Research On Natural Freezing To Treat Hard-degradable Industrial Wastewater

As an energy-saving and environment-protecting wastewater treatment method, natural freezing makes use of rich natural cold energy in our northern region to solve the problems of water pollution and save energy. Recently, it has brought to the concerned scholar's attention. Natural freezing water treatment method does not need to add any chemical medicine and cause secondary pollution, it has features of simple process, easy operation, low cost and saving energy. And it has developed a new way for a water treatment technology.Based on the freezing concentration theory, hard-degradable industrial wastewater was taken as the object of study under the man-made natural climate environment. Two methods of with-stirring and without-stirring were used to analyze the separation efficiency. The industry wastewater was taken as the object of study. The experiment results showed that the ice sample can obviously divided into several layers after industrial wastewater was frozen. More than 80 percent of pollutants could be removed in the cleaned layer of the ice crystal in the way of without-stirring, while in the way of without-stirring more than 90 percent of pollutants could be removed in the cleaned layer of the ice crystal. Further, research on the influence of wastewater concentration and freezing temperature on the removal of pollutants under different ice product rate was carried out in the way of without-stirring. The result showed that increasing water concentration and lower freezing temperature will reduce the separation efficiency. And in the way of with-stirring research on the influence of wastewater concentration and stirring speed on the removal of pollutants under different ice product rate was carried out. The result showed that reducing water concentration and speeding up the stirring speed will reduce the separation efficiency. The effective way to improve the purity of ice was discussed include the way of eliminating subcooling degree, selecting suitable initial temperature, muti-stage freezing, pre-processing (filtering) and so on.In this article, a preliminary study on the natural freezing treatment of industrial wastewater was carried on. And it hopes that it can provide some reference for the future further research and application.