The Research Of Coagulation And Settlement On Water Reclamation

Water reclamation has gained great importance in the world as a result of the water resource crisis. Coagulation and settlement are universal processes in water reclamation. But the designing and operating parameters of water reclamation processes are mostly based on water supply process. Consequently, there are two problems in the water reclamation. Firstly, the qualities of reclaimed water are different of that of natural water. The dosage is blindly and has a bad economy. Secondly, sludge production is high and brings trouble to management. In this study, the effluent of JIZHUANGZI wastewater treatment plant was used as raw water for water reclamation. The coagulation condition and parameters were studied so as to improve the treatment efficiency.The static jar tests were used for lab-scale experiments and the results were taken as a reference for JIZHUANGZI water reclamation plant operation. The optimal coagulant is PAC by single factor tests and the optimal coagulation accelerator is taken as HPAM. The optimal stirring speed and settlement time are confirmed by four-factor orthogonal tests. Moreover, other optimal parameters were confirmed such as pH and temperature range. Turbidity, color, CODCr, pH and TP were used to evaluate treatment effect. The operating parameters were applied to treat the effluent of WWPT and the final effluent accord with water reclamation standard. The turbidity removal was 80% and CODCr removal was 53% with a TP removal of 90%.Chemical settlement is a main way for phosphorus removal. The mechanisms of phosphorus removal, optimal agent, the effect of pH and coagulant accelerator on phosphorus removal were analyzed in this study. Results showed that the optimal condition of turbidity removal met that of phosphorus removal. The mathematics model was build up based on the experiments results. The relation among coagulant dose, raw water turbidity, CODCr and TP were stimulated and validated.