Experimental Study And Design On Ecological Floating Bed For Water Purification

It is a focus to utilize plants for improving water environment at ecological remediation, which plays an important role at purifying water quality and beautifying surroundings. On the basis of existing plant resources in the area of Zhenjiang, this paper first makes an test research about purifying wastewater with vegetation which have been more worth enjoying and more economic in the land, such as Canna, Vetiveria, Coleusblumeihybr, Catharanthus, Oryza, Petunia, Melampodium and Tagetes. With the form of floating bed, it designs a static test about purifying water quality using plants selected, and preliminarily researches the function of plant root system. It also discusses about designing and applying of floating bed according to actual water quality of river. The result indicates:Melampodium and Tagetes are unsuitable to grow among sewage, but other six plant can grow normally. Weights of all plants have certain growth when reaped. Canna and Vetiveria production capacity are best among six plants, which their biomass increase 1515g and 1119.5g respectively; Petunia is the worst, only 46.6g.From the static test, results indicate that six kinds of plants system have effect on purifying water quality, which pH value is to drop, dissolves oxygen concentration is to increase, TN, NH₃-N, TP and COD concentration notably drop in water. Plant systems average efficiency of removal total nitrogen and total phosphorus are up to 51.7%～93.8% and 53.7%～93.8% respectively, which get rid of pollutants in water to a great extent; COD removal efficiency is 54.9%～87.1% in plants system because of sedimentation, assimilation and degradability; but NH₃-N removal efficiency is only 58.5%～69.5% which has great disparity compared with other tests, and there will be deep analysis. Meanwhile, the removal of nitrogen and phosphorus has relations with plants growth in water. The removal effect is remarkable when growing stage, while worse when maturing stage. The result is Vetiveria, Canna, Coleusblumeihybr, Oryza, Catharanthus and Petunia, from the first to the last, according to comprehensive appraisal of six kinds of plants purification capability.From root restoring oxygen test, advanced terraneous plants can come into being aerenchyma and adventitious roots under hypoxia environments, supply oxygen to roots and form root region effects which accelerates pollutant removal in water body.There has comprehensive evaluation on purification water of six kinds of plants through purification ability, resisting adversity, management, economic value and beautifying. On the basis of static test data, from best to worst, the result is Vetiveria, Canna, Coleusblumeihybr, Catharanthus, Oryza and Petunia.