The Optimization And Selection In Coagulant Process And The Design Of Chemical Room For The Yellow River Intake And Supply Project

The purpose of this paper is to obtain the optimal coagulation conditions for The Yellow River intake and supply project through the coagulation test. According the characteristics and variability of temperature of raw water from The Yellow River, coagulants is screened out. The optimal dosage and dosing conditions of coagulants is also determined through the experiments. All of these aims are to optimize the effect of coagulation of raw water. The providing operating parameters for the running of clarifier tank.The study imitated water purification to carry on enhanced coagulation treatments on the Yellow River raw and the water of low temperature and low turbidity, analyzing water quality parameters and full-scale experiment study including PAC,AS,Ferric trichloride in order to select the fittest coagulation to micro-polluted raw water. According to the design manual and the results of our experiments, the chemical room was designed.The results of the experiments are as follows. 1. The optimal coagulant for the Yellow River raw is Polyaluminium Chloride. Enhanced coagulation's effect factors are:flocculant's category,the dose,PH value,the result of mixing,temperature and so on. The result of enhanced coagulation Shows that the best condition is:PAC's dose is 30mg/L,the gradient of speed is 120～170s-1,controling PH 6.5-8.0. Controling temperature above 20℃. 2. The test of low temperature and low turbidity water was based on the above experiments. The PAC was chose as the coagulant. The test by using different coagulant reaction conditions of low temperature and low turbidity water showed that the coagulant dosage, pH, stirring intensity has a certain influence, are there is an optimum range. When the PAC dosage was 10mg/L, it can achieve better removal, continue to increase the dosage of PAC, the removal of low temperature and low turbidity water is not obvious. When rapid mixing gradient to 600s-1, rapid mixing time of 5min, stirring slow gradient of 20s-1, the slow mixing time of 20min, the effluent turbidity was the best. PH value can be controlled within 7.0-8.0...