复合人工湿地处理污染河水和湿地植物筛选研究

【作者】 范云爽；

【导师】 蒋云东；

【作者基本信息】 昆明理工大学 ， 环境科学， 2010， 硕士

【摘要】 近年来,我国地表水污染依然十分严重,七大水系水质总体为中度污染,湖泊营养化问题突出。洱海是云南第二大淡水湖,也是中国第七大淡水湖,正在由贫中营养状态向富营养化状态过渡,主要污染物有总悬浮物、耗氧有机物、氮、磷、挥发性酸、硫化物等。弥苴河是洱海重要的来水河,占洱海流域面积的60%,占洱海总入水量的51%。弥苴河水质的好坏,决定了洱海的水质。工业发展和农村面源污染的加重导致弥苴河水质一度降为Ⅳ类,经过整治后,水质已有所好转。人工湿地由于其在污水处理方面的处理效果比较好且稳定,管理和运行的费用低廉等特点,被广泛地应用于控制非点源污染、各类工业污水和市政生活湖水治理、净化与修复受损害污染河流和湖库等方面。本研究针对弥苴河的不同季节来水情况,选择了由沉淀池-生物氧化塘-一级表流湿地-二级表流湿地组成的复合人工湿地来处理弥苴河河水。结果表明：当湿地运行一段时间趋于稳定后,温度就成为影响人工湿地去除效率的重要因素之一。复合人工湿地对污染物的去除率,由于湿地刚建成,5、6月份最低,最高的为9、10月份,11月和12月的去除率比较稳定,说明湿地运行已基本平稳,但是去除率有所下降,这可能跟温度的降低有关系。通过对流量控制模拟高、中、低三种不同的水力负荷下的复合人工湿地去污效率研究,发现在不同的水力负荷下,复合湿地对污染物的去除效率存在着明显的差异,总的来说,当水力负荷较小时,去除率较高。最佳的水力负荷应该为0.16 m·d-1。通过对污染物沿程浓度变化的研究,发现沉淀池和氧化塘在去污方面发挥作用较小,但是对于消减污染负荷和总的高去除率,也起到了一定的作用。复合湿地去除效率好于任何一个单独的处理单元。湿地挺水植物作为复合人工湿地的一个重要组成部分,本文对湿地植物进行了初步研究,结果表明：对植物泌氧能力对DO的影响研究可以看出,白天太阳光照逐渐变强时,实验水中的溶解氧浓度迅速上升,说明这段时间挺水植物光合作用较强,释放了比较多的氧气。而当太阳光照较弱或没有光照时,溶解氧浓度开始迅速下降,说明这段时间挺水植物光合作用较弱,消耗了大量的氧气。六种挺水植物的根系泌氧能力差异不是特别显著,以累计泌氧浓度(DO)来衡量六种挺水植物泌氧能力大小茭白>芦苇>梭鱼草>再力花>美人蕉(Canna glauca)>水葱。对六种挺水植物的去污效果实验结果来看,六种挺水植物对总氮、总磷、CODcr、氨氮的去除效果较为明显,并且对总氮、CODcr、氨氮有植物的去除效果都要明显好于无植物系统,而总磷的去除,植物系统和无植物系统没有明显差异,说明植物在总氮、CODcr、氨氮的去除方面发挥了主导的作用,而对总磷的去除则是辅助作用。从实验结果来看,去污效果较好的植物有芦苇、茭白、梭鱼草,而再力花、美人蕉、水葱的去污效率则相对较差。对六种挺水植物在水中腐烂分解时的营养物质释放强度进行了研究,六种植物释放有机质和TN在第4天左右就达到了最高值,而对TP的释放则在第10天才达到最高值,说明植物磷的释放比较缓慢,和植物体内磷含量进行相关性分析,表明磷的释放和植物体内的磷含量密切相关。综合不同营养物质的累计释放强度,可以看出,梭鱼草、美人蕉、茭白释放强度较强,再力花和芦苇释放强度较弱,在选择湿地植物时综合考虑植物吸收污染物能力的情况下,可以优先考虑再力花、芦苇等这些释放强度较弱的植物,避免植物腐烂对水质产生影响。更多还原

