Study On Enhanced Coagulation Technology Of Low Temperature Water Based Dahuofang Reservoir

Coagulation is an important part of the process of water treatment,the coagulation can make the water impurities with the colloidal particles agglutination,and through the subsequent treatment to remove.On the premise that the water purification plant faces the reform of drinking water,in order to cope with the continuous change of drinking water source,especially the water quality of the winter in cold regions,the method of enhanced coagulation is used to improve the water purification effect and meet the drinking water requirements.In this paper,the main water source of surface water supply in Liaoning Province,Dahufang water source,that is studied by the beaker test on Coagulation Process of Winter Low Temperature Water.At first,the optimal coagulant?PAM?dosing time and optimum settling time were selected by single factor test for the normal low temperature and low turbidity water with turbidity,CODMn,UV254 and chroma as the index.The main technical parameters of coagulation are:coagulation?PAC?dosage,coagulation time,coagulant dosage and so on.By orthogonal test,the traditional coagulation process with PAC and PAM as coagulant,the optimum process parameters were?PAC?mg/L?=50,?PAM?mg/L?=1.5,t?min?=20 and pH=7,.And then for the low temperature PAC coagulation effect of poor phenomenon,under the conditions of PAC and PAF coagulant,the preoxidation coagulation test of sodium hypochlorite was carried out.The effects of permanganate index?turbidity,CODMn,UV254 and chroma?were investigated.The optimum process parameters that PAC as a coagulant were?_PAC?mg/L?=30,?_NaClO?mg/L?=4,?_PAM?mg/L?=1.5 and pH=7 by orthogonal test.The optimum process parameters that PAF as a coagulant were?PAF?mg/L?=30,?NaClO?mg/L?=4,?PAM?mg/L?=1 and pH=7.Finally,Turbidity removal effects of the pre-oxidation coagulation PAC and PAF were compared respectively.Turbidity sedimentation effects of the pre-oxidation coagulation PAC and PAF were compared,and the dosage conditions of PAM were optimized to compare the coagulation effect of PAM anion and cation.And the presence or absence of PAM sedimentation effect,the test shows that the addition of PAM can only accelerate the process of coagulation without increasing the coagulation effect.the coagulation effect of PAC,PAF and sodium hypochlorite was compared with that of low temperature and high turbidity raw water after flooding.The best coagulation scheme was selected as the method of strengthening coagulation with polyaluminium chloride and polyacrylamide,?PAC?dosage(?_PAC)is 50mg/L,PAM dosage is generally 0.2mg/L.Through the coagulation test with different water quality in low temperature period,the best coagulation method was selected to establish a complete response to Dahufang water coagulation program...