Research Of The Coagulation Purification Treatment Initial Rainwater Runoff Of Thetangxi River

The rains washed out with pollutant of initial rainwater runoff caused serious pollution and destruction, the early rain runoff belongs to nonpoint source pollution, the impact on water quality has become increasingly apparent, cause more research and attention.This thesis mainly selected ten drain in hefei tangxi river to measure the initial rainwater runoff, the measured data shows that:the TP (Total Phosphorus, TP) concentration about0-5 mg/L, the TN (Total Nitrogen, TN) concentration around 0-16 mg/L, the SS (Suspended Solids, SS) about 60-1200 mg/L, the turbidity around 20-200 NTU. Combining with the actual selection,choose TP for 2 mg/L; TN for 4 mg/L; SS for 200 mg/L; Turbidity for 150 NTU to matching simulation initial rainwater runoff. The compound coagulant with diatomite and PAC (Polyaluminium Chloride, PAC) is obtained by single factor experiment, conventional coagulation experiment results show that:Through orthogonal experiment, the compound coagulant dosage is 75 mg/L, coagulation condition of revolving speed to 500 r/min, the settling time is set to 50 min, the TP, TN removal rate of the sample is the best optimal parameters for subsequent experiments. quartz powder regulating the turbidity of water under the condition of the coagulation treatment on simulation initial rainwater runoff, TP,TN removal rate generally present the trend with the increase of turbidity variation rate, then leveling off or decline, consistent with theory. sediment regulating the turbidity of simulation initial rainwater runoff,comprehensive to TP, TN removal, the turbidity of 0-100 NTU range, dosing best for 30 mg/L; the turbidity in 100-450 NTU,600-750 NTU, dosing for 75 mg/L; Within the range 450-600 NTU, select 50 mg/L dosing is most appropriate.Studied for the coagulation process by Zeta (Zeta potential, Zeta) potential mechanism, the infrared spectrum analysis and ultraviolet spectrum analysis, adding the compound coagulant for reaction, the Zeta potential of the experimental group change is stable, consistent with theory. This show that mixed dosing coagulant, coagulant provide positive ions into the water diffusion and adsorption layer, the settlement of colloid particle aggregation, compressed double electric layer effect. By means of infrared spectrum analysis there are many chemical bonds in the process of coagulation, this also shows that the diatomite with PAC composite adding with polymer structure, compared with the single coagulant compound produced more impact.,by ultraviolet spectrum analysis, the composite coagulant lead to a new bond order to develop more stability, the comprehensive analysis results show that the coagulation mechanism of both compressed double electric layer, adsorption electrical neutralization and adsorption bridging and the trap swept volume.