Experimental Study On The Treatment Of Kongmu Lake Based On Micro Vortex Flocculation Technology With Different Combination Of Vortex

Coagulation(mixing and flocculation),sedimentation,filtration and disinfection is the main process of traditional drinking water treatment at home and abroad.Among them,Which flocculation is a very important component,the effects of flocculation have an important impact on the subsequent precipitation,filtration and other processes.Firstly,coagulant and the optimum dosage were selected by coagulation and sedimentation beaker test.Then the effects of flocculation time and coagulant dosage on flocs performance and flocculation efficiency were investigated under different working conditions about different dosage ratio of vortex reactor,by applying micro-vortex flocculation technology with independent intellectual property of our school.The best parameter of vortex reactor dosage ratio and operational limits of the micro-vortex flocculation tank are optimized,which can provide the data reference for the practical engineering application.The raw water used in the test was taken from Kongmu Lake of East China Jiaotong University,which ammonia nitrogen and total phosphorus index is relatively high because of school's domestic sewage.The values of parameters reflecting water quality are listed below:water temperature is 18~25 ?,pH value is 6.35~7.18,turbidity is 7.689~13.389 NTU,potassium permanganate index(CODMn)is 5.220~6.956 mg/L,UV254 is 0.0822~0.1088abs/cm.The main test results and conclusions are as follows:1.Coagulation and sedimentation beaker testThrough series of coagulation and sedimentation beaker tests,the removal rate of turbidity,CODMn,NH3-N and TP in the flocculation process with three coagulant(aluminum sulfate(Al2(SO4)3),ferric chloride(FeCl3)and polyaluminium chloride(PAC))was studied.It turns out that the optimal coagulant is PAC and the optimal dosage of 22 mg/L.2.Under the conditions of PAC dosage was 22 mg/L,the flocculation time respectively are 42.8?21.4?14.3?10.7?8.6min(the influent flow rate respectively are 2?4?6?8?10m3/h),The effects of different vortex reactor dosage ratios of micro-vortex flocculation tank on floc performance and flocculation efficiency were studied.the results are as follows:(1)With increasing influent flow,turbidity,CODMn,UV254 of effluent flow all decreased at first and then increased,the floc equivalent diameter and fractal dimension increased firstand then reduced.(2)The flocculation effect of the micro-vortex flocculation tank with the vortex reactor is better than that of the flocculation tank without the vortex reactor.the best working condition is :The raw water in the flocculation zone firstly flows through the HJTM-2 type of vortex reactor,The ratio of the flocculation time flowing through the HJTM-2 type vortex reactor(aperture 25 mm)and the HJTM-1 type vortex reactor(aperture 35 mm)is 1: 2.(3)under the best working condition,At the case of 6m3/h inflow(flocculation time is14.3min),the effluent turbidity,CODMn,UV254 was lowest,of 0.42 NTU ? 2.56mg/L ?0.041abs/cm,removal rate of turbidity,CODMn,UV254 reached 96.26%?56.01%?52.81%,respectively.The maximum floc equivalent diameter was 1.17 mm,and the fractal dimension is 1.77.3.At the case of 6m3/h inflow(flocculation time is 14.3min),with PAC dosage was gradually increased from 10mg/L to 26 mg/L,the effefts of coagulant dosage on the effluent turbidity,CODMn,UV254,floc equivalent diameter and fractal dimension under different working conditions were studied,results as following:(1)With increasing coagulant dosage,turbidity,CODMn,UV254 of effluent flow all decreased at first and then increased,the floc equivalent diameter and fractal dimension increased first and then reduced.(2)under the best working condition,when the dosage of PAC was 22mg/L,the effluent turbidity,CODMn,UV254 was lowest,of 0.41NTU?2.02mg/L?0.036abs/cm,removal rate of turbidity,CODMn,UV254 reached 96.81%?64.12%?55.56%,respectively.The maximum floc equivalent diameter was 1.39 mm,and the fractal dimension is 1.73.4.The optimal parameters of the vortex reactor dosage ratios in the micro-vortex flocculation tank were optimized,and the optimum parameters such as the coagulant dosage and the flocculation time were determined.The technical guidance and data reference were provided for the engineering application.