Research Of Removal Of Phosphorus With Biological Modified Materials Change Eutrophic Water Ecosystem State

This work is based on the global water problem as the research background and carrys out the relevant experiments from the key factor "P" of eutrophication in water pollution. In the process of experiments of phosphorus removal and control in water, using mussel shells as based material to discuss about the best modified methods including the best modified temperature and time, and also discuss upon the equipment needed for making modified materials. At the same time to explore the environment function of modified mussel shells, such as the purification function to eutrophication of water, as well as the change of ecological system process when phosphorus has been removed from natural water.As the results show, modified mussel shells are good at removing TP in the polluted water after modification in 750℃,800℃,850℃ for 1 hour, and removal rate of TP remains above 99% in 30 mg/L KH2PO4, and compared with the modified mussel shells under low temperature including 650℃ and 700 ℃,the total phosphorus removal rate is about 88%. So considering the consumption of energy of calcining mussel shells in muffle, the best condition of modification is to calcine under 750℃ for one hour. Modified mussel shells powder purifies the polluted water in 30-40 minutes approaching the greatest TP effect.In the same modified coditions- calcined under 750℃ for one hour, oysters and scallops also matain such fabulous ability of water purification. This proves that the modified condition could be deceloped. The capacity of mussel shells in phosphorus removal,3-15 g mussel shells could use 7-12 times to deal with the polluted water, and the largest amount of phosphorus mass between 596-722 mg. When changing the way of putting modified mussel shells into the water, the using times of 3-15 g material getting to 8-12 times and the maximum removal mass is up to 687-743 mg.When putting the modified marerial into the eutrophicated water, TP would decrease with the increasing mass of that marerial. At the initial phase, the TP could decrease between 80%-92%, however TN may also decrease for 50%. The pH of water is getting high, staying at 8.8 to 12.5. And the content of chlorophyll would also reduce from 120μg/L to 50-108μg/L. Verified by the environment, when the mass of TP and chlorophyll fall to the first class of water quality standards in our country, the polluted water transforms from turbid state to the clear state. The dosing quantity of mussel shells powder of 7 g is capable to make the water ecological system state change.