Experimental Study On Mechanism Of Nutrient Release From Lake Polluted Sediment And Impact On Water Quality

Lake sediment,as the carrier of the pollutant,not only can absorb pollutant from the overlying water,meanwhile,can also release pollutant into water.Aim at the serious problem that lake sediment was polluted severely,to study release process of sediment nutrients and the effects of different environmental factors on the nutrient release regularity,to provide reliable basis for taking measures to keep water and sediment of lake healthy,this manuscript take static simulation experiment on release of sediment nutrients,change the pH?temperature and DO,and then get the influence of factors' changing on the release regularity,and study the release mechanism of nitrogen and phosphorus under different factors.The sediment samples are took from polluted area in Wuhan Moshui Lake,the forms and release influence of sediment nitrogen and phosphorus are analyzed,physical and chemical properties of sediment are also measured and analyzed,including moisture content,particle size distribution leaching liquid and Loss-on-Ignition,this manuscript respectively explores the release situation when the pH is 4,7,10 and temperature is 10?,20?,25? and dissolved oxygen is scarce,normal and enriched.The experiment found that the relationship between release of phosphorus and pH is like a parabola,release rate of phosphorus will increase under the acidic or alkaline environment,and the rate of nitrogen will decrease when pH increase,this regularity is mainly related to organic matter in the sediment.And the higher the temperature,nitrogen and phosphorus of sediment are more easy to release,besides,release rate will also increase,it is mainly associated with the metabolic activity of microorganisms.However,the rise of temperature effect on the release of phosphorus is slightly more noticeable than nitrogen.Under anaerobic conditions,nitrogen and phosphorus are easy to release from sediment,and the release rate is also bigger than other situations.Nutrients release from lake sediment is affected by many factors,the release process and rule will change because of the factors.Studying the release process of sediment nitrogen and phosphorus and the influence of environmental factors on release process,is conducive to understand nutrient circulation process on the surface of sediment-water,can also provide some scientific basises to deal with lake eutrophication and to maintain a better lake environment.