carrier was 2.3 卤0.3 / L, which was 89.3% higher than that of PE carrier. The results of SEM and fish showed that the composite carrier had the ability to enrich microorganism. In the biofilm of compound carrier, the different types of bacteria consist of mutualistic or symbiotic system, and the number of nitrifying bacteria is more. The advantages of the composite carrier in the performance of membrane suspension make the effluent COD and NH4-N reach the National Grade A standard on the 20th day, which is 12 days earlier than the PE carrier, and shortens the start-up time of MBBR process. SBMBBR experiment. The density of the modified support increased to 0.972g / cm ~ (-3) and the contact angle decreased to 72.4.with the addition of multicomponent modifier. During the experiment, the NH4-N removal efficiency of the two SBMBBRs process was obviously better than that of the traditional SBR process, and the effluent NH4-N of SBMBBR2 with modified carrier reached the first class A standard on the 18th day. SBMBBR1 with PE carrier and SBR without carrier were 2 days and 8 days earlier than that of SBMBBR1 with PE carrier and SBR without carrier respectively. In the later stage of the experiment, the best removal efficiency of total nitrogen was SBMBBR1, followed by SBR. The average removal rate of total nitrogen in SBMBBR2 was 20% higher than that in SBR. The NH4-N removal rate of the two SBMBBRs processes is faster than that of the SBMBBRs process in a single cycle. Moreover, the spatial heterogeneity of biofilm creates favorable environmental conditions for the realization of simultaneous nitrification and denitrification (SND) and makes the removal efficiency of total nitrogen in SBMBBRs process better. In addition, the modified carrier has good membrane performance, the removal rate of total nitrogen of SBMBBR2 at the end of aerobic and secondary anoxia in a single cycle is 20.2% and 18.4% higher than that of SBR, respectively.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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