利用水生植物净化河涌污水能力的比较研究

Comparative study on the ability which utilized hydrophytes purify polluted water of river

关键词:  水生植物  污染水体  净化  水质改善

Key words:  hydrophytes  polluted water  purify  water quality improvement

摘要:

以8种水生植物为材料,在单一、复合种植的组合条件下,对污染物的去除效率及各植物的生长发育状况进行研究。结果表明:总磷、总氮、氨氮、浊度等水质指标的去除速率随着处理时间延长而逐渐升高,而COD_Mn的去除效果为开始较高,然后有所降低,后期又提高的波动现象。整体上除个别植物种类外,所有组合单元的处理效果均优于对照。经过植物净化处理,原污水的TP含量约为重污染水Ⅴ类水的4倍、TN含量为Ⅴ类水的5～6倍、水中上述污染物有30%～33.3%的种植组合达到Ⅲ类水的水平,其中20%～25%的组合达到了Ⅱ类水的水平。其他20%～30%的种植组合能使TP、TN污染物含量减少2～3倍,污染水水质相当或接近于Ⅴ类水的水平。原污水氨氮含量为Ⅴ类水的6～7倍,经过植物各组合的处理,58.3%组合的水平在Ⅲ类水以上,其中50%的组合达到Ⅱ类水的水平。其他约35%的组合使氨氮含量减少4～5倍,接近Ⅴ类水的水平。在植物形态学指标方面,除个别大薸单元出现负增长及植株坏死外,其余植物根、茎、叶有一定增长,表明植物能适应这样的污水而生长; 植物复合种植比单一种植单元的处理表现出更高的净化水平及稳定性,应得到重视; 挺水植物比漂浮植物和沉水植物的净化能力强,在水处理实践中可优先考虑。

Abstract:

The paper explored the purify effects to polluted water on 8 hydrophytes:Acorus calamus,Phragmites australis,Pistia stratiotes,Canna indica,Hydrocotyle vulgaris,Alternanthera bettzickiana,Eichhornia crassipes and Myriophyllum verticillatum,they were setted up for tow groups which were cultivated in pollution water with single species and several species compound planting,and then formed 12 planting units,thereby carried out the comparative study on these hydrophytes purify ability to pollutants of river and compared the removal efficiency and the situation of growth and development. Two groups treatments all had the purification ability to pollutants,with the time extension,the purified efficiency rise gradually to total phosphorus(TP),total nitrogen(TN),ammonia nitrogen(NH₃-N)and turbidity; the removal efficiency of COD_Mn showed that in the initiate period it was higher,then the efficiency had a little drop,and rise again,reached a high purifying efficiency. In all treaments,about 30%-33.3% treatments made the primary polluted water which TP content was 4 times and TN content was 5-6 times as that of Ⅴ grade water reached Ⅲ grade water level,among 20%-25% of them reached Ⅱ grade water level; other treaments,about 20%-30% made TP,TN content dropped 2-3 times,so that the polluted water reached Ⅴgrade or nearⅤgrade water level. In aspect of ammonia nitrogen content,passed through plants purification,the 58.3% planting units(treaments)had made the polluted water that ammonia nitrogen content was 6-7 times as that of Ⅴgrade water reached Ⅲ grade water level,among of them,about 50% planting units reached Ⅱ grade water level; other about 35% units were purified to approach Ⅴgrade water level. Seen the efficiency in whole,except of exceptional species,the purification efficiency of all group treatments were higher than contrast. In the respect of plant morphology,except of Pistia stratiotes presented some leaves lose,their root,stem and leaves of other plants were increase,showed that these plants adapt to these pollution water. The purification level and effect showed that compound species planting were better and more stable than single species planting,the purification ability of emerged aquatic plants were stronger than floating plants and submerged plants. The research results shall provide the theoretical foundation and reference for establishing the hydrophytes communities which is strong ability to purify pollutants,the landscape effect is better and the structures is stable.