Study On Purification Ability Of Hydrophytes To Domestic Sewage In City

The five indexes(TP, TN, COD_cr, DO and BOD₅) under three concentration levels of domestic sewage(CODcr50-60mg/L, 150-180mg/L and 350-400mg/L) were set to compare purification ability of 12 different hydrophytes(Cyperus alternifolius L.,Arundo donax L., Zizania caduciflora (Turca.) Hand-Mazz, Typha orientalis Presl, Scirpus triqueter L., Acorus calamus L., Zantedeschia Aethiopica (L.) Spreng, Eichhornia crassipes (Mart.) Solms, Nymphaea tetragona Georgi, Pistia stratiotes L., Spirodela polyrhiza (L.) Schleid and Ceratophyllum demersum L.); Study the recycle feasibility of depurated sewage in waterscape; Discuss the correlation between the content of proline, MDA in frond and the reaction as plants in adversity; Summarize the mode of plant arrangement in sewage recycle which can give attention to purification effect and landscape. The results indicated:1. The purification ability of hydrophytesAll the twelve hydrophytes showed good purification effect. In 10ds, TP, TN, CODcr, BOD₅ were purified and DO increased obviously under three concentration levels of sewage, and the longer the time prolonged the higher the rate of purified was. Eichhornia crassipes (Mart.) Solms, Pistia stratiotes L., Nymphaea tetragona Georgi, Spirodela polyrhiza (L.) Schleid and Zantedeschia Aethiopica (L.) Spreng reprented excellent purified effect all the time under three concentration levels of sewage, so they can be important plants in application; Acorus calamus L., Scirpus triquetex L. and Ceratophyllum demersum L. didn't show purge ascendant and can't be used in sewage purge.Taking purge rate and purge speed into account, Spirodela polyrhiza (L.) Schleid, Eichhornia crassipes (Mart.) Solms and Arundo donax L. showed best purge effect to TP; Eichhornia crassipes (Mart.) Solms and Nymphaea tetragona Georgi showed best purge effect to TN; Zantedeschia Aethiopica (L.) Spreng and Nymphaea tetragonaGeorgi showed best purge effect to CODcr; Zantedeschia Aethiopica (L.) Spreng, Pistia stratiotes L. and Nymphaea tetragona Georgi showed best purge effect to BOD5.2. Sewage recycle in waterscapeWith the purge effect of hydrophytes, not only the five matter(TP> TTSK CODo\ DO and BOD5) was depurated effectually both under low(CODcr50-60mg/L) and middling(CODcrl50-180mg/L) levels of sewage, but also the final contents touched the relational nation standard in sewage recycle, so the two kinds of sewage can be used in Sewage recycle into waterscape.3. Hydrophytes resistance in sewageThe content of proline and MAD reflects hydrophytes' resistance degree and carrying capacity in sewage. Spirodela polyrhiza (L.) Schleid) and Ceratophyllum demersum L. show weak carrying capacity; Arundo donax L., Zizania caduciflora (Turca.) Hand-Mazz, Acorus calamus L. and Pistia stratiotes L. represent carrying capacity of middle; Typha orientalis Presl, Scirpus triqueter L. and Nymphaea tetragona Georgi show stong carrying capacity. The carrying capacity of Cyperus alternifolius L., Zantedeschia Aethiopica (L.) Spreng and Eichhornia crassipes (Mart.) Solms should be studied more by other experiment.4. The mode of plant arrangmentWhen planting, the hydrophytes which showed excellent purification effect, such as Pistia stratiotes L., Zantedeschia,Aethiopica (L.) Spreng, Nymphaea tetragona Georgi, Spirodela polyrhiza (L.) Schleid and Eichhornia crassipes (Mart.) Solms, will be put in together or separately anteriorly to enhance purge speed of sewage. Kinds of float vegetation, submerged vegetation and emergent vegetation which showed good purification effect will be put in together medially to enhance purge rate, purge speed and incarnate biodiversity, plants landscape. Pistia stratiotes L., Zantedeschia,Aethiopica (L.) Spreng, Nymphaea tetragona Georgi, Spirodela polyrhiza (L.) Schleid and Eichhornia crassipes (Mart.) Solms will represent at the end to purify sewage ulteriorly. Finally, the sewage which has up to standard can be used in landscape.