人工湿地强化技术及其效能研究

发布时间：2018-10-16 22:15

【摘要】：人工湿地在实际运行过程中营养物(如氮和磷)的去除效果不稳定(尤其是温度降低时),限制了人工湿地在我国大规模推广应用。因此,研究强化人工湿地对废水中污染物去除能力,尤其是对氮、磷的净化能力,就显得非常重要。本文通过建立不同强化措施来提高人工湿地的运行性能,研究表明每天间歇曝气12/d、人工湿地中添加玉米秸秆、铁碳微电解基质的应用以及上行流模式水循环能够提高人工湿地的运行性能,研究结果人工湿地的常年稳定运行运行提供技术支撑,对我国污水的治理及生态环境改善具有重要意义。本研究主要得出以下结论:(1)采用每天间歇曝气12h能够明显提高人工湿地的运行性能,其氨氮(93.9%)、总氮(95.4%)和COD去除率(92.8%)明显高于不曝气人工湿地,分别比不曝气人工湿地提高了11.0%、12.2%和20.7%。在不同C/N比进水条件下,12h/d间歇曝气人工湿地的氨氮的去除率在98.4-100%之间,氨氮去除效率没有明显下降,但是,曝气系统内的COD去除率会随着C/N比增加而降低,其研究表明每天间歇曝气12h适合于C/N在3.1-9.2之间污水的处理。温度下降时,每天间歇曝气12h人工湿地中氨氮和COD去除率没有明显下降,氨氮和COD去除率分别维持97.7%以上和80.7-98.0%之间。而未曝气人工湿地系统的氨氮和COD去除率受温度影响较大,氨氮去除率下降了2.9%-11.2%,COD去除率在43.4-75.2%之间。以上研究结果说明,采用每天间歇曝气12 h的方式能够增强人工湿地去除效果,在温度降低时,还能维持较好的运行性能。(2)人工湿地中添加缓释碳源能够提高人工湿地的反硝化速率。不同总氮浓度实验表明,所有人工湿地的氨氮和总磷去除率分别维持在87.4%和91%以上,但是,随着总氮浓度提升到179.2 mg/L时,人工湿地硝氮去除率下降。如玉米芯、木块和空白人工湿地的硝氮去除率分别降至86.8,84.7和76.2%,但是玉米秸秆人工湿地依旧维持较高的硝氮去除率(92.1%)。温度影响实验研究表明,添加缓释碳源的人工湿地在温度下降时,人工湿地氨氮和总氮去除率有所下降,但也依旧能够维持较高的氨氮、硝氮和总氮去除率。尤其是添加玉米秸秆的人工湿地,在温度降低时,即使当进水总氮浓度提高到179.2mg/l时,氨氮、硝氮和总氮的去除率分别维持在89.7%、81.0%和82.8%。以上研究结果说明,采用缓释碳源添加(尤其是玉米秸秆)的方式能够在一定程度上加快反硝化过程,提高人工湿地的硝氮去除率,尤其是在温度降低时还能维持较好的运行性能,十分适合于高总氮浓度废水的处理。(3)铁碳微电解基质的人工湿地具有强大的总磷吸附能力,当进水的总磷浓度升高至32.8mg/l,人工湿地总磷去除率依旧可维持在96.6%以上,同时,人工湿地也具有较高的氨氮、硝氮、总氮以及cod去除率。温度实验研究表明,人工湿地的总磷去除率受温度影响较小(总磷去除率在96.0%以上),但是氨氮、硝氮和总氮去除率会随温度变化出现波动,其氨氮、硝氮、总氮和cod去除率也较高,分别在82.8%、81.9%、85.8和80.3%以上。铁碳微电解人工湿地在cod浓度提高时,cod去除率也较高(在83.8%以上),同时,也具有较高的氨氮(92.9%)、硝氮(94.1%)、总氮(95.2%)及总磷(95.3%)去除率。当硝氮浓度升高到75.8mg/l时,铁碳微电解人工湿地也能很好的去除硝氮(去除率在92.4%以上),以上研究结果表明,铁碳微电解基质不仅适合于高总磷浓度废水的处理,也适合于有机物浓度和高硝氮浓度废水的处理。(4)上行流人工湿地具有较为优异的运行性能,具有最高的氨氮(99.7%)、硝氮(87.2%)、总氮(93.1%)、总磷(95.4%)和cod(87.7%)去除率,下行流和平流流人工湿地次之,静止流人工湿地运行性能最差。温度实验研究表明,不同构型的人工湿地的运行性能均受温度的影响,尤其是下行流、平行流和静止流人工湿地的运行性能受温度影响较大,但是上行流人工湿地相对于其他人工湿地受温度影响较小,其氨氮、硝氮、总氮、总磷和cod去除率维持在94.8%、67.6%、78.4%、98.5%和77.9%以上。总的来说,通过本次实验研究表明,采用每天间歇曝气12h/d、添加缓释碳源(尤其是玉米秸秆)、铁碳微电解基质的应用以及采用上行流运行的强化措施均能很好的增强人工湿地的运行性能,尤其是在温度降低时还能维持较好的运行性能。此外,研究结果可为人工湿地的实际应用中根据不同的废水特点选择合适的强化措施提供参考依据。
[Abstract]:The removal of nutrients (such as nitrogen and phosphorus) during the actual operation of the constructed wetland is unstable (especially when the temperature is reduced), which limits the large-scale popularization and application of the constructed wetland in China. Therefore, it is very important to study the ability of artificial wetland to remove pollutants from waste water, especially nitrogen and phosphorus. Through the establishment of different strengthening measures to improve the operation performance of the artificial wetland, the research shows that the application of the corn stalk, the iron-carbon micro-electrolysis matrix in the artificial wetland and the water circulation of the upstream flow mode can improve the running performance of the artificial wetland through the establishment of different strengthening measures. The research results provide technical support for perennial stable operation of artificial wetland, which is of great significance to the treatment of sewage in China and improvement of ecological environment. The main conclusions are as follows: (1) The operation performance of artificial wetland is obviously improved by using intermittent aeration for 12h per day, and the ammonia nitrogen (93.9%), total nitrogen (95.4%) and COD removal rate (92.8%) are obviously higher than that of non-aeration artificial wetland. 11. 0%, 12. 2% and 20. 7% higher than that of the unaerated artificial wetland, respectively. Under the condition of different C/ N ratio, the removal rate of ammonia nitrogen was 98. 4-100%, and the removal efficiency of ammonia nitrogen was not obviously decreased. However, the removal rate of COD in aeration system decreased with the increase of C/ N ratio. The study shows that the intermittent aeration for 12h per day is suitable for the treatment of sewage between C/ N and 3. 1-9. 2. When the temperature drops, the removal rate of ammonia nitrogen and COD in the artificial wetland is not obviously decreased, and the removal rate of ammonia nitrogen and COD is above 97. 7% and 80. 7-98. 0%, respectively. The removal rate of ammonia nitrogen and COD in the unaerated wetland system was greatly influenced by temperature, the removal rate of ammonia nitrogen decreased by 2.9%-11.2%, and the COD removal rate was 43. 4-75. 2%. The results of the above study indicate that the removal effect of artificial wetland can be enhanced by intermittent aeration for 12 hours per day, and better operation performance can be maintained when the temperature is reduced. (2) adding sustained-release carbon source in the artificial wetland can improve the denitrification rate of the artificial wetland. The results of different total nitrogen concentration show that the ammonia nitrogen and total phosphorus removal rate of all artificial wetland are maintained at 87. 