Enhanced Coagulation Reduce The Residual Aluminum In Drinking Water

The new national standard of aluminum for drinking water is 0.2mg/L, while the excess of aluminum harm to human beings, how to control the residual aluminum effectively in drinking water was crucial.This article study enhanced coagulation and filtration process on the impact of residual aluminum in drinking water.Focused on the enhanced coagulation process on the impact of residual aluminum in drinking water. Studies have shown that residual aluminum content in drinking water affect with raw water pH, and coagulation parameters (intensity of rapid mixing, rapid mixing time, slow stirring intensity, settling time, etc.). the impact laws of various factors on the residual aluminum water and the corresponding control measures were found by experiments.The experiment results indicated: we can effectively reduce residual aluminum in drinking water by controlling the coagulation conditions. The optimum coagulation conditions of reduce residual aluminum in drinking water is : the intensity of rapid mixing is 258.3S^-1, rapid mixing time is 2 minute, slow stirring intensity is 20.1S^-1, slow stirring time is 15 minute, settling time is 30 minute. In that condition there is the lowest amount of residual aluminum in drinking water; when the raw water pH is 6.5-7.5, there are the maximum amount of the formation of aluminum hydroxide and the lowest amount of residual aluminum in drinking water,and the coagulation is the best. In the filtration stage , the optimum filter thickness is 90cm. We can found that turbidity is not the key factor of filtration from the filtration time, the amount of aluminum hydroxide and aluminum hydrolysis in water are the key factor.