水葫芦的开发利用

作者论述了水葫芦的生长习性、化学组成及利用价值，对其开发利用提出了几点建议。     

Contribution of water hyacinth (Eichhornia crassipes (Mart.) Solms) grown under different nutrient conditions to Fe-removal mechanisms in constructed wetlands

Severe contamination of water resources including groundwater with iron (Fe) due to various anthropogenic activities has been a major environmental problem in industrial areas of Sri Lanka. Hence, the use of the obnoxious weed, water hyacinth (Eichhornia crassipes (Mart.) Solms) in constructed wetlands (floating aquatic macrophyte-based plant treatment systems) to phytoremediate Fe-rich wastewaters seems to be an appealing option. Although several studies have documented that hyacinths are good metal-accumulating plants none of these studies have documented the ability of this plant grown under different nutrient conditions to remove heavy metals from wastewaters. This paper, therefore, reports the phytoremediation efficiencies of water hyacinth grown under different nutrient conditions for Fe-rich wastewaters in batch-type constructed wetlands. This study was conducted for 15 weeks after 1-week acclimatization by culturing young water hyacinth plants (average height of 20+/-2cm) in 590L capacity fiberglass tanks under different nutrient concentrations of 1-fold [28 and 7.7mg/L of total nitrogen (TN) and total phosphorous (TP), respectively], 2-fold, 1/2-fold, 1/4-fold and 1/8-fold with synthetic wastewaters containing 9.27Femg/L. Another set-up of hyacinths containing only Fe as a heavy metal but without any nutrients (i.e., 0-fold) was also studied. A mass balance was carried out to investigate the phytoremediation efficiencies and to determine the different mechanisms governing Fe removal from the wastewaters. Fe removal was largely due to phytoremediation mainly through the process of rhizofiltration and chemical precipitation of Fe2O3 and FeOH3 followed by flocculation and sedimentation. However, chemical precipitation was more significant especially during the first 3 weeks of the study. Plants grown in the 0-fold set-up showed the highest phytoremediation efficiency of 47% during optimum growth at the 6th week with a highest accumulation of 6707Femg/kg dry weight. Active effluxing of Fe back to the wastewater at intermittent periods and with time was a key mechanism of avoiding Fe phytotoxicity in water hyacinth cultured in all set-ups. Our study elucidated that water hyacinth grown under nutrient-poor conditions are ideal to remove Fe from wastewaters with a hydraulic retention time of approximately 6 weeks.     

人工浮岛在丁香湖水质改善中的应用

针对丁香湖水体恶化产生蓝藻的问题,在湖中设置人工浮岛对水质进行改善,浮岛植物以凤眼莲为主,辅以美人蕉等搭配.人工浮岛运行后,对水体中TN、TP指标净化效果良好,TN的去除率为48.1%～52.1%,TP的去除率为55.0%～64.4%,而且具有一定的景观效果.     

水葫芦各部位富集能力的研究

通过对水葫芦根、茎、叶三部位脂肪、蛋白质、糖、钙、镁及重金属元素 (Fe、Cu、Pb、Zn、Cd、Cr)含量的测定 ,发现水葫芦茎、叶、根中脂肪、蛋白质、糖的含量无明显差异。整株植株营养价值与大白菜接近。金属元素在根部富集较多 ,而且其中大部分是吸附在根的表面。     

温度对凤眼莲浮岛净化效果影响的研究

以凤眼莲浮床为研究对象,研究不同温度下浮床的净化效率、水生植物生长情况和植物体中氮磷的累积量。研究结果表明,凤眼莲浮岛对TN、TP的去除率与温度并不成正相关。浮岛的处理效果主要与浮岛植物的生物量有关,其处理效率随着生物量的增加而增加。凤眼莲浮岛25℃时处理效率明显高于35℃和15℃。在北方地区浮岛技术的生态学价值要显著于环境工程价值。     

凤眼莲腐烂分解对湖泊水质的影响

在南京莫愁湖生态工程围区内,将凤眼莲(EichhorniacrassipesSolms)压入水下,待其自然腐烂分解,跟踪监测水质变化情况,研究凤眼莲腐烂分解对湖泊水质的影响.结果表明,初冬压入水下的凤眼莲到次年3月中旬左右开始腐烂并对湖泊水体产生一定污染,4月中旬左右达到高峰,到5月中旬左右污染影响明显下降.水质变化呈抛物线状,可划分为4个阶段.由于残体释放量与水体自净力之间存在此消彼长的关系,提高湖泊水体自净能力是降低冬季水生植物死亡污染水体的关键所在.