| As a traditional technology of improving eutrophic water, bio-floating bed technology, with no environmental risk and secondary pollution, has advantage on removing water pollutants directly, making full use of the water without occupying land, adapting to a wide range of water depth, and low cost, easier operating and managing. It has broad prospect on practical application.In this paper, we chose two cold-resistant floating bed plants to study——Iris Pseudacorus L.a?nd Siberian Iris, Canna indica was comparative part. The paper's main contents as follows: (1) bio-floating bed Planting Patterns; (2) Contrast studies on floating bed plants'effect on eutrophic water; (3)the adapt ability of floating bed plants to organic pollutants and pH value in water; (4) floating bed plants'growth characteristis and management.This study developed a new type of planting device, which composed of floating body,planting basket,floating bed plant,filler,artificial plants and fixture. The floating body included floating board and floating block. The buoyancy of floating board should slightly smaller than the weight summation of floating board,planting basket,filler and artificial plants. The buoyancy of floating body should greater than the weight summation of floating body,planting basket,filler,artificial plants and 1.5 times of floating bed plant weight, in order to guarantee floating board under the water, remove the artificial marks, forming a natural landscape picture. The floating board and floating block were made of foam reinforcement composite material. It improved strength and durability, and making simple and cheap. Planting basket combine filler were more reliable; what's more, bio-film could degradation of nitrogen and organic pollutants in water. The artificial plant chose Polyvinyl alcohol-formaldehyde-based wire as material, used run-in form fixed different from traditional way, it reduced wire mutual twining and raised wire suspension density, and it was more favorable for the growth of bio-film adhesion as well. Iris Pseudacorus L. improved the water quality throughout 8 months (from Apr. to Nov.), Canna indica improved the water quality throughout 11 months (from Feb. to Dec.), and the time of water quality improvement of ?Siberian Iris throughout 5 months (from Jul. to Nov.). The three kinds of plants and artificial plant all produced the effect on remove TP, their average removal rates of TP were in the following order: Iris Pseudacorus L. (86.92mg/(m2.d))>Canna indica(36.60mg/(m2.d)>artificial plant(33.91mg/(m2.d))> Siberian Iris(24.91mg/(m2.d)). The annual remove grosses of TP were in the following order: Iris Pseudacorus L.(? 21207.64mg/(m2.y))> artificial plant(12376.80mg/(m2.y))>Siberian Iris(8318.93mg/(m2.y))> Canna indica(5599.17mg/(m2.y)). Their average removal rates of TN were in the following order: Iris Pseudacorus L. (763.79mg(/m2.d))> Canna indica(384.04mg(/m2.d)), > Siberian Iris(301.81mg/(m2.d))> artificial plant(221.16mg/(m2.d)). The annual remove grosses of TN were in the following order: Iris Pseudacorus L.1?86365.78mg/(m2.y)>Siberian Iri(s100805.43mg(/m2.y))> artificial plan(t80724.82mg(/m2.y)), and Canna indica(58758.69mg/(m2.y)).The absorption of TP, TN with the abovewater of Iris Pseudacorus L., Canna indica and Siberian Iris to occupy system of removing proportion are 44.79%, 31.01%, 38.17% and 23.66%, 21.28%, 12.89%respectively. The absorption of TP, TN with the underwater of Iris Pseudacorus L., Canna indica and Siberian Iris to occupy system of removing proportion are 6.02%,3.68%, 2.51%and 1.34%, 0.26%,0.19%respectively. Therefore, floating bed plants play a important role in remove nitrogen and phosphorus in eutrophic water. This study shows that nitrogen and phosphorus mainly accumulation in plants'abovewater part, so we can remove most of nitrogen and phosphorus in water through reaping plants'abovewater part.Iris Pseudacorus L has the Stronger adapt ability of organic pollutants and pH value in water, Iris Pseudacorus L c?ould grow when CODMn≤40mg/L and 5≤pH≤9 in water. And when CODMn≤20mg/L in water, Iris Pseudacorus L grows very well. After comprehensive compared four kinds of floating bed plants, it showed that Iris Pseudacorus L h?as the best effect on removing water pollutants, keeping the water clean for a long time, it was semi-evergreen plants, only need once transplant, and harvested an annual, natural germination, life-long growth, easy management, so considering sustainable use, we suggested that choosing Iris Pseudacorus L as the main plant to improve water quality. Secondly, Siberian Iris is evergreen, the workload of management is not arduous, and had good landscape effect, so we recommended that choosing Siberian Iris decorative plant of landscape floating bed plants. Finally, no matter the effect on removing pollutants or management, Canna indica w?as both worse than Iris Pseudacorus L a?nd ?Siberian Iris ?s?o we don't recommend it. |
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