Development Of Submerged Ecological Bed And Its Application In The Water Purification Of River Course

In recent years,the eutrophication of water bodies lead to the deterioration of water environment and decline of water transparency.Compared with other purification technology of water quality,the purification technology by submerged plant is better,with good purifying effect,low operating cost and no secondary pollution to the environment.This paper intends to solve the following problems:First: Solve the effect of the purification technology by submerged plant due to the decline of water transparency caused by the eutrophication of water bodies.Second: Development of a new type of submerged ecological bed,to improve the problems in existing technology,such as undesirability in the material selection,unreasonable of the structure and the way of water level control is too much trouble.Third: Research the purification effect by different kinds of submerged plant,and the combination of floating ecological bed and submerged bed with artificial aquatic mat.To provide theoretical basis and technical support for the water quality purification technology by submerged plant.The main conclusions are as follows:We researched and developed a new type of submerged ecological bed with double positioning independently,the frame of the submerged ecological bed was made of UPVC which is corrosion-resistance material with high strength,low cost,and no secondary pollution.With the aid of buoyancy,the equipment adjusted the Niche of submerged plant in the light compensation depth of vertical space in water,which was used to solve the limitation on the growth of submerged plant caused by the water transparency in the process of water remediation,at the same time avoided the phenomenon of photoinhibition.On this basis,we independently researched and developed a purification equipment of water quality which combination of submerged ecological bed and floating ecological bed and biofilm technology.It simulated the environment of natural water body utmost,and conducive to the recovery of ecological community in the water.After combination,the spatial arrangement and the application scope of submerged ecological bed were greatly expanded,it's conducive to the promotion of this purification technology of water quality in urban river.The string artificial plant was chose to be used in the barricading test for three months in HaiTai north-south River.The purpose of this barricading test was to observe the status and the purification ability of three kinds of submerged plant(Ceratophyllum demersum,Myriophyllum spicatum and Potamogeton pectinatus).During the test,the Myriophyllum spicatum and the Potamogeton pectinatus grew well,however the Ceratophyllum demersum declined and decomposed very soon.Myriophyllum spicatum showed the best removal effect of TN,the removal rate was 42.9%.Removal rates of TP in each treatment groups were more than 70.0%.And the removal rates of chlorophyll-a were over 88.9%,the strongest allelopathic effects on algae growth was Ceratophyllum demersum.Compared with the single string artificial plant,the combination of Ceratophyllum demersum and string artificial plant had a faster speed of bioflom attachment,and the biomass was bigger.Submerged plant(Ceratophyllum demersum,Myriophyllum spicatum and Potamogeton pectinatus),emerged plant(Canna,Acorus calamus,Lythrum salicaria)and string artificial plant were used in the ecological submerged bed-coupling the floating bed and then put it in JiZhuangZi Demonstration River.The plants planted in July,and then the plants grew well after a month.The changes of water quality were monitored from June to October.The results showed that the water quality of JiZhuangZi River was in the condition of moderate to severe eutrophication.During the unrainy season,nitrogen and phosphorus mainly existed as particulate nitrogen and phosphorus.In the rainy season,the water quality was poorer,the concentrations of total dissolved nitrogen and total dissolved phosphorus were higher.The main pollution source of JiZhuangZi River was the reverse flow from the river after the ZhongShiYou Bridge(1400 m).During the period of stable operation,the concentration of pollutants reduced from 1400 m to 600 m in the river.The removal rates of TN,nitrate nitrogen,TP and soluble orthophosphate were 39.4%,72.1%,39.4% and 72.1%,respectively.The concentrated rainfall in early September was 203.4 mm,caused the deterioration of water quality indicators.The black and smelly sludge discharged from the outfall impeded the photosynthesis process of submerged plants.Therefore,we should set prefiltering link before the submerged ecological bed in practical engineering.