Combined Process For Treating Sorghum Water Test And Retrofit Design

It was found that the source water of Dahuofang Reservoir contains Cyclops in the temperature range of 8?18.Aiming at the problem of water containing Cyclops in the effluent of a water plant in Panjin,which diverts water from Dahuofang Reservoir,a combined process of coagulation pre-oxidation-coagulation-composite filter material was proposed to treat the water source containing Cyclops in Dahuofang Reservoir.Firstly,the beaker pre-oxidation experiment of water source containing Cyclops was carried out.ClO 2(chlorine dioxide)and NaClO(sodium hypochlorite)were selected to study the pre-oxidant with the best inactivation effect for water quality of cyclops.The results showed that when the dosage of sodium hypochlorite was below 0.5 mg/L,the removal effect of sodium hypochlorite was slightly better than that of chlorine dioxide,but both of them could not meet the requirements.When the dosage of sodium hypochlorite was increased,the removal effect of sodium hypochlorite gradually improved,but the ultimate removal efficiency was difficult to reach 100%,and the contact time needed was longer;while chlorine dioxide dosage was 1.When 0 mg/L,it can achieve better removal effect with shorter contact time.Therefore,it is concluded that the removal effect of chlorine dioxide on Cyclops is better.After that,the coagulation experiment was carried out.PAC(polyaluminium chloride)was used as coagulant to investigate the removal effect of PAC on Cyclops under different dosage,and the removal mechanism of PAC on Cyclops was explored.The results show that the coagulation-sedimentation process unit can not completely remove the cyclops,but increasing the dosage of PAC properly will produce obvious alum in the water,which will significantly improve the removal rate of cyclops.When the dosage of PAC reaches 20 mg/L,the removal rate of Cyclops in this process unit reaches the maximum,which is 35%.However,the floc formed by 20mg/LPAC was unstable,and the activity of Cyclops was restored after 2 hours.Therefore,10mg/L PAC was the best dosage of coagulant in this experiment.Then,the removal effect of traditional quartz sand filter material and coal-sand composite filter material on Cyclops was compared and the removal mechanism was explored.The results showed that when the siphon flea was intercepted by the composite filter unit alone,the homogeneous filter material with the diameter between 0.5 mm and 1.2 mm could not completely intercept the corpse of the siphon flea in the sand.The composite filter material can completely intercept cyclops.Therefore,anthracite-quartz sand composite filter material was selected as the experimental filter material for the removal of Cyclops in subsequent experiments.The homogeneous quartz sand filter material used in this experiment can theoretically filter through it,and completely intercept any impurities with particle size greater than 0.077 mm.But in the experiment,the siphon flea,which should have been intercepted by the filter material,penetrated the filter layer.This is because in the ideal state,the filter materials are arranged densely,close to each other without leaving any excess voids,and the filter materials are arranged evenly and regularly and squeezed together.However,under actual conditions,when the material fills the filter or filter column,the arrangement between the filters is not the same.In order to form a stable structure during the actual arrangement of filter materials,there may be a gap between the filter materials,so that substances that could be intercepted by the filter layer can penetrate the filter layer.It is through these cracks that the siphon fleas detected in the filtered water penetrate the filter layer and enter the filtered water.The results show that the dosage of chlorine dioxide is 0.2 mg/L,the dosage of PAC is 10 mg/L,the filtration speed is v=8 m/h,the hydraulic retention time is 90 min,and the gradation of filter column is L/d=1078.Finally,the removal rate of Cyclops reached 100%.The cumulative removal rate of coagulation-precipitation unit is about 33%,and that of filtration unit is about 77%.After pre-oxidation,the removal rates of coagulation sedimentation unit and filtration unit have been greatly improved.