Study on Coagulation Pretreatment of Laboratory Wastewater

The wastewater discharged from laboratories does harm to the environment, and there is no mature treatment method of it. According to the characteristics of laboratory wastewater , the coagulation treatment of the laboratory wastewater using inorganic polymer flocculants, such as PAC and PFS, was studied in this paper. The coagulation factors also studied include the optimum dosages of these flocculants, the pH value , the settling time and the different wastewater quality. The following research results were obtained: (1) PAC was the most appropriate flocculant in coagulation treatment of laboratory wastewater. (2) It can obtain the best effect when the dosage of PAC was 80 mg/l, pH was 5 and the settling time was 30 min.On this condition, the removal rate of turbidity was more than 95%,and the removal rate of COD was more than 40%. (3) Coagulation treatment can be a unit of laboratory wastewater processing , having a good pretreatment effect, Lay good foundation for the follow-up processing.