Study On The Impact Of Thermal Discharge From Power Plant On Phytoplankton Based On Hydrodynamic Conditions Xiangshan Bay

In recent years, with the continued development of the national economy, thedemand for electricity sharp rise in coastal electrical energy to further tension. In orderto fully meet the large demand for power plant cooling water, a growing number oflarge coastal thermal (nuclear) power plants gradually built and put into operation totake advantage of sea water as cooling water. In the process of plant operation, coolingwater and the waste heat discharged into the surrounding waters, forming thermaldischarge, with the characteristics of large quantity of heat. Discharge water spreadingto around seawaterfollowed by the thermal discharge from the outfall, while theinfluence aereof thermal pollution is the most widely. Studies have shown thattemperature of thermal discharge was7centigradeto10centigradehigher than theseawater usually.Especially in the summer sea natural water temperature is high,combined with the warm drainage caused by coastal power plants around the unusualincrease in ocean water temperature, water temperature is much higher than thetemperature suitable for survival of marine organisms, resulting in the death of manymarine organisms.Weakest activity of phytoplankton, which is the food of zooplanktonand benthic organisms.The impact of phytoplankton is bound to impact the growth andreproduction of these organisms.At present, the impact on ecological environmentcaused by thermal discharge from coastal power plant has been growing concern, butthe existing qualitative researchsare insufficient to support supervision and managementof thermal discharge. Therefore, quantitative analysis of the impact of the thermalpollution on phytoplankton of thermal discharge from coastal power plant, to providedatasupport for the ecological compensation of the thermal discharge,and providetheoretical basis to relevant departments for the supervision and management of the coastal power planthas great significance.Consider the diffusion of the thermal discharge by the hydrodynamic conditions,the numerical calculation of hydrodynamic and offshore enclosure experiment wereused, combined with the dynamic conditions of sea water, to study temperaturedistribution characteristics and the impact on the surrounding phytoplankton of thethermal discharge quantitatively. The specific contents and conclusions include:(1) Xiangshan Guohua Ninghai Power Plant was analyzed and researchedas anexample. The backgroundenvironmentof the waters nearby the power plantbeforeopreationwas analyzed.Itwas shown that the distribution of the water temperature ismore uniform surrounding before the plant began working. Water temperature of the seaarea is basically the same.There is no local high temperature. The average of basicsurface water temperature maintained at30.0to31.0centigrade. The average of bottomwater temperature is basically maintained at29.0to30.4centigrade. The inside of baywater temperature is higher than the outside of the bay. The coastal water temperature ishigher than the offshore trend.(2) With three dimensional diffusion model FVCOM model, the temperaturedistribution of thermal discharge nearby the power plant was analyzed to determinetemperature envelope distribution and estimate the different temperaturel gradientdiffusion aresa of the thermal discharge in the summer of2011. Thermal dischargedistribution is characterized as follows. It tend to spread to the inner bay at high tide,while tend to spread outside bay at low tide. The surface temperature is generally higherthan the bottom.The area of the surface temperature diffusion is greater than the bottom.The surface thermal discharge was mainly within the1.5centigradewarming envelope,while the bottom is mainly distributed in1centigrade warming envelope. The areasbetween0.8and1centigrade warming envelope of surface and bottom were closer.Thearea of higher than1centigrade warming envelope of surface was more thanthe bottom.Thermal discharge of strong temperature more than2centigrade was mainly distributedin the surface.(3) The SPSS19.0software was used toanalysethe data of enclosure experimentlast for7days in summer of2011.And the response relation of thermal dischargewarming andCoscinodiscus Jonesianusbiomass was analyzed quantitatively. The results show that, when the temperature risingbetween0.2and0.8centigrade,itwouldpromoteCoscinodiscus Jonesianus growth and reproduction, while thetemperature risingbetween0.8and2centigrade, whichwill restrain. And the loss ofCoscinodiscus Jonesianus biomasscaused by thermal discharge in different gradient oftemperature warming was calculated quantitatively. The water temperature of1.0,1.5and2.0centigrade, Coscinodiscus Jonesianus biomass were reduced by6.38%,17.95%and26.17%. The projections of biomass above2centigrade temperature rise, the watertemperature increased3and4centigrade and above, biomass decreased by37.73%and57.51%.(4) Combination of hydrodynamic conditions, analysis of the numerical results, thevolume of influenced waters in summer near Xiangshan Bay Power Plant was estimate.And enclosure experiment data was statistical analyzed.The thermal discharge resultingin0.8℃,1℃,1.5℃,2℃and above strong temperature risein the summer from powerplant was calculated. Respectively, resulting in Coscinodiscus Jonesianusbiomass730.1886billion cells,2120.6280billion cells,236.0593billion cells, and463.8480billion cells, with a total of3550.7237cells. Provide a basis for relevantdepartments to supervision and management on the thermal discharge from coastalpower plant as well as ecological compensation.