【作者】 孙宜敏；

【导师】 由文辉；

【作者基本信息】 华东师范大学 ， 生态学， 2004， 硕士

【摘要】 随着人口的增长和社会经济的发展，农业面源、工业点源及生活源含氮磷污水数量在不断增加，而对污水处理和水质管理则明显滞后，大量直接排出的未处理污水已造成地表水环境严重污染，富营养化水域日渐增多，使我国面临着严峻的淡水资源氮磷污染和富营养化问题。所以急需一种操作方法简便、运行费用低廉、对氮磷去除效果好的水体生态修复方法和废水处理方法。利用水生植物净化废水不仅能够去除其中的污染物质，而且还可将收获的水生植物加工处理作为新的能源、饲料、肥料或工业原料，实现资源化回收利用，是一种最为经济有效和容易推广的处理技术，受到广大学者的高度重视。 浮萍是一种小型漂浮植物，具有生长快、蛋白质含量高、收割简便、对氮磷吸收率高等特性。本文通过种群生长实验对浮萍生长能力以及对水体中氮素的形态浓度和磷素浓度的耐受能力进行研究，挑选出相对生长率最快、对氮磷耐受性好的青萍作为研究对象，设置不同氮素形态、比例及浓度和不同磷浓度，研究室内静态条件下青萍对氮磷有机污水的净化效果，以期为进一步开展利用浮萍净化氮磷有机污水和富营养化水体的研究与应用提供有益的参考依据。主要研究结果如下： 1、青萍对水体中的氮磷营养均有较高的吸收富集效率。氮磷浓度的降低速率随水体中氮磷浓度的升高而升高，而对氮磷的去除率随水体中氮磷浓度的升高而降低。水体中的氨氮浓度以负指数形式降低，总磷及溶解性正磷酸盐浓度与处理时间显著负相关。 2、营养液中NO₃^-：NH₄⁺为7.5：2.5时，青萍的生长情况最佳，生物量积累最多，对氨氮和总氮的去除效果最好，去除率分别为99.9％和65.3％，对硝态氮的去除率也达到68.6％。青萍体内氮含量随氨氮比例及浓度的升高而升高。 3、青萍对氨氮的吸收利用能力高于对硝态氮的吸收利用能力。相同浓度水平下，营养液中氨氮的去除率比硝态氮的去除率高10％～20％，即使在氨氮为唯一氮源，青萍生长受到抑制的情况下，氨氮的去除率仍然比硝态氮高出约4％。 4、磷元素充足的条件下，随着营养液中磷浓度的升高，青萍体内的总磷含量随之升高，但是青萍的生物量没有显著的增长，说明青萍能够过量吸收磷元素并在体内积累。几种磷浓度中，青萍生长情况均良好，对营养液中总磷与溶解性正磷酸盐的吸收利用效率极高，两者的去除率分别达到90％和88％以上。 通过研究发现，浮萍对水体中高浓度氮磷营养元素的耐受性和去除能力很高，适合用于对富营养化的天然水体进行生态修复或者对生活污水、养殖废水、畜禽粪便等氮磷含量高的有机废水进行净化处理。浮萍种群增长能力极强，主要通过生物量的增长实现对氮磷营养的吸收去除。在应用时，应定期收割以保持青萍旺盛的种群生长力，保证净化效果。而且浮萍浮歼对污染水体中氮磷吸收富集作用研究营养丰富，可直接作为鱼类饵料、畜禽饲料或竹为绿肥还田，也司以哟一为沼气发酵的原料〕如果能够合理、有效地开发利用，就能人人促进养殖业、渔业和生态农业的发展。更多还原

【Abstract】 Population growth and society development have generated increasing amounts of wastewater containing high content of nitrogen (N) and phosphorus (P) from agriculture, industry and urban life. On the contrary, the treatment and quality control of sewerage disposal lagged far behind. Large amount of wastewater is discharged directly into rivers, lakes and other water bodies. This is frequently causing eutrophication of surface water and groundwater contamination. Our country is facing more and more serious situation of N and P pollution and eutrophication of reliable freshwater resource. A low-cost and easy-operate measure characterized with high reduction rate of N and P for wastewater treatment and bioremediation of surface water is urgently needed to establish.The application of aquatic macrophytes in wastewater decontamination not only can remove the pollutant out of the system. In addition, they assimilate nutrients into a high-quality biomass that may be processable to new resource, feedstuff, fertilizer or industrial material. This technique combines wastewater treatments with source reuses and is an economical-efficient and easy-spreading option for the purification of wastewater.In this study, the growth competence and tolerance ability to the forms and strength of N and P of several duckweed species were studied through population growth experiment. Lemna perpusilla is chosen for its highest relative growth rate (RGR) and good endurance to N and P to study the removal rate of N and P in high organic load wastewater by static experiments indoors, in order to get some useful information for further application of duckweed in decontamination of nutrient elements from wastewater and eutrophicated water body. The following were the results:1.Lemna perpusilla has high efficiency in absorbing and concentrating N and P from wastewater. The reduction speed is increasing along with the concentration of N and P in water, whereas the removal rate of N and P is descending. The ammonia concentration descends as a negative exponent, while TP and phosphate decrease linearly.2.When the ratio of nitrate/ammonia in medium is 7.5: 2.5, Lemna perpusilla grows best and has the most biomass. In the meantime, the reduction of ammonia and TN is optimal with removal rate of 99.9% and 65.3%, and that of nitrate is 68.6%. The content of N in Lemna perpusilla is increasing when the ammonia strength is higher.3.The absorption capability to ammonia of duckweed is stronger than to nitrate. As in the same strength level, the removal rate of ammonia is 10%~20% higher than nitrate. Even as the growth of duckweed is inhibited in a full ammonia circumstance, the removal rate of ammonia is 4% higher than nitrate.4.If phosphorus is enough, when the strength of P is higher, the content of P in Lemna perpusilla is higher too, but the biomass of Lemna perpusilla isn’t increasing significantly. This suggests that Lemna perpusilla can absorb P more than demand and store it inside its body. Lemna perpusilla grows well in any phosphorus strength and absorbs TP and PO43-efficiently. The removal rate of TP and phosphate is above 90% and 88%.The great tolerance and removal capability of duckweed to strong strength N and P is very considerable, so the application of duckweed in bioremediation of eutrophicated water body and post treatment of domestic sewage and septic tank effluent etc is reliable. Duckweed population grows rapidly and removes the nutrients mainly by biomass increasing. Harvest termly can keep duckweed population in high growth rates, therefore the duckweed-based system can work steadily. As duckweed has rich nutrients, it can be used as feedstuff for fishes, pigs, ruminants and chicken. And it can be used as ecological fertilizer and material of biogas. Under reasonable and efficient utilization, duckweed-based technology can improve the development of fish culture, stockbreeding and ecological agriculture greatly.更多还原