Study On Transport And Diffusion Of Concentrated And Heated Brine Discharge Into The Sea

Desalination of seawater is becoming an effective way to solve the lack of water resource, but it also lead to adverse environmental effects because of its heated brine discharge. In order to research the influence of the discharge from the desalination plant, software (MIKE) is applied to simulate the transport and diffusion of the concentrated and heated brine discharged from the desalination plant into coastal water and predict the diffusion process of heated brine influenced by currents, monsoon and wave. The main conclusions in the dissertation are as follows:(1) MIKE is applied to hydraulic modeling in Koge Bay in Denmark, the results of numerical modeling are consistent with the observed data, it can be used in simulating research of marine hydrodynamic characteristics.(2) According to the simulation of the concentrated and heated brine discharge in Koge Bay, if the discharge of heated brine is one million tons per day, the salinity and temperature changed periodically in a way and the temperature is similar to the salinity. The discharge of one million tons per day heated brine will only lead to the rise of salinity and temperature in the outlet area significantly. In contrast, it has no influence on the rest of the water in the bay.(3) Adopt the3-D model to simulate the heated brine discharged into ideal flume, the current plays an important role in the diffusion of heated brine. The temperature and the salinity present periodic characteristic subjected to the actions of current. In vertical directions, the depth-averaged velocity decreases with the depth increases, on the contrary, the temperature and salinity increases with the depth increases and the surface rises less, the bottom rises more.(4) The simulation of heated brine discharged from a desalination plant situated on the western coast of Bohai Bay under pure tidal currents and the combined action of wave and currents indicates that if the discharged of heated brine is one million tons per day, it will mainly effect the area which maximum distance from the outlet is6.27km and most of the waters will not be affected. The current plays a major role in the diffusion of heated brine discharged by the coastal area but wave has little effect on the diffusion of heated brine.