两种降低原水pH控制出厂水铝含量的生产试验

Two Productive Experiments to Reduce pH for Raw Water and Control Aluminum Content in Finished Water of WTP

针对西江季节性pH偏高导致QL水厂的出厂水铝超标风险增大的问题,中山开展了两种降低原水pH控制出厂水余铝的生产性试验。试验结果表明,用酸性混凝剂硫酸铝需投加55 mg/L以上才能使出厂水余铝稳定达标,但混凝效果不佳且滤池反冲洗周期缩短,药剂成本为0.036元/m^(3);投加CO_(2)调节pH控铝技术,有效降低原水pH,出厂水余铝稳定达标,投加2 mg/L CO_(2),原水pH值从8.6下降到8.0,可保持出厂水浑浊度小于0.2 NTU,余铝质量浓度小于0.2 mg/L,药剂成本为0.028元/m^(3)。应用于应急预警分级得出,当pH值>8.0,必须投加CO_(2)。

In view of the problem that the seasonal pH of Xijiang River leads to the increase risk of aluminum in the finished water of QL water treatment plant(WTP),Zhongshan carried out two productive experiments to reduce the pH of raw water and control the residual aluminum in the finished water.The test results showed that the acid flocculant such as aluminum sulfate needed to be added more than 55 mg/L in order to make the finished water residual aluminum stable up to the standard,but the coagulation effect was not good,the filter backwashing cycle was shortened,and the cost of the agent was 0.036 yuan/m.Compared with the acidic flocculant pH adjustment,the addition of CO_(2)to adjust pH and to control aluminum technology could effectively reduce the pH value of the raw water,and the residual aluminum of the finished water was stable up to standard.As adding 2 mg/L CO_(2),the pH value of the raw water decreased from 8.6 to 8.0,and the turbidity of the factory water was maintained below 0.2 NTU,and the residual aluminum mass concentration was less than 0.2 mg/L,and the cost of the agent was 0.028 yuan/m^(3).The technology can be applied to the grading of emergency warning that CO_(2)must be added when the pH value is higher than 8.0.