| By using biological and ecological restoration technology which included aquatic plants, artificial floating island and ecological riverbank technology, doing experiment indoor and outdoor is to explore the dynamic characteristics of complex biological systems and the purification function of wastewater quality. At the same time of improving water quality, it can recovery the river’s ecosystem and increase species diversity. Researching above three kinds of phytoremediation technology qualitatively and quantitatively results the following conclusion.In order to study on purification effect of Artificial floating island (AFI) on urban landscape water, the experiment is conducted respectively in laboratory and outdoor pool in Dalian with canna indica loaded on the AFI. Water samples for laboratory testing, observation, analysis and research, the results show that AFI has obvious effects on water purification, in laboratory the removal rate of TN, TP and COD were91.35%,45.46%and56.49%respectively; outdoor the removal rate of TN, TP and COD were55.24%,84.33%and24.25%respectively. The experimental results prove that urban landscape water treatment by AFI has broad application prospects.The plant ecological restoration measures are taken to impact water quality within the area of reservoir. Compared with the water quality before the implementation of engineering, DO not produce major changes. Transparency has significantly increased. Total nitrogen removal rate was21.7%. Ammonia nitrogen concentration was as same as before. Nitrate nitrogen concentration was reduced by42.67%. Total phosphorus removal rate was60%. COD removal rate was61%. BOD5concentration almost did not change. Heavy metal such as mercury, cadmium and chromium all can reach monitoring lower limit after the project. Others, such as petroleum, volatile phenol and cyanide, all have different degrees of decline. Reservoir area’s temperature has great changes all the year round, so it has certain influence on the water quality. DO, transparency, nitrogen and chlorophyll have larger fluctuation than others according to different seasons. And COD and phosphorus almost have no changes. At the same time, trees, flowers and birds etc within the reservoir area constitute the wetland scenery and the harmony of man and nature.Plants combined with three-dimensional geotechnical biological gauze pad technology used to protect sand embankment test section. These plants should have characteristics of drought resistance, cold resistance, alkali resistance and barren resistance. Based on the effect observation of biological soil and water conservation before and after planting, planting surface coverage can reach80%-93%after six months, the soil erosion decrease from3200t.km-2.a-1to200～634t.km-2.a-1, and the project has obvious effect on keeping interception of rainfall infiltration. According to the measures of the effect of soil improvement, after planting one year, available nitrogen increased by0.04mg/kg, available phosphorus increased by0.03mg/kg, potassium increased by0.02mg/kg. organic matter content also have little improvement. Through the experimental comparison, three-dimensional geotechnical biological gauze pad technology’s effect is better, it has stronger persistence, higher rate of grass growth and more coverage rate compared with the slope without a net. But from the point of reducing the project cost, it can be taken in some area where soil and water loss seriously, instead of traditional slope protection methods. |
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