Experiment and Application of Freeze Purification Process in Pastoral Area for Drinking Water Safety

It is concluded that freeze concentration can remove most salinity, ammonia nitrogen and chemical oxygen demand (COD) from water in the Wuliangsuhai Lake, which is a grassland lake in Inner Mongolia, through freezing experiment. The removal rate of salinity, ammonia nitrogen and COD can be respectively up to 75%, 93% and 97% through single, secondary and three times freeze concentration. The removal rate increases firstly and then decreases as ice thickened. With the rate of area and depth of container increasing, the removal rate decreases, however, the growth rate of ice increases. So 16.00 cm(2)/cm is selected as the best rate in this experiment. The result shows that freeze purification process can be used easily and widely in Pastoral area that is rich in cold energy, wind energy and solar energy. This process has low cost, low energy consumption and no pollution, which can provide reference for drinking water safety in Pastoral area.