The Research Of The Main Physical And Chemical Characteristics Of Modern Sediment In Dianchi Lake

Dianchi Lake is famous plateau fresh water lake in China, the water pollution of Dianchi Lake is very serious, the nitrogen, phosphorus exceed standard seriously, the water body is serious in eutrophication. For this reason, the pollution control of Dianchi Lake was listed as one of the key national " three rivers and three lakes" control projects during" the Ninth Five-Year Plan".The sediment has an important effect on eutrophication process of lake as the interior load source of nutriment of lake. The sediment of Dianchi Lake of eutrophication is abundant. Though having taken some sorts of control measures for many years, the eutrophication of Dianchi Lake has not received effective control. "Algal Bloom" appears in large range for long time, especially the open lake of Dianchi Lake. So the effect of eutrophication of Dianchi Lake of sediment can't be ignored.Based on the research of modern sediemnt of Dianchi Lake, the thesis is concerned about some physical and chemical characteristics(including magnetic susceptibility, ammoniac nitrogen and effective phosphprus etc.) and thermodynamics analysis of spontaneous mineral of iron. The research indicates that the modern sediment is divided three layers: polluted layer,transition zone and unpolluted layer. Just the pollute layer cause Dianchi Lake environmental pollution. The high value district of ammoniac nitrogen distributes near northern part Haigeng mainly, middle part increase slightly, have most lower near southern part, the content of ammoniac nitrogen of the polluted layer sediment lower than the lower layer; the high value district of effective phosphorus distributes near Haikou-Jinning, from the north to the south, the content of effective phosphorus increases progressively, the content of effective phosphorus of the polluted layer sediment obviously higher than the lower layer. The magnetic susceptibility of Dianchi lake modern sediment decreases progressively from the edge to the middle of the lake, distributes with the heavymineral of sediment basically unanimous, increases along with the degree of depth, negatively correlates with the total phosphorus.According to the thermodynamics analysis of spontaneous mineral of iron, we assumed: when sewage disposal, if sulphur is eliminated prior, this makes the consistency of iron's ion keep high relatively, it will react with phosphorus, produce heterosite, vivianite precipitate. This will decrease the interior load of the phosphorus in sediment, and reduce the consistency of the phosphorus in the Dianchi Lake.The control of lake eutrophication is a urgent task that is very important and complicated. The control of interior pollution should be paid attention while strengthening the control of outer pollution.