【Abstract】 In recent years, China’s surface water pollution was still very serious, The seven major river systems was moderately polluted water in general,Lake eutrophication is still a prominent problem. Erhai Lake is the second largest freshwater lake in Yunnan.it also is the seventh largest freshwater lake in China,is being in the transition from poor nutritional status to the eutrophication. Major pollutants are total suspended solids, ozone-depleting substances, nitrogen, phosphorus, volatile acid, sulfur and so on. Mi Ju River is the most important tributary of Erhai Lake, its drainage area accounts for 60% of Erhai Lake basin area, water accounts for the water inflow in Erhai 51% of the total. The water quality of Mi Ju River determines the water quality of Erhai Lake. Industrial development and critical rural non-point source pollution leaded to the water quality of Mi Ju River was once reduced to IV class, after remediation, water quality has improved.Constructed wetland for its good and stable effectiveness in dealing with sewage treatment, lower cost of operation and management features, has been widely applied to control non-point source pollution, purification and repair damaged rivers and so on.In this study,for Mi Ju river circumstances of runoff in different seasons, Chosen by the sedimentation tank-bio-oxidation pond-one sheet-flow constructed wetland-two sheet-flow constructed wetland composed of complex artificial wetland to deal with Mi Ju river water. The results showed that:When the wetland run for some time to stabilize, temperature effects has become an important factor in removal efficiency of artificial wetlands.The highest removal efficiency of composite artificial wetland happened in September and October, the lowest in May and June. The removal rate in November and December was relatively stable, Description of wetland operation has been basically stable, but the removal rate decreased, which may be attributed to the lower temperature.Through decontamination efficiency study in three kinds of high, medium and low simulation hydraulic load of the composite artificial wetlands,we found that, in different hydraulic load, there were obvious differences in the removal efficiency of pollutants, in general, when the hydraulic load was small, the removal rate was higher. The best hydraulic load should be 0.16 m·d-1 Through the the study of concentration of pollutants along the way in the composite wetlands, it found that sedimentation tanks and oxidation pond to play a small role in the decontamination, but it also played a certain role in reducing the high pollution load and the total removal rate.The removal efficiency of composite wetlands is better than any one single processing unit.Wetland plants was an important part of constructed wetlands.In this paper, I studied the screening of wetland plants Preliminary,the results showed that:from the study of plant oxygen secretion can be seen,during the day when the light was strong, the concentration of dissolved oxygen increased rapidly in water, indicating during this time the plant photosynthesis was main, respiration was less. When light was weak or there is no light, the dissolved oxygen concentration began to decline rapidly, indicating during this time the respiration of plant was main, the respiration consumed a great deal of oxygen. Radial oxygen loss of six kinds of wetland plants’ difference is not particularly significant, in order to measure the radial oxygen loss.I used the concentration of accumulated dissolved oxygens:Zizania latifolia (Griseb) Stapf>Phragmites australis>Pontederia cordata> Thalia dealbata>Canna glauca>Scirpus validus Vahl.From the experimental results of decontamination effects of the six kinds of macrophytes, we have seen the six kinds of water plants’removal effect on TN, TP, CODcr, NH3 is obvious, and for TN, CODcr, NH3,the system have plants’remove results were significantly better than non-plant system, while the TP removal, there is no significant difference between the plants and non-plant systems, indicating plant has played a leading role in the removal of TN, CODcr, NH3, while the plant played a supporting role in the removal of TP. From the experimental results,we have seen that better-performing plants include Phragmites australis, Zizania latifolia (Griseb) Stapf, Pontederia cordata, while the decontamination efficiency of Thalia dealbata, Canna glauca, Scirpus validus Vahl is relatively poor.We studied the release strength of the nutrients in six kinds of macrophytes. the release of CODcr and TN in six plants reached the highest value in the fourth day, while the release of TP reached the highest value in the tenth day, indicating the release rates of phosphorus is relatively slow, and it is closely related with the phosphorus content in plants. Based on a comprehensive analysis of the release strength of nutrients, we can see the release intensity of Pontederia cordata, Canna glauca and Zizania latifolia (Griseb.) Stapf were stronger than Thalia dealbata and Phragmites australis, in the selection of wetland plants, you can give priority to Thalia dealbata, Phragmites australis with weak release intensity could avoid the impact of water quality by decomposition of plants.更多还原