Porous Ceramic Filter Balls Combine With Submerged Plants Treatment For Phosphorus In The Sediments Of Eutrophic Lakes

As the external phosphorus obtains control effect, the internal phosphorus in the sediments migration into water by dissolution, diffusion, exchange. Thus it becomes an important source of maintaining eutrophic phosphorus pollution degree. Submerged plants have been used as an effective way to control phosphorus in the sediments. Porous ceramic filter balls also have certain adsorption effect on phosphorus in sediments. This experiment investigated the influencing factors of phosphorus release from the sediments andceramic filter balls removal phosphorus in the sediments, the effects of Vallisneria removal phosphorus in the sediments, and tried to combine Vallisneria with porous ceramic filter balls to enhance removal efficiency.(1)Sediment sample is collected from Small south lake of the West Lake in Hangzhou, the particle size distribution shows that the sediments have the ability to adsorb pollutants and resuspension ability is strong. The total phosphorus(TP) in sediments is 1423mg/kg, and inorganic phosphorus makes up 80.49% of TP, the content of Ca-P and Fe/Al-P in IP basically equivalent, the phosphorus in the sediments exists great potential release.(2)Compared with the overlying water is distilled water, the phosphorus relase in the sediments are less when overlying water is from the real lake. Illumination has an inhibitory effect on phosphorus release from the sediments. The minimum amout of TP, OP release appears in the vicinity of the p H=8.0, acidic condition inhibit the Fe/Al-P release, alkaline condition inhibit the Ca-P release. Phosphorus release amount of dynamic process is 1.61 times higher than the static process, and the equilibrium time is much shorter. Phosphorus release amount of 20? is minimum of 10?, 20?, 30?, and when the temperature is 10?, conversion part of the Fe/Al-P to Ca-P.(3)The equilibrium time of poprous ceramic filter balls dynamic adsorption process is 12 h. When the sediment is 5g, the best dosage of ceramic filter ball is 8g. The temperature is 50?, the amount of TP reduction was the largest, the presence of Fe/Al-P transfer to Ca-P at this stage. As the p H increased, the reduction amount of TP and IP performance in the shape of “U”, the reduction of Fe/Al-P increasd, Ca-P reduction decreased. In the static release process, Adding ceramic filter balls in addition to the sediment Ca-P increased, reduction of the others phosphorus forms in the sediments significantly increased overall.(4)In vallisneria group, vallisneria has limited effect on removal phosphorus in sediments. 5cm ceramic filter balls goup has certain removal effect on all the forms of phosphorus in the sediments, the removal efficiency of OP, Fe/Al-P is more significant, the removal effect of Ca-P compared to be poorer. Compared different combined group(vallisneria- ceramic filter balls group), removal effect of vallisneria-5cm ceramic filter balls goup is the best, compared with vallisneria-2cm ceramic filter balls goup which ranked second, the reducing rate of TP, OP, IP, Fe/Al-P, Ca-P respectively increased 16.14%?27.53%?13.08%?44.88%?-17.80%.On the other hand, if we make a simple sum of vallisneria goup and 5cm ceramic filter balls goup in reduction, the redctions of vallisneria- 5cm ceramic filter balls group in TP, OP, IP, Fe/Al-P, Ca-P are 2.32, 3.36, 1.93, 1.74, 4.39 times of it. Therefore, it may be considered there is mutual promotion between vallisneria and ceramic filter balls in the removal process of phosphorus in the sediments.