Experimental Study On Cavitation Degradation Of Water Supply Micro-pollutants Humic Acid By Centrifugal Pump

As a typical drinking water source of micro-contaminated organic matter,humic acid is widely present in natural waters.Once the humic acid content of the water purification plant exceeds the standard,in the chlorination process after the raw water enters the water purification plant,HA reacts easily with chlorine to produce chlorination by-products DBPs,trihalomethanes,carcinogens THMs and MX(strong Mutagenic disinfection by-products).The physical and chemical properties of HA are very stable and it is difficult to be degraded by the conventional treatment process of the water purification plant.Based on experimental research,the paper determines the effect of centrifugal pump hydraulic cavitation degradation of HA,centrifugal pump structural parameters and operation control parameters,and provides technical support for the structural design of centrifugal pump hydraulic cavitation device.The centrifugal pump model used in the test was SG32200.The effects of the number of centrifugal pump blades,flow rate,water pH,initial concentration of HA and cycle time were studied.The main research contents include:(1)Centrifugal pump flow rate,water pH value,initial pH concentration and cycle time are certain.The number of blades of the centrifugal pump is 4 pieces,6 pieces,8 pieces and 10 pieces,respectively.The effect of the effect determines the optimal number of blades.(2)Control the flow rate by controlling the front valve of the pump.The low flow rate points are 1.0、1.2、1.4、1.6、and 1.8 m/s,respectively,and the high flow rate nodes are 2.5、3.0、3.5、and 4.0 m/s,respectively.The cycle time,the initial concentration of HA,and the number of centrifugal pump blades were fixed.The oxidation reagent was not added,and the influence of the flow rate on the degradation effect of HA was analyzed to determine the optimum flow rate.(3)For the optimal number of leaves n and the optimum flow rate,the initial concentration of HA was 5.0、6.0、7.0、8.0、9.0、10.0 mg/L,and the concentration degradation test was carried out to determine the optimal initial concentration of HA.(4)The pH control range is from 4.5 to 8.5,the gradient of change is 1.0,the remaining parameters are fixed,and the relationship between pH value and HA removal rate is analyzed.(5)Sampling every 30 minutes from the time when the centrifugal pump is operated for 60 minutes to 180 minutes,the optimum cycle time is determined.The results of the centrifugal test of the centrifugal pump blade number show that the optimal number of blades of the SG32200 centrifugal pump is 6 pieces;the optimum flow rate is 1.6m/s and 3.5m/s under the two different flow rates of different uses,the optimum pH The value is 5.5,the optimum initial concentration of HA is 6 mg/L,and the cycle time is 150 min.