| In recent years,self-ballasted flocculation technology has been continuously developed.Self-ballasted flocculation reactors designed with self-ballasted flocculation as the core technology have been successfully used in many fields such as high turbidity water treatment,high chroma water treatment and high SS water treatment,which has a high processing load in the case of maintaining a good processing effect.However,the research on the choice of operating conditions of the reactor and the growth kinetics of flocs in the suspended layer of the reactor are insufficient.This paper takes self-ballasted flocculation reactor as the main research object,constructing a mathematical model about the kinetic parameters of SS in and out of the reactor and exploring the influence of operating condition control conditions and the dynamic characteristics of the reactor suspension layer and the effect of the reactor operating effect.The main conclusions are as follows:(1)Taking the kinetic equilibrium in the flotation suspension layer of the self-ballasted flocculation reactor as the research content and taking the initial microfloc particles colliding with each other and combining as the initial equilibrium formula,a mathematical model about the kinetic parameters of the reactor inlet and outlet water SS is derived and constructed:(?).The change law of the value of effective collision coefficient?is verified by the test data:The smaller the G value is,the higher the polymer coverage(under appropriate dosage conditions)is,the longer the residence time is,and the higher the effective collision coefficient?is.(2)The experimental data is used to explain the correlation between the operating conditions and dynamic parameters:Kinetic parameters such as floc particle size,suspended layer volume concentration,and floc particle effective density have a positive correlation with PAM dosage;The floc particle size is negatively correlated with the stirring G value,and the volume concentration of the suspended layer and the floc particle effective density are positively correlated with the stirring G value;The particle size of flocs is positively correlated with the rising velocity of water flow,and the volume concentration of the suspended layer and the effective density of floc particles are negatively correlated with the rising velocity of water flow;The relationship between raw water concentration and kinetic characteristic parameters is obviously divided into two stages:above the optimal agent turbidity stage,the two present a positive correlation,and below the optimal agent turbidity stage,the two exhibit a negative correlation.(3)According to the test data,the influence rules of various process control parameters on the treatment effect of the reactor are explained.The relationship model(?)between the removal rate(%)of the raw water SS from the reactor and the rising speed of the water flow and Two-stage linear relationship model(y=A?x+B)between the removal rate(%)of raw water SS and the raw water concentration in the reactor are established.Finally,the optimal selection of working conditions for the raw water with a concentration of 430mg/L:The best dosage of PAC is 55mg/L,the best dosage of PAM is 1.5mg/L,the best stirring G value is 87.37s-1(in this experiment,the stirring speed is 8r/min),and the best water flow rate is 13m/h.For the high SS raw water with an SS concentration of 450 mg/L,the removal rate of the influent SS by the reactor can reach 95.63%under better working conditions.Through the above research,the kinetic balance in the suspended layer of the self-ballasted flocculation reactor is clarified,the influence of the reactor operating condition control conditions on the kinetic characteristic parameters and reactor treatment effect is revealed,the theoretical system of ballasted flocculation kinetics has been improved to avoid blindness and randomness in actual design and engineering applications,and it has high practical application value and good environmental benefits. |
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