Research Of Automatic Scale Removal Technology And Aeration Characteristics Of Drinking Water

Groundwater has always been an important source of domestic water in suburban counties and rural areas due to its stable water supply conditions and relatively good water quality.However,drinking hot water has long been a habit in our country.When groundwater is used as drinking water,it is easy to form scale after boiling,which is not only hard to accept but also may cause a lot of potential harm.With the improvement of living standards in China,solving the problem of scale caused by boiling drinking water and improving users'satisfaction with drinking water has become one of the hot spots in the water supply industry.In this paper,on the basis of the acid-base balanced aeration method for scale removal,a technical scheme that directly provides hydrogen ions,improves the original method of adding acid to introduce anion,and combines with the automatic control technology to develop scale removal equipment that can be used in small water supply system(daily treatment amount is 20m~3/d).Experiment selected scale more underground water plant(C)in Shandong Province,an industrial park water point(B)as well as underground water plant(A)in Shanxi province as the research object.By controlling the turbidity treatment after boiling water and untreated water mixing ratio key parameters such as gas water ratio,and for A long time continuous operation test,verify the applicability of the equipment for different water scale removal effect research conclusion is as follows:(1)The test of the equipment in A,B and C showed that the effluent water quality of the equipment met the sanitary standard of drinking water,the pH value was basically the same as that of raw water,and the anion concentration was not increased,which could well solve the scaling problem.For water source A,when the mixing ratio of treated water and untreated water is adjusted to 1:6 and the gas-water ratio is adjusted to 7:1,the hardness is reduced by 21.8%,the alkalinity is reduced by 40.0%,and the turbidity of warm boiled water can be reduced from 9.0~18.0NTU to less than0.5NTU.For water point B,when the mixing ratio of treated water and untreated water is adjusted to 1:5,and the gas-water ratio is adjusted to 7:1,the hardness is reduced by16.7%,the alkalinity is reduced by 36.4%,and the turbidity of warm boiled water can be reduced from 16.0~21.0NTU to less than 0.5NTU.For water source C with raw water hardness exceeding 450mg/L,when the mixing ratio of treated water and untreated water is adjusted to 3:7 and the gas-water ratio is 8:1,the hardness is reduced by 30.2%,that is,from 530 mg/L to less than 380mg/L,and the alkalinity is reduced by 62.5%,that is,from 320mg/L to less than 120mg/L.The turbidity of warm boiled water can be reduced from 18.0~25.0NTU to less than 0.5NTU.The alkalinity of effluent and turbidity of warm boiled water decrease with the increase of ratio of treated water to untreated water.The effluent pH of the equipment increases with the increase of gas-water ratio.The increase of residence time has a certain effect on the pH of water outlet.The residence time is selected as 20min~25min according to the experimental results.(2)This equipment adopts PLC automatic control system this time,which can realize intelligent switching and setting of working conditions during operation.When the hydrogen ion exchange resin in a resin tank fails,it will automatically close the electric switch valve of the current resin tank to stop water intake,and open the valve of the next resin tank to stop water intake,until the failure of the ion exchange resin in the last resin tank.The equipment will be recycled and backwashed,and then reset to work.Resin tank with the pH value of water to determine whether the exchange of resin tank failure,in order to complete the automatic operation of the system,reduce labor costs.Continuous operation experiments were carried out in water source A and C,and the working condition of equipment was switched normally,and the operation difficulty was reduced compared with manual control,thus improving the stability and reliability of equipment operation.(3)Through the field test,the cost of a ton of water treatment is controlled at0.30~0.60 yuan,which is suitable for drinking water with large scale and high hardness.Among them,for the water source whose hardness of raw water exceeds the national standard,such as water source C,the total hardness can be reduced to meet the national water yield standard,and the effect of no scale after boiling can be achieved.The cost of water treatment per ton does not exceed 0.60 yuan,far lower than other processes.(4)By analyzing the flow characteristics of gas-liquid two-phase flow in the aeration tank under different conditions,and using PIV software to connect the bubble plume mass transfer and bubble mass transfer,it provides a basis for the optimization and application of the model.It is found that the velocity and radius affect each other and restrict each other in the mass transfer of bubble diffusion.