北方灌区沟渠氮磷自然净化效果的研究

发布时间：2018-05-19 11:34

本文选题：沟渠 + 氮　；参考：《沈阳大学》2017年硕士论文

【摘要】：氮和磷是农作物正常生长必需的营养物质,也是农田水生态系统污染的重要组成物质。农田中的灌溉渠道和排水沟道,不仅能对农田水分进行调节,而且具有线性湿地特征。沟渠中底泥吸附,植物吸收、微生物降解等不仅可以影响污染物迁移和转变还能对其进行减量去除。因此,沟渠具有水利和生态双重功能。本文以沈阳市浑北灌区排水沟渠为研究对象,通过室外试验和实验室试验;研究了北方灌区排水沟渠中不同形态的氮、磷的运移变化规律,沟渠植物对氮、磷的截留效应,微生物对氮磷的去除效果,底泥对氮磷的吸附效应及其影响因素。通过试验研究得出的结论如下:总氮、总磷及氨氮浓度易受施肥和降雨的影响,随时间的波动性较强;6月和8月表现出波峰,7月份浓度有最小值。沟渠系统对氮磷有较强截留净化效果,尤其是氨氮和总磷去除率较高。总氮去除率在15.79%~36.11%。氨氮的去除率6月份最高,达到了62.5%。总磷去除率在46.24%~63.44%。不同形态的氮含量在各级渠系中有从上游向下游汇集的规律,其峰值从毛沟逐步向斗、支、干沟迁移。水生植物可以增强截留效果:水生植物的存在使得沟渠对总氮、总磷截留率分别增加了11.5%、7.8%。水生植物可以加快氮磷从水体向下迁移进入底泥的速度,从而强化去除效果。三种植物中,芦苇对氨氮的截留能力最强,菖蒲对磷的吸收能力最强。底泥微生物对氮的截留去除作用十分明显,对磷的去除不明显。有微生物的底泥氨氮的截留量比相同条件下无微生物底泥高0.028mg/g。氮(磷)吸附量与样品自身含氮(磷)量有关,底泥含氮(磷)量越高吸附氨氮(磷)的能力越弱。氮磷等温吸附曲线符合朗格缪尔方程和弗兰德利希方程。氮磷吸附动力学过程均符合准二级动力学方程。温度升高不利于氨氮的吸附但有有利于磷的吸附。支沟、干沟、农沟底泥样品对氨氮吸附能力随着p H值上升而逐渐增大。p H=7时,支沟、干沟、农沟底泥对磷的吸附量达到最大值,分别为91.56、39.86、41.56mg/kg;其他条件下吸附量都有所降低。随着p H增大底泥的吸附速率是增大的。沟渠底泥对氨氮的吸附能力随着COD含量的增加表现出明显降低。COD浓度在50mg/L时,磷平衡吸附量达到最大值,分别为89.72、48.72、52.75mg/kg;其他条件下吸附量均有所降低。
[Abstract]:Nitrogen and phosphorus are essential nutrients for the normal growth of crops as well as an important component of farmland water ecosystem pollution. Irrigation channels and drainage channels in farmland can not only regulate the water of farmland, but also have the characteristics of linear wetlands. The adsorption of sediment, plant absorption, and microbial degradation in the ditch can not only affect the pollutants. Therefore, the ditches have dual functions of water conservancy and ecology. In this paper, the drainage ditches in Hun north irrigation area of Shenyang city are taken as the research object. Through outdoor experiments and laboratory tests, the changes of nitrogen and phosphorus migration and change of different forms in the drainage canals of the northern irrigation area are studied, and the interception of nitrogen and phosphorus in the ditch plants. Effect, removal effect of nitrogen and phosphorus by microorganism, adsorption effect of sediment on nitrogen and phosphorus and its influencing factors. The conclusion is as follows: total nitrogen, total phosphorus and ammonia nitrogen are easily affected by fertilization and rainfall, and the fluctuation of nitrogen and phosphorus is stronger with time. In June and August, the peak and the concentration in July are minimum. The ditch system has a better effect on nitrogen and phosphorus. The removal rate of ammonia nitrogen and total phosphorus is high, and the removal rate of total nitrogen is highest in June, the removal rate of 15.79%~36.11%. ammonia nitrogen is highest, and the nitrogen content of 62.5%. total phosphorus removal rate in different forms of 46.24%~63.44%. is collected from upstream to downstream, and its peak is gradually moved from the furrow to the bucket, branch and dry ditch. Aquatic plants can enhance the interception effect: the existence of aquatic plants makes the trench to total nitrogen, the total phosphorus interception rate increases by 11.5%, 7.8%. aquatic plants can accelerate the speed of nitrogen and phosphorus migration from the water into the bottom mud, thus strengthening the removal efficiency. In the three plants, reed has the strongest ability to intercept ammonia nitrogen, and the absorption energy of Acorus calamus to phosphorus The removal of nitrogen by microorganism is very obvious, and the removal of phosphorus is not obvious. The interception of ammonia nitrogen with microbial sediment is related to the 0.028mg/g. nitrogen (phosphorus) adsorption capacity and the nitrogen (phosphorus) content of the sample under the same condition. The higher the nitrogen (phosphorus) content of the sediment is, the weaker the ability to adsorb ammonia nitrogen (phosphorus). The temperature adsorption curve conforms to the Langmuir equation and the Friendly F equation. The kinetic process of nitrogen and phosphorus adsorption is in accordance with the quasi two stage kinetic equation. The increase of temperature is not conducive to the adsorption of ammonia nitrogen but is beneficial to the adsorption of phosphorus. The adsorption capacity of the sediment in the branch ditch, the dry ditch, the ammonia nitrogen adsorption capacity increases with the P H value and gradually increases.P H=7, branch ditch, dry ditch, The adsorption capacity of phosphorus in the sediment of the agricultural gully reached the maximum value of 91.56,39.86,41.56mg/kg, respectively, and the adsorption capacity was reduced under the other conditions. With the increase of P H, the adsorption capacity of the sediment was increased. The adsorption capacity of the sediment to ammonia nitrogen in the ditch was obviously reduced by the increase of the content of COD, and the equilibrium adsorption capacity of phosphorus reached the highest when the concentration of.COD was reduced to 50mg/L. The maximum value is 89.72,48.72,52.75mg/kg, and the adsorption capacity decreases under other conditions.
【学位授予单位】：沈阳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X52

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