应对藻类污染时高pH原水的应急投加试验

Emergency dosing test of high pH raw water in response to algae bloom

藻类暴发会导致水体的pH值升高到8.0以上,造成投加聚合氯化铝的水厂出厂水中余铝含量升高,甚至超标。试验发现余铝含量与混凝沉淀后水体的pH值密切相关,为了将出厂水中余铝含量控制在较低水平,建议把混凝沉淀后的pH值控制在7.5左右。硫酸溶液、二氧化碳、硫酸铝都能有效调节北江原水pH值,均可用于发生藻类污染时应对高pH原水的应急投加。

Algae bloom will cause the pH value of the water body to rise above 8.0, resulting in the increase of residual aluminum content in the treated water of the waterworks with polyaluminium chloride(PAC) as coagulant, or even exceeding the standard. It is found that the residual aluminum content is closely related to the pH value after coagulation and sedimentation. In order to control the residual aluminum content at a low level, it is recommended to control the pH value after coagulation and sedimentation at about 7.5. Sulfuric acid solution, carbon dioxide and aluminum sulfate could effectively adjust the pH value of the Beijiang River raw water, and could be used for the emergency dosing of high pH raw water in case of algae bloom.