4% and 91%, respectively. However, as the total nitrogen concentration is increased to 172.2mg/ L, the removal rate of nitrate nitrogen in artificial wetland decreases. The removal rates of nitrate and nitrogen from corn cobs, wood blocks and blank artificial wetland decreased to 86.8, 84.7 and 76.2% respectively, but the removal rate of nitrate nitrogen in maize straw artificial wetland was still higher (92.1%). The experimental study on temperature effect showed that the removal rate of ammonia nitrogen and total nitrogen in artificial wetland was decreased when the temperature of artificial wetland was decreased, but higher ammonia nitrogen, nitrate nitrogen and total nitrogen removal rate could still be maintained. In particular, the removal rates of ammonia nitrogen, nitrate nitrogen and total nitrogen were maintained at 89. 7%, 81. 0% and 82.8%, respectively, when the total nitrogen concentration was increased to 179. 2mg/ l. According to the above research results, the denitrification process can be accelerated to a certain extent by adopting a slow-release carbon source addition (especially corn straw), so that the denitrification rate of the artificial wetland can be improved, especially when the temperature is reduced, good running performance can be maintained, and is very suitable for the treatment of high total nitrogen concentration wastewater. (3) The artificial wetland of the iron-carbon micro-electrolysis substrate has strong total phosphorus adsorption capacity, and when the total phosphorus concentration of the water is increased to 32.8mg/ l, the total phosphorus removal rate of the artificial wetland can still be maintained at 96. 6%, meanwhile, the artificial wetland also has higher ammonia nitrogen, nitrate nitrogen, total nitrogen and cod removal rate. The experimental study shows that the total phosphorus removal rate of artificial wetland is less affected by temperature (total phosphorus removal rate is above 96.0%), but the removal rate of ammonia nitrogen, nitrate nitrogen and total nitrogen will fluctuate with temperature. The removal rate of ammonia nitrogen, nitrate nitrogen, total nitrogen and cod is also high, 82.8% and 81.9% respectively. 85. 8 and 80. 3%. At the same time, the COD removal rate was higher (83.8%), but also higher ammonia nitrogen (92.9%), nitrate nitrogen (94.1%), total nitrogen (95.2%) and total phosphorus (95.3%). When the concentration of nitrate nitrogen rises to 75. 8mg/ l, the iron-carbon micro-electrolysis artificial wetland can also remove nitrate nitrogen very well (the removal rate is over 92.4%), the above research results show that the iron-carbon micro-electrolysis substrate is not only suitable for the treatment of high total phosphorus concentration wastewater, and is also suitable for the treatment of organic matter concentration and high nitrate nitrogen concentration wastewater. (4) The upstream artificial wetland has excellent running performance, with the highest ammonia nitrogen (99. 7%), nitrate nitrogen (87.2%), total nitrogen (93.1%), total phosphorus (95.4%) and cod (87.7%) removal rate, followed by the second place in the downstream flow, and the rest flow artificial wetland has the worst performance. The experimental results show that the operating performance of the constructed wetland is influenced by the temperature, especially the downstream, parallel flow and static flow artificial wetland are affected by the temperature, but the upstream artificial wetland is less affected by the temperature with respect to the other artificial wetland. The removal rates of ammonia nitrogen, nitrate nitrogen, total nitrogen, total phosphorus and cod were 94.8%, 66.7%, 78.4%, 95.8% and 77.9% respectively. In general, the application of slow-release carbon source (especially maize straw), iron-carbon micro-electrolysis substrate and intensified measure adopting upstream flow can well enhance the operation performance of artificial wet land by adopting intermittent aeration for 12h/ day, adding slow-release carbon source (especially maize straw). especially when the temperature is reduced. In addition, the research results can provide reference basis for selecting appropriate strengthening measures according to different wastewater characteristics in the practical application of artificial wetland.
【学位授予单位】：中国科学院大学(中国科学院东北地理与农业生态研究所)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X703